WorldWideScience

Sample records for thermal annealing effects

  1. Electro-optical characteristics of indium tin oxide (ITO) films: effect of thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, D.V.; Salehi, A.; Aliyu, Y.H.; Bunce, R.W. [University of Wales College of Cardiff (United Kingdom). School of Electrical, Electronics and System Engineering

    1996-02-01

    The effect of thermal annealing on the electrical and optical characteristics of ITO films prepared by reactive sputtering and thermal evaporation have been studied. The effect of the thermal annealing is to improve the conductivity and the optical transmission in the shorter wavelength region. The conductivity of the films increases with annealing temperature, this behaviour is associated with grain growth in the film. (author)

  2. Metallic nanowire networks: effects of thermal annealing on electrical resistance

    Science.gov (United States)

    Langley, D. P.; Lagrange, M.; Giusti, G.; Jiménez, C.; Bréchet, Y.; Nguyen, N. D.; Bellet, D.

    2014-10-01

    Metallic nanowire networks have huge potential in devices requiring transparent electrodes. This article describes how the electrical resistance of metal nanowire networks evolve under thermal annealing. Understanding the behavior of such films is crucial for the optimization of transparent electrodes which find many applications. An in-depth investigation of silver nanowire networks under different annealing conditions provides a case study demonstrating that several mechanisms, namely local sintering and desorption of organic residues, are responsible for the reduction of the systems electrical resistance. Optimization of the annealing led to specimens with transmittance of 90% (at 550 nm) and sheet resistance of 9.5 Ω sq-1. Quantized steps in resistance were observed and a model is proposed which provides good agreement with the experimental results. In terms of thermal behavior, we demonstrate that there is a maximum thermal budget that these electrodes can tolerate due to spheroidization of the nanowires. This budget is determined by two main factors: the thermal loading and the wire diameter. This result enables the fabrication and optimization of transparent metal nanowire electrodes for solar cells, organic electronics and flexible displays.

  3. The Effect of Thermal Annealing Processes on Structural and Photoluminescence of Zinc Oxide Thin Film

    Directory of Open Access Journals (Sweden)

    Huai-Shan Chin

    2013-01-01

    Full Text Available This study used radio frequency sputtering at room temperature to prepare a zinc oxide (ZnO thin film. After deposition, the thin film was placed in a high-temperature furnace to undergo thermal annealing at different temperatures (300, 400, 500, and 600°C and for different dwelling times (15, 30, 45, and 60 min. The objective was to explore the effects that the described process had on the thin film’s internal structure and luminescence properties. A scanning electron microscope topographic image showed that the size of the ZnO crystals grew with increases in either the thermal annealing temperature or the dwelling time. However, significant differences in the levels of influence caused by increasing the thermal annealing temperature or dwelling time existed; the thermal annealing temperature had a greater effect on crystal growth when compared to the dwelling time. Furthermore, the crystallization directions of ZnO (002, (101, (102, and (103 can be clearly observed through an X-ray diffraction analysis, and crystallization strength increased with an increase in the thermal annealing temperature. The photoluminescence measurement spectra showed that ultraviolet (UV emission intensity increased with increases in thermal annealing temperature and dwelling time. However, when the thermal annealing temperature reached 600°C or when the dwelling time reached 60 min, even exhibited a weak green light emission peak.

  4. Thermally and Electrically Conductive Nanopapers from Reduced Graphene Oxide: Effect of Nanoflakes Thermal Annealing on the Film Structure and Properties

    Directory of Open Access Journals (Sweden)

    M. Mar Bernal

    2017-12-01

    Full Text Available In this study, we report a novel strategy to prepare graphene nanopapers from direct vacuum filtration. Instead of the conventional method, i.e., thermal annealing nanopapers at extremely high temperatures prepared from graphene oxide (GO or partially reduced GO, we fabricate our graphene nanopapers directly from suspensions of fully reduced graphene oxide (RGO, obtained after RGO and thermal annealing at 1700 °C in vacuum. By using this approach, we studied the effect of thermal annealing on the physical properties of the macroscopic graphene-based papers. Indeed, we demonstrated that the enhancement of the thermal and electrical properties of graphene nanopapers prepared from annealed RGO is strongly influenced by the absence of oxygen functionalities and the morphology of the nanoflakes. Hence, our methodology can be considered as a valid alternative to the classical approach.

  5. Effect of thermal annealing on ZnO:Al thin films grown by spray pyrolysis

    Science.gov (United States)

    El Manouni, A.; Manjón, F. J.; Perales, M.; Mollar, M.; Marí, B.; Lopez, M. C.; Ramos Barrado, J. R.

    2007-07-01

    We report the effect of thermal annealing in air on the structural and optical properties of undoped and aluminium-doped (1%-4%) zinc oxide (AZO) thin films, grown by the spray pyrolysis technique on quartz substrates. Films were characterized by X-ray diffraction, low-temperature photoluminescence, electrical resistivity, and Raman spectroscopy after annealing at temperatures between 500 and 900 ∘C. Annealing in air improves the long-range order crystalline quality of the bulk crystals, but promotes a number of point defects in the surface affecting both the resistivity and the photoluminescence.

  6. Atomic-scale investigation of graphene grown on Cu foil and the effects of thermal annealing.

    Science.gov (United States)

    Cho, Jongweon; Gao, Li; Tian, Jifa; Cao, Helin; Wu, Wei; Yu, Qingkai; Yitamben, Esmeralda N; Fisher, Brandon; Guest, Jeffrey R; Chen, Yong P; Guisinger, Nathan P

    2011-05-24

    We have investigated the effects of thermal annealing on ex-situ chemically vapor deposited submonolayer graphene islands on polycrystalline Cu foil at the atomic-scale using ultrahigh vacuum scanning tunneling microscopy. Low-temperature annealed graphene islands on Cu foil (at ∼430 °C) exhibit predominantly striped Moiré patterns, indicating a relatively weak interaction between graphene and the underlying polycrystalline Cu foil. Rapid high-temperature annealing of the sample (at 700-800 °C) gives rise to the removal of Cu oxide and the recovery of crystallographic features of the copper that surrounds the intact graphene. These experimental observations of continuous crystalline features between the underlying copper (beneath the graphene islands) and the surrounding exposed copper areas revealed by high-temperature annealing demonstrates the impenetrable nature of graphene and its potential application as a protective layer against corrosion.

  7. Effects of thermal annealing on the evolution of He bubbles in zirconia

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Shuyan [State Key Laboratory of Nuclear Physics and Technology, Center for Applied Physics and Technology, Peking University, Beijing 100871 (China); Velisa, Gihan [Horia Hulubei National Institute for Physics and Nuclear Engineering, P.O.B. MG-6, 077125 Magurele (Romania); Debelle, Aurélien [Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Univ. Paris-Sud, CNRS-IN2P3, Bât. 108, 91405 Orsay (France); Yang, Tengfei; Wang, Chenxu [State Key Laboratory of Nuclear Physics and Technology, Center for Applied Physics and Technology, Peking University, Beijing 100871 (China); Thomé, Lionel [Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Univ. Paris-Sud, CNRS-IN2P3, Bât. 108, 91405 Orsay (France); Xue, Jianming; Yan, Sha [State Key Laboratory of Nuclear Physics and Technology, Center for Applied Physics and Technology, Peking University, Beijing 100871 (China); Wang, Yugang, E-mail: ygwang@pku.edu.cn [State Key Laboratory of Nuclear Physics and Technology, Center for Applied Physics and Technology, Peking University, Beijing 100871 (China)

    2014-05-01

    Single crystals of yttria-stabilized zirconia were implanted with 100 keV He ions at two fluences of 9 × 10{sup 16} and 3 × 10{sup 17} cm{sup −2} (5 and 17 He at.%). In order to investigate the effect of thermal annealing on the evolution of both zirconia lattice and implanted He, the samples were annealed at several temperatures ranging from 500 °C to 1400 °C. Three complementary analysis techniques, RBS/C, AFM and TEM were used to study structural damage and surface morphology of the crystal before and after implantation. Results show different He evolution phenomena under the two implantation fluences. It is inferred that, at the lower fluence, the migration and agglomeration of He ions lead to bubble formation after annealing. These bubbles jack up sample surface causing the deformation of surface region and the damage level of surface region increase accordingly. As the temperature continues to increase, He gradually releases and the damage recovers. However, at the higher fluence, the He concentration is sufficient to induce bubble precipitation without annealing. He release and damage recovering is less efficient upon annealing.

  8. MoO3 Thickness, Thermal Annealing and Solvent Annealing Effects on Inverted and Direct Polymer Photovoltaic Solar Cells

    Directory of Open Access Journals (Sweden)

    Guillaume Wantz

    2012-11-01

    Full Text Available Several parameters of the fabrication process of inverted polymer bulk heterojunction solar cells based on titanium oxide as an electron selective layer and molybdenum oxide as a hole selective layer were tested in order to achieve efficient organic photovoltaic solar cells. Thermal annealing treatment is a common process to achieve optimum morphology, but it proved to be damageable for the performance of this kind of inverted solar cells. We demonstrate using Auger analysis combined with argon etching that diffusion of species occurs from the MoO3/Ag top layers into the active layer upon thermal annealing. In order to achieve efficient devices, the morphology of the bulk heterojunction was then manipulated using the solvent annealing technique as an alternative to thermal annealing. The influence of the MoO3 thickness was studied on inverted, as well as direct, structure. It appeared that only 1 nm-thick MoO3 is enough to exhibit highly efficient devices (PCE = 3.8% and that increasing the thickness up to 15 nm does not change the device performance. 

  9. MoO3 Thickness, Thermal Annealing and Solvent Annealing Effects on Inverted and Direct Polymer Photovoltaic Solar Cells

    OpenAIRE

    Guillaume Wantz; Lionel Hirsch; Bertrand Pavageau; Michel Lahaye; Lionel Derue; Sylvain Chambon

    2012-01-01

    16 pages; International audience; Several parameters of the fabrication process of inverted polymer bulk heterojunction solar cells based on titanium oxide as an electron selective layer and molybdenum oxide as a hole selective layer were tested in order to achieve efficient organic photovoltaic solar cells. Thermal annealing treatment is a common process to achieve optimum morphology, but it proved to be damageable for the performance of this kind of inverted solar cells. We demonstrate usin...

  10. Effects of thermal annealing and reirradiation on toughness of reactor pressure vessel steels

    Energy Technology Data Exchange (ETDEWEB)

    Nanstad, R.K.; Iskander, S.K.; Sokolov, M.A. [Oak Ridge National Lab., TN (United States)] [and others

    1997-02-01

    One of the options to mitigate the effects of irradiation on reactor pressure vessels (RPV) is to thermally anneal them to restore the toughness properties that have been degraded by neutron irradiation. This paper summarizes recent experimental results from work performed at the Oak Ridge National Laboratory (ORNL) to study the annealing response, or {open_quotes}recovery,{close_quotes} of several irradiated RPV steels; it also includes recent results from both ORNL and the Russian Research Center-Kurchatov Institute (RRC-KI) on a cooperative program of irradiation, annealing and reirradiation of both U.S. and Russian RPV steels. The cooperative program was conducted under the auspices of Working Group 3, U.S./Russia Joint Coordinating Committee for Civilian Nuclear Reactor Safety (JCCCNRS). The materials investigated are an RPV plate and various submerged-arc welds, with tensile, Charpy impact toughness, and fracture toughness results variously determined. Experimental results are compared with applicable prediction guidelines, while observed differences in annealing responses and reirradiation rates are discussed.

  11. Investigation of effect of annealing on thermally evaporated ZnSe thin films through spectroscopic techniques

    Science.gov (United States)

    Mahesha, M. G.; Rashmitha; Meghana, N.; Padiyar, Meghavarsha

    2017-09-01

    ZnSe thin films have been grown on clean glass substrates by thermal evaporation technique and deposited films have been annealed at 473 K. William-Hall method has been adopted to extract information on crystallite size and internal strain in the film from X-ray diffractogram. Effect of annealing on ZnSe films has been analyzed by spectroscopic techniques which include optical absorption, Raman, and photoluminescence spectroscopy. From optical absorption, band gap has been estimated along with other optical parameters like refractive index and extinction coefficient. Also, Urbach tail, which originates near bad edge due to structural disorders, has been characterized. Raman spectra have been analyzed to get the information on the influence of crystallite size and strain effect on peak position, intensity and width. Photoluminescence spectra have been recorded and analyzed to get an insight on defect levels induced due to vacancies, interstadials, and impurity complexes.

  12. Highly Efficient Organic UV Photodetectors Based on Polyfluorene and Naphthalenediimide Blends: Effect of Thermal Annealing

    Directory of Open Access Journals (Sweden)

    Gorkem Memisoglu

    2012-01-01

    Full Text Available A solution-processed organic ultraviolet photodetector (UV-PD is introduced. The active layer of the UV-PD consists of poly(9,9-dioctyl fluorenyl-2,7–yleneethynylene (PFE and N,N′-bis-n-butyl-1,4,5,8- naphthalenediimide (BNDI with a weight ratio of 3 : 1 in chloroform. The effect of thermal annealing on the device properties was investigated from room temperature to 80∘C. The full device structure of ITO/PEDOT:PSS/PFE:BNDI (3 : 1/Al gave responsivity of 410 mA/W at −4 V under 1 mW/cm2 UV light at 368 nm when 60∘C of annealing temperature was used during its preparation. The devices that were annealed over the crystallization temperature of PFE showed a charge transfer resistance increase and a mobility decrease.

  13. Fluorine implantation effects on Ta2O5 dielectrics on polysilicon treated with post rapid thermal annealing

    Science.gov (United States)

    Chen, Hsiang; Kao, Chyuan Haur; Huang, Bo Yun; Lo, Wen Shih

    2013-10-01

    This paper investigates effects of fluorine implantation with post rapid thermal annealing on electrical characteristics and material properties of tantalum pentoxide (Ta2O5) dielectrics. The electrical behaviors of the dielectrics under various implantation doses were measured. To investigate annealing effects, secondary ion mass spectrometry (SIMS) was used to measure depth profiles of various atoms inside the dielectrics with and without annealing. In addition, atomic force microscopy measurements visualize the surface roughness and material properties of the dielectrics with different implantation doses. The dielectric performance can be significantly improved by an appropriate fluorine implantation dose of 1 × 1015 ions/cm2 with post annealing at 800 °C. The improvements in electrical characteristics were caused by the appropriate incorporation of the fluorine atoms presented in SIMS profiles and the removal of the dangling bonds and traps. The Ta2O5 dielectric incorporated with appropriate fluorine implantation and annealing treatments shows great promise for future generation of memory applications.

  14. Thermal annealing and pressure effects on BaFe2‑x Co x As2 single crystals

    Science.gov (United States)

    Shin, Dongwon; Jung, Soon-Gil; Prathiba, G.; Seo, Soonbeom; Choi, Ki-Young; Kim, Kee Hoon; Park, Tuson

    2018-01-01

    We investigate the pressure and thermal annealing effects on BaFe2‑x Co x As2 (Co-Ba122) single crystals with x  =  0.1 and 0.17 via electrical transport measurements. The thermal annealing treatment not only enhances the superconducting transition temperature (T c) from 9.6 to 12.7 K for x  =  0.1 and from 18.1 to 21.0 K for x  =  0.17, but also increases the antiferromagnetic transition temperature (T N). Simultaneous enhancement of T c and T N by the thermal annealing treatment indicates that thermal annealing could substantially improve the quality of the Co-doped Ba122 samples. Interestingly, T c of the Co-Ba122 compounds shows a scaling behavior with a linear dependence on the resistivity value at 290 K, irrespective of tuning parameters such as chemical doping, pressure, and thermal annealing. These results not only provide an effective way to access the intrinsic properties of the BaFe2As2 system, but may also shed a light on designing new materials with higher superconducting transition temperature.

  15. Effects of thermal annealing on C/FePt granular multilayers: in situ and ex situ studies

    Energy Technology Data Exchange (ETDEWEB)

    Babonneau, D [Laboratoire de Metallurgie Physique, UMR 6630 CNRS, Universite de Poitiers, SP2MI, Teleport 2, Boulevard M et P Curie, BP 30179, 86962 Futuroscope Chasseneuil Cedex (France); Abadias, G [Laboratoire de Metallurgie Physique, UMR 6630 CNRS, Universite de Poitiers, SP2MI, Teleport 2, Boulevard M et P Curie, BP 30179, 86962 Futuroscope Chasseneuil Cedex (France); Toudert, J [Laboratoire de Metallurgie Physique, UMR 6630 CNRS, Universite de Poitiers, SP2MI, Teleport 2, Boulevard M et P Curie, BP 30179, 86962 Futuroscope Chasseneuil Cedex (France); Girardeau, T [Laboratoire de Metallurgie Physique, UMR 6630 CNRS, Universite de Poitiers, SP2MI, Teleport 2, Boulevard M et P Curie, BP 30179, 86962 Futuroscope Chasseneuil Cedex (France); Fonda, E [Synchrotron SOLEIL, L' Orme des Merisiers, St-Aubin, BP 48, 91192 Gif-sur-Yvette Cedex (France); Micha, J S [UMR SPrAM 5819 CNRS, CEA-Grenoble/DRMFC, 17 avenue des martyrs, 38054 Grenoble Cedex 9 (France); Petroff, F [Unite Mixte de Physique CNRS/THALES associee a l' Universite Paris-Sud XI, Route departementale 128, 91767 Palaiseau Cedex (France)

    2008-01-23

    The comprehensive study of C/FePt granular multilayers prepared by ion-beam sputtering at room temperature and subsequent annealing is reported. The as-deposited multilayers consist of carbon-encapsulated FePt nanoparticles (average size {approx}3 nm) with a disordered face-centered-cubic structure. The effects of thermal annealing on the structural and magnetic properties are investigated by using dedicated ex situ and in situ techniques, including high-resolution transmission electron microscopy, extended x-ray absorption fine structure, magnetometry, and coupled grazing incidence small-angle x-ray scattering and x-ray diffraction. Our structural data show that the particle size and interparticle distance increase slightly with annealing at temperatures below 790 K by thermally activated migration of Fe and Pt atoms. We find that thermal annealing at temperatures above 870 K results in the dramatic growth of the FePt nanoparticles by coalescence and their gradual L1{sub 0} ordering. In addition, we observe a preferential graphitization of the carbon matrix, which provides protection against oxidation for the FePt nanoparticles. Magnetization measurements indicate that progressive magnetic hardening occurs after annealing. The dependences of the blocking temperature, saturation magnetization, coercivity, and magnetocrystalline anisotropy energy on the annealing temperature are discussed on the basis of the structural data.

  16. Effect of thermal annealing on a novel polyamide–imide polymer membrane for aggressive acid gas separations

    KAUST Repository

    Vaughn, Justin T.

    2012-05-01

    A fluorinated, 6FDA based polyamide-imide is investigated for the purification of CH 4 from CO 2 and H 2S containing gas streams. Dense polymer films were thermally annealed and showed that increased annealing temperatures at constant annealing time caused transport behavior that does not resemble physical aging. Free volume increased after annealing at 200°C for 24h relative to annealing at 150°C for the same time. CO 2 and CH 4 permeabilities and diffusivities did not decrease as a result of the higher annealing temperature, and in fact, were shown to increase slightly. A change to the intrinsic microstructure that cannot be described by simple, densification based physical aging is hypothesized to be the reason for this trend. Furthermore, annealing increased CO 2 induced plasticization resistance and a temperature of 200°C was shown to have the greatest effect on plasticization suppression. Annealing at 200°C for 24h suppressed pure gas CO 2 plasticization up to 450psia. Fluorescence spectroscopy revealed increased intramolecular charge transfer, which is presumably due to increased electron conjugation over the N-phenyl bond. Additionally, intermolecular charge transfer increased with thermal annealing, as inferred from fluorescence intensity measurements and XRD patterns. 50/50 CO 2/CH 4 mixed gas permeation measurements reveal stable separation performance up to 1000psia. Ternary mixed gas feeds containing toluene/CO 2/CH 4 and H 2S/CO 2/CH 4 show antiplasticization, but more importantly, selectivity losses due to plasticization did not occur up to 900psia of total feed pressure. These results show that the polyamide-imide family represents a promising class of separation materials for aggressive acid gas purifications. © 2012 Elsevier B.V.

  17. The Effect of Thermal Annealing on the Optical Band Gap of Cd1 ...

    African Journals Online (AJOL)

    ... for an hour at temperatures of 100°C, 200°C and 300°C and the absorption spectra again recorded. It was observed that thermal annealing decreased the band gap of the samples; this may be due to improving crystallinity or alternatively, a phase transformation taking place in the samples as a result of the heat treatment.

  18. Annealing and polycrystallinity effects on the thermal conductivity of supported CVD graphene monolayers.

    Science.gov (United States)

    Raja, Shyamprasad N; Osenberg, David; Choi, Kyoungjun; Park, Hyung Gyu; Poulikakos, Dimos

    2017-10-19

    The thermal transport properties of graphene are strongly influenced by its contact environment and the strength of such interactions can be used to tailor these properties. Here we find that annealing suppresses the basal plane thermal conductivity (κ) of graphene supported on silicon dioxide, due to the increased conformity of graphene to the nanoscale asperities of the substrate after annealing. Intriguingly, increasing the polycrystallinity of graphene, grown by chemical vapor deposition on copper, increases the severity of this suppression after annealing, revealing the role of grain boundaries and associated defects in aiding phonon scattering by the substrate. In highly polycrystalline graphene, the value of κ after annealing is comparable to that after significant fluorination of an identical unannealed sample. Our experiments employ the suspended micro-bridge platform for basal plane thermal conductivity measurements. Using xenon difluoride gas for the final release also enables the investigation of thermal transport in graphene in contact with polymers. We find evidence for weaker phonon scattering in graphene, due to a 10 nm thick polymer layer on top compared to the pre-existing silicon dioxide substrate, which is a promising result for flexible electronics applications of graphene.

  19. Thermal annealing in neutron-irradiated tribromobenzenes

    DEFF Research Database (Denmark)

    Siekierska, K.E.; Halpern, A.; Maddock, A. G.

    1968-01-01

    The distribution of 82Br among various products in neutron-irradiated isomers of tribromobenzene has been investigated, and the effect of thermal annealing examined. Reversed-phase partition chromatography was employed for the determination of radioactive organic products, and atomic bromine...

  20. Thermal annealing effects on ultra-violet luminescence properties of Gd doped AlN

    Energy Technology Data Exchange (ETDEWEB)

    Kita, Takashi; Ishizu, Yuta; Tsuji, Kazuma; Harada, Yukihiro [Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501 (Japan); Chigi, Yoshitaka; Nishimoto, Tetsuro; Tanaka, Hiroyuki; Kobayashi, Mikihiro [YUMEX INC., 400 Itoda, Yumesaki, Himeji, Hyogo 671-2114 (Japan); Ishihara, Tsuguo; Izumi, Hirokazu [Hyogo Prefectural Institute of Technology, 3-1-12 Yukihira, Suma, Kobe 654-0037 (Japan)

    2015-04-28

    We studied energy transfer from AlN to doped Gd{sup 3+} ions as a function of the post-thermal annealing temperature. Gd-doped AlN thin films were deposited on fused-silica substrates using a reactive radio-frequency magnetron sputtering technique. The film is a c-axis oriented polycrystal. The intra-orbital electron transition in Gd{sup 3+} showed an atomically sharp luminescence at 3.9 eV (318 nm). The photoluminescence (PL) excitation spectrum exhibited a resonant peak, indicating efficient energy transfer from the host AlN crystal to Gd{sup 3+} ions. The PL intensity increases approximately ten times by thermal annealing. The PL decay lifetime becomes long with annealing, and mid-gap luminescence relating to the crystal defects in AlN was also found to be reduced by annealing. These results suggest that energy dissipation of excited carriers in AlN was suppressed by annealing, and the efficiency of energy transfer into Gd{sup 3+} was improved.

  1. Effects of Thermal Annealing Upon the Morphology of Polymer-Fullerene Blends

    KAUST Repository

    Verploegen, Eric

    2010-08-18

    Grazing incidence X-ray scattering (GIXS) is used to characterize the morphology of poly(3-hexylthiophene) (P3HT)-phenyl-C61-butyric acid methyl ester (PCBM) thin film bulk heterojunction (BHJ) blends as a function of thermal annealing temperature, from room temperature to 220 °C. A custom-built heating chamber for in situ GIXS studies allows for the morphological characterization of thin films at elevated temperatures. Films annealed with a thermal gradient allow for the rapid investigation of the morphology over a range of temperatures that corroborate the results of the in situ experiments. Using these techniques the following are observed: the melting points of each component; an increase in the P3HT coherence length with annealing below the P3HT melting temperature; the formation of well-oriented P3HT crystallites with the (100) plane parallel to the substrate, when cooled from the melt; and the cold crystallization of PCBM associated with the PCBM glass transition temperature. The incorporation of these materials into BHJ blends affects the nature of these transitions as a function of blend ratio. These results provide a deeper understanding of the physics of how thermal annealing affects the morphology of polymer-fullerene BHJ blends and provides tools to manipulate the blend morphology in order to develop high-performance organic solar cell devices. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. The effect of thermal annealing on the properties of thin alumina films prepared by low pressure MOCVD

    NARCIS (Netherlands)

    Haanappel, V.A.C.; Haanappel, V.A.C.; van de Vendel, D.; van Corbach, H.D.; Fransen, T.; Gellings, P.J.

    1995-01-01

    Thin amorphous alumina films were prepared on stainless steel, type AISI 304, by low pressure metal-organic chemical vapour deposition. The effect of thermal annealing in nitrogen (for 2, 4 and 17 h at 600, 700 and 800 °C) on the film properties, including the protection of the underlying substrate

  3. Morphological, thermal and annealed microhardness ...

    Indian Academy of Sciences (India)

    The effects of annealing temperature on the microhardness of IPNs were studied using the Vickers method. SEM indicates the homogeneous morphological features for IPN. The role of gelatin, AN and crosslinker on the developed hard biopolymer has been described with the help of DSC thermograms and microhardness ...

  4. Effects of thermal annealing on the magnetic interactions in nanogranular Fe-Ag thin films

    Energy Technology Data Exchange (ETDEWEB)

    Alonso, J.; Fdez-Gubieda, M.L.; Svalov, A. [Departamento de Electricidad y Electronica, Universidad del Pais Vasco (UPV/EHU), Campus de Leioa, 48940 Leioa (Spain); Meneghini, C. [Dipartimento di Fisica ' E. Amaldi' , Universita degli Studi Roma Tre, 00146 Roma (Italy); Orue, I. [SGIker, Universidad del Pais Vasco (UPV/EHU), Campus de Leioa, 48940 Leioa (Spain)

    2012-09-25

    Highlights: Black-Right-Pointing-Pointer Fe{sub x}Ag{sub 100-x} granular thin films with competing interactions (25 {<=} x{<=} 35). Black-Right-Pointing-Pointer Annealing up to 200 Degree-Sign C mainly modifies the interface of Fe nanoparticles. Black-Right-Pointing-Pointer Annealing reduces RKKY interactions in Fe{sub 25}Ag{sub 75}. Black-Right-Pointing-Pointer Annealing favors exchange interactions and ferromagnetic order in Fe{sub 35}Ag{sub 65}. - Abstract: In this paper we have studied, by analysing the evolution of the magnetic behaviour during thermal treatment, the role of the interparticle magnetic interactions in Fe{sub x}Ag{sub 100-x} granular thin films prepared by sputtering deposition technique. Two compositions have been selected: x = 25 and 35, below and around the magnetic percolation of the system, respectively, according to our previous works. The structure of these thin films has been studied by X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) measurements. To analyse the magnetic behaviour, DC magnetic measurements have been carried out after progressively annealing the samples at different temperatures (0 {<=} T{sub ann} {<=} 200 Degree-Sign C). These measurements have revealed that, upon thermal treatment, the frustrated state at low temperatures (T < 80 K) for the x = 25 sample tends to disappear, probably due to the weakening of RKKY interactions after the segregation of soluted Fe atoms in the Ag matrix. However, dipolar interactions are not affected by the annealing. On the contrary, at x = 35, around the magnetic percolation, the annealing gives rise to an increasingly ordered interface, thereby enhancing the transfer of the direct exchange interactions.

  5. Effect of thermal annealing treatment with titanium chelate on buffer layer in inverted polymer solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhiyong [College of Science, Shenyang Agricultural University, Shenyang 110866 (China); Wang, Ning, E-mail: ning_wang@outlook.com [School of Electrical and Electronic and Engineering, Nanyang Technological University 639798 (Singapore); Fu, Yan, E-mail: 1060945062@qq.com [College of Science, Shenyang Agricultural University, Shenyang 110866 (China)

    2016-12-15

    Highlights: • The TIPD layer as electron extraction layer and instead of Ca or LiF. • Impact of the work function of TIPD layer by thermal annealing treatment. • Importance of TIPD layer as electron extraction layer for work function and potential barrier. - Abstract: The solution processable electron extraction layer (EEL) is crucial for polymer solar cells (PSCs). Here, we investigated titanium (diisopropoxide) bis(2,4-pentanedionate) (TIPD) as an EEL and fabricated inverted PSCs with a blend of poly(3-hexylthiophene) (P3HT) and indene-C60 bisadduct (ICBA) acting as the photoactive layer, with a structure of ITO/TIPD/P3HT:ICBA/MoO{sub 3}/Ag. After thermal annealing treatment at 150 °C for 15 min, the PSC performances increased from 3.85% to 6.84% and they achieve stable power conversion efficiency (PCE), with a similar PCE compared with TiO{sub 2} as an EEL by the vacuum evaporated method. Fourier transform infrared spectroscopy (FTIR) and ultraviolet photoelectron spectroscopy (UPS) confirmed that the TIPD decomposed and formed the Ti=O bond, and the energy level of the lowest unoccupied molecular orbital and the highest occupied molecular orbital increased. The space charge limited current (SCLC) measurements further confirmed the improvement in electron collection and the transport ability using TIPD as the EEL and thermal annealing.

  6. Influence of thermal annealing on the memory effect in MIS structures containing crystalline Si nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Meier, Sebastian; Brueggemann, R. [Institut fuer Physik, Carl von Ossietzky Universitaet Oldenburg, 26111 Oldenburg (Germany); Kirilov, Kiril [Department of Solid State Physics and Microelectronics, Sofia Univ. (Bulgaria); Levi, Zelma; Manolov, E. [Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd., 1784 Sofia (Bulgaria); Nedev, N. [Instituto de Ingenieria Universidad Autonoma de Baja California, Benito Juarez Blvd., s/n, C.P. 21280, Mexicali, Baja California, Mexico (Mexico)

    2007-07-01

    Silicon nanocrystals embedded in a SiO{sub 2} matrix are fabricated by thermal annealing of Metal/SiO{sub 2}/SiO{sub x}/c-Si structures (x=1.15) at 1000 C in N{sub 2} atmosphere for 30 or 60 min. High frequency C-V measurements demonstrate that both types of sample can be charged negatively or positively by applying a positive or negative bias voltage to the gate. The clockwise hysteresis windows of 30 and 60 min annealed samples are about 7 and 5.5 V for the {+-}12 V scanning range (E{sub ox}={+-}2.4 MV/cm), respectively. Although the samples annealed for 60 min have a smaller hysteresis window, they have two important advantages compared to the 30 min annealed ones: a lower defect density at the c-Si wafer/SiO{sub 2} interface and a smaller value of the fixed oxide charge close to this interface.

  7. Investigation of thermal annealing effects on microstructural and optical properties of HfO{sub 2} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Modreanu, M. [Tyndall National Institute, Cork (Ireland)]. E-mail: mircea.modreanu@tyndall.ie; Sancho-Parramon, J. [Tyndall National Institute, Cork (Ireland); Durand, O. [Thales Research and Technology France, Route Departementale 128, F-91767 Palaiseau Cedex (France); Servet, B. [Thales Research and Technology France, Route Departementale 128, F-91767 Palaiseau Cedex (France); Stchakovsky, M. [Horiba Jobin-Yvon, Thin Film Division, Chilly-Mazarin (France); Eypert, C. [Horiba Jobin-Yvon, Thin Film Division, Chilly-Mazarin (France); Naudin, C. [HORIBA Jobin-Yvon Raman Division, Villeneuve d' Ascq (France); Knowles, A. [HORIBA Jobin-Yvon Ltd., Raman Division, Middlesex (United Kingdom); Bridou, F. [Laboratoire Charles Fabry de l' Institut d' Optique, CNRS, Unite mixte de Recherche 85801, 91403 Orsay Cedex (France); Ravet, M.-F. [Laboratoire Charles Fabry de l' Institut d' Optique, CNRS, Unite mixte de Recherche 85801, 91403 Orsay Cedex (France)

    2006-10-31

    In the present paper, we investigate the effect of thermal annealing on optical and microstructural properties of HfO{sub 2} thin films (from 20 to 190 nm) obtained by plasma ion assisted deposition (PIAD). After deposition, the HfO{sub 2} films were annealed in N{sub 2} ambient for 3 h at 300, 350, 450, 500 and 750 deg. C. Several characterisation techniques including X-ray reflectometry (XRR), X-ray diffraction (XRD), spectroscopic ellipsometry (SE), UV Raman and FTIR were used for the physical characterisation of the as-deposited and annealed HfO{sub 2} thin films. The results indicate that as-deposited PIAD HfO{sub 2} films are mainly amorphous and a transition to a crystalline phase occurs at a temperature higher than 450 deg. C depending on the layer thickness. The crystalline grains consist of cubic and monoclinic phases already classified in literature but this work provides the first evidence of amorphous-cubic phase transition at a temperature as low as 500 deg. C. According to SE, XRR and FTIR results, an increase in the interfacial layer thickness can be observed only for high temperature annealing. The SE results show that the amorphous phase of HfO{sub 2} (in 20 nm thick samples) has an optical bandgap of 5.51 eV. Following its transition to a crystalline phase upon annealing at 750 deg. C, the optical bandgap increases to 5.85 eV.

  8. Effect of thermal annealing treatment with titanium chelate on buffer layer in inverted polymer solar cells

    Science.gov (United States)

    Liu, Zhiyong; Wang, Ning; Fu, Yan

    2016-12-01

    The solution processable electron extraction layer (EEL) is crucial for polymer solar cells (PSCs). Here, we investigated titanium (diisopropoxide) bis(2,4-pentanedionate) (TIPD) as an EEL and fabricated inverted PSCs with a blend of poly(3-hexylthiophene) (P3HT) and indene-C60 bisadduct (ICBA) acting as the photoactive layer, with a structure of ITO/TIPD/P3HT:ICBA/MoO3/Ag. After thermal annealing treatment at 150 °C for 15 min, the PSC performances increased from 3.85% to 6.84% and they achieve stable power conversion efficiency (PCE), with a similar PCE compared with TiO2 as an EEL by the vacuum evaporated method. Fourier transform infrared spectroscopy (FTIR) and ultraviolet photoelectron spectroscopy (UPS) confirmed that the TIPD decomposed and formed the Tidbnd O bond, and the energy level of the lowest unoccupied molecular orbital and the highest occupied molecular orbital increased. The space charge limited current (SCLC) measurements further confirmed the improvement in electron collection and the transport ability using TIPD as the EEL and thermal annealing.

  9. Effect of Thermal Annealing in Ammonia on the Properties of InGaN Nanowires with Different Indium Concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, Cristopher; Cordones, Amy; Andrews, Sean; Gao, Hanwei; Fu, Anthony; Leone, Stephen; Yang, Peidong

    2012-10-02

    The utility of an annealing procedure in ammonia ambient is investigated for improving the optical characteristics of InxGa1?xN nanowires (0.07 ≤ x ≤ 0.42) grown on c-Al2O3 using a halide chemical vapor deposition method. Morphological studies using scanning electron microscopy confirm that the nanowire morphology is retained after annealing in ammonia at temperatures up to 800 ?C. However, significant indium etching and composition inhomogeneities are observed for higher indium composition nanowires (x = 0.28, 0.42), as measured by energy-dispersive X-ray spectroscopy and Z-contrast scanning transmission electron microscopy. Structural analyses, using X-ray diffraction and high-resolution transmission electron microscopy, indicate that this is a result of the greater thermal instability of higher indium composition nanowires. The effect of these structural changes on the optical quality of InGaN nanowires is examined using steady-state and time-resolved photoluminescence measurements. Annealing in ammonia enhances the integrated photoluminescence intensity of InxGa1?xN nanowires by up to a factor of 4.11 ? 0.03 (for x = 0.42) by increasing the rate of radiative recombination. Fitting of photoluminescence decay curves to a Kohlrausch stretched exponential indicates that this increase is directly related to a larger distribution of recombination rates from composition inhomogeneities caused by annealing. The results demonstrate the role of thermal instability on the improved optical properties of InGaN nanowires annealed in ammonia.

  10. Preparation and Thermal Characterization of Annealed Gold Coated Porous Silicon

    Directory of Open Access Journals (Sweden)

    Afarin Bahrami

    2012-01-01

    Full Text Available Porous silicon (PSi layers were formed on a p-type Si wafer. Six samples were anodised electrically with a 30 mA/cm2 fixed current density for different etching times. The samples were coated with a 50–60 nm gold layer and annealed at different temperatures under Ar flow. The morphology of the layers, before and after annealing, formed by this method was investigated by scanning electron microscopy (SEM. Photoacoustic spectroscopy (PAS measurements were carried out to measure the thermal diffusivity (TD of the PSi and Au/PSi samples. For the Au/PSi samples, the thermal diffusivity was measured before and after annealing to study the effect of annealing. Also to study the aging effect, a comparison was made between freshly annealed samples and samples 30 days after annealing.

  11. Thermal Annealing Effect on Poly(3-hexylthiophene): Fullerene:Copper-Phthalocyanine Ternary Photoactive Layer

    Science.gov (United States)

    Derouiche, H.; Mohamed, A. B.

    2013-01-01

    We have fabricated poly(3-hexylthiophene) (P3HT)/copper phthalocyanine (CuPc)/fullerene (C60) ternary blend films. This photoactive layer is sandwiched between an indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT/PSS) photoanode and a bathocuproine (BCP)/aluminium photocathode. The thin films have been characterized by atomic force microscope (AFM) and ultraviolet/visible spectroscopy in order to study the influence of P3HT doping on the morphological and optical properties of the photoactive layer. We have also compared the I-V characteristics of three different organic solar cells: ITO/PEDOT:PSS/CuPc0.5:C600.5/BCP/Al and ITO/PEDOT:PSS/P3HT0.3:CuPc0.3:C600.4/BCP/Al with and without annealing. Both structures show good photovoltaic behaviour. Indeed, the incorporation of P3HT into CuPc:C60 thin film improves all the photovoltaic characteristics. We have also seen that thermal annealing significantly improves the optical absorption ability and stabilizes the organic solar cells making it more robust to chemical degradation. PMID:23766722

  12. Effects of Annealing Conditions on Mixed Lead Halide Perovskite Solar Cells and Their Thermal Stability Investigation

    Science.gov (United States)

    Yang, Haifeng; Zhang, Jincheng; Chang, Jingjing; Lin, Zhenhua; Chen, Dazheng; Xi, He; Hao, Yue

    2017-01-01

    In this work, efficient mixed organic cation and mixed halide (MA0.7FA0.3Pb(I0.9Br0.1)3) perovskite solar cells are demonstrated by optimizing annealing conditions. AFM, XRD and PL measurements show that there is a better perovskite film quality for the annealing condition at 100 °C for 30 min. The corresponding device exhibits an optimized PCE of 16.76% with VOC of 1.02 V, JSC of 21.55 mA/cm2 and FF of 76.27%. More importantly, the mixed lead halide perovskite MA0.7FA0.3Pb(I0.9Br0.1)3 can significantly increase the thermal stability of perovskite film. After being heated at 80 °C for 24 h, the PCE of the MA0.7FA0.3Pb(I0.9Br0.1)3 device still remains at 70.00% of its initial value, which is much better than the control MAPbI3 device, where only 46.50% of its initial value could be preserved. We also successfully fabricated high-performance flexible mixed lead halide perovskite solar cells based on PEN substrates. PMID:28773199

  13. Thermal Annealing Effect on Poly(3-hexylthiophene: Fullerene:Copper-Phthalocyanine Ternary Photoactive Layer

    Directory of Open Access Journals (Sweden)

    H. Derouiche

    2013-01-01

    Full Text Available We have fabricated poly(3-hexylthiophene (P3HT/copper phthalocyanine (CuPc/fullerene (C60 ternary blend films. This photoactive layer is sandwiched between an indium tin oxide (ITO/poly(3,4-ethylenedioxythiophene:poly(styrene sulfonate (PEDOT/PSS photoanode and a bathocuproine (BCP/aluminium photocathode. The thin films have been characterized by atomic force microscope (AFM and ultraviolet/visible spectroscopy in order to study the influence of P3HT doping on the morphological and optical properties of the photoactive layer. We have also compared the characteristics of three different organic solar cells: ITO/PEDOT:PSS/CuPc0.5:C600.5/BCP/Al and ITO/PEDOT:PSS/P3HT0.3:CuPc0.3:C600.4/BCP/Al with and without annealing. Both structures show good photovoltaic behaviour. Indeed, the incorporation of P3HT into CuPc:C60 thin film improves all the photovoltaic characteristics. We have also seen that thermal annealing significantly improves the optical absorption ability and stabilizes the organic solar cells making it more robust to chemical degradation.

  14. Modeling the effects of ion dose and crystallographic symmetry on the morphological evolution of embedded precipitates under thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Li, Kun-Dar, E-mail: kundar@mail.nutn.edu.tw

    2014-10-01

    Highlights: •We model the faceted precipitates formation by post-implantation annealing. •The anisotropic interfacial energy and diffusion kinetics play crucial roles. •The evolutions of faceted precipitates, including Ostwald ripening, are revealed. •The mechanism of the nucleation and growth is based on the atomic diffusion. •The effects of ion dose and crystallographic symmetry are also investigated. -- Abstract: Thermal annealing is one of the most common techniques to synthesize embedded precipitates by ion implantation process. In this study, an anisotropic phase field model is presented to investigate the effects of ion dose and crystallographic symmetry on the morphological formation and evolution of embedded precipitates during post-implantation thermal annealing process. This theoretical model provides an efficient numerical approach to understand the phenomenon of faceted precipitates formation by ion implantation. As a theoretical analysis, the interfacial energy and diffusion kinetics play prominent roles in the mechanism of atomic diffusion for the precipitates formation. With a low ion dose, faceted precipitates are developed by virtue of the anisotropic interfacial energy. As an increase of ion dose, connected precipitates with crystallographic characters on the edge are appeared. For a high ion dose, labyrinth-like nanostructures of precipitates are produced and the characteristic morphology of crystallographic symmetry becomes faint. These simulation results for the morphological evolutions of embedded precipitates by ion implantation are corresponded with many experimental observations in the literatures. The quantitative analyses of the simulations are also well described the consequence of precipitates formation under different conditions.

  15. Effect of thermal annealing on structural and optical properties of In{sub 2}S{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Choudhary, Sonu, E-mail: sonuchoudhary1983@gmail.com [Department of Physics, Mohanlal Sukhadia University, Udaipur-313001 (India)

    2015-08-28

    There is a highly need of an alternate of toxic materials CdS for solar cell applications and indium sulfide is found the most suitable candidate to replace CdS due to its non-toxic and environmental friendly nature. In this paper, the effect of thermal annealing on the structural and optical properties of indium sulfide (In{sub 2}S{sub 3}) thin films is undertaken. The indium sulfide thin films of 121 nm were deposited on glass substrates employing thermal evaporation method. The films were subjected to the X-ray diffractometer and UV-Vis spectrophotometer respectively for structural and optical analysis. The XRD pattern show that the as-deposited thin film was amorphous in nature and crystallinity is found to be varied with annealing temperature. The optical analysis reveals that the optical band gap is varied with annealing. The optical parameters like absorption coefficient, extinction coefficient and refractive index were calculated. The results are in good agreement with available literature.

  16. Pure thermal sensitisation and pre-dose effect of OSL in both unfired and annealed quartz samples

    Energy Technology Data Exchange (ETDEWEB)

    Oniya, Ebenezer O., E-mail: ebenezer.oniya@aaua.edu.ng [Physics and Electronics Department, Adekunle Ajasin University, 342111 Akungba Akoko (Nigeria); Polymeris, George S. [Institute of Nuclear Sciences, Ankara University, Beşevler 06100, Ankara (Turkey); Jibiri, Nnamdi N. [Department of Physics, University of Ibadan, Ibadan (Nigeria); Tsirliganis, Nestor C. [Department of Archaeometry and Physicochemical Measurements, R.C. ‘Athena’, P.O. Box 159, Kimmeria University Campus, 67100 Xanthi (Greece); Babalola, Israel A. [Department of Physics, University of Ibadan, Ibadan (Nigeria); Kitis, George [Nuclear Physics Laboratory, Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)

    2017-06-01

    The sensitisation of quartz has attracted much attention since its thorough understanding is important in luminescence studies and dating applications. The present investigation examines the influence of pure thermal activation and predose treatments on the sensitisation of different components of linearly modulated optically stimulated luminescence (LM-OSL) measured at room temperature (RT) thereby eliminating undesired thermal quenching effects. Annealed and unfired quartz samples from Nigeria were used. The OSL measurements were carried out using an automated RISØTL/OSL reader (model-TL/OSL–DA–15). A new approach was adopted to match each of the resolved components of the RT-LM-OSL to respective thermoluminescence (TL) peaks that share the same electron trap and recombination centers. Pure thermal activation and pre-dose treatments respectively affect the sensitisation of all the components of the RT-LM-OSL in a similar manner as the one reported for the 110 °C TL peak but without thermal quenching contributions. Component C4 in annealed samples that was identified to share the same electron trap and recombination centers with the 110 °C TL peak was also proved appropriate for RT-LM-OSL, instead of the initial part of the continuous wave (CW) OSL signal, thus the methods can serve as complementary dating methods.

  17. Pure thermal sensitisation and pre-dose effect of OSL in both unfired and annealed quartz samples

    Science.gov (United States)

    Oniya, Ebenezer O.; Polymeris, George S.; Jibiri, Nnamdi N.; Tsirliganis, Nestor C.; Babalola, Israel A.; Kitis, George

    2017-06-01

    The sensitisation of quartz has attracted much attention since its thorough understanding is important in luminescence studies and dating applications. The present investigation examines the influence of pure thermal activation and predose treatments on the sensitisation of different components of linearly modulated optically stimulated luminescence (LM-OSL) measured at room temperature (RT) thereby eliminating undesired thermal quenching effects. Annealed and unfired quartz samples from Nigeria were used. The OSL measurements were carried out using an automated RISØTL/OSL reader (model-TL/OSL-DA-15). A new approach was adopted to match each of the resolved components of the RT-LM-OSL to respective thermoluminescence (TL) peaks that share the same electron trap and recombination centers. Pure thermal activation and pre-dose treatments respectively affect the sensitisation of all the components of the RT-LM-OSL in a similar manner as the one reported for the 110 °C TL peak but without thermal quenching contributions. Component C4 in annealed samples that was identified to share the same electron trap and recombination centers with the 110 °C TL peak was also proved appropriate for RT-LM-OSL, instead of the initial part of the continuous wave (CW) OSL signal, thus the methods can serve as complementary dating methods.

  18. Optimized Laser Thermal Annealing on Germanium for High Dopant Activation and Low Leakage Current

    DEFF Research Database (Denmark)

    Shayesteh, Maryam; O' Connell, Dan; Gity, Farzan

    2014-01-01

    In this paper, state-of-the-art laser thermal annealing is used to fabricate Ge diodes. We compared the effect of laser thermal annealing (LTA) and rapid thermal annealing (RTA) on dopant activation and electrical properties of phosphorus and Arsenic-doped n +/p junctions. Using LTA, high carrier...

  19. Effect of thermal annealing on the structural, optical and dielectrical properties of P3HT:PC{sub 70}BM nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Aloui, Walid, E-mail: alouiwalid26@yahoo.fr [Laboratory of Condensed Matter and Nanosciences, Faculty of Sciences of Monastir, Avenue of the Environment, 5019 Monastir (Tunisia); Adhikari, Tham [Department of Chemistry, Queen’s University, Kingston, ON K7L 3N6 (Canada); Nunzi, Jean-Michel [Department of Chemistry, Queen’s University, Kingston, ON K7L 3N6 (Canada); Department of Physics, Engineering Physics and Astronomy, Queen’s University, Kingston, ON K7L 3N6 (Canada); Bouazizi, Abdelaziz [Laboratory of Condensed Matter and Nanosciences, Faculty of Sciences of Monastir, Avenue of the Environment, 5019 Monastir (Tunisia)

    2016-06-15

    Highlights: • A typical structure of ITO/PEDOT: PSS/P3HT: PC{sub 70}BM/Al was fabricated. • Charge carrier diffusion and recombination have been calculated. • AFM and optical results show that thermal annealing promotes the phase separation. • The annealing process improves the transport of charges. - Abstract: The effect of thermal annealing on the optical, structural and the dielectric properties of P3HT:PC{sub 70}BM blended films were investigated. By means of atomic force microscopy, we observed the morphology evolution of the annealed P3HT:PC{sub 70}BM nanocomposites. Raman spectroscopy showed a substantial ordering in the polymer film after annealing. The absorption spectra of the annealed P3HT:PC{sub 70}BM films were improved and red shifted than un-annealed samples. The results indicate that the P3HT in the nanocomposite becomes an ordered structure with annealing. The ordered P3HT facilitates the charge transport. From the photoluminescence measurements, the formation of polymer crystallites was observed upon annealing. Thus, the device efficiency reaches 2.2% after annealing at 150 °C. Impedance spectroscopy shows the classical complex plan curves; the low frequency is related to the effective lifetime of charge carriers and the high frequency corresponds to the diffusion time of these carriers. Global mobilities are in the range 3.8–4.6 × 10{sup −3} cm{sup 2} V{sup −1} s{sup −1}.

  20. Effect of Thermal Annealing on Machining-Induced Residual Stresses in Inconel 718

    Science.gov (United States)

    Madariaga, A.; Aperribay, J.; Arrazola, P. J.; Esnaola, J. A.; Hormaetxe, E.; Garay, A.; Ostolaza, K.

    2017-08-01

    Nickel-based alloys are widely employed in the manufacturing of aero-engines. These alloys are difficult to machine, and tensile residual stresses are generated during machining. These tensile residual stresses can negatively affect the performance of aero-engine components. Nevertheless, residual stresses can vary due to thermal or mechanical loading. These variations must be considered to evaluate the real influence of residual stresses on component behavior. This paper studies the effect of thermal loads on machining-induced residual stresses in the alloy Inconel 718. A ring-shaped Inconel 718 part was face-turned, and specimens were extracted from it. Specimens were exposed at 550 and 650 °C for 10 min, 1 and 10 h. Residual stresses were measured, and microstructure was observed before and after thermal exposure. Residual stress variations found after thermal exposure were the consequence of two factors: relaxation of strain bands during the early stage of exposure and diffusion-controlled creep. In addition, a modified Zener-Wert-Avrami model is proposed to predict residual stress relaxation caused by the diffusion-controlled creep. Once having fitted the modified Zener-Wert-Avrami model, the study was extended for a wider range of temperatures (400-650 °C). This analysis showed that surface residual stresses do not relax significantly at temperatures below 500 °C.

  1. Effect of an in-situ thermal annealing on the structural properties of self-assembled GaSb/GaAs quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Fernández-Delgado, N., E-mail: natalia.fernandezdelgado@alum.uca.es [Department of Material Science, Metallurgical Engineering and Inorganic Chemistry, IMEYMAT, University of Cádiz, 11510, Puerto Real, Cádiz (Spain); Herrera, M. [Department of Material Science, Metallurgical Engineering and Inorganic Chemistry, IMEYMAT, University of Cádiz, 11510, Puerto Real, Cádiz (Spain); Chisholm, M.F. [Scanning Transmission Electron Microscopy Group, Oak Ridge National Laboratory, TN (United States); Kamarudin, M.A. [Department of Physics, Lancaster University, Lancaster, LA1 4YB (United Kingdom); Department of Physics, Faculty of Science, Universiti Putra Malaysia, 43400, UPM Serdang, Selangor (Malaysia); Zhuang, Q.D.; Hayne, M. [Department of Physics, Lancaster University, Lancaster, LA1 4YB (United Kingdom); Molina, S.I. [Department of Material Science, Metallurgical Engineering and Inorganic Chemistry, IMEYMAT, University of Cádiz, 11510, Puerto Real, Cádiz (Spain)

    2017-02-15

    Highlights: • GaSb QDs are more elongated and Sb is less concentrated after the thermal annealing. • The density of misfit dislocations in GaSb QDs is reduced after the annealing. • Threading dislocations in GaSb/GaAs QDs are Sb-rich after the thermal annealing. • The gliding of a threading dislocation favors Sb diffusion in GaSb/GaAs QDs. - Abstract: In this work, the effect of the application of a thermal annealing on the structural properties of GaSb/GaAs quantum dots (QDs) is analyzed by aberration corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and electron energy loss spectroscopy (EELS) Our results show that the GaSb/GaAs QDs are more elongated after the annealing, and that the interfaces are less abrupt due to the Sb diffusion. We have also found a strong reduction in the misfit dislocation density with the annealing. The analysis by EELS of a threading dislocation has shown that the dislocation core is rich in Sb. In addition, the region of the GaAs substrate delimited by the threading dislocation is shown to be Sb-rich as well. An enhanced diffusion of Sb due to a mechanism assisted by the dislocation movement is discussed.

  2. Effect of thermal annealing in vacuum on the photovoltaic properties of electrodeposited Cu2O-absorber solar cell

    Directory of Open Access Journals (Sweden)

    Dimopoulos T.

    2014-07-01

    Full Text Available Heterojunction solar cells were fabricated by electrochemical deposition of p-type, cuprous oxide (Cu2O absorber on sputtered, n-type ZnO layer. X-ray diffraction measurements revealed that the as-deposited absorber consists mainly of Cu2O, but appreciable amounts of metallic Cu and cupric oxide (CuO are also present. These undesired oxidation states are incorporated during the deposition process and have a detrimental effect on the photovoltaic properties of the cells. The open circuit voltage (VOC, short circuit current density (jSC, fill factor (FF and power conversion efficiency (η of the as-deposited cells are 0.37 V, 3.71 mA/cm2, 35.7% and 0.49%, respectively, under AM1.5G illumination. We show that by thermal annealing in vacuum, at temperatures up to 300 °C, compositional purity of the Cu2O absorber could be obtained. A general improvement of the heterojunction and bulk materials quality is observed, reflected upon the smallest influence of the shunt and series resistance on the transport properties of the cells in dark and under illumination. Independent of the annealing temperature, transport is dominated by the space-charge layer generation-recombination current. After annealing at 300 °C the solar cell parameters could be significantly improved to the values of: VOC = 0.505 V, jSC = 4.67 mA/cm2, FF = 47.1% and η = 1.12%.

  3. Effect of Thermal Annealing on Carbon in In-situ Phosphorous-Doped Si{sub 1-x}C{sub x} films

    Energy Technology Data Exchange (ETDEWEB)

    Adam, Thomas, E-mail: tadam@us.ibm.com [IBM Research at Albany Nanotech, 257 Fuller Road, Albany, NY 12203 (United States); Loubet, Nicolas [STMicroelectronics at Albany Nanotech, 257 Fuller Road, Albany, NY 12203 (United States); Reznicek, Alexander; Paruchuri, Vamsi [IBM Research at Albany Nanotech, 257 Fuller Road, Albany, NY 12203 (United States); Sampson, Ron [STMicroelectronics at Albany Nanotech, 257 Fuller Road, Albany, NY 12203 (United States); Sadana, Devendra [IBM Research, 1101 Kitchawan Road, Yorktown, NY 10598 (United States)

    2012-02-01

    The effect of thermal heat treatment on carbon in in-situ phosphorous-doped silicon-carbon is studied as a function of annealing temperature and type. Films of 0 to 2% carbon were deposited using cyclic chemical vapor deposition at reduced pressures. Secondary ion-mass spectroscopy and high-resolution X-ray diffraction were employed to extract the total and substitutional carbon concentration in samples with phosphorous levels of mid-10{sup 20} cm{sup -3}. It was found that millisecond laser annealing drastically improves substitutionality while high thermal budget treatments (furnace, rapid-thermal, or spike annealing) resulted in an almost complete loss of substitutional carbon, independent of preceding or subsequent laser heat treatments.

  4. Origin of reverse annealing effect in hydrogen-implanted silicon

    Energy Technology Data Exchange (ETDEWEB)

    Di, Zengfeng [Los Alamos National Laboratory; Nastasi, Michael A [Los Alamos National Laboratory; Wang, Yongqiang [Los Alamos National Laboratory

    2009-01-01

    In contradiction to conventional damage annealing, thermally annealed H-implanted Si exhibits an increase in damage or reverse annealing behavior, whose mechanism has remained elusive. On the basis of quantitative high resolution transmission electron microscopy combined with channeling Rutherford backscattering analysis, we conclusively elucidate that the reverse annealing effect is due to the nucleation and growth of hydrogen-induce platelets. Platelets are responsible for an increase in the height and width the channeling damage peak following increased isochronal anneals.

  5. High-dose neutron irradiation of MgAl{sub 2}O{sub 4} spinel: effects of post-irradiation thermal annealing on EPR and optical absorption

    Energy Technology Data Exchange (ETDEWEB)

    Ibarra, A. [EURATOM/CIEMAT Fusion Association, Inst. Investigacion Basica, Av. Complutense, 22, E-28040 Madrid (Spain)]. E-mail: angel.ibarra@ciemat.es; Bravo, D. [Departamento de Fisica de Materiales, Facultad de Ciencias (C-IV), Universidad Autonoma de Madrid, Cantoblanco, E-28049 Madrid (Spain); Lopez, F.J. [Departamento de Fisica de Materiales, Facultad de Ciencias (C-IV), Universidad Autonoma de Madrid, Cantoblanco, E-28049 Madrid (Spain); Garner, F.A. [Pacific Northwest National Laboratory, Richland, WA (United States)

    2005-02-01

    Electron paramagnetic resonance (EPR) and optical absorption spectra were measured during thermal annealing of stoichiometric MgAl{sub 2}O{sub 4} spinel that was previously irradiated in the Materials Open Test Assembly in the Fast Flux Test Facility (FFTF/MOTA) at {approx}680 K to {approx}50 dpa. Both F and F{sup +} centres are to persist up to very high temperatures (over 1000 K) suggesting the operation of an annealing mechanism controlled by the thermal stability of extended defects. Using X-ray irradiation following the different annealing steps it was shown that an optical absorption band at 37,000 cm{sup -1} is related to a sharp EPR band at g = 2.0005 and that the defect causing these effects is the F{sup +} centre.

  6. Effect of thermal annealing on the microstructures and photocatalytic performance of silver orthophosphate: The synergistic mechanism of Ag vacancies and metallic Ag

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Tingjiang, E-mail: tingjiangn@163.com [The Key Laboratory of Life-Organic Analysis, College of Chemistry and Chemical Engineering, Qufu Normal University, Qufu, Shandong 273165 (China); State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Guan, Wenfei; Xiao, Ying; Tian, Jun; Qiao, Zheng; Zhai, Huishan; Li, Wenjuan; You, Jinmao [The Key Laboratory of Life-Organic Analysis, College of Chemistry and Chemical Engineering, Qufu Normal University, Qufu, Shandong 273165 (China)

    2017-01-01

    Highlights: • Ag{sub 3}PO{sub 4} was initially prepared via ion-exchange reaction and then annealed in air. • Thermal annealing also resulted in the formation of metallic Ag and Ag vacancies. • The annealed samples exhibited superior activity to the pristine sample. • Both Ag vacancies and metallic Ag contributed to the high activity. - Abstract: In this work, a simple thermal annealing route has been developed to improve the photocatalytic performance of silver orthophosphate (Ag{sub 3}PO{sub 4}) photocatalyst toward organic pollutants degradation under visible light irradiation. The experimental results indicated that thermal treatment of Ag{sub 3}PO{sub 4} led to an obvious lattice shift towards right and significantly narrowed band gap energies due to the formation of Ag vacancies and metallic Ag during Ag{sub 3}PO{sub 4} decomposition. These structural variations notably affected the photocatalytic performance of Ag{sub 3}PO{sub 4} photocatalysts. The activity of the annealed samples was found to be significantly enhanced toward the degradation of MO dye. The highest activity was observed over the sample annealed at 400 °C, which exceeded that of pristine Ag{sub 3}PO{sub 4} by a factor of about 21 times. By means of photoluminescence spectroscopy and photoelectrochemical measurements, we propose that the enormous enhancement in activity was mainly attributed to the efficient separation of photogenerated electrons and holes driven by the synergistic effect of Ag vacancies and metallic Ag. The strong interaction between annealed particles also inhibited the dissolution of Ag{sup +} from Ag{sub 3}PO{sub 4} into aqueous solution, contributing to an improved photocatalytic stability. The strategy presented here provides an ideal platform for the design of other highly efficient and stable Ag-based photocatalysts for broad applications in the field of photocatalysis.

  7. The effect of rapid thermal annealing on the photoluminescence of InAsN/InGaAs dot-in-a-well structures

    Energy Technology Data Exchange (ETDEWEB)

    Gargallo-Caballero, R; Miguel-Sanchez, J; Guzman, A; Hierro, A; Munoz, E [Instituto de Sistemas Optoelectronicos y MicrotecnologIa (ISOM)-Departamento de IngenierIa Electronica, ETSI Telecomunicacion, Universidad Politecnica de Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain)], E-mail: rgargallo@die.upm.es

    2008-03-21

    The effect of post-growth rapid thermal annealing on the optical characteristics of InAsN/InGaAs dot-in-a-well DWELL structures grown by molecular beam epitaxy on GaAs(1 0 0) has been studied. InAs/InGaAs DWELL structures have been used as a reference. Photoluminescence measurements of these samples show similar optical effects, such as a blueshift of the peak wavelength and a reduction of the full width of at half maximum PL emission, in both types of structures up to an annealing temperature of 750 deg. C. Nevertheless, at 850 deg. C, these effects are much more pronounced in the structures with N. These results suggest that an additional As-N interdiffusion process inside the InAsN quantum dots plays a dominant role in these effects at high annealing temperatures (850 deg. C) on InAsN/InGaAs structures.

  8. Effects of Thermal Annealing on the Optical Properties of Titanium Oxide Thin Films Prepared by Chemical Bath Deposition Technique

    OpenAIRE

    H.U. Igwe; O.E. Ekpe; E.I. Ugwu

    2010-01-01

    A titanium oxide thin film was prepared by chemical bath deposition technique, deposited on glass substrates using TiO2 and NaOH solution with triethanolamine (TEA) as the complexing agent. The films w ere subjected to post deposition annealing under various temperatures, 100, 150, 200, 300 and 399ºC. The thermal treatment streamlined the properties of the oxide films. The films are transparent in the entire regions of the electromagnetic spectrum, firmly adhered to the substrate and resistan...

  9. Annealing Effect on the Thermoelectric Properties of Bi2Te3 Thin Films Prepared by Thermal Evaporation Method

    Directory of Open Access Journals (Sweden)

    Jyun-Min Lin

    2013-01-01

    Full Text Available Bismuth telluride-based compounds are known to be the best thermoelectric materials within room temperature region, which exhibit potential applications in cooler or power generation. In this paper, thermal evaporation processes were adopted to fabricate the n-type Bi2Te3 thin films on SiO2/Si substrates. The influence of thermal annealing on the microstructures and thermoelectric properties of Bi2Te3 thin films was investigated in temperature range 100–250°C. The crystalline structures and morphologies were characterized by X-ray diffraction and field emission scanning electron microscope analyses. The Seebeck coefficients, electrical conductivity, and power factor were measured at room temperature. The experimental results showed that both the Seebeck coefficient and power factor were enhanced as the annealing temperature increased. When the annealing temperature increased to 250°C for 30 min, the Seebeck coefficient and power factor of n-type Bi2Te3-based thin films were found to be about −132.02 μV/K and 6.05 μW/cm·K2, respectively.

  10. Thermal Effect on the Optical and Morphological Properties of TiO{sub 2} Thin Films Obtained by Annealing a Ti Metal Layer

    Energy Technology Data Exchange (ETDEWEB)

    Butt, M. A.; Fomchenkov, S. A. [Samara National Research University, Samara (Russian Federation)

    2017-01-15

    Titanium metal layers of different thicknesses were deposited on optical glass, quartz and ceramic at 50 ℃ and 150 ℃ substrate temperatures with the help of magnetron deposition. The metal layers were converted into a rutile phase of TiO{sub 2} at different annealing temperatures. The effect of thermal annealing on the morphology and the refractive index of the thin film was investigated. The film's quality and roughness were found to depend on the substrate's temperature during metal film deposition and on the annealing temperature. The TiO{sub 2} thin films obtained on ceramic and glass substrates were seem to show less surface roughness at low substrate temperature as compared to the quartz substrate.

  11. EFFECT OF PRE-ANNEALING TEMPERATURE ON THE GROWTH OF ALIGNED α-Fe2O3 NANOWIRES VIA A TWO-STEP THERMAL OXIDATION

    Science.gov (United States)

    Rashid, Norhana Mohamed; Kishi, Naoki; Soga, Tetsuo

    2016-03-01

    Pre-annealing as part of a two-step thermal oxidation process has a significant effect on the growth of hematite (α-Fe2O3) nanowires on Fe foil. High-density aligned nanowires were obtained on iron foils pre-annealed at 300∘C under a dry air flow for 30min. The X-ray diffraction (XRD) patterns indicate that the nanowires are transformed from the small α-Fe2O3 grains and uniquely grow in the (110) direction. The formation of a high-density of small grains by pre-annealing improved the alignment and density of the α-Fe2O3 nanowires.

  12. Thermal Annealing Effect on Optical Properties of Binary TiO2-SiO2 Sol-Gel Coatings

    Directory of Open Access Journals (Sweden)

    Xiaodong Wang

    2012-12-01

    Full Text Available TiO2-SiO2 binary coatings were deposited by a sol-gel dip-coating method using tetrabutyl titanate and tetraethyl orthosilicate as precursors. The structure and chemical composition of the coatings annealed at different temperatures were analyzed by Raman spectroscopy and Fourier Transform Infrared (FTIR spectroscopy. The refractive indices of the coatings were calculated from the measured transmittance and reflectance spectra. An increase in refractive index with the high temperature thermal annealing process was observed. The Raman and FTIR results indicate that the refractive index variation is due to changes in the removal of the organic component, phase separation and the crystal structure of the binary coatings.

  13. The effects of precursor concentration and thermal annealing on the growth of zinc oxide nanostructures grown on silicon substrate

    Science.gov (United States)

    Paculba, H. M. D.; Alguno, A. C.; Vequizo, R. M.

    2015-06-01

    This study focuses on the growth of Zinc Oxide (ZnO) nanostructures on SiO2/Si(100) substrate via chemical bath deposition (CBD) with varying NH4OH concentration and annealing temperature. The grown ZnOnanostructures were characterized via SEM-EDS for the surface morphology and elemental composition and UV-Vis spectroscopy for the reflectance measurement. Increasing the concentration of NH4OH produced denser ZnOnanostructures composed of rods having smaller diameter. It is believed that at higher concentration of NH4OH, more Zn(OH)2 seed will act as nucleation site for ZnOformation which suggests higher probability of ZnOgrowth. Thermal annealing increased the average diameter of ZnOnanorods. Annealing provided enough energy for unstable atoms to rearrange into a more suitable position. This would result to larger rods that have been formed in expense of the smaller rods. Furthermore, it is confirmed in the UV-Vis spectroscopy results that ZnOnanostructures were successfully grown on SiO2/Si(100) substrate. This successful growth of ZnOnanostructures is a promising material for solar cell technology.

  14. Rapid magnetic hardening by rapid thermal annealing in NdFeB-based nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Chu, K.-T.; Jin, Z Q; Chakka, Vamsi M; Liu, J P [Department of Physics, University of Texas at Arlington, Arlington, TX 76019 (United States)

    2005-11-21

    A systematic study of heat treatments and magnetic hardening of NdFeB-based melt-spun nanocomposite ribbons have been carried out. Comparison was made between samples treated by rapid thermal annealing and by conventional furnace annealing. Heating rates up to 200 K s{sup -1} were adopted in the rapid thermal processing. It was observed that magnetic hardening can be realized in an annealing time as short as 1 s. Coercivity of 10.2 kOe in the nanocomposites has been obtained by rapid thermal annealing for 1 s, and prolonged annealing did not give any increase in coercivity. Detailed results on the effects of annealing time, temperature and heating rate have been obtained. The dependence of magnetic properties on the annealing parameters has been investigated. Structural characterization revealed that there is a close correlation between magnetic hardening and nanostructured morphology. The coercivity mechanism was also studied by analysing the magnetization minor loops.

  15. Thermally assisted quantum annealing of a 16-qubit problem

    Science.gov (United States)

    Dickson, N. G.; Johnson, M. W.; Amin, M. H.; Harris, R.; Altomare, F.; Berkley, A. J.; Bunyk, P.; Cai, J.; Chapple, E. M.; Chavez, P.; Cioata, F.; Cirip, T.; Debuen, P.; Drew-Brook, M.; Enderud, C.; Gildert, S.; Hamze, F.; Hilton, J. P.; Hoskinson, E.; Karimi, K.; Ladizinsky, E.; Ladizinsky, N.; Lanting, T.; Mahon, T.; Neufeld, R.; Oh, T.; Perminov, I.; Petroff, C.; Przybysz, A.; Rich, C.; Spear, P.; Tcaciuc, A.; Thom, M. C.; Tolkacheva, E.; Uchaikin, S.; Wang, J.; Wilson, A. B.; Merali, Z.; Rose, G.

    2013-05-01

    Efforts to develop useful quantum computers have been blocked primarily by environmental noise. Quantum annealing is a scheme of quantum computation that is predicted to be more robust against noise, because despite the thermal environment mixing the system's state in the energy basis, the system partially retains coherence in the computational basis, and hence is able to establish well-defined eigenstates. Here we examine the environment's effect on quantum annealing using 16 qubits of a superconducting quantum processor. For a problem instance with an isolated small-gap anticrossing between the lowest two energy levels, we experimentally demonstrate that, even with annealing times eight orders of magnitude longer than the predicted single-qubit decoherence time, the probabilities of performing a successful computation are similar to those expected for a fully coherent system. Moreover, for the problem studied, we show that quantum annealing can take advantage of a thermal environment to achieve a speedup factor of up to 1,000 over a closed system.

  16. Thermally assisted quantum annealing of a 16-qubit problem.

    Science.gov (United States)

    Dickson, N G; Johnson, M W; Amin, M H; Harris, R; Altomare, F; Berkley, A J; Bunyk, P; Cai, J; Chapple, E M; Chavez, P; Cioata, F; Cirip, T; Debuen, P; Drew-Brook, M; Enderud, C; Gildert, S; Hamze, F; Hilton, J P; Hoskinson, E; Karimi, K; Ladizinsky, E; Ladizinsky, N; Lanting, T; Mahon, T; Neufeld, R; Oh, T; Perminov, I; Petroff, C; Przybysz, A; Rich, C; Spear, P; Tcaciuc, A; Thom, M C; Tolkacheva, E; Uchaikin, S; Wang, J; Wilson, A B; Merali, Z; Rose, G

    2013-01-01

    Efforts to develop useful quantum computers have been blocked primarily by environmental noise. Quantum annealing is a scheme of quantum computation that is predicted to be more robust against noise, because despite the thermal environment mixing the system's state in the energy basis, the system partially retains coherence in the computational basis, and hence is able to establish well-defined eigenstates. Here we examine the environment's effect on quantum annealing using 16 qubits of a superconducting quantum processor. For a problem instance with an isolated small-gap anticrossing between the lowest two energy levels, we experimentally demonstrate that, even with annealing times eight orders of magnitude longer than the predicted single-qubit decoherence time, the probabilities of performing a successful computation are similar to those expected for a fully coherent system. Moreover, for the problem studied, we show that quantum annealing can take advantage of a thermal environment to achieve a speedup factor of up to 1,000 over a closed system.

  17. Effect of rapid thermal annealing on the Mo back contact properties for Cu{sub 2}ZnSnSe{sub 4} solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Placidi, Marcel, E-mail: mplacidi@irec.cat [Catalonia Institute for Energy Research (IREC), Jardins de les Dones de Negre 1, pl.2, 08930 St Adrià del Besòs, Barcelona (Spain); Espindola-Rodriguez, Moises; Lopez-Marino, Simon; Sanchez, Yudania; Giraldo, Sergio; Acebo, Laura; Neuschitzer, Markus [Catalonia Institute for Energy Research (IREC), Jardins de les Dones de Negre 1, pl.2, 08930 St Adrià del Besòs, Barcelona (Spain); Alcobé, Xavier [Centres Científics i Tecnològics (CCiTUB), Lluis Solé i Sabarís 1, 08028 Barcelona (Spain); Pérez-Rodríguez, Alejandro [Catalonia Institute for Energy Research (IREC), Jardins de les Dones de Negre 1, pl.2, 08930 St Adrià del Besòs, Barcelona (Spain); IN2UB, Departament d’Electrònica, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona (Spain); Saucedo, Edgardo [Catalonia Institute for Energy Research (IREC), Jardins de les Dones de Negre 1, pl.2, 08930 St Adrià del Besòs, Barcelona (Spain)

    2016-08-05

    The effect of a rapid thermal process (RTP) on the molybdenum (Mo) back contact for Cu{sub 2}ZnSnSe{sub 4} (CZTSe) solar cells is here investigated. It is shown that the annealing of the Mo layer during 5 min at 550 °C, not only improves the crystalline quality of the back contact (avoiding the absorber decomposition at this region because Mo becomes more resistant to the selenization), but also helps achieving higher crystalline quality of the absorber with bigger grains, reducing the current leakage through the heterojunction. We demonstrate that this is related to the relaxation of the compressive stress of the CZTSe absorber, when synthesized on the RTP annealed substrates. CZTSe solar cells prepared on annealed Mo films exhibited higher short circuit current densities and higher open circuit voltages, resulting in 10% and 33% higher fill factors and efficiencies. - Highlights: • An RTP annealing applied for the first time on Mo for CZTSe solar cells. • Clear improvement of the efficiency from 5.7 to 7.6% with RTP treatment. • Discussion of this improvement with adequate material/device characterizations. • Stress-induced defects responsible of the electrical leakage are revealed.

  18. Effects of Rapid Thermal Annealing on the Structural, Electrical, and Optical Properties of Zr-Doped ZnO Thin Films Grown by Atomic Layer Deposition

    Directory of Open Access Journals (Sweden)

    Jingjin Wu

    2016-08-01

    Full Text Available The 4 at. % zirconium-doped zinc oxide (ZnO:Zr films grown by atomic layer deposition (ALD were annealed at various temperatures ranging from 350 to 950 °C. The structural, electrical, and optical properties of rapid thermal annealing (RTA treated ZnO:Zr films have been evaluated to find out the stability limit. It was found that the grain size increased at 350 °C and decreased between 350 and 850 °C, while creeping up again at 850 °C. UV–vis characterization shows that the optical band gap shifts towards larger wavelengths. The Hall measurement shows that the resistivity almost keeps constant at low annealing temperatures, and increases rapidly after treatment at 750 °C due to the effect of both the carrier concentration and the Hall mobility. The best annealing temperature is found in the range of 350–550 °C. The ZnO:Zr film-coated glass substrates show good optical and electrical performance up to 550 °C during superstrate thin film solar cell deposition.

  19. Effect of growth temperature, thermal annealing and nitrogen doping on optoelectronic properties of sputter-deposited ZnTe films

    Energy Technology Data Exchange (ETDEWEB)

    Rakhshani, A.E., E-mail: ali.rakhshani@ku.edu.kw

    2013-06-01

    Thin films of zinc telluride were grown on glass substrate at different temperatures by magnetron sputtering. Nitrogen-doped films were also prepared at different doping levels. Films underwent a post deposition thermal annealing at low pressure of nitrogen. The film structure, optical and electrical properties were studied using various techniques. The results revealed that the films are composed from nano-size grains (3 – 19 nm) with cubic lattice structure. The grain growth during deposition is thermally activated with the activation energy of 108 meV. Direct optical transitions occurring from the valence band and also from the spin-orbit valence band to either a band gap defect level (for as-grown films) or to the conduction band (for annealed films) have been observed. The valence band split energy is found to be in the range 0.82 – 1.10 eV. The defect level, likely related to oxygen impurities, is located 1.77 eV above the valence band edge. The band gap energy of the annealed films is in the range 2.13 – 2.20 eV and the films doped with nitrogen, at optimum condition, have a free hole concentration and mobility of 2.9 × 10{sup 18} cm{sup −3} and 1.4 cm{sup 2} V{sup −1} s{sup −1}, respectively. - Highlights: • Undoped and nitrogen doped ZnTe films were grown on glass by sputtering technique. • Growth temperature varied in the range 35– 305 °C. • Optimum doping was achieved at the N{sub 2}/(N{sub 2} + Ar) flow rate ratio of 2%. • At optimum condition 2.9 × 10{sup 18} holes/cm{sup 3} with mobility 1.4 cm{sup 2} V{sup −1} s{sup −1} were obtained. • The split valence band and oxygen defects contribute to the absorption of light.

  20. Analysis of improved photovoltaic properties of pentacene/C 60 organic solar cells: Effects of exciton blocking layer thickness and thermal annealing

    Science.gov (United States)

    Yoo, Seunghyup; Potscavage, William J.; Domercq, Benoit; Han, Sung-Ho; Li, Tai-De; Jones, Simon C.; Szoszkiewicz, Robert; Levi, Dean; Riedo, Elisa; Marder, Seth R.; Kippelen, Bernard

    2007-10-01

    We report on the photovoltaic properties of organic solar cells based on pentacene and C 60 thin films with a focus on their spectral responses and the effect of thermal annealing. Spectra of external quantum efficiency (EQE) are measured and analyzed with a one-dimensional exciton diffusion model dependent upon the complex optical functions of pentacene films, which are measured by spectroscopic ellipsometry. An improvement in EQE is observed when the thickness of the bathocuproine (BCP) layer is decreased from 12 nm to 6 nm. Detailed analysis of the EQE spectra indicates that large exciton diffusion lengths in the pentacene films are responsible for the overall high EQE values near wavelengths of 668 nm. Analysis also shows that improvement in the EQE of devices with the thinner BCP layer can be attributed to a net gain in optical field distribution and improvement in carrier collection efficiency. An improvement in open-circuit voltage ( VOC) is also achieved through a thermal annealing process, leading to a net increase in power conversion efficiency. Integration of the EQE spectrum with an AM1.5 G spectrum yields a predicted power conversion efficiency of 1.8 ± 0.2%. The increase in VOC is attributed to a significant reduction in the diode reverse saturation current upon annealing.

  1. Rapid thermal annealing and modulation-doping effects on InAs/GaAs quantum dots photoluminescence dependence on excitation power

    Energy Technology Data Exchange (ETDEWEB)

    Chaâbani, W. [Laboratoire Matériaux-Molécules et Applications, Institut Préparatoire aux Etudes Scientifiques et Techniques, Université de Carthage, La Marsa 2070 (Tunisia); Melliti, A., E-mail: adnenmelliti@yahoo.fr [Laboratoire Matériaux-Molécules et Applications, Institut Préparatoire aux Etudes Scientifiques et Techniques, Université de Carthage, La Marsa 2070 (Tunisia); Maaref, M.A. [Laboratoire Matériaux-Molécules et Applications, Institut Préparatoire aux Etudes Scientifiques et Techniques, Université de Carthage, La Marsa 2070 (Tunisia); Testelin, C. [Institut des NanoSciences de Paris, UPMC Univ., Paris 06, UMR 7588, F-75005 Paris (France); CNRS, UMR 7588, INSP, F-75005 Paris (France); Lemaître, A. [Laboratoire de Photonique et Nanostructures (LPN), CNRS, Route de Nozay, F-91460 Marcoussis (France)

    2016-07-15

    The optical properties of p-doped and annealed InAs/GaAs quantum dots (QDs) was investigated by photoluminescence (PL) as a function of temperature and excitation power density (P{sub exc}). At low-T, PL spectra of rapid thermal annealing (RTA) and p-modulation doped QDs show an energy blueshift and redshift, respectively. A superlinear dependence of integrated PL intensity on P{sub exc} at high-T was found only for undoped QD. The superlinearity was suppressed by modulation-doping and RTA effects. A linear dependence of I{sub PL} at all temperatures and a decrease of the carrier-carrier Coulomb interaction at high-T was found after RTA.

  2. Perpendicular Structure Formation of Block Copolymer Thin Films during Thermal Solvent Vapor Annealing: Solvent and Thickness Effects

    Directory of Open Access Journals (Sweden)

    Qiuyan Yang

    2017-10-01

    Full Text Available Solvent vapor annealing of block copolymer (BCP thin films can produce a range of interesting morphologies, especially when the perpendicular orientation of micro-domains with respect to the substrate plays a role. This, for instance, allows BCP thin films to serve as useful templates for nanolithography and hybrid materials preparation. However, precise control of the arising morphologies is essential, but in most cases difficult to achieve. In this work, we investigated the solvent and thickness effects on the morphology of poly(styrene-b-2 vinyl pyridine (PS-b-P2VP thin films with a film thickness range from 0.4 L0 up to 0.8 L0. Ordered perpendicular structures were achieved. One of the main merits of our work is that the phase behavior of the ultra-high molecular weight BCP thin films, which hold a 100-nm sized domain distance, can be easily monitored via current available techniques, such as scanning electron microscope (SEM, atomic force microscope (AFM, and transmission electron microscope (TEM. Systematic monitoring of the self-assembly behavior during solvent vapor annealing can thus provide an experimental guideline for the optimization of processing conditions of related BCP films systems.

  3. Co-Ir interface alloying induced by thermal annealing

    Science.gov (United States)

    Carlomagno, I.; Drnec, J.; Scaparro, A. M.; Cicia, S.; Vlaic, S.; Felici, R.; Meneghini, C.

    2016-11-01

    Using angular resolved X-ray Photoelectron Spectroscopy (XPS), Magneto Optic Kerr Effect (MOKE) and X-ray Absorption Spectroscopy (XAS), we characterize the structural and magnetic evolution upon annealing of two thin Co films (8 and 9 Monolayers) deposited on Ir(111). The XAS data collected in the near Co K edge region (XANES), interpreted with ab-initio simulations, show that intermixing takes place at the Co-Ir interface. Using a linear combination analysis, we follow the intermixing during the thermally driven diffusion process. At 500 °C, the interface between Co and Ir(111) roughens slightly, but no alloy formation is detected. At 600 °C, the Co film loses integrity and MOKE data show a rearrangement of the magnetic domains. Annealing to higher temperatures results in CoxIr1 - x alloy formation and Ir segregation on the surface.

  4. Thermal annealing of junctions with amorphous and polycrystalline ferromagnetic electrodes

    Science.gov (United States)

    Dimopoulos, T.; Gieres, G.; Wecker, J.; Wiese, N.; Sacher, M. D.

    2004-12-01

    In this work we study Al-oxide-based tunnel junctions with amorphous Co60Fe20B20 and polycrystalline Co90Fe10 ferromagnetic (FM) electrodes. Focus is given on the evolution of the tunnel magnetoresistance and barrier characteristics (resistance-area product, effective thickness, height, and asymmetry) as a function of the annealing temperature up to 400°C. Junctions with two CoFeB electrodes show the largest thermal stability of the tunnel magnetoresistance. Substituting firstly one and then both CoFeB electrodes with CoFe leads to an increasingly faster degradation of the spin-dependent transport upon annealing. The observed differences suggest an improved interface quality between the amorphous FM and the Al oxide.

  5. Evolution of nano-structures of silver due to rapid thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Mondal, Shyamal, E-mail: shyamal.mondal@saha.ac.in; Bhattacharyya, S. R., E-mail: shyamal.mondal@saha.ac.in [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata-700064 (India)

    2014-04-24

    This report deals with rapid thermal annealing (RTA) effect on continuous silver film on Si(100) substrate. For this purpose silver films of different thicknesses were deposited and subsequently annealed at 500 and 800 °C. The as-deposited and annealed samples were investigated by scanning electron microscope (SEM). Formations of different nano-structures have been observed. Fragmentation of formed nanoislands also observed at temperature below melting temperature.

  6. Effect of thermal annealing on electron spin relaxation of beryllium-doped In0.8Ga0.2As0.45P0.55 bulk

    Directory of Open Access Journals (Sweden)

    Hao Wu

    2016-08-01

    Full Text Available The effect of thermal annealing on the electron spin relaxation of beryllium-doped In0.8Ga0.2As0.45P0.55 bulk was investigated by time-resolved spin-dependent pump and probe reflection measurement with a high time resolution of 200 fs. Three similar InGaAsP samples were examined one of which was annealed at 800 °C for 1 s, one was annealed at 700 °C for 1 s and the other was not annealed after crystal growth by molecular beam epitaxy. Although the carrier lifetimes of the 700 °C-annealed sample and the unannealed sample were similar, that of the 800 °C-annealed sample was extended to 11.6 (10.4 ns at 10 (300 K, which was more than two (four times those of the other samples. However, interestingly the spin relaxation time of the 800 °C-annealed sample was found to be similar to those of the other two samples. Particularly at room temperature, the spin relaxation times are 143 ps, 147 ps, and 111 ps for the 800 °C-annealed sample, 700 °C-annealed sample, and the unannealed sample, respectively.

  7. Effect of thermal annealing on electron spin relaxation of beryllium-doped In{sub 0.8}Ga{sub 0.2}As{sub 0.45}P{sub 0.55} bulk

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Hao; Harasawa, Ryo; Yasue, Yuya; Aritake, Takanori; Jiang, Canyu; Tackeuchi, Atsushi, E-mail: atacke@waseda.jp [Department of Applied Physics, Waseda University, Shinjuku, Tokyo 169-8555 (Japan); Ji, Lian; Lu, Shulong [Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Dushu Lake Higher Education Town, Ruoshui Road 398, Suzhou Industrial Park, Suzhou (China)

    2016-08-15

    The effect of thermal annealing on the electron spin relaxation of beryllium-doped In{sub 0.8}Ga{sub 0.2}As{sub 0.45}P{sub 0.55} bulk was investigated by time-resolved spin-dependent pump and probe reflection measurement with a high time resolution of 200 fs. Three similar InGaAsP samples were examined one of which was annealed at 800 °C for 1 s, one was annealed at 700 °C for 1 s and the other was not annealed after crystal growth by molecular beam epitaxy. Although the carrier lifetimes of the 700 °C-annealed sample and the unannealed sample were similar, that of the 800 °C-annealed sample was extended to 11.6 (10.4) ns at 10 (300) K, which was more than two (four) times those of the other samples. However, interestingly the spin relaxation time of the 800 °C-annealed sample was found to be similar to those of the other two samples. Particularly at room temperature, the spin relaxation times are 143 ps, 147 ps, and 111 ps for the 800 °C-annealed sample, 700 °C-annealed sample, and the unannealed sample, respectively.

  8. Advanced phase change composite by thermally annealed defect-free graphene for thermal energy storage.

    Science.gov (United States)

    Xin, Guoqing; Sun, Hongtao; Scott, Spencer Michael; Yao, Tiankai; Lu, Fengyuan; Shao, Dali; Hu, Tao; Wang, Gongkai; Ran, Guang; Lian, Jie

    2014-09-10

    Organic phase change materials (PCMs) have been utilized as latent heat energy storage and release media for effective thermal management. A major challenge exists for organic PCMs in which their low thermal conductivity leads to a slow transient temperature response and reduced heat transfer efficiency. In this work, 2D thermally annealed defect-free graphene sheets (GSs) can be obtained upon high temperature annealing in removing defects and oxygen functional groups. As a result of greatly reduced phonon scattering centers for thermal transport, the incorporation of ultralight weight and defect free graphene applied as nanoscale additives into a phase change composite (PCC) drastically improve thermal conductivity and meanwhile minimize the reduction of heat of fusion. A high thermal conductivity of the defect-free graphene-PCC can be achieved up to 3.55 W/(m K) at a 10 wt % graphene loading. This represents an enhancement of over 600% as compared to pristine graphene-PCC without annealing at a comparable loading, and a 16-fold enhancement than the pure PCM (1-octadecanol). The defect-free graphene-PCC displays rapid temperature response and superior heat transfer capability as compared to the pristine graphene-PCC or pure PCM, enabling transformational thermal energy storage and management.

  9. The effect of the rapid thermal annealing on the interdiffusion and the reaction at the interface of the binary system Cr/Si

    Energy Technology Data Exchange (ETDEWEB)

    Merabet, A. [Laboratoire Physique et Mecanique des Materiaux Metalliques, Departement d' O.M.P., Faculte des Sciences de l' Ingenieur, Universite de Setif, Setif 19000 (Algeria)]. E-mail: merabet_abdelali@yahoo.fr

    2004-12-15

    In order to understand the growth mechanism of the silicides and the effect of the dopant on the electrical activity, a thin layer of chromium (100 nm) is deposited on the single crystal silicon (1 0 0) substrate implanted (10{sup 15} As{sup +} atoms/cm{sup 2}, 100 keV) and non implanted. Afterwards, we performed a rapid thermal annealing in the interval of temperature (450-600 deg. C) for a fixed duration of 45 s. The samples are analyzed by X ray-diffraction (XRD) and Rutherford backscattering spectrometry (RBS). The electrical activity has been investigated by the method of the four-point probes. The analysis of the samples by XRD and RBS showed that the rapid thermal annealing (RTA) leads to a reaction at the interface Cr/Si inducing the formation and the growth of the unique silicide CrSi{sub 2}. It is also established that the kinetics growth of CrSi{sub 2} presents a linear evolution with temperature. This fact shows that the growth is governed by a chemical reaction of the interface. Sheet resistance measurements have been performed to study the electrical behavior for these structures. It is worth to point out that the presence of the implanted arsenic in the single crystal silicon increased the resistance in a significant manner.

  10. Effect of thermal annealing on structural properties of GeSn thin films grown by molecular beam epitaxy

    Science.gov (United States)

    Zhang, Z. P.; Song, Y. X.; Li, Y. Y.; Wu, X. Y.; Zhu, Z. Y. S.; Han, Y.; Zhang, L. Y.; Huang, H.; Wang, S. M.

    2017-10-01

    GeSn alloy with 7.68% Sn concentration grown by molecular beam epitaxy has been rapidly annealed at different temperatures from 300°C to 800°C. Surface morphology and roughness annealed below or equal to 500°C for 1 min have no obvious changes, while the strain relaxation rate increasing. When the annealing temperature is above or equal to 600°C, significant changes occur in surface morphology and roughness, and Sn precipitation is observed at 700°C. The structural properties are analyzed by reciprocal space mapping in the symmetric (004) and asymmetric (224) planes by high resolution X-ray diffraction. The lateral correlation length and the mosaic spread are extracted for the epi-layer peaks in the asymmetric (224) diffraction. The most suitable annealing temperature to improve both the GeSn lattice quality and relaxation rate is about 500°C.

  11. Rapid thermal annealing and crystallization mechanisms study of silicon nanocrystal in silicon carbide matrix

    Directory of Open Access Journals (Sweden)

    Wan Zhenyu

    2011-01-01

    Full Text Available Abstract In this paper, a positive effect of rapid thermal annealing (RTA technique has been researched and compared with conventional furnace annealing for Si nanocrystalline in silicon carbide (SiC matrix system. Amorphous Si-rich SiC layer has been deposited by co-sputtering in different Si concentrations (50 to approximately 80 v%. Si nanocrystals (Si-NC containing different grain sizes have been fabricated within the SiC matrix under two different annealing conditions: furnace annealing and RTA both at 1,100°C. HRTEM image clearly reveals both Si and SiC-NC formed in the films. Much better "degree of crystallization" of Si-NC can be achieved in RTA than furnace annealing from the research of GIXRD and Raman analysis, especially in high-Si-concentration situation. Differences from the two annealing procedures and the crystallization mechanism have been discussed based on the experimental results.

  12. Thermal Performance of an Annealed Pyrolytic Graphite Solar Collector

    Science.gov (United States)

    Jaworske, Donald A.; Hornacek, Jennifer

    2002-01-01

    A solar collector having the combined properties of high solar absorptance, low infrared emittance, and high thermal conductivity is needed for applications where solar energy is to be absorbed and transported for use in minisatellites. Such a solar collector may be used with a low temperature differential heat engine to provide power or with a thermal bus for thermal switching applications. One concept being considered for the solar collector is an Al2O3 cermet coating applied to a thermal conductivity enhanced polished aluminum substrate. The cermet coating provides high solar absorptance and the polished aluminum provides low infrared emittance. Annealed pyrolytic graphite embedded in the aluminum substrate provides enhanced thermal conductivity. The as-measured thermal performance of an annealed pyrolytic graphite thermal conductivity enhanced polished aluminum solar collector, coated with a cermet coating, will be presented.

  13. Solution-processed n-type fullerene field-effect transistors prepared using CVD-grown graphene electrodes: improving performance with thermal annealing.

    Science.gov (United States)

    Jeong, Yong Jin; Yun, Dong-Jin; Jang, Jaeyoung; Park, Seonuk; An, Tae Kyu; Kim, Lae Ho; Kim, Se Hyun; Park, Chan Eon

    2015-03-07

    Solution-processed organic field effect transistors (OFETs), which are amenable to facile large-area processing methods, have generated significant interest as key elements for use in all-organic electronic applications aimed at realizing low-cost, lightweight, and flexible devices. The low performance levels of n-type solution-processed bottom-contact OFETs unfortunately continue to pose a barrier to their commercialization. In this study, we introduced a combination of CVD-grown graphene source/drain (S/D) electrodes and fullerene (C60) in a solution-processable n-type semiconductor toward the fabrication of n-type bottom-contact OFETs. The C60 coating in the channel region was achieved by modifying the surface of the oxide gate dielectric layer with a phenyl group-terminated self-assembled monolayer (SAM). The graphene and phenyl group in the SAMs induced π-π interactions with C60, which facilitated the formation of a C60 coating. We also investigated the effects of thermal annealing on the reorganization properties and field-effect performances of the overlaying solution-processed C60 semiconductors. We found that thermal annealing of the C60 layer on the graphene surface improved the crystallinity of the face-centered cubic (fcc) phase structure, which improved the OFET performance and yielded mobilities of 0.055 cm(2) V(-1) s(-1). This approach enables the realization of solution-processed C60-based FETs using CVD-grown graphene S/D electrodes via inexpensive and solution-process techniques.

  14. Thermal Annealing Effect on Structural, Morphological, and Sensor Performance of PANI-Ag-Fe Based Electrochemical E. coli Sensor for Environmental Monitoring

    Directory of Open Access Journals (Sweden)

    Norshafadzila Mohammad Naim

    2015-01-01

    Full Text Available PANI-Ag-Fe nanocomposite thin films based electrochemical E. coli sensor was developed with thermal annealing. PANI-Ag-Fe nanocomposite thin films were prepared by oxidative polymerization of aniline and the reduction process of Ag-Fe bimetallic compound with the presence of nitric acid and PVA. The films were deposited on glass substrate using spin-coating technique before they were annealed at 300°C. The films were characterized using XRD, UV-Vis spectroscopy, and FESEM to study the structural and morphological properties. The electrochemical sensor performance was conducted using I-V measurement electrochemical impedance spectroscopy (EIS. The sensitivity upon the presence of E. coli was measured in clean water and E. coli solution. From XRD analysis, the crystallite sizes were found to become larger for the samples after annealing. UV-Vis absorption bands for samples before and after annealing show maximum absorbance peaks at around 422 nm–424 nm and 426 nm–464 nm, respectively. FESEM images show the diameter size for nanospherical Ag-Fe alloy particles increases after annealing. The sensor performance of PANI-Ag-Fe nanocomposite thin films upon E. coli cells in liquid medium indicates the sensitivity increases after annealing.

  15. Thermal Annealing Effect on Structural, Morphological, and Sensor Performance of PANI-Ag-Fe Based Electrochemical E. coli Sensor for Environmental Monitoring.

    Science.gov (United States)

    Mohammad Naim, Norshafadzila; Abdullah, H; Umar, Akrajas Ali; Abdul Hamid, Aidil; Shaari, Sahbudin

    2015-01-01

    PANI-Ag-Fe nanocomposite thin films based electrochemical E. coli sensor was developed with thermal annealing. PANI-Ag-Fe nanocomposite thin films were prepared by oxidative polymerization of aniline and the reduction process of Ag-Fe bimetallic compound with the presence of nitric acid and PVA. The films were deposited on glass substrate using spin-coating technique before they were annealed at 300 °C. The films were characterized using XRD, UV-Vis spectroscopy, and FESEM to study the structural and morphological properties. The electrochemical sensor performance was conducted using I-V measurement electrochemical impedance spectroscopy (EIS). The sensitivity upon the presence of E. coli was measured in clean water and E. coli solution. From XRD analysis, the crystallite sizes were found to become larger for the samples after annealing. UV-Vis absorption bands for samples before and after annealing show maximum absorbance peaks at around 422 nm-424 nm and 426 nm-464 nm, respectively. FESEM images show the diameter size for nanospherical Ag-Fe alloy particles increases after annealing. The sensor performance of PANI-Ag-Fe nanocomposite thin films upon E. coli cells in liquid medium indicates the sensitivity increases after annealing.

  16. Effect of thermal annealing on scintillation properties of Ce:Gd{sub 2}Y{sub 1}Ga{sub 2.7}Al{sub 2.3}O{sub 12} under different atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chao; Ding, Dongzhou; Wu, Yuntao; Li, Huanying; Chen, Xiaofeng; Shi, Jian; Wang, Qingqing; Ye, Le; Ren, Guohao [Chinese Academy of Sciences, Shanghai Institute of Ceramics, Shanghai (China)

    2017-05-15

    Cerium-doped 1% Ce:Gd{sub 2}Y{sub 1}Ga{sub 2.7}Al{sub 2.3}O{sub 12}(GYGAG) single crystal samples grown via Czochralski method were annealed under air, O{sub 2} and N{sub 2} atmospheres from 350 to 1400 C. The X-ray excited luminescence spectra, energy spectra and UV as well as thermally stimulated luminescence (TSL) spectra were performed comparatively on ''as-grown'' and thermally annealed samples. It was found that the luminescence efficiency after annealing in air and O{sub 2} was significantly enhanced compared to the non-annealed samples and this phenomenon was suggested to be caused by the existence of some oxygen vacancies in the Ce:GYGAG crystals. And the oxygen vacancies in the as-grown GYGAG crystals can be effectively eliminated by means of annealing in O{sub 2} containing atmosphere without changing the luminescence mechanism. From the TSL curves before and after annealing, three traps within 77-650 K were found to be related to oxygen vacancies. (orig.)

  17. Effects of thermal annealing on the optical, spectroscopic, and structural properties of tris (8-hydroxyquinolinate) gallium films grown on quartz substrates

    Energy Technology Data Exchange (ETDEWEB)

    Muhammad, Fahmi Fariq, E-mail: fahmi982@gmail.com [Low Dimensional Materials Research Center, Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Department of Physics, Faculty of Science and Engineering, University of Koya, Koya, Kurdistan Region (Iraq); Sulaiman, Khaulah [Low Dimensional Materials Research Center, Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2011-10-03

    Highlights: {yields} Achieving a broad absorption band for Gaq3 covering the whole UV and some parts of visible spectra. {yields} Increasing photoluminescence emission to five times stronger than that of pristine film. {yields} Conformational changes towards the formation of crystalline {alpha}-Gaq3 polymorph. {yields} Determination of glass transition temperature for Gaq3 (T{sub g} 182 deg. C) and Alq3 (T{sub g} = 173 deg. C). {yields} Improving and understanding the physical properties of Gaq3 film by means of thermal treatment. - Abstract: In this study we report the optical, spectroscopic, and structural properties of vacuum deposited tris (8-hydroxyquinolinate) gallium film upon thermal annealing in the temperature range from 85 deg. C to 255 deg. C under a flowing nitrogen gas for 10 min. The optical UV-vis-NIR and luminescence spectroscopy measurements were performed to estimate the absorption bands, optical energy gap (E{sub g}), and photoluminescence (PL) of the films. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) techniques were used to probe the spectroscopic and structural nature of the films. We show that, by annealing the films from 85 deg. C to 235 deg. C, it is possible to achieve an enhanced absorption and increased photoluminescence to five times stronger than that of the pristine film. The PL quenching at 255 deg. C was attributed to the presence of plainer chains allow easy going for excitons to a long distance due to the crystalline region formation of {alpha}-Gaq3 polymorph. The reduction in E{sub g} and infrared absorption bands upon annealing were referred to the enhancement in {pi}-{pi} interchain interaction and conformational changes by re-arrangement of the Gaq3 quinolinate ligands, respectively. Stokes shift for the films were observed and calculated. From the differential scanning calorimetry, DSC measurements, higher glass transition temperature was observed for Gaq3 (T{sub g} = 182 deg. C) compared to

  18. Study of a Thermal Annealing Approach for Very High Total Dose Environments

    Science.gov (United States)

    Dhombres, S.; Michez, A.; Boch, J.; Saigné, F.; Beauvivre, S.; Kraehenbuehl, D.; Vaillé, J.-R.; Adell, P. C.; Lorfèvre, E.; Ecoffet, R.; Roig, F.

    2014-12-01

    Total dose effect remains one challenging issue for electronics systems intended to space applications. For high total dose missions, like Jupiter missions, or for scientific instruments for which functionality and precision must be guaranteed, dose effect is one of the main drawbacks. So, new solutions must be found in order to ensure the reliability of the mission. In this paper, an analysis of a thermal annealing approach is done. This approach consists of applying isothermal annealing cycles to a device such that its electrical characteristics can be regenerated after being degraded by total ionizing dose. The analysis is based on experimental results obtained on Power MOSFET and CMOS APS imager. The impact of electric field during annealing is also investigated. It is shown that thermal annealing can be applied to electronic devices in order to extend their lifetime.

  19. Effects of thickness and annealing condition on magnetic properties and thermal stabilities of Ta/Nd/NdFeB/Nd/Ta sandwiched films

    Science.gov (United States)

    Liu, Wen-Feng; Zhang, Min-Gang; Zhang, Ke-Wei; Zhang, Hai-Jie; Xu, Xiao-Hong; Chai, Yue-Sheng

    2016-11-01

    Ta/Nd/NdFeB/Nd/Ta sandwiched films are deposited by magnetron sputtering on Si (100) substrates, and subsequently annealed in vacuum at different temperatures for different time. It is found that both the thickness of NdFeB and Nd layer and the annealing condition can affect the magnetic properties of Ta/Nd/NdFeB/Nd/Ta films. Interestingly, the thickness and annealing temperature show the relevant behaviors that can affect the magnetic properties of the film. The high coercivity of 24.1 kOe (1 Oe = 79.5775 A/m) and remanence ratio (remanent magnetization/saturation magnetization) of 0.94 can be obtained in a Ta/Nd(250 nm)/NdFeB(600 nm)/Nd(250 nm)/Ta film annealed for 3 min at 1023 K. In addition, the thermal stability of the film is also linked to the thickness of NdFeB and Nd layer and the annealing temperature as well. The excellent thermal stability can be achieved in a Ta/Nd(250 nm)/NdFeB(600 nm)/Nd(250 nm)/Ta film annealed at 1023 K. Program supported by the National Natural Science Foundation of China (Grant No. 51305290), the Higher Education Technical Innovation Project of Shanxi Province, China (Grant No. 2013133), the Fund Program for the Scientific Activities of Selected Returned Overseas Professionals of Shanxi Province, China (Grant No. 2015003), and the Program for the Key Team of Scientific and Technological Innovation of Shanxi Province, China (Grant No. 2013131009).

  20. Effect of thermal annealing on the optical and electrical properties of boron doped a-SiO{sub x}:H for thin-film silicon solar cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jinjoo [College of Information and Communication Engineering, Sungkyunkwan University, Suwon, 440-746 (Korea, Republic of); Shin, Chonghoon [Department of Energy Science, Sungkyunkwan University, Suwon, 440-746 (Korea, Republic of); Lee, Sunwha [College of Information and Communication Engineering, Sungkyunkwan University, Suwon, 440-746 (Korea, Republic of); Applied Optics and Energy Research Group, Korea Institute of Industrial Technology, Oryong-dong 1110-9, Buk-ku, Gwangju 506-824 (Korea, Republic of); Kim, Sunbo; Jung, Junhee; Balaji, Nagarajan [Department of Energy Science, Sungkyunkwan University, Suwon, 440-746 (Korea, Republic of); Dao, Vinh Ai; Lee, Youn-Jung [College of Information and Communication Engineering, Sungkyunkwan University, Suwon, 440-746 (Korea, Republic of); Yi, Junsin, E-mail: yi@yurim.skku.ac.kr [College of Information and Communication Engineering, Sungkyunkwan University, Suwon, 440-746 (Korea, Republic of)

    2015-07-31

    The p-type layer in a p-i-n thin-film solar cell plays a crucial role in determining efficiency. The requirements for p-type layer films are high optical band gap (E{sub g}), narrow valence band tail to minimize optical absorption, high dark conductivity, and low activation energy to reduce the parasitic series resistance of the solar cell. We investigated the effects of temperature during film growth and post-deposition thermal annealing on the optical and electronic properties of p-type amorphous silicon oxide films (p-a-SiO{sub x}:H) for thin-film silicon solar cell applications. The activation energy of thermally annealed p-a-SiO{sub x}:H film prepared at low substrate temperature decreased from 0.72 eV to 0.56 eV with similar E{sub g}. Our improvements are explained in the changed ratio of conjugation with the three- and four-fold coordinated boron atoms by the shift of the B (1 s) X-ray photoelectron spectrum. Taking into account the reversible electrical change by thermal annealing while maintaining high optical properties, we propose necessary process-procedure conditions for obtaining high photovoltaic performance in thin-film-Si solar cells with high-quality p-a-SiO{sub x}:H. We carried out device modeling of p-i-n junction amorphous silicon solar cells by employing a thermal annealing effect on p-type a-SiO{sub x}:H layer, using an advanced semiconductor analysis simulator. Due to reduced E{sub a} with high E{sub g} of p-type a-SiO{sub x}:H layer after thermal annealing, the solar cell performance of the open circuit voltage, fill factor, and conversion efficiency improved by 11.1%, 60.42%, and 53.75%, respectively. - Highlights: • We investigated the effects thermal annealing on p-a-SiO{sub x}:H films. • The E{sub a} property of annealed p-a-SiO{sub x}:H film prepared at low temperature decreased. • The simulated performance of solar cell with annealed p-type a-SiO{sub x}:H improved.

  1. Thermal annealing of femtosecond laser written structures in silica glass

    NARCIS (Netherlands)

    Witcher, J.J.; Reichman, W.B.; Fletcher, L.B.; Troy, N.W.; Krol, D.M.

    2013-01-01

    We have investigated the thermal stability of femtosecond laser modification inside fused silica. Raman and FL spectroscopy show that fs-laser induced non-bridging oxygen hole center (NBOHC) defects completely disappear at 300 °C, whereas changes in Si-O ring structures only anneal out after heat

  2. Photothermal deflection technique investigation of annealing temperature and time effects on optical and thermal conductivity of V/V2O5 alternating layers structure

    Science.gov (United States)

    Khalfaoui, A.; Ilahi, S.; Abdel-Rahman, M.; Zia, M. F.; Alduraibi, M.; Ilahi, B.; Yacoubi, N.

    2017-10-01

    The VxOy material is fabricated by alternating multilayer of V/V2O5. Two sets of VxOy are presented annealed at 300 °C and 400 °C for 20, 30 and 40 min. We have determined optical absorption spectra of the two sets by comparison between experimental and theoretical PDS amplitude signal. In fact, a variation of the bandgap energy from 2.34eV to 2.49 eV has found for both set annealed at 300 °C and 400 °C for various annealing time. The variation of bandgap energy is discussed testifying a structural and compositional change. Moreover, thermal conductivity of the set annealed at 400 °C showed a variation from 1.96 W/m K to 6.2 W/m K noting a decrease up to 2.89 W/m K for that annealed for 30 min.

  3. Enhanced bolometric properties of TiO2-x thin films by thermal annealing

    Science.gov (United States)

    Ashok Kumar Reddy, Y.; Shin, Young Bong; Kang, In-Ku; Lee, Hee Chul; Sreedhara Reddy, P.

    2015-07-01

    The effect of thermal annealing on the bolometric properties of TiO2-x films was investigated. The test-patterned TiO2-x samples were annealed at 300 °C temperature in order to enhance their structural and electrical properties for effective infrared image sensor device applications. The crystallinity was changed from amorphous to rutile/anatase in annealed TiO2-x films. Compared to the as-deposited samples, a decrement of the band gap and a decrease of the electrical resistivity were perceived in annealed samples. We found that the annealed samples show linear current-voltage (I-V) characteristic performance, which implies that ohmic contact was well formed at the interface between the TiO2-x and the Ti electrode. Moreover, the annealed TiO2-x sample had a significantly low 1/f noise parameter (1.21 × 10-13) with a high bolometric parameter (β) value compared to those of the as-deposited samples. As a result, the thermal annealing process can be used to prepare TiO2-x film for a high-performance bolometric device.

  4. The effect of low temperature thermal annealing on the magnetic properties of Heusler Ni–Mn–Sn melt-spun ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Llamazares, J.L. Sánchez, E-mail: jose.sanchez@ipicyt.edu.mx [Instituto Potosino de Investigación Científica y Tecnológica A.C., Camino a la Presa San José 2055, Col. Lomas 4a, San Luis Potosí S.L.P. 78216, México (Mexico); Quintana-Nedelcos, A. [Instituto Potosino de Investigación Científica y Tecnológica A.C., Camino a la Presa San José 2055, Col. Lomas 4a, San Luis Potosí S.L.P. 78216, México (Mexico); Marmara University, Department of Material and Metalurgy Eng., Kadıkoy 34777, Istanbul (Turkey); Ríos-Jara, D. [Instituto Potosino de Investigación Científica y Tecnológica A.C., Camino a la Presa San José 2055, Col. Lomas 4a, San Luis Potosí S.L.P. 78216, México (Mexico); Sánchez-Valdes, C.F. [Instituto Potosino de Investigación Científica y Tecnológica A.C., Camino a la Presa San José 2055, Col. Lomas 4a, San Luis Potosí S.L.P. 78216, México (Mexico); Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, AP 14, Ensenada 22860, Baja California, México (Mexico); and others

    2016-03-01

    We report the effect of low temperature vacuum annealing (823 K; 550 °C) on the elemental chemical composition, structural phase transition temperatures, phase structure, and magnetic properties of Ni{sub 50.6}Mn{sub 36.3}Sn{sub 13.1} as-solidified ribbons. Their elemental chemical composition, highly oriented columnar-like microstructure and single-phase character (L2{sub 1}-type crystal structure for austenite) remain unchanged after this low temperature annealing. Annealed ribbons show a reduction of interatomic distances which lead to a small change in the characteristic phase transition temperatures (~3–6 K) but to a significant rise of ~73 and 63% in the saturation magnetization of the martensite and austenite phases, respectively, that can be strictly ascribed to the strengthening of ferromagnetic interactions due to the change in interatomic distances. - Highlights: • We study the effect of low temperature annealing on Ni{sub 50.6}Mn{sub 36.3}Sn{sub 13.1} melt-spun ribbons. • Low temperature annealing preserves the crystal structure, composition and microstructure of the ribbons. • Low temperature annealing reduces the cell volume. • The strengthening of the ferromagnetic exchange interaction significant increases σ{sub S}.

  5. Effects of rapid thermal annealing on two-dimensional delocalized electronic states of the epitaxial N δ-doped layer in GaAs

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Yasuhiro; Harada, Yukihiro; Baba, Takeshi; Kaizu, Toshiyuki; Kita, Takashi [Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501 (Japan)

    2016-03-14

    We have conducted rapid thermal annealing (RTA) for improving the two-dimensional (2D) arrangement of electronic states in the epitaxial nitrogen (N) δ-doped layer in GaAs. RTA rearranged the N-pair configurations in the GaAs (001) plane and reduced the number of non-radiative recombination centers. Furthermore, a Landau shift, representing the 2D delocalized electronic states in the (001) plane, was observed at around zero magnetic field intensity in the Faraday configuration.

  6. Nano structure evolution in P3HT:PC61BM blend films due to the effects of thermal annealing or by adding solvent

    Science.gov (United States)

    Fan, Xing; Zhao, Su-Ling; Chen, Yu; Zhang, Jie; Yang, Qian-Qian; Gong, Wei; Yuan, Meng-Yao; Xu, Zheng; Xu, Xu-Rong

    2015-07-01

    Crystallographic dynamics of blend films of regioregular poly(3-hexylthiophene) (P3HT) mixed with [6-6-]-phenyl-C61-butyric acid methyl ester (PC61BM) treated by thermal annealing or by adding solvent 1,8-diiodooctane (DIO) are characterized by 2D-grazing incidence x-ray diffraction (2D-GIXRD). The results show that the P3HT chains are primarily oriented with the thiophene ring edge-on to the substrate, with a small fraction of chains oriented plane-on. The interplanar spacing becomes narrow after being treated by DIO, and the coherence length of the P3HT crystallites increases after being treated by thermal annealing or DIO, which is accompanied by a change in the orientation angle of the P3HT lamellae. The increased ordering of P3HT packing induced by thermal annealing or adding DIO contributes to enhanced photovoltaic performance. Project supported by the National Natural Science Foundation of China (Grant Nos. 51272022 and 11474018), the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20120009130005), and the Fundamental Research Funds for the Central Universities of China (Grant No. 2012JBZ001).

  7. Thermalization, Freeze-out, and Noise: Deciphering Experimental Quantum Annealers

    Science.gov (United States)

    Marshall, Jeffrey; Rieffel, Eleanor G.; Hen, Itay

    2017-12-01

    By contrasting the performance of two quantum annealers operating at different temperatures, we address recent questions related to the role of temperature in these devices and their function as "Boltzmann samplers." Using a method to reliably calculate the degeneracies of the energy levels of large-scale spin-glass instances, we are able to estimate the instance-dependent effective temperature from the output of annealing runs. Our results corroborate the "freeze-out" picture which posits two regimes, one in which the final state corresponds to a Boltzmann distribution of the final Hamiltonian with a well-defined "effective temperature" determined at a freeze-out point late in the annealing schedule, and another regime in which such a distribution is not necessarily expected. We find that the output distributions of the annealers do not, in general, correspond to a classical Boltzmann distribution for the final Hamiltonian. We also find that the effective temperatures at different programing cycles fluctuate greatly, with the effect worsening with problem size. We discuss the implications of our results for the design of future quantum annealers to act as more-effective Boltzmann samplers and for the programing of such annealers.

  8. Characterization of the ion-amorphization process and thermal annealing effects on third generation SiC fibers and 6H-SiC

    Directory of Open Access Journals (Sweden)

    Huguet-Garcia Juan

    2015-01-01

    Full Text Available The objective of the present work is to study the irradiation effects on third generation SiC fibers which fulfill the minimum requisites for nuclear applications, i.e. Hi-Nicalon type S, hereafter HNS, and Tyranno SA3, hereafter TSA3. With this purpose, these fibers have been ion-irradiated with 4 MeV Au ions at room temperature and increasing fluences. Irradiation effects have been characterized in terms of micro-Raman Spectroscopy and Transmission Electron Microscopy and compared to the response of the as-irradiated model material, i.e. 6H-SiC single crystals. It is reported that ion-irradiation induces amorphization in SiC fibers. Ion-amorphization kinetics between these fibers and 6H-SiC single crystals are similar despite their different microstructures and polytypes with a critical amorphization dose of ∼3 × 1014 cm−2 (∼0.6 dpa at room temperature. Also, thermally annealing-induced cracking is studied via in situ Environmental Scanning Electron Microscopy. The temperatures at which the first cracks appear as well as the crack density growth rate increase with increasing heating rates. The activation energy of the cracking process yields 1.05 eV in agreement with recrystallization activation energies of ion-amorphized samples.

  9. The kinetics of swelling in block copolymer thin films during ``solvo-microwave'' and solvo-thermal annealing: The effect of vapour pressure

    Science.gov (United States)

    Mokarian-Tabari, Parvanrh; Collins, Timothy; Cummins, Cian; Delgado Simão, Claudia; Sotomayor, Clivia; Morris, Michael A.

    2015-03-01

    Long annealing time associated with high chi block copolymers is a major disadvantage for their integration in industrial applications. Microwave-assisted microphase separation appears to offer considerable benefits in reducing annealing times for BCPs. However, despite the promise of this technique, little is known about the mechanism of how microwave irradiation might sponsor the molecular motion that accompanies microphase separation. In our earlier work we carried out an in situ temperature measurement during ``solvo-microwave'' annealing of poly(styrene-b-lactic acid) (PS- b-PLA) in presence of THF and also in the conventional oven. Comparing the results indicated that vapour pressure of THF might have a major role to achieve fast self- assembly (60 seconds) in PS- b-PLA film. Here, we study the kinetics of swelling by monitoring the pressure through in situ pressure experiments during ``solvo-microwave'' and solvo-thermal annealing. The preliminary data suggest that the rate at which the THF pressure increases is the key factor. This suggests that kinetics, i.e., the rate of film swelling and diffusion, affects the order and the coherence length of the pattern. We estimated the defect density in the patterns by our recently developed defect analysis software.

  10. Nitrogen Gas Flow Ratio and Rapid Thermal Annealing Temperature Dependences of Sputtered Titanium Nitride Gate Work Function and Their Effect on Device Characteristics

    Science.gov (United States)

    Liu, Yongxun; Hayashida, Tetsuro; Matsukawa, Takashi; Endo, Kazuhiko; Masahara, Meishoku; O'uchi, Shinich; Sakamoto, Kunihiro; Ishii, Kenichi; Tsukada, Junichi; Ishikawa, Yuki; Yamauchi, Hiromi; Ogura, Atsushi; Suzuki, Eiichi

    2008-04-01

    A sputtered titanium nitride (TiN) metal gate has systematically been investigated, and the dependences of TiN work function (φTiN) and device performance on nitrogen gas flow ratio [RN=N2/(N2+Ar)] in sputtering and rapid thermal annealing (RTA) temperature (TR) are clarified. It is experimentally found that φTiN slightly decreases from 4.87 to 4.78 eV with increasing RN from 17 to 83%, and it markedly decreases with increasing TR. The analysis of the electrical characteristics of fabricated metal-oxide-semiconductor field-effect transistors (MOSFETs) shows that the optimal RN range is 17-50%, and a higher RN offers a lower Vth owing to the lower φTiN. The origin of φTiN decrease with increasing RN and TR is discussed. The obtained results indicate that φTiN can be controlled by sputtering and RTA conditions, and are very useful for setting the appropriate Vth for lightly doped channel devices such as a FinFET.

  11. Dating thermal events at Cerro Prieto using fission track annealing

    Energy Technology Data Exchange (ETDEWEB)

    Sanford, S.J.; Elders, W..

    1981-01-01

    Data from laboratory experiments and geologic fading studies were compiled from published sources to produce lines of iso-annealing for apatite in time-temperature space. Fission track ages were calculated for samples from two wells at Cerro Prieto, one with an apparently simple and one with an apparently complex thermal history. Temperatures were estimated by empirical vitrinite reflectance geothermometry, fluid inclusion homogenization and oxygen isotope equilibrium. These estimates were compared with logs of measured borehole temperatures.

  12. Thermal annealing of natural, radiation-damaged pyrochlore

    Energy Technology Data Exchange (ETDEWEB)

    Zietlow, Peter; Mihailova, Boriana [Hamburg Univ. (Germany). Dept. of Earth Sciences; Beirau, Tobias [Hamburg Univ. (Germany). Dept. of Earth Sciences; Stanford Univ., CA (United States). Dept. of Geological Sciences; and others

    2017-03-01

    Radiation damage in minerals is caused by the α-decay of incorporated radionuclides, such as U and Th and their decay products. The effect of thermal annealing (400-1000 K) on radiation-damaged pyrochlores has been investigated by Raman scattering, X-ray powder diffraction (XRD), and combined differential scanning calorimetry/thermogravimetry (DSC/TG). The analysis of three natural radiation-damaged pyrochlore samples from Miass/Russia [6.4 wt% Th, 23.1.10{sup 18} α-decay events per gram (dpg)], Panda Hill/Tanzania (1.6 wt% Th, 1.6.10{sup 18} dpg), and Blue River/Canada (10.5 wt% U, 115.4.10{sup 18} dpg), are compared with a crystalline reference pyrochlore from Schelingen (Germany). The type of structural recovery depends on the initial degree of radiation damage (Panda Hill 28%, Blue River 85% and Miass 100% according to XRD), as the recrystallization temperature increases with increasing degree of amorphization. Raman spectra indicate reordering on the local scale during annealing-induced recrystallization. As Raman modes around 800 cm{sup -1} are sensitive to radiation damage (M. T. Vandenborre, E. Husson, Comparison of the force field in various pyrochlore families. I. The A{sub 2}B{sub 2}O{sub 7} oxides. J. Solid State Chem. 1983, 50, 362, S. Moll, G. Sattonnay, L. Thome, J. Jagielski, C. Decorse, P. Simon, I. Monnet, W. J. Weber, Irradiation damage in Gd{sub 2}Ti{sub 2}O{sub 7} single crystals: Ballistic versus ionization processes. Phys. Rev. 2011, 84, 64115.), the degree of local order was deduced from the ratio of the integrated intensities of the sum of the Raman bands between 605 and 680 cm{sup -1} divided by the sum of the integrated intensities of the bands between 810 and 860 cm{sup -1}. The most radiation damaged pyrochlore (Miass) shows an abrupt recovery of both, its short- (Raman) and long-range order (X-ray) between 800 and 850 K, while the weakly damaged pyrochlore (Panda Hill) begins to recover at considerably lower temperatures (near 500 K

  13. Rapid thermal annealing effect on the spatial resistivity distribution of AZO thin films deposited by pulsed-direct-current sputtering for solar cells applications

    Energy Technology Data Exchange (ETDEWEB)

    Ayachi, Boubakeur, E-mail: boubakeur.ayachi@ed.univ-lille1.fr [Institute of Electronics, Microelectronics and Nanotechnology, Lille 1 University, Avenue Poincaré, UMR 8520, CS 60069, Villeneuve d’Ascq 59652 (France); Aviles, Thomas [CROSSLUX, Avenue Georges Vacher, ZI Rousset Peynier, Immeuble CCE, Rousset 13106 (France); Vilcot, Jean-Pierre [Institute of Electronics, Microelectronics and Nanotechnology, Lille 1 University, Avenue Poincaré, UMR 8520, CS 60069, Villeneuve d’Ascq 59652 (France); Sion, Cathy [Institute of Electronics, Microelectronics and Nanotechnology, Lille 1 University, Avenue Poincaré, UMR 8520, CS 60069, Villeneuve d’Ascq 59652 (France); Ecole Centrale Lille, Cité Scientifique – CS20048, Villeneuve d’Ascq 59651 (France)

    2016-03-15

    Graphical abstract: - Highlights: • High quality pulsed-DC sputtered AZO thin films were obtained after RTA treatment. • RTA for 30 s was sufficient to achieve uniform spatial resistivity distribution. • RTA for longer than 1 min showed a small increase in resistivity value. • Such improvement was attributed to grain boundaries passivation and doping activation. • In the framework of low cost solar cells development, RTA process would be helpful. - Abstract: Room temperature deposited aluminium-doped zinc oxide thin films on glass substrate, using pulsed-DC magnetron sputtering, have shown high optical transmittance and low electrical resistivity with high uniformity of its spatial distribution after they were exposed to a rapid thermal annealing process at 400 °C under N{sub 2}H{sub 2} atmosphere. It is particularly interesting to note that such an annealing process of AZO thin films for only 30 s was sufficient, on one hand to improve their optical transmittance from 73% to 86%, on the other hand to both decrease their resistivity from 1.7 × 10{sup −3} Ω cm to 5.1 × 10{sup −4} Ω cm and achieve the highest uniformity spatial distribution. To understand the mechanisms behind such improvements of the optoelectronic properties, electrical, optical, structural and morphological changes as a function of annealing time have been investigated by using hall measurement, UV–visible spectrometry, X-ray diffraction and scanning electron microscope imaging, respectively.

  14. Thermal annealing effect on structural and thermoelectric properties of hexagonal Bi2Te3 nanoplate thin films by drop-casting technique

    Science.gov (United States)

    Hosokawa, Yuichi; Wada, Kodai; Tanaka, Masaki; Tomita, Koji; Takashiri, Masayuki

    2018-02-01

    High-purity hexagonal bismuth telluride (Bi2Te3) nanoplates were prepared by a solvothermal synthesis method, followed by the fabrication of nanoplate thin films by the drop-casting technique. The Bi2Te3 nanoplates exhibited a single-crystalline phase with a rhombohedral crystal structure. The nanoplates had a flat surface with edge sizes ranging from 500 to 2000 nm (average size of 1000 nm) and a thickness of less than 50 nm. The resulting Bi2Te3 nanoplate thin films were composed of well-aligned hexagonal nanoplates along the surface direction with an approximate film thickness of 40 µm. To tightly connect the nanoplates together within the thin films, thermal annealing was performed at different temperatures. We found that the thermoelectric properties, especially the Seebeck coefficient, were very sensitive to the annealing temperature. Finally, the optimum annealing temperature was determined to be 250 °C and the Seebeck coefficient and power factor were ‑300 µV/K and 3.5 µW/(cm·K2), respectively.

  15. Positron annihilation studies on reactor irradiated and thermal annealed ferrocene

    Energy Technology Data Exchange (ETDEWEB)

    Marques Netto, A. [Laboratorio de Espectroscopia de Aniquilacao de Positrons-LEAP, Depto. de Quimica, ICEX, Univ. Federal de Minas Gerais-UFMG, Belo Horizonte, MG (Brazil); Carvalho, R.S. [Laboratorio de Espectroscopia de Aniquilacao de Positrons-LEAP, Depto. de Quimica, ICEX, Univ. Federal de Minas Gerais-UFMG, Belo Horizonte, MG (Brazil); Magalhaes, W.F. [Laboratorio de Espectroscopia de Aniquilacao de Positrons-LEAP, Depto. de Quimica, ICEX, Univ. Federal de Minas Gerais-UFMG, Belo Horizonte, MG (Brazil); Sinisterra, R.D. [Laboratorio de Espectroscopia de Aniquilacao de Positrons-LEAP, Depto. de Quimica, ICEX, Univ. Federal de Minas Gerais-UFMG, Belo Horizonte, MG (Brazil)

    1996-10-01

    Retention and thermal annealing following (n, {gamma}) reaction in solid ferrocene, Fe(C{sub 5}H{sub 5}){sub 2}, were studied by positron annihilation lifetime spectroscopy (PAL). Positronium (Ps) formation was observed in the non-irradiated compound with a probability or intensity (I{sub 3}) of 30%. Upon irradiation of the compound with thermal neutrons in a nuclear reactor, I{sub 3} decreases with increasing irradiation time. Thermal treatment again increases I{sub 3} values from 16% to 25%, revealing an important proportion of molecular reformation without variation of the ortho-positronium lifetime ({tau}{sub 3}). These results point out the major influence of the electronic structure as determining the Ps yields in the pure complex. In the irradiated and non irradiated complexes the results are satisfactorily explained on the basis of the spur model. (orig.)

  16. Study of the effect of thermal annealing on the optical and electrical properties of vacuum evaporated amorphous thin films in the system Ge20Te80-xBix

    Science.gov (United States)

    Bhatia, K. L.; Kishore, Nawal; Malik, Jitender; Singh, Mahender; Kundu, R. S.; Sharma, Ashwani; Srivastav, B. K.

    2002-03-01

    We systematically studied the effect of thermal annealing on the optical and electrical properties of amorphous semiconducting thin films in the system Ge20Te80-xBix (x = 0, 0.19, 2.93, 7.35) prepared by flash evaporation in a vacuum of 1 × 10-6 Torr. The films are characterized by x-ray diffraction (XRD) and electron probe micro analysis. The annealing temperature is kept at 150 °C, 180 °C and 220 °C. No crystallization of the thin films is achieved on annealing up to the temperature of 150 °C. At a higher temperature of annealing, microcrystals of Te, Bi2Te3, Ge-Te, etc, are observed along with an amorphous phase as indicated by XRD analysis. The fundamental optical absorption edge and reflection spectra of as-prepared and annealed films are determined. Optical interband transitions are observed for various films (as-prepared and annealed). The presence of crystalline Bi2Te3 in films annealed at 220 °C is also supported by the reflection spectrum. The optical energy gap (Eg), the slope parameter (Δ) of the absorption edge and the tailing parameter (B-1) of the energy band tails are computed from the optical data. The dc electrical conductivity (σdc) of various films is studied in the temperature range of 150-450 K. We observe that two types of conduction take place: conduction through extended states in the higher temperature region, and conduction through localized states in the band tails and at the Fermi level by the hopping process assisted by phonons at lower temperatures. The data at higher temperatures have been fitted with the expression σdc = σ0exp(-ΔE/kT) and the electrical parameters, ΔE and σ0, are also determined. It is observed that the bismuth concentration and annealing temperature dependences of the optical and electrical parameters are different in the two regions of compositions, x ≤ 2.93 and x > 2.93, indicating structural differences in the two sets of compositions. It is pointed out that the bulk form of these amorphous

  17. Self-Healing Thermal Annealing: Surface Morphological Restructuring Control of GaN Nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Conroy, Michele; Li, Haoning; Zubialevich, Vitaly Z.; Kusch, Gunnar; Schmidt, Michael; Collins, Timothy; Glynn, Colm; Martin, Robert W.; O’Dwyer, Colm; Morris, Michael D.; Holmes, Justin D.; Parbrook, Peter J.

    2016-12-07

    With advances in nanolithography and dry etching, top-down methods of nanostructuring have become a widely used tool for improving the efficiency of optoelectronics. These nano dimensions can offer various benefits to the device performance in terms of light extraction and efficiency, but often at the expense of emission color quality. Broadening of the target emission peak and unwanted yellow luminescence are characteristic defect-related effects due to the ion beam etching damage, particularly for III–N based materials. In this article we focus on GaN based nanorods, showing that through thermal annealing the surface roughness and deformities of the crystal structure can be “self-healed”. Correlative electron microscopy and atomic force microscopy show the change from spherical nanorods to faceted hexagonal structures, revealing the temperature-dependent surface morphology faceting evolution. The faceted nanorods were shown to be strain- and defect-free by cathodoluminescence hyperspectral imaging, micro-Raman, and transmission electron microscopy (TEM). In-situ TEM thermal annealing experiments allowed for real time observation of dislocation movements and surface restructuring observed in ex-situ annealing TEM sampling. This thermal annealing investigation gives new insight into the redistribution path of GaN material and dislocation movement post growth, allowing for improved understanding and in turn advances in optoelectronic device processing of compound semiconductors.

  18. Rapid thermal annealing of FePt and FePt/Cu thin films

    Energy Technology Data Exchange (ETDEWEB)

    Brombacher, Christoph

    2011-01-10

    Chemically ordered FePt is one of the most promising materials to reach the ultimate limitations in storage density of future magnetic recording devices due to its high uniaxial magnetocrystalline anisotropy and a corrosion resistance superior to rare-earth based magnets. In this study, FePt and FePt/Cu bilayers have been sputter deposited at room temperature onto thermally oxidized silicon wafers, glass substrates and self-assembled arrays of spherical SiO{sub 2} particles with diameters down to 10 nm. Millisecond flash lamp annealing, as well as conventional rapid thermal annealing was employed to induce the phase transformation from the chemically disordered A1 phase into the chemically ordered L1{sub 0} phase. The influence of the annealing temperature, annealing time and the film thickness on the ordering transformation and (001) texture evolution of FePt films with near equiatomic composition was studied. Whereas flash lamp annealed FePt films exhibit a polycrystalline morphology with high chemical L1{sub 0} order, rapid thermal annealing can lead to the formation of chemically ordered FePt films with (001) texture on amorphous SiO{sub 2}/Si substrates. The resultant high perpendicular magnetic anisotropy and large coercivities up to 40 kOe are demonstrated. Simultaneously to the ordering transformation, rapid thermal annealing to temperatures exceeding 600 C leads to a break up of the continuous FePt film into separated islands. This dewetting behavior was utilized to create regular arrays of FePt nanostructures on SiO{sub 2} particle templates with periods down to 50 nm. The addition of Cu improves the (001) texture formation and chemical ordering for annealing temperatures T{sub a} {<=}600 C. In addition, the magnetic anisotropy and the coercivity of the ternary FePtCu alloy can be effectively tailored by adjusting the Cu content. The prospects of FePtCu based exchange spring media, as well as the magnetic properties of FePtCu nanostructures fabricated

  19. Preparation of Reduced Graphene Oxide:ZnO Hybrid Cathode Interlayer Using In Situ Thermal Reduction/Annealing for Interconnecting Nanostructure and Its Effect on Organic Solar Cell.

    Science.gov (United States)

    Zheng, Ding; Huang, Wei; Fan, Pu; Zheng, Yifan; Huang, Jiang; Yu, Junsheng

    2017-02-08

    A novel hybrid cathode interlayer (CIL) consisting of reduced graphene oxide and zinc oxide (ZnO) is realized in the inverted organic solar cells (OSCs). A dual-nozzle spray coating system and facile one-step in situ thermal reduction/annealing (ITR/ITA) method are introduced to precisely control the components of the CIL, assemble ZnO with graphene oxide, and reduce graphene oxide into in situ thermal reduced graphene oxide (IT-RGO), simultaneously. The ZnO:IT-RGO hybrid CIL shows high electric conductivity, interconnecting nanostructure, and matched energy level, which leads to a significant enhancement in the power conversion efficiency from 6.16% to 8.04% for PTB7:PC71BM and from 8.02% to 9.49% for PTB7-Th:PC71BM-based OSCs, respectively. This newly developed spray-coated ZnO:IT-RGO hybrid CIL based on one-step ITR/ITA treatment has the high potential to provide a facile pathway to fabricate the large-scale, fast fabrication, and high performance OSCs.

  20. Formation and Device Application of Ge Nanowire Heterostructures via Rapid Thermal Annealing

    OpenAIRE

    Tang, Jianshi; Wang, Chiu-Yen; Xiu, Faxian; Zhou, Yi; Chen, Lih-Juann; Wang, Kang L.

    2011-01-01

    We reviewed the formation of Ge nanowire heterostructure and its field-effect characteristics by a controlled reaction between a single-crystalline Ge nanowire and Ni contact pads using a facile rapid thermal annealing process. Scanning electron microscopy and transmission electron microscopy demonstrated a wide temperature range of 400~500°C to convert the Ge nanowire to a single-crystalline Ni2Ge/Ge/Ni2Ge nanowire heterostructure with atomically sharp interfaces. More importantly, we studie...

  1. Enhanced bulk heterojunction devices prepared by thermal and solvent vapor annealing processes

    Energy Technology Data Exchange (ETDEWEB)

    Forrest, Stephen R.; Thompson, Mark E.; Wei, Guodan; Wang, Siyi

    2017-09-19

    A method of preparing a bulk heterojunction organic photovoltaic cell through combinations of thermal and solvent vapor annealing are described. Bulk heterojunction films may prepared by known methods such as spin coating, and then exposed to one or more vaporized solvents and thermally annealed in an effort to enhance the crystalline nature of the photoactive materials.

  2. Laser thermal annealing of Ge, optimized for highly activated dopants and diode ION/IOFF ratios

    DEFF Research Database (Denmark)

    Shayesteh, M.; O'Connell, D.; Gity, F.

    2014-01-01

    The authors compared the influence of laser thermal annealing (LTA) and rapid thermal annealing (RTA) on dopant activation and electrical performance of phosphorus and arsenic doped n+/p junction. High carrier concentration above 1020 cm-3 as well as an ION/IOFF ratio of approximately 105 and ide...

  3. Thermal annealing study on P3HT: PCBM based bulk heterojunction organic solar cells using impedance spectroscopy

    Science.gov (United States)

    Gollu, Sankara Rao; Sharma, Ramakant; G, Srinivas; Gupta, Dipti

    2014-10-01

    Recently, Thermal annealing is an important process for bulk heterojunction organic solar cells (BHJ OSCs) to improve the device efficiency and performance of the organic solar cells. Here in, we have examined the changes in the efficiency and morphology of P3HT: PCBM film according to the thermal annealing temperature to find the changes during the annealing process by measuring the optical absorption, atomic force microscope and X-ray diffraction. We also investigated the effect of different annealing process conditions (without, pre- and post-annealing) on the device performance of the inverted bulk heterojunction organic solar cells consist the structure of ITO/ ZnO / P3HT: PCBM / MoO3/ Al by measuring AC impedance characteristics. Particularly, the power conversion efficiency (PCE), crystalline nature of the polymer, light absorption and the surface smoothness of P3HT: PCBM films are significantly improved after the annealing process. These results indicated the improvement in terms of PCE, interface smoothness between the P3HT: PCBM and MoO3 layers of the post annealed device originated from the decrease of series resistance between P3HT: PCBM layer and Al electrodes, which could be due to decrease in the effective life time of charge carriers.

  4. Effect of Secondary Annealing Process on Critical Current Density in Highly Textured Bi-2212 Superconducting System

    Science.gov (United States)

    Aksan, M. A.; Madre, M. A.; Rasekh, Sh.; Constantinescu, G.; Torres, M. A.; Diez, J. C.; Sotelo, A.; Yakinci, M. E.

    2015-09-01

    Bi-2212 samples prepared by a solid-state reaction technique have been grown from the melt using the laser floating zone method. After annealing the as-grown bars, the samples showed a good grain alignment and a high transport critical current density. Secondary annealing processes were performed on the annealed samples with the aim of producing Bi-2212 phase controlled decomposition. Hence, the Bi-2201 phase and the secondary phases, which act as effective pinning centers, were obtained with the secondary annealing process. After these thermal treatments, the transport critical current densities of samples significantly increased, when compared to the annealed ones. The maximum critical current density was achieved when the samples were subjected to secondary annealing at 680°C for 168 h with an improvement of ~80%, compared to the annealed ones. Moreover, it was found that magnetization of the secondarily annealed samples was also increased. The magnetic critical current densities in these secondary annealed samples were about 3 times higher than the values obtained for the annealed ones. These results clearly indicate that the secondary annealing processes lead to the formation of effective pinning centers in the bulk material.

  5. Cluster-assembled cubic zirconia films with tunable and stable nanoscale morphology against thermal annealing

    KAUST Repository

    Borghi, F.

    2016-08-05

    Nanostructured zirconium dioxide (zirconia) films are very promising for catalysis and biotechnological applications: a precise control of the interfacial properties of the material at different length scales and, in particular, at the nanoscale, is therefore necessary. Here, we present the characterization of cluster-assembled zirconia films produced by supersonic cluster beam deposition possessing cubic structure at room temperature and controlled nanoscale morphology. We characterized the effect of thermal annealing in reducing and oxidizing conditions on the crystalline structure, grain dimensions, and topography. We highlight the mechanisms of film growth and phase transitions, which determine the observed interfacial morphological properties and their resilience against thermal treatments. Published by AIP Publishing.

  6. Cluster-assembled cubic zirconia films with tunable and stable nanoscale morphology against thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Borghi, F.; Lenardi, C.; Podestà, A.; Milani, P., E-mail: pmilani@mi.infn.it [CIMAINA and Dipartimento di Fisica, Università degli Studi di Milano, via Celoria 16, 20133 Milano (Italy); Sogne, E. [CIMAINA and Dipartimento di Fisica, Università degli Studi di Milano, via Celoria 16, 20133 Milano (Italy); European School of Molecular Medicine (SEMM), IFOM-IEO, Milano (Italy); Merlini, M. [Dipartimento di Scienze della Terra “Ardito Desio”, Università degli Studi di Milano, via Mangiagalli 32, 20133 Milano (Italy); Ducati, C. [Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom)

    2016-08-07

    Nanostructured zirconium dioxide (zirconia) films are very promising for catalysis and biotechnological applications: a precise control of the interfacial properties of the material at different length scales and, in particular, at the nanoscale, is therefore necessary. Here, we present the characterization of cluster-assembled zirconia films produced by supersonic cluster beam deposition possessing cubic structure at room temperature and controlled nanoscale morphology. We characterized the effect of thermal annealing in reducing and oxidizing conditions on the crystalline structure, grain dimensions, and topography. We highlight the mechanisms of film growth and phase transitions, which determine the observed interfacial morphological properties and their resilience against thermal treatments.

  7. Implications of Thermal Annealing on the Benzene Vapor Sensing Behavior of PEVA-Graphene Nanocomposite Threads.

    Science.gov (United States)

    Patel, Sanjay V; Cemalovic, Sabina; Tolley, William K; Hobson, Stephen T; Anderson, Ryan; Fruhberger, Bernd

    2018-02-14

    The effect of thermal treatments, on the benzene vapor sensitivity of polyethylene (co-)vinylacetate (PEVA)/graphene nanocomposite threads, used as chemiresistive sensors, was investigated using DC resistance measurements, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). These flexible threads are being developed as low-cost, easy-to-measure chemical sensors that can be incorporated into smart clothing or disposable sensing patches. Chemiresistive threads were solution-cast or extruded from PEVA and resistance with successive anneals. Threads heated to ≥80 °C showed improved limits of detection, resulting from improved signal-noise, when exposed to benzene vapor in dry air. In addition, annealing increased the speed of response and recovery upon exposure to and removal of benzene vapor. DSC results showed that the presence of graphene raises the freezing point, and may allow greater crystallinity, in the nanocomposite after annealing. SEM images confirm increased surface roughness/area, which may account for the increase response speed after annealing. Benzene vapor detection at 5 ppm is demonstrated with limits of detection estimated to be as low as 1.5 ppm, reflecting an order of magnitude improvement over unannealed threads.

  8. Microstructural analysis of the thermal annealing of ice-Ih using EBSD

    Science.gov (United States)

    Hidas, Károly; Tommasi, Andréa; Mainprice, David; Chauve, Thomas; Barou, Fabrice; Montagnat, Maurine

    2017-04-01

    Rocks deformed in the middle crust and deeper in the Earth typically remain at high temperature for extended time spans after the cessation of deformation. This results in annealing of the deformation microstructure by a series of thermally activated, diffusion-based processes, namely: recovery and static recrystallization, which may also modify the crystal preferred orientation (CPO) or texture. Understanding the effects of annealing on the microstructure and CPO is therefore of utmost importance for the interpretation of the microstructures and for the estimation of the anisotropy of physical properties of lower crustal and mantle rocks. Ice-Ih -the typical form of water ice on the Earth's surface, with hexagonal crystal symmetry- deforms essentially by glide of dislocations on the basal plane [1], thus it has high viscoplastic anisotropy, which induces strong heterogeneity of stresses and strains at both the intra- and intergranular scales [2-3]. This behavior makes ice-Ih an excellent analog material for silicate minerals that compose the Earth. In situ observations of the evolution of the microstructures and CPO during annealing enable the study of the interplay between the various physical processes involved in annealing (recovery, nucleation, grain growth). They also allow the analysis of the impact of the preexisting deformation microstructures on the microstructural and CPO evolution during annealing. Here we studied the evolution of the microstructure of ice-Ih during static recrystallization by stepwise annealing experiments. We alternated thermal annealing and electron backscatter diffraction (EBSD) analyses on polycrystalline columnar ice-Ih pre-deformed in uniaxial compression at temperature of -7 °C to strains of 3.0-5.2. Annealing experiments were carried out at -5 °C and -2 °C up to a maximum of 3.25 days, typically in 5-6 steps. EBSD crystal orientation maps obtained after each annealing step permit the description of microstructural changes

  9. Study the Effect of Annealing Temperature on Optical and Structural Properties of Zinc Oxide Thin Film Prepared by Thermal Chemical Vapor Deposition

    Science.gov (United States)

    Adawiah, R.; Rafaie, H. A.; Rusop, M.

    2009-06-01

    Zinc oxide (ZnO) thin films deposited on silicon and glass substrate were prepared using chemical vapor deposition (CVD) method utilizing zinc acetate dihydrate as the zinc sources. The deposited film then annealed at 300° C to 500° C for 1 hour. The optical and structural properties of ZnO thin films were characterized using photoluminescence (PL) and Scanning Electron Microscopy (SEM) respectively. SEM images show that the ZnO thin film on silicon substrate formed unique morphology of flower-like and ball-shaped structures at annealing temperature 300° C and 400° C. Increasing annealing temperature to 450° C for ZnO deposited on glass substrate had increased the grain size of particle which implies the improvement of crystalline grain of thin film. PL results observed that the defect of oxygen vacancy decreased after annealing process for films deposited on silicon substrate. The blue peak emission at 437 nm appears only on the glass substrate. Based on the highest PL intensity value, the optimum annealing temperature for silicon and glass substrate is 350° C and 450° C respectively.

  10. Effects of rapid thermal annealing on structural, chemical, and electrical characteristics of atomic-layer deposited lanthanum doped zirconium dioxide thin film on 4H-SiC substrate

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Way Foong, E-mail: wayfoong317@yahoo.com.sg [Institute of Nano Optoelectronics Research and Technology, School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia); Centre for Research Initiatives (CRI) Natural Sciences, Universiti Sains Malaysia, 11800 Penang (Malaysia); Quah, Hock Jin, E-mail: jinquah1st@hotmail.com [Institute of Nano Optoelectronics Research and Technology, School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia); Centre for Research Initiatives (CRI) Natural Sciences, Universiti Sains Malaysia, 11800 Penang (Malaysia); Lu, Qifeng, E-mail: Qifeng@liverpool.ac.uk [Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool L69 3GJ (United Kingdom); Mu, Yifei, E-mail: Y.mu@student.liverpool.ac.uk [Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool L69 3GJ (United Kingdom); Ismail, Wan Azli Wan, E-mail: azli.ismail@mimos.my [Advance Analytical Services Lab, MIMOS Wafer Fab, MIMOS Berhad, Technology Park Malaysia, 57000 Kuala Lumpur (Malaysia); Rahim, Bazura Abdul, E-mail: bazura@mimos.my [Advance Analytical Services Lab, MIMOS Wafer Fab, MIMOS Berhad, Technology Park Malaysia, 57000 Kuala Lumpur (Malaysia); Esa, Siti Rahmah, E-mail: rahmah.esa@mimos.my [Advance Analytical Services Lab, MIMOS Wafer Fab, MIMOS Berhad, Technology Park Malaysia, 57000 Kuala Lumpur (Malaysia); Kee, Yeh Yee, E-mail: yy.kee@mimos.my [Advance Analytical Services Lab, MIMOS Wafer Fab, MIMOS Berhad, Technology Park Malaysia, 57000 Kuala Lumpur (Malaysia); Zhao, Ce Zhou, E-mail: cezhou.zhao@xjtlu.edu.cn [Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool L69 3GJ (United Kingdom); Department of Electrical and Electronic Engineering, Xi’an Jiaotong-Liverpool University, Suzhou, Jiangsu 215123 (China); and others

    2016-03-01

    Graphical abstract: - Highlights: • Studies of RTA temperatures on La doped ZrO2 atomic layer deposited on 4HSiC. • Oxygen vacancies improved insulating and catalytic properties of La doped ZrO2. • 700 °C annealed sample showed the highest EB, k value, and sensitivity on O2. • La doped ZrO2 was proposed as a potential metal reactive oxide on 4H-SiC. - Abstract: Effects of rapid thermal annealing at different temperatures (700–900 °C) on structural, chemical, and electrical characteristics of lanthanum (La) doped zirconium oxide (ZrO{sub 2}) atomic layer deposited on 4H-SiC substrates have been investigated. Chemical composition depth profiling analysis using X-ray photoelectron spectroscopy (XPS) and cross-sectional studies using high resolution transmission electron microscopy equipped with energy dispersive X-ray spectroscopy line scan analysis were insufficient to justify the presence of La in the investigated samples. The minute amount of La present in the bulk oxide was confirmed by chemical depth profiles of time-of-flight secondary ion mass spectrometry. The presence of La in the ZrO{sub 2} lattice led to the formation of oxygen vacancies, which was revealed through binding energy shift for XPS O 1s core level spectra of Zr−O. The highest amount of oxygen vacancies in the sample annealed at 700 °C has yielded the acquisition of the highest electric breakdown field (∼ 6.3 MV/cm) and dielectric constant value (k = 23) as well as the highest current–time (I–t) sensor response towards oxygen gas. The attainment of both the insulating and catalytic properties in the La doped ZrO{sub 2} signified the potential of the doped ZrO{sub 2} as a metal reactive oxide on 4H-SiC substrate.

  11. Effective dopant activation by susceptor-assisted microwave annealing of low energy boron implanted and phosphorus implanted silicon

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Zhao; Vemuri, Rajitha N. P.; Alford, T. L., E-mail: TA@asu.edu [School of Matter, Transport, and Energy, Arizona State University, Tempe, Arizona 85287 (United States); David Theodore, N. [CHD-Fab, Freescale Semiconductor Inc., 1300 N. Alma School Rd., Chandler, Arizona 85224 (United States); Lu, Wei; Lau, S. S. [Department of Electrical Engineering, University of California, San Diego, California 92093 (United States); Lanz, A. [Department of Mathematics, Norfolk State University, Norfolk, Virginia 23504 (United States)

    2013-12-28

    Rapid processing and reduced end-of-range diffusion result from susceptor-assisted microwave (MW) annealing, making this technique an efficient processing alternative for electrically activating dopants within ion-implanted semiconductors. Sheet resistance and Hall measurements provide evidence of electrical activation. Susceptor-assisted MW annealing, of ion-implanted Si, enables more effective dopant activation and at lower temperatures than required for rapid thermal annealing (RTA). Raman spectroscopy and ion channeling analyses are used to monitor the extent of ion implantation damage and recrystallization. The presence and behavior of extended defects are monitored by cross-section transmission electron microscopy. Phosphorus implanted Si samples experience effective electrical activation upon MW annealing. On the other hand, when boron implanted Si is MW annealed, the growth of extended defects results in reduced crystalline quality that hinders the electrical activation process. Further comparison of dopant diffusion resulting from MW annealing and rapid thermal annealing is performed using secondary ion mass spectroscopy. MW annealed ion implanted samples show less end-of-range diffusion when compared to RTA samples. In particular, MW annealed P{sup +} implanted samples achieve no visible diffusion and equivalent electrical activation at a lower temperature and with a shorter time-duration of annealing compared to RTA. In this study, the peak temperature attained during annealing does not depend on the dopant species or dose, for susceptor-assisted MW annealing of ion-implanted Si.

  12. Infrared study on annealing effect on conformation of zinc stearate.

    Science.gov (United States)

    Ishioka, Tsutomu; Kiritani, Atsushi; Kojima, Takuya

    2007-04-01

    The molecular conformation and thermal transition behavior of two zinc stearate specimens, unannealed one and annealed one, were compared. The unannealed specimen has one thermal transition at 134 degrees C. Annealing was made by increasing temperature to 150 degrees C and cooling to room temperature slowly. This annealed specimen has an exothermic peak at 103 degrees C, and endothermic shoulders and a peak at 118, 124 and 131 degrees C, respectively. The observed frequencies of all bands of the unannealed specimen at room temperature are assigned to the all-trans conformation. We found new bands at 858, 823, 793, 766, 688, and 604 cm-1 for the annealed specimen. Based on the normal mode analyses, these bands are assigned to the TGT conformation at the COO end, where T means trans and G means gauche. The annealed specimen consists of almost all-trans molecule but partial molecules have the TGT conformation.

  13. Effect of non-vacuum thermal annealing on high indium content InGaN films deposited by pulsed laser deposition.

    Science.gov (United States)

    Wang, Tzu-Yu; Ou, Sin-Liang; Shen, Kun-Ching; Wuu, Dong-Sing

    2013-03-25

    InGaN films with 33% and 60% indium contents were deposited by pulsed laser deposition (PLD) at a low growth temperature of 300 °C. The films were then annealed at 500-800 °C in the non-vacuum furnace for 15 min with an addition of N(2) atmosphere. X-ray diffraction results indicate that the indium contents in these two films were raised to 41% and 63%, respectively, after annealing in furnace. In(2)O(3) phase was formed on InGaN surface during the annealing process, which can be clearly observed by the measurements of auger electron spectroscopy, transmission electron microscopy and x-ray photoelectron spectroscopy. Due to the obstruction of indium out-diffusion by forming In(2)O(3) on surface, it leads to the efficient increment in indium content of InGaN layer. In addition, the surface roughness was greatly improved by removing In(2)O(3) with the etching treatment in HCl solution. Micro-photoluminescence measurement was performed to analyze the emission property of InGaN layer. For the as-grown InGaN with 33% indium content, the emission wavelength was gradually shifted from 552 to 618 nm with increasing the annealing temperature to 800 °C. It reveals the InGaN films have high potential in optoelectronic applications.

  14. Postshock Annealing and Postannealing Shock in Equilibrated Ordinary Chondrites: Implications for the Thermal and Shock Histories of Chondritic Asteroids

    Science.gov (United States)

    Rubin, Alan E.

    2006-01-01

    In addition to shock effects in olivine, plagioclase, orthopyroxene and Ca-pyroxene, petrographic shock indicators in equilibrated ordinary chondrites (OC) include chromite veinlets, chromite-plagioclase assemblages, polycrystalline troilite, metallic Cu, irregularly shaped troilite grains within metallic Fe-Ni, rapidly solidified metal-sulfide intergrowths, martensite and various types of plessite, metal-sulfide veins, large metal and/or sulfide nodules, silicate melt veins, silicate darkening, low-Ca clinopyroxene, silicate melt pockets, and large regions of silicate melt. The presence of some of these indicators in every petrologic type-4 to -6 ordinary chondrite (OC) demonstrates that collisional events caused all equilibrated OC to reach shock stages S3-S6. Those type-4 to -6 OC that are classified as shock-stage S1 (on the basis of sharp optical extinction in olivine) underwent postshock annealing due to burial beneath materials heated by the impact event. Those type-4 to -6 OC that are classified S2 (on the basis of undulose extinction and lack of planar fractures in olivine) were shocked to stage S3-S6, annealed to stage S1 and then shocked again to stage S2. Some OC were probably shocked to stage 253 after annealing. It seems likely that many OC experienced multiple episodes of shock and annealing. Because 40Ar-39Ar chronological data indicate that MIL 99301 (LL6, Sl) was annealed approximately 4.26 Ga ago, presumably as a consequence of a major impact, it seems reasonable to suggest that other equilibrated S1 and S2 OC (which contain relict shock features) were also annealed by impacts. Because some type-6 S1 OC (e.g., Guarena, Kernouve, Portales Valley, all of which contain relict shock features) were annealed 4.44-4.45 Ga ago (during a period when impacts were prevalent and most OC were thermally metamorphosed), it follows that impact-induced annealing could have contributed significantly to OC thermal metamorphism.

  15. Effects of substrate annealing on the gold-catalyzed growth of ZnO nanostructures

    Directory of Open Access Journals (Sweden)

    Skåre Daniel

    2011-01-01

    Full Text Available Abstract The effects of thermal substrate pretreatment on the growth of Au-catalyzed ZnO nanostructures by pulsed laser deposition are investigated. C-plane sapphire substrates are annealed prior to deposition of a thin Au layer. Subsequent ZnO growths on substrates annealed above 1,200°C resulted in a high density of nanosheets and nanowires, whereas lower temperatures led to low nanostructure densities. Separate Au film annealing experiments at 700°C showed little variation in the size and density of the Au catalyst droplets with substrate annealing temperature. The observed variation in the density of nanostructures is attributed to the number of surface nucleation sites on the substrate, leading to a competition between nucleation promoted by the Au catalyst and surface nucleation sites on the rougher surfaces annealed below 1,200°C.

  16. Thermal annealing of protocrystalline a-Si:H

    NARCIS (Netherlands)

    Muller, T.F.G.; Arendse, C.J.; Halindintwali, S.; Knoesen, D.; Schropp, R.E.I.

    2011-01-01

    It proves difficult to obtain a set of protocrystalline silicon materials with different characteristics from the same deposition chamber to study the exact nature of these transition region materials. Hot-wire deposited protocrystalline silicon was thus isochronically annealed at different

  17. The stabilization of the sensitivity of TLD-100 by combined UV irradiation and thermal annealing

    Science.gov (United States)

    Necmeddin Yazýcý, A.; Öztürk, Zihni

    2001-06-01

    In this study, a new experimental annealing procedure, which is based on combined UV(253.7+/-1.2 nm) irradiation and thermal annealing (300 °C for 30 min followed by 90 °C for 6 h) is introduced to reduce the large standard deviation (8-20% between consecutive ten cycles) observed after standard annealing (400 °C for 1 h followed by 100 °C for 10 min) on the main dosimetric peak 5 of thermoluminescence dosimeter TLD-100. The results indicate that when the combined UV irradiation and thermal annealing protocol is applied, the standard deviation in the area of the main dosimetric peak 5 is reduced to less than 10% for the consecutive ten-cycle operation.

  18. Relationship between beta radiation induced thermoluminescence and thermal annealing procedures in ZrO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Rivera, T. [ESIME-IPN, Culhuacan, 04430 Mexico D.F. (Mexico); Azorin, J.; Campero, A.; Velasquez, C. [UAM-I, 09340 Mexico D.F. (Mexico); Furetta, C. [Physics Department, Rome University ' ' La Sapienza' ' , Rome (Italy)

    2004-07-01

    The influence of thermal treatment on the glow curve characteristics of undoped ZrO2 polycrystalline powder were studied in the range 700 to 1100 . The TL intensity of annealed ZrO2 powder, previously exposed to a given beta dose, submitted to different thermal treatments in the range from 700 to 1100 increases as the annealing temperature is increased. The TL glow curve of ZrO2 powder beta irradiated at absorbed doses up to 20 Gy exhibited a single peak centered at 200 . Furthermore, if the absorbed dose is increased up to 25 Gy the glow curve changes, appearing a second peak with its maximum centered at 250 . Then, it could be concluded that the TL response of ZrO2 powder is closely related to the annealing procedures and the creation of charge trapping centers corresponding to the 200 and 250 TL peaks depends on the annealing temperature. (Author)

  19. Electric field assisted thermal annealing reorganization of graphene oxide/polystyrene latex films

    Directory of Open Access Journals (Sweden)

    2011-09-01

    Full Text Available Graphene/polymer films were prepared by casting water dispersion of graphene oxide (GO in the presence of polystyrene (PS latex particles. The samples were heated up to 180°C and exposed to an external electric voltage during their annealing. We observed that for the GO/PS films deposited before the electric field assisted thermal annealing the polymer latex was embedded in the graphene sheets, while the electric field assisted thermal annealing induces a phase separation with the enrichment of the PS phase above an underlying GO layer. For the films annealed under an external electric field we have also found that as the electric current passes through the GO film, GO could be recovered to reduced GO with decreased resistance.

  20. Thermal annealing of fission tracks in fluorapatite, chlorapatite, manganoanapatite, and Durango apatite: experimental results

    Energy Technology Data Exchange (ETDEWEB)

    Ravenhurst, C.E.; Roden-Tice, M.K.; Miller, D.S. [Rensselaer Polytechnic Inst., Dept. of Earth and Environmental Sciences, Troy, New York (United States)]. E-mail: cravenhu@hotmail.com

    2003-07-01

    It is well known that the optically measured lengths of fission tracks in apatite crystals are a function of etching conditions, crystallographic orientation of the track, composition of the crystal, and the state of thermal annealing. In this study we standardize etching conditions and optimize track length measurability by etching until etch pits formed at the surface of each apatite crystal reached widths of about 0.74 {mu}m. Etching times using 5M HNO{sub 3} at 21{sup o}C were 31 s for Otter Lake, Quebec, fluorapatite; 47 s for Durango, Mexico, apatite; 33 s for Portland, Connecticut, manganoanapatite; and 11 s for Bamle, Norway, chlorapatite. An etching experiment using two etchant strengths (5M and 1.6M HNO{sub 3}) revealed that, despite significant differences in etch pit shape, fission-track length anisotropy with respect to crystallographic orientation of the tracks is not a chemical etching effect. A series of 227 constant-temperature annealing experiments were carried out on nuclear reactor induced tracks in oriented slices of the apatites. After etching, crystallographic orientations of tracks were measured along with their lengths. The 200-300 track lengths measured for each slice were ellipse-fitted to give the major (c crystallographic direction) and minor (a crystallographic direction) semi-axes used to calculate equivalent isotropic lengths. The equivalent isotropic length is more useful than mean length for thermal history analysis because the variation caused by anisotropy has been removed. Using normalized etching procedures and equivalent isotropic length data, we found that the fluorapatite anneals most readily, followed by Durango apatite, manganoanapatite, and lastly chlorapatite. (author)

  1. Structural, Optical, and Dielectric Properties of Azure B Thin Films and Impact of Thermal Annealing

    Science.gov (United States)

    Zeyada, H. M.; Zidan, H. M.; Abdelghany, A. M.; Abbas, I.

    2017-07-01

    Thin films of azure B (AB) have been prepared by thermal evaporation. Structural, optical, and dielectric characteristics of as-prepared and annealed samples were studied. AB is polycrystalline in as-synthesized powder form. Detailed x-ray diffraction studies showed amorphous structure for pristine and annealed films. Fourier-transform infrared vibrational spectroscopy indicated minor changes in molecular bonds of AB thin films either after deposition or after thermal annealing. Optical transmittance and reflection spectra of prepared thin films were studied at nearly normal light incidence in the spectral range from 200 nm to 2500 nm, showing marked changes without new peaks. Annealing increased the absorption coefficient and decreased the optical bandgap. Onset and optical energy gaps of pristine films were found to obey indirect allowed transition with values of 1.10 eV and 2.64 eV, respectively. Annealing decreased the onset and optical energy gaps to 1.0 eV and 2.57 eV, respectively. The dispersion parameters before and after annealing are discussed in terms of a single-oscillator model. The spectra of the dielectric constants ( ɛ 1, ɛ 2) were found to depend on the annealing temperature in addition to the incident photon energy.

  2. Ex Situ Thermal Cycle Annealing of Molecular Beam Epitaxy Grown HgCdTe/Si Layers

    Science.gov (United States)

    2010-01-01

    matched bulk CdZnTe substrates. Recent work6 on CdTe/Si has shown that in situ thermal cycle annealing (TCA), where annealing is performed intermittently...was grown on a bulk CdZnTe substrate for comparison. The HgCdTe was grown at 185C, with a growth rate of 2 lm/h. The typical HgCdTe layer...Cd composition. The HgCdTe layers grown on bulk CdZnTe samples, which were subjected to annealing condi- tions similar to those for the HgCdTe layers

  3. Morphology of oxygen precipitates in silicon wafers pre-treated by rapid thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Kot, D., E-mail: kot@ihp-microelectronics.com; Kissinger, G.; Schubert, M. A. [IHP, Im Technologiepark 25, 15236 Frankfurt (Oder) (Germany); Sattler, A. [Siltronic AG, Hanns-Seidel-Platz 4, 81737 München (Germany)

    2014-05-05

    The morphology of oxygen precipitates in Czochralski silicon wafers pre-treated by rapid thermal annealing (RTA) and subjected to a heat treatment in the temperature range between 800 °C and 1000 °C was investigated by scanning transmission electron microscopy. The samples were pre-treated by RTA in order to establish a defined supersaturation of vacancies. It was found that in such vacancy-rich samples subjected to an annealing at 800 °C three dimensional dendrites are formed. Until now, it was known that during annealing at 800 °C plate-like oxygen precipitates are formed.

  4. Post-irradiation annealing effects on hardness and intergranular corrosion in type 304 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Asano, Kyoichi [Tokyo Electric Power Co. Inc., Yokohama (Japan). Materials Engineering Dept.; Katsura, Ryoei; Kodama, Mitsuhiro; Nishimura, Seiji [Nippon Nuclear Fuel Development Co., Ltd., Ibaraki (Japan); Fukuya, Kouji [Toshiba Corp., Yokohama (Japan). Nuclear Engineering Lab.; Nakata, Kiyotomo [Hitachi Ltd., Ibaraki (Japan). Hitachi Research Lab.

    1995-12-31

    The effects of post-irradiation annealing on hardness and grain boundary corrosion were investigated on stainless steel irradiated to 1.2 {times} 10{sup 26}n/m{sup 2}(E > 1 MeV). A commercial purity type 304 steel sample was annealed at temperatures between 673K and 1,323K for terms between 300s and 360ks. Only a slight decrease in hardness was observed by annealing at 723K for 3.6ks, while significant recovery was observed at 923K and above. This dependence on annealing temperature reflected recovery in damage microstructures. Annealing at all temperatures resulted in improved corrosion resistance when evaluated by the HNO{sub 3}/Cr{sup 6+} test. In the oxalic acid test, Strauss test and double loop electrochemical potentiokinetic reactivation test, no significant change from as-irradiated material occurred at 723K and below regarding intergranular corrosion while at 773K to 923K, thermal sensitization was observed and the reactivation ratio was larger than in unirradiated material. Annealing at 1,173K led to the irradiation induced degradation in corrosion resistance being recovered to almost the same level as that in unirradiated material. Helium bubble formation was observed after annealing at 923K and above, however, no brittle grain boundary failure occurred through all the test procedures including post-annealing straining.

  5. Formation and Device Application of Ge Nanowire Heterostructures via Rapid Thermal Annealing

    Directory of Open Access Journals (Sweden)

    Jianshi Tang

    2011-01-01

    Full Text Available We reviewed the formation of Ge nanowire heterostructure and its field-effect characteristics by a controlled reaction between a single-crystalline Ge nanowire and Ni contact pads using a facile rapid thermal annealing process. Scanning electron microscopy and transmission electron microscopy demonstrated a wide temperature range of 400~500°C to convert the Ge nanowire to a single-crystalline Ni2Ge/Ge/Ni2Ge nanowire heterostructure with atomically sharp interfaces. More importantly, we studied the effect of oxide confinement during the formation of nickel germanides in a Ge nanowire. In contrast to the formation of Ni2Ge/Ge/Ni2Ge nanowire heterostructures, a segment of high-quality epitaxial NiGe was formed between Ni2Ge with the confinement of Al2O3 during annealing. A twisted epitaxial growth mode was observed in both two Ge nanowire heterostructures to accommodate the large lattice mismatch in the NixGe/Ge interface. Moreover, we have demonstrated field-effect transistors using the nickel germanide regions as source/drain contacts to the Ge nanowire channel. Our Ge nanowire transistors have shown a high-performance p-type behavior with a high on/off ratio of 105 and a field-effect hole mobility of 210 cm2/Vs, which showed a significant improvement compared with that from unreacted Ge nanowire transistors.

  6. A change in domain morphology in optical superlattice LiNbO sub 3 induced by thermal annealing

    CERN Document Server

    Lu Yan Qing; Luo Qi; Zhu Yong Yuan; Chen Xiang Fei; Xue Cheng Cheng; Ming Nai Ben

    1997-01-01

    Optical superlattice LiNbO sub 3 crystals were grown by the Czochralski method. The effect of thermal annealing below the Curie temperature on domain structures of a sample with good periodicity was studied. It was found that the periodic domain structure remained unchanged at annealing temperature lower than 1000 deg. C and began to deteriorate when annealed at above 1000 deg. C. A sample at 1100 deg. C for an hour almost changed to a single-domain structure except that a 60 mu m single-domain layer with reversed spontaneous polarization was formed at the edge of the sample. These results are useful for revealing the mechanism of formation of the periodic domain structure and designing a more favourable temperature field to improve the crystals' quality. A space-charge-field model was proposed to explain the phenomena. (author)

  7. Effects of rapid thermal annealing on the properties of HfO{sub 2}/La{sub 2}O{sub 3} nanolaminate films deposited by plasma enhanced atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Duo; Cheng, Xinhong, E-mail: xh-cheng@mail.sim.ac.cn; Zheng, Li; Wang, Zhongjian; Xu, Dawei; Xia, Chao; Shen, Lingyan; Wang, Qian; Yu, Yuehui [State Key Laboratory of Functional Materials for Informatics, SIMIT, Chinese Academy of Sciences, Shanghai 200050, People' s Republic of China and University of Chinese Academy of Sciences, Beijing 100049 (China); Shen, DaShen [Department of Electrical and Computer Engineering, University of Alabama in Huntsville, Huntsville, Alabama 35899 (United States)

    2015-01-15

    In this work, HfO{sub 2}/La{sub 2}O{sub 3} nanolaminate films were deposited on Si substrates by plasma enhanced atomic layer deposition with in situ plasma treatment. Different annealing treatments were adopted to change films structure and performance. The upper HfO{sub 2} layers in HfO{sub 2}/La{sub 2}O{sub 3} nanolaminates were easily crystallized after annealing at 800 °C, while all the La{sub 2}O{sub 3} layers kept amorphous. X-ray photoelectron spectroscopy results indicated that LaO(OH) and La(OH){sub 3} peaks became weak, H{sub 2}O molecules in laminates evaporated during high-temperature annealing. Band diagram analysis showed that valence band offset and band gap widened after 800 °C annealing. Annealing, especially 800 °C annealing, had gentle effect on leakage current, but could obviously change capacitance and permittivity due to tetragonal and cubic phase formed in the HfO{sub 2} film.

  8. Annealing effects on deuterium retention behavior in damaged tungsten

    Directory of Open Access Journals (Sweden)

    S. Sakurada

    2016-12-01

    Full Text Available Effects of annealing after/under iron (Fe ion irradiation on deuterium (D retention behavior in tungsten (W were studied. The D2 TDS spectra as a function of heating temperature for 0.1dpa damaged W showed that the D retention was clearly decreased as the annealing temperature was increased. In particular, the desorption of D trapped by voids was largely reduced by annealing at 1173K. The TEM observation indicated that the size of dislocation loops was clearly grown, and its density was decreased by the annealing above 573K. After annealing at 1173K, almost all the dislocation loops were recovered. The results of positron annihilation spectroscopy suggested that the density of vacancy-type defects such as voids, was decreased as the annealing temperature was increased, while its size was increased, indicating that the D retention was reduced by the recovery of the voids. Furthermore, it was found that the desorption temperature of D trapped by the voids for damaged W above 0.3dpa was shifted toward higher temperature side. These results lead to a conclusion that the D retention behavior is controlled by defect density. The D retention in the samples annealed during irradiation was less than that annealed after irradiation. This result shows that defects would be quickly annihilated before stabilization by annealing during irradiation.

  9. Epitaxial nickel and cobalt suicide formation by rapid thermal annealing

    Science.gov (United States)

    Chevallier, J.; Larsen, A. Nylandsted

    1986-02-01

    Thin films of epitaxial NiSi2 and CoSi2 were formed by short-duration incoherent light exposure of evaporated Ni or Co films on Si single crystals. The crystalline quality of these suicides is comparable to what has been obtained for long-duration furnace annealed suicides, as deduced from channeling measurements. NiSi2 is of high crystalline quality at all temperatures at which it is formed whereas the CoSi2 films recrystallize at a temperature of ˜980°C.

  10. Growth of Ni2Si by rapid thermal annealing: Kinetics and moving species

    Science.gov (United States)

    Ma, E.; Lim, B. S.; Nicolet, M.-A.; Natan, M.

    1987-10-01

    The growth kinetics is characterized and the moving species is identified for the formation of Ni2Si by Rapid Thermal Annealing (RTA) of sequentially deposited Si and Ni films on a Si substrate. The interfacial Ni2Si layer grows as the square root of time, indicating that the suicide growth process is diffusion-limited. The activation energy is 1.25±0.2 eV in the RTA temperature range of 350 450° C. The results extend those of conventional steady-state furnace annealing quite fittingly, and a common activation energy of 1.3±0.2 eV is deduced from 225° to 450° C. The marker experiment shows that Ni is the dominant moving species during Ni2Si formation by RTA, as is the case for furnace annealing. It is concluded that the two annealing techniques induce the same growth mechanisms in Ni2Si formation.

  11. Effect of isochronal annealing on phase transformation studies of ...

    Indian Academy of Sciences (India)

    Abstract. The effect of isochronal annealing on the phase transformation in iron oxide nanoparticles is reported in this work. Iron oxide ... The phase transformation is complete at annealing temperature of 442◦C as confirmed by differential ..... Han S, Yu T, Park J, Koo B, Joo J, Hyeon T, Hong S and Im J. 2004 J. Phys. Chem.

  12. Effect of isochronal annealing on phase transformation studies of ...

    Indian Academy of Sciences (India)

    The effect of isochronal annealing on the phase transformation in iron oxide nanoparticles is reported in this work. Iron oxide nanoparticles were successfully synthesized using an ash supported technique followed by annealing for 2 h at various temperatures between 300 and 700° C. It was observed using X-ray diffraction ...

  13. Modulating the morphology of hydrogel particles by thermal annealing: mixed biopolymer electrostatic complexes

    Science.gov (United States)

    Wu, Bi-cheng; McClements, David Julian

    2015-11-01

    Biopolymer hydrogel particles formed by electrostatic complexation of proteins and polysaccharides have various applications within the food and other industries, including as delivery systems for bioactive compounds, as texture modifiers, and as fat replacers. The functional attributes of these electrostatic complexes are strongly influenced by their morphology, which is determined by the molecular interactions between the biopolymer molecules. In this study, electrostatic complexes were formed using an amphoteric protein (gelatin) and an anionic polysaccharide (pectin). Gelatin undergoes a helix-to-coil transition when heated above a critical temperature, which impacts its molecular interactions and hydrogel formation. The aim of this research was to study the influence of thermal annealing on the properties of hydrogel particles formed by electrostatic complexation of gelatin and pectin. Hydrogel particles were fabricated by mixing 0.5 wt% gelatin and 0.01 wt% pectin at pH 10 (where both were negatively charged) at various temperatures, followed by acidification to pH 5 (where they have opposite charges) with controlled acidification and stirring. The gelation ({{T}\\text{g}} ) and melting temperature ({{T}\\text{m}} ) of the electrostatic complexes were measuring using a small amplitude oscillation test: {{T}\\text{g}}=26.3 °C and {{T}\\text{m}}=32.3 °C. Three annealing temperatures (5, 30 and 50 °C) corresponding to different regimes (T{{T}\\text{m}} ) were selected to control the configuration of the gelatin chain. The effects of formation temperature, annealing temperature, and incubation time on the morphology of the hydrogel particles were characterized by turbidity, static light scattering, and microscopy. The results of this study will facilitate the rational design of hydrogel particles with specific particle dimensions and morphologies, which has important implications for tailoring their functionality for various applications.

  14. Effect of annealing on the compositional modulation of InAlAsSb

    Energy Technology Data Exchange (ETDEWEB)

    Baladés, N., E-mail: nuria.balades@uca.es [INNANOMAT group, Departamento de Ciencia de los Materiales e I. M. y Q. I., Instituto Universitario de Investigación en Microscopía Electrónica y Materiales (IMEYMAT), CEIMAR, Universidad de Cádiz, 11510 Puerto Real, Cádiz (Spain); Sales, D.L.; Herrera, M.; Delgado, F.J. [INNANOMAT group, Departamento de Ciencia de los Materiales e I. M. y Q. I., Instituto Universitario de Investigación en Microscopía Electrónica y Materiales (IMEYMAT), CEIMAR, Universidad de Cádiz, 11510 Puerto Real, Cádiz (Spain); González, M. [U.S Naval Research Laboratory, 4555 Overlook Ave. SW, Washington D.C. 20375 (United States); Sotera Defense Solutions, 430 National Business Pkwy # 100, Annapolis Junction, MD 20701 (United States); Clark, K.; Pinsunkajana, P. [Intelligent Epitaxy Technology, Inc. Richardson, TX, 75801 (United States); Hoven, N.; Hubbard, S. [Rochester Institute of Technology, 85 Lomb Memorial Drive, Rochester, NY 14623 (United States); Tomasulo, S.; Walters, J.R. [U.S Naval Research Laboratory, 4555 Overlook Ave. SW, Washington D.C. 20375 (United States); Molina, S.I. [INNANOMAT group, Departamento de Ciencia de los Materiales e I. M. y Q. I., Instituto Universitario de Investigación en Microscopía Electrónica y Materiales (IMEYMAT), CEIMAR, Universidad de Cádiz, 11510 Puerto Real, Cádiz (Spain)

    2017-02-15

    Highlights: • A post-growth annealing under As overpressure over 500 °C for several minutes induces a blue-shift in the InAlAsSb emission. • TEM analysis evidences that the small compositional fluctuations of the as-grown samples disappear after being annealed. • Annealing stimulates atomic diffusion of the quaternary, homogenizing their constituents and enhancing structural quality. - Abstract: The effect of a post-growth thermal treatment in two different heterostructures with InAlAsSb as the top layer grown by molecular beam epitaxy lattice-matched to InP, have been studied by diffraction contrast transmission electron microscopy (TEM). This novel top cell layer material with application in ultra-high efficiency solar cells were grown on (001) InP substrate with or without an InGaAs buffer layer. Initial photoluminescence (PL) measurements revealed deviations from their predicted bandgap, suggesting non-random atomic distribution of the quaternary layer. Then, a thermal annealing was performed at different temperatures and times. The effect on the structure of the InAlAsSb active layer caused by the new arrangement of layers and the post-growth annealing treatments has been reported. Our results show that the small compositional fluctuations of the as-grown heterostructures disappear after being annealed, and the bandgap energy correspondingly increases towards the predicted value.

  15. Manipulating the adhesion of electroless nickel-phosphorus film on silicon wafers by silane compound modification and rapid thermal annealing

    OpenAIRE

    Hsu, Chin-Wei; Wang, Wei-Yen; Wang, Kuan-Ting; Chen, Hou-An; Wei, Tzu-Chien

    2017-01-01

    In this study, the effect of 3-2-(2-aminoethylamino) ethylamino propyl trimethoxysilane (ETAS) modification and post rapid thermal annealing (RTA) treatment on the adhesion of electroless plated nickel-phosphorus (ELP Ni-P) film on polyvinyl alcohol-capped palladium nanoclusters (PVA-Pd) catalyzed silicon wafers is systematically investigated. Characterized by pull-off adhesion, atomic force microscopy, X-ray spectroscopy and water contact angle, a time-dependent, three-staged ETAS grafting m...

  16. Structural and compositional properties of CZTS thin films formed by rapid thermal annealing of electrodeposited layers

    Science.gov (United States)

    Lehner, J.; Ganchev, M.; Loorits, M.; Revathi, N.; Raadik, T.; Raudoja, J.; Grossberg, M.; Mellikov, E.; Volobujeva, O.

    2013-10-01

    In this work Cu2ZnSnS4 (CZTS) thin films were formed by rapid thermal annealing (RTA) of sequentially electrodeposited Cu-Zn and Sn films in 5% H2S containing atmosphere. Six different thermal profiles were used in the experiments. In three of these, the temperature ramping up was varied, while the variable in the other three profiles was the cooling down rate. The optimising parameters for RTA of electrodeposited films were found and annealed films were characterised by X-ray diffraction (XRD), micro-Raman spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM+EDS). The material parameters such as lattice strain and crystallite size were also determined and the influence of annealing temperature and heating rate on these parameters was discussed.The pathway of MoS2 formation was investigated.

  17. Mathematical Simulation of Porous Glass Thermal Processes at Annealing Stage

    Science.gov (United States)

    Grushko, I. S.

    2017-11-01

    The mathematical model of the porous glass heat field under conditions of complex heat exchange in the process of the technological stage of annealing is presented. The model includes calculations of the radiation, convective and molecular components. The mathematical model is based on the finite element method. The model is realised in the software Ansys. The statement of the problem is given. The object under study, i.e., model structural features, is presented. The method of model structure obtaining, the initials and boundary conditions are given. The theoretical basis of the methods, approaches and of the optimal calculation parameters choice principles are presented. The estimation of the model adequacy by means of the experimental verification is given. The comparison of the obtained data with the experimental results is performed. The relative error of calculation using the developed model does not exceed 15%.

  18. Evolution of vertical phase separation in P3HT:PCBM thin films induced by thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Karagiannidis, P.G.; Georgiou, D.; Pitsalidis, C.; Laskarakis, A. [Lab for Thin Films-Nanosystems and Nanometrology - LTFN Department of Physics, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki (Greece); Logothetidis, S., E-mail: logot@auth.gr [Lab for Thin Films-Nanosystems and Nanometrology - LTFN Department of Physics, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki (Greece)

    2011-10-03

    Highlights: {center_dot} Investigation of distribution of P3HT and PCBM in blend films. {center_dot} Thermal annealing of P3HT:PCBM blends leading to rapid polymer crystallization. {center_dot} A demixing process resulting to accumulation of P3HT at surface. {center_dot} PCBM segregation at the bottom layers of films. {center_dot} Inappropriate morphology for electron extraction at organic metal-cathode interface. - Abstract: The achievement of the desirable morphology at the nanometer scale of bulk heterojunctions consisting of a conjugated polymer with fullerene derivatives is a prerequisite in order to optimize the power conversion efficiency of organic solar cells. The various experimental conditions such as the choice of solvent, drying rates and annealing have been found to significantly affect the blend morphology and the final performance of the photovoltaic device. In this work, we focus on the effects of post deposition thermal annealing at 140 deg. C on the blend morphology, the optical and structural properties of bulk heterojunctions that consist of poly(3-hexylthiophene) (P3HT) and a methanofullerene derivative (PCBM). The post thermal annealing modifies the distribution of the P3HT and the PCBM inside the blend films, as it has been found by Spectroscopic Ellipsometry studies in the visible to far-ultraviolet spectral range. Phase separation was identified by AFM and GIXRD as a result of a slow drying process which took place after the spin coating process. The increase of the annealing time resulted to a significant increase of the P3HT crystallinity at the top regions of the blend films.

  19. Annealing temperature effect on the optical properties of thermally oxidized nano-crystalline ZrO2 thin films grown on glass substrates

    Science.gov (United States)

    Larijani, M. M.; Hasani, E.; Safa, S.

    2014-01-01

    Optical properties of zirconium oxide films on glass substrates deposited by thermal oxidation method have been studied at different temperatures. Optical characteristics of films such as refractive index, extinction coefficient, average thickness and optical dielectric constants were calculated using Swanepoel's method. X-ray diffraction analysis (XRD) and atomic force microscopy were performed to investigate the film structure and morphology. It was found out that the optical properties of zirconium oxide films are affected by oxidation temperature which are due to changes of film microstructure and surface roughness.

  20. Rectangular nanovoids in helium-implanted and thermally annealed MgO(100)

    NARCIS (Netherlands)

    Kooi, B.J.; Veen, A. van; Hosson, J.Th.M. De; Schut, H.; Fedorov, A.V.; Labohm, F.

    2000-01-01

    Cleaved MgO(100) single crystals were implanted with 30 keV 3He ions with doses varying from 1×10^19 to 1×10^20 m-2 and subsequently thermally annealed from 100 to 1100 °C. Transmission electron microscopy observations revealed the existence of sharply rectangular nanosize voids at a depth slightly

  1. Synthesis of B–Sb by rapid thermal annealing of B/Sb multilayer films

    Indian Academy of Sciences (India)

    layer with predetermined thickness of boron and antimony and subsequently subjecting the multilayer to rapid thermal annealing. The films were characterized by measuring microstructural, optical and compositional properties. 2. Experimental. Multilayer films of B and Sb were deposited onto Si and fused silica substrates ...

  2. Magnetic structure of Fe-based amorphous and thermal annealed microwires

    Energy Technology Data Exchange (ETDEWEB)

    Olivera, J. [Depto. Fisica, Universidad de Oviedo, Calvo Sotelo s/n, 33007 Oviedo (Spain); Provencio, M. [Instituto de Ciencia de Materiales, CSIC, Cantoblanco, 28049 Madrid (Spain); Prida, V.M. [Depto. Fisica, Universidad de Oviedo, Calvo Sotelo s/n, 33007 Oviedo (Spain); Hernando, B. [Depto. Fisica, Universidad de Oviedo, Calvo Sotelo s/n, 33007 Oviedo (Spain)]. E-mail: grande@pinon.ccu.uniovi.es; Santos, J.D. [Depto. Fisica, Universidad de Oviedo, Calvo Sotelo s/n, 33007 Oviedo (Spain); Perez, M.J. [Depto. Fisica, Universidad de Oviedo, Calvo Sotelo s/n, 33007 Oviedo (Spain); Gorria, P. [Depto. Fisica, Universidad de Oviedo, Calvo Sotelo s/n, 33007 Oviedo (Spain); Sanchez, M.L. [Depto. Fisica, Universidad de Oviedo, Calvo Sotelo s/n, 33007 Oviedo (Spain); Belzunce, F.J. [Depto. Ciencia de los Materiales e Ingenieria Metalurgica, Universidad de Oviedo, Independencia 13, 33004 Oviedo (Spain)

    2005-07-15

    The magnetic structure of amorphous and thermal annealed glass coated microwires is studied by thermomagnetic, DSC, and Bitter domain pattern techniques. The long-range dipolar interaction between parallel aligned microwires and the appearance of large Barkhausen jumps steps in the axially magnetized loops are discussed in terms of reversal magnetization process.

  3. Annealing and etching effects on strain and stress sensitivity of polymer optical fibre Bragg grating sensors

    DEFF Research Database (Denmark)

    Pospori, A.; Marques, C. A.F.; Sáez-Rodríguez, D.

    2017-01-01

    Thermal annealing and chemical etching effects on the strain and stress sensitivity of polymer optical fibre based sensors are investigated. Bragg grating sensors have been photo-inscribed in PMMA optical fibre and their strain and stress sensitivity has been characterised before and after any...

  4. A helium-based model for the effects of radiation damage annealing on helium diffusion kinetics in apatite

    Science.gov (United States)

    Willett, Chelsea D.; Fox, Matthew; Shuster, David L.

    2017-11-01

    Widely used to study surface processes and the development of topography through geologic time, (U-Th)/He thermochronometry in apatite depends on a quantitative description of the kinetics of 4He diffusion across a range of temperatures, timescales, and geologic scenarios. Empirical observations demonstrate that He diffusivity in apatite is not solely a function of temperature, but also depends on damage to the crystal structure from radioactive decay processes. Commonly-used models accounting for the influence of thermal annealing of radiation damage on He diffusivity assume the net effects evolve in proportion to the rate of fission track annealing, although the majority of radiation damage results from α-recoil. While existing models adequately quantify the net effects of damage annealing in many geologic scenarios, experimental work suggests different annealing rates for the two damage types. Here, we introduce an alpha-damage annealing model (ADAM) that is independent of fission track annealing kinetics, and directly quantifies the influence of thermal annealing on He diffusivity in apatite. We present an empirical fit to diffusion kinetics data and incorporate this fit into a model that tracks the competing effects of radiation damage accumulation and annealing on He diffusivity in apatite through geologic time. Using time-temperature paths to illustrate differences between models, we highlight the influence of damage annealing on data interpretation. In certain, but not all, geologic scenarios, the interpretation of low-temperature thermochronometric data can be strongly influenced by which model of radiation damage annealing is assumed. In particular, geologic scenarios involving 1-2 km of sedimentary burial are especially sensitive to the assumed rate of annealing and its influence on He diffusivity. In cases such as basement rocks in Grand Canyon and the Canadian Shield, (U-Th)/He ages predicted from the ADAM can differ by hundreds of Ma from those

  5. Influence of mechanical milling and thermal annealing on electrical ...

    Indian Academy of Sciences (India)

    Wintec

    the cation distribution. The dielectric constant is smaller by an order of magnitude and the dielectric loss is three orders of magnitude smaller for the milled sample compared to that of the bulk. In the case of cobalt ferrite, the observed decrease in conductivity, when the grain size is increased from 8–92 nm upon thermal.

  6. Enhancement of phosphors-solubility in ZnO by thermal annealing

    Science.gov (United States)

    Mahmood, K.; Amin, N.; Ali, A.; Nabi, M. Ajaz un; Imran Arshad, M.; Zafar, M.; Asghar, M.

    2015-12-01

    We have demonstrated the effect of annealing temperature on the diffusion density of phosphors in zinc oxide. The P-dopant P430 was sprayed on ZnO pellets and annealed at different temperatures from 500 to 1000 °C with a step of 100 °C for one hour using a programmable furnace. The concentration of P was controlled by varying the annealing temperature and the maximum solubility of P (3% At) was achieved at annealing 800 °C determined by energy dispersive X-ray diffraction (EDX) measurements. X-ray diffraction (XRD) confirmed the hexagonal structure of ZnO and showed that the growth direction was along the c-axis. We observed a maximum up shift in the (002) plane at an annealing temperature of 800 °C, suggesting that P atoms replaced Zn atoms in the structure which results in the reduction of the lattice constant. Room temperature photoluminescence (PL) spectrum consists of a peak at 3.28 eV and related to band edge emission, but samples annealed at 800 and 900 °C have an additional donor acceptor pair peak at 3.2 eV. Hall effect measurements confirmed the p-type conductivity of the sample annealed at 800 °C.

  7. Influence of Rapid Thermal Annealing on the Characteristics of InGaN/GaN MQWs

    Directory of Open Access Journals (Sweden)

    Tian Yuan

    2016-01-01

    Full Text Available N-type InGaN/GaN multiple-quantum-wells (MQWs were grown on sapphire substrates by metal organic chemical vapor deposition (MOCVD. The crystal quality and optical properties of samples after rapid thermal annealing (RTA at different temperatures in a range from 400 to 800°C are investigated by X-ray diffraction (XRD and photoluminescence (PL spectrum. The experimental results show that the peaks of InGaN, InN and In can be observed in all samples. And the results are induced by the phase separation and In-clusters. The luminescence peak of the samples annealed showed a red shift. It is caused by strain stress relaxation during the RTA process. Furthermore, some defects can be eliminated and the best annealing temperature is from 500°C to 700°C.

  8. An anti-bacterial approach to nanoscale roughening of biomimetic rice-like pattern PP by thermal annealing

    Science.gov (United States)

    Jafari Nodoushan, Emad; Ebrahimi, Nadereh Golshan; Ayazi, Masoumeh

    2017-11-01

    In this paper, we introduced thermal annealing treatment as an effective way of increasing the nanoscale roughness of a semi-crystalline polymer surface. Annealing treatment applied to a biomimetic microscale pattern of rice leaf to achieve a superhydrophobic surface with a hierarchical roughness. Resulted surfaces was characterized by XRD, AFM and FE-SEM instruments and showed an increase of roughness and cristallinity within both time and temperature of treatment. These two parameters also impact on measured static contact angle up to 158°. Bacterial attachment potency has an inverse relationship with the similarity of surface pattern dimensions and bacterial size and due to that, thermal annealing could be an effective way to create anti-bacterial surface beyond its effect on water repellency. Point in case, the anti-bacterial properties of produced water-repellence surfaces of PP were measured and counted colonies of both gram-negative (E. coli) and gram-positive (S. aureus) bacteria reduced with the nature of PP and hierarchical pattern on that. Anti-bacterial characterization of the resulted surface reveals a stunning reduction in adhesion of gram-positive bacteria to the surface. S. aureus reduction rates equaled to 95% and 66% when compared to control blank plate and smooth surface of PP. Moreover, it also could affect the other type of bacteria, gram-negative (E. coli). In the latter case, adhesion reduction rates calculated 66% and 53% when against to the same controls, respectively.

  9. Thermal annealing behaviour of Pd Schottky contacts on melt-grown single crystal ZnO studied by IV and CV measurements

    Energy Technology Data Exchange (ETDEWEB)

    Mtangi, W., E-mail: wilbert.mtangi@up.ac.za [Department of Physics, University of Pretoria, Private Bag X20, Hatfield 0028 (South Africa); Auret, F.D.; Chawanda, A.; Janse van Rensburg, P.J.; Coelho, S.M.M.; Nel, J.M.; Diale, M.; Schalkwyk, L. van [Department of Physics, University of Pretoria, Private Bag X20, Hatfield 0028 (South Africa); Nyamhere, C. [Department of Physics, P.O. Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth 6031 (South Africa)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer Highly rectifying Pd/ZnO contacts have been fabricated. Black-Right-Pointing-Pointer The rectification behaviour decrease with annealing temperature. Black-Right-Pointing-Pointer The surface donor concentration increases with increase in annealing temperature. Black-Right-Pointing-Pointer The depletion layer width at a specific reverse voltage decreases with increase in annealing temperature. - Abstract: Current-voltage (IV) and capacitance-voltage (CV) measurement techniques have successfully been employed to study the effects of annealing highly rectifying Pd/ZnO Schottky contacts. IV results reveal a decrease in the contact quality with increasing annealing temperature as confirmed by a decrease in the zero bias barrier height and an increase in the reverse current measured at -1.5 V. An average barrier height of (0.77 {+-} 0.02) eV has been calculated by assuming pure thermionic emission for the as-deposited material and as (0.56 {+-} 0.03) eV after annealing at 550 Degree-Sign C. The reverse current has been measured as (2.10 {+-} 0.01) Multiplication-Sign 10{sup -10} A for the as-deposited and increases by 5 orders of magnitude after annealing at 550 Degree-Sign C to (1.56 {+-} 0.01) Multiplication-Sign 10{sup -5} A. The depletion layer width measured at -2.0 V has shown a strong dependence on thermal annealing as it decreases from 1.09 {mu}m after annealing at 200 Degree-Sign C to 0.24 {mu}m after annealing at 500 Degree-Sign C, resulting in the modification of the dopant concentration within the depletion region and hence the current flowing through the interface from pure thermionic emission to thermionic field emission with the donor concentrations increasing from 6.90 Multiplication-Sign 10{sup 15} cm{sup -3} at 200 Degree-Sign C to 6.06 Multiplication-Sign 10{sup 16} cm{sup -3} after annealing at 550 Degree-Sign C. This increase in the volume concentration has been explained as an effect of a conductive channel

  10. Thermal Annealing induced relaxation of compressive strain in porous GaN structures

    KAUST Repository

    Ben Slimane, Ahmed

    2012-01-01

    The effect of annealing on strain relaxation in porous GaN fabricated using electroless chemical etching is presented. The Raman shift of 1 cm-1 in phonon frequency of annealed porous GaN with respect to as-grown GaN corresponds to a relaxation of compressive strain by 0.41 ± 0.04 GPa. The strain relief promises a marked reduction in threading dislocation for subsequent epitaxial growth.

  11. Controlling Growth High Uniformity Indium Selenide (In2Se3) Nanowires via the Rapid Thermal Annealing Process at Low Temperature.

    Science.gov (United States)

    Hsu, Ya-Chu; Hung, Yu-Chen; Wang, Chiu-Yen

    2017-09-15

    High uniformity Au-catalyzed indium selenide (In2Se3) nanowires are grown with the rapid thermal annealing (RTA) treatment via the vapor-liquid-solid (VLS) mechanism. The diameters of Au-catalyzed In2Se3 nanowires could be controlled with varied thicknesses of Au films, and the uniformity of nanowires is improved via a fast pre-annealing rate, 100 °C/s. Comparing with the slower heating rate, 0.1 °C/s, the average diameters and distributions (standard deviation, SD) of In2Se3 nanowires with and without the RTA process are 97.14 ± 22.95 nm (23.63%) and 119.06 ± 48.75 nm (40.95%), respectively. The in situ annealing TEM is used to study the effect of heating rate on the formation of Au nanoparticles from the as-deposited Au film. The results demonstrate that the average diameters and distributions of Au nanoparticles with and without the RTA process are 19.84 ± 5.96 nm (30.00%) and about 22.06 ± 9.00 nm (40.80%), respectively. It proves that the diameter size, distribution, and uniformity of Au-catalyzed In2Se3 nanowires are reduced and improved via the RTA pre-treated. The systemic study could help to control the size distribution of other nanomaterials through tuning the annealing rate, temperatures of precursor, and growth substrate to control the size distribution of other nanomaterials. Graphical Abstract Rapid thermal annealing (RTA) process proved that it can uniform the size distribution of Au nanoparticles, and then it can be used to grow the high uniformity Au-catalyzed In2Se3 nanowires via the vapor-liquid-solid (VLS) mechanism. Comparing with the general growth condition, the heating rate is slow, 0.1 °C/s, and the growth temperature is a relatively high growth temperature, > 650 °C. RTA pre-treated growth substrate can form smaller and uniform Au nanoparticles to react with the In2Se3 vapor and produce the high uniformity In2Se3 nanowires. The in situ annealing TEM is used to realize the effect of heating rate on Au nanoparticle

  12. An efficient method combining thermal annealing and acid leaching ...

    Indian Academy of Sciences (India)

    Thus obtained silica was investigated by inductively coupled plasma atomic emission spectrometry (ICP–AES) method. Major impurities present in silica sand were Al, K, Fe, Na, Ca, Mg and B. Among the new products, almost major impurities were removed effectively. Indeed purity degree, given by characterization of ...

  13. Annealing study and thermal investigation on bismuth sulfide thin films prepared by chemical bath deposition in basic medium

    Science.gov (United States)

    Dachraoui, O.; Merino, J. M.; Mami, A.; León, M.; Caballero, R.; Maghraoui-Meherzi, H.

    2018-02-01

    Bismuth sulfide thin films were prepared by chemical bath deposition using thiourea as sulfide ion source in basic medium. First, the effects of both the deposition parameters on film growth as well as the annealing effect under argon and sulfur atmosphere on as-deposited thin films were studied. The parameters were found to be influential using the Doehlert matrix experimental design methodology. Ranges for a maximum surface mass of films (3 mg cm-2) were determined. A well-crystallized major phase of bismuth sulfide with stoichiometric composition was achieved at 190 °C for 3 h. The prepared thin films were characterized using grazing incidence X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray analysis. Second, the bandgap energy value was found to be 1.5 eV. Finally, the thermal properties have been studied for the first time by means of the electropyroelectric (EPE) technique. Indeed, the thermal conductivity varied in the range of 1.20-0.60 W m-1 K-1, while the thermal diffusivity values increased in terms of the annealing effect ranging from 1.8 to 3.5 10-7 m2 s-1.

  14. Thermal annealing study of F center clusters in LiF single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Izerrouken, M., E-mail: izerrouken@yahoo.co [Centre de Recherche Nucleaire de Draria (CRND), BP 43, Sebbala, Draria, Alger (Algeria); Guerbous, L. [Centre de Recherche Nucleaire d' Alger (CRNA), 2 Bd Frantz Fanon, BP 399, Alger gare (Algeria); Meftah, A. [LRPCSI, Universite 20 Aout 55 route d' El-Hadaik, BP 26, 21000 Skikda (Algeria)

    2010-01-21

    The present work is devoted to study the thermal annealing process of F center clusters (F{sub n}) induced in LiF single crystal under high-dose gamma-rays and high reactor neutrons fluence irradiations. With heating under argon atmosphere, the F-type center aggregates and gives rise to a new absorption band at 500 nm attributed to Li colloids. The optical density associated with F{sub 2} center observed in gamma-ray irradiated LiF decreases with increasing annealing temperature and exhibits two distinct annealing processes with activation energies E{sub 1}=0.9+-0.3 eV and E{sub 2}=1.6+-0.5 eV. Also, it is clear from the results that the F{sub 3}{sup +} and F{sub 2} emission bands positions are affected by the irradiated dose. Reactor neutrons irradiation induces large Li colloids. These colloids persist even after annealing at 450 deg. C.

  15. Improved behavior of cooper-amine complexes during thermal annealing for conductive thin film synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Ayag, Kevin Ray; Panama, Gustavo; Paul, Shrabani; Kim, Hong Doo [Dept. of Advanced Materials Engineering for Information and Electronics, Kyung Hee University, Yongin (Korea, Republic of)

    2017-02-15

    Previous studies successfully produced conductive thin films from organo-metallic-compounds-based inks. Some inks like those made from copper salt and amines, however, tend to move during thermal annealing and, thus, affect the conductive pattern on the substrate. In this study, conductive inks were synthesized by forming complexes of copper with amines and/or blended amines. To build-up an organo-metallic framework and preserve the pattern throughout the annealing period, diamine was added to the complex in different proportions. The prepared inks were coated on glass substrate and were annealed on a hot plate at 170°C under the gaseous mixture of formic acid and alcohol for 5 min. The metallic film was observed to retain the original pattern of the ink during and after annealing. Adhesion on the substrate was also improved. Inks with blended amines produced films with lower resistivities. The lowest electrical resistivity recorded was 4.99 μΩ cm, three times that of bulk copper.

  16. Interfacial Characterizations of a Nickel-Phosphorus Layer Electrolessly Deposited on a Silane Compound-Modified Silicon Wafer Under Thermal Annealing

    Science.gov (United States)

    Lai, Kuei-Chang; Wu, Pei-Yu; Chen, Chih-Ming; Wei, Tzu-Chien; Wu, Chung-Han; Feng, Shien-Ping

    2016-10-01

    Front-side metallization of a Si wafer was carried out using electroless deposition of nickel-phosphorus (Ni-P) catalyzed by polyvinylpyrrolidone-capped palladium nanoclusters (PVP-nPd). A 3-[2-(2-Aminoethylamino)ethylamino] propyl-trimethoxysilane (ETAS) layer was covalently bonded on the Si surface as bridge linker to the Pd cores of PVP-nPd clusters for improving adhesion between the Ni-P layer and the Si surface. To investigate the effects of an interfacial ETAS layer on the Ni silicide formation at the Ni-P/Si contact, the Ni-P-coated Si samples were thermally annealed via rapid thermal annealing (RTA) from 500°C to 900°C for 2 min. To compare with the ETAS sample, the sputtered Ni layer on Si and electroless Ni-P layer on ion-Pd-catalyzed Si (both are standard processes) were also investigated. The microstructural characterizations for the Ni-P or Ni layer deposited on the Si wafer were performed using x-ray diffractometer, scanning electron microscopy, and transmission electron microscopy. Our results showed that the ETAS layer acted as a barrier to slow the atomic diffusion of Ni toward the Si side. Although the formation of Ni silicides required a higher annealing temperature, the adhesion strength and contact resistivity measurements of annealed Ni-P/Si contacts showed satisfactory results, which were essential to the device performance and reliability during thermal annealing.

  17. Effect of Post-HALT Annealing on Leakage Currents in Solid Tantalum Capacitors

    Science.gov (United States)

    Teverovsky, Alexander

    2010-01-01

    Degradation of leakage currents is often observed during life testing of tantalum capacitors and is sometimes attributed to the field-induced crystallization in amorphous anodic tantalum pentoxide dielectrics. However, degradation of leakage currents and the possibility of annealing of degraded capacitors have not been investigated yet. In this work the effect of annealing after highly accelerated life testing (HALT) on leakage currents in various types of solid tantalum capacitors was analyzed. Variations of leakage currents with time during annealing at temperatures from 125 oC to 180 oC, thermally stimulated depolarization (TSD) currents, and I-V characteristics were measured to understand the conduction mechanism and the reason for current degradation. Annealing resulted in a gradual decrease of leakage currents and restored their initial values. Repeat HALT after annealing resulted in reproducible degradation of leakage currents. The observed results are explained based on ionic charge instability (drift/diffusion of oxygen vacancies) in the tantalum pentoxide dielectrics using a modified Schottky conduction mechanism.

  18. Thermally induced phase transformation in multi-phase iron oxide nanoparticles on vacuum annealing

    Science.gov (United States)

    Anupama, A. V.; Keune, W.; Sahoo, B.

    2017-10-01

    The evolution of magnetic phases in multi-phase iron oxide nanoparticles, synthesized via the transferred arc plasma induced gas phase condensation method, was investigated by X-ray diffraction, vibrating sample magnetometry and 57Fe Mössbauer spectroscopy. The particles are proposed to be consisting of three different iron oxide phases: α-Fe2O3, γ-Fe2O3 and Fe3O4. These nanoparticles were exposed to high temperature (∼935 K) under vacuum (10-3 mbar He pressure), and the thermally induced phase transformations were investigated. The Rietveld refinement of the X-ray diffraction data corroborates the least-squares fitting of the transmission Mössbauer spectra in confirming the presence of Fe3O4, γ-Fe2O3 and α-Fe2O3 phases before the thermal treatment, while only Fe3O4 and α-Fe2O3 phases exist after thermal treatment. On thermal annealing in vacuum, conversion from γ-Fe2O3 to Fe3O4 and α-Fe2O3 was observed. Interestingly, we have observed a phase transformation occurring in the temperature range ∼498 K-538 K, which is strikingly lower than the phase transformation temperature of γ-Fe2O3 to α-Fe2O3 (573-623 K) in air. Combining the results of Rietveld refinement of X-ray diffraction patterns and Mössbauer spectroscopy, we have attributed this phase transformation to the phase conversion of a metastable ;defected and strained; d-Fe3O4 phase, present in the as-prepared sample, to the α-Fe2O3 phase. Stabilization of the phases by controlling the phase transformations during the use of different iron-oxide nanoparticles is the key factor to select them for a particular application. Our investigation provides insight into the effect of temperature and chemical nature of the environment, which are the primary factors governing the phase stability, suitability and longevity of the iron oxide nanomaterials prepared by the gas-phase condensation method for various applications.

  19. Sintering and annealing effects on undoped yttria transparent ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Letue, Laetitia; Petit, Johan, E-mail: johan.petit@onera.fr; Ritti, Marie-Hélène; Lalanne, Sylvie; Landais, Stéphane

    2017-06-15

    Transparent yttrium oxide (Y{sub 2}O{sub 3}) ceramics were processed by several densifications steps without any doping species. The green bodies were obtained by the aqueous way and sintered at high temperature under vacuum and then under high pressure. We studied the effects of different sintering cycles and air annealing at different steps of the process on the density and the grain growth. We also focused on the reaction between yttria ceramics and BN-coated graphite crucible which occurs during HIP. We noted that a low heating rate and two annealing steps are necessary to improve our samples’ transparency. - Highlights: • The quality of transparent ceramics is compared with the tested process parameters. • Air annealing is critical when using a carbon environment in the process. • Intra-granular pores, and so the final transparency, are directly linked to the sintering heating rates.

  20. Rapid thermal annealing of InAs/GaAs quantum dots under a GaAs proximity cap

    Energy Technology Data Exchange (ETDEWEB)

    Babinski, Adam; Jasinski, J.; Boz(overdot)ek, R.; Szepielow, A.; Baranowski, J. M.

    2001-10-15

    The effect of postgrowth rapid thermal annealing (RTA) on GaAs proximity-capped structures with self-assembled InAs/GaAs quantum dots (QDs) is investigated using transmission electron microscopy (TEM) and photoluminescence (PL). As can be seen from the TEM images, QDs increase their lateral sizes with increasing annealing temperature (up to 700 C). QDs cannot be distinguished after RTA at temperature 800 C or higher, and substantial thickening of the wetting layer can be seen instead. The main PL peak blueshifts as a result of RTA. We propose that in the as-grown sample as well, as in samples annealed at temperatures up to 700 C, the peak is due to the QDs. After RTA at 800 C and higher the PL peak is due to a modified wetting layer. Relatively fast dissolution of QDs is explained in terms of strain-induced lateral Ga/In interdiffusion. It is proposed that such a process may be of importance in proximity-capped RTA, when no group-III vacancy formation takes place at the sample/capping interface.

  1. Effect of annealing on graphene incorporated poly-(3-hexylthiophene):CuInS2 photovoltaic device

    Science.gov (United States)

    Kumari, Anita; Singh, Inderpreet; Dixit, Shiv Kumar

    2014-10-01

    The effect of thermal annealing on the power conversion efficiency (PCE) of poly(3-hexylthiophene) (P3HT):CuInS2 quantum dot:graphene photovoltaic device has been studied by analyzing optical characteristics of composite films and electrical characteristics of the device with structure indium tin oxide/poly[ethylene dioxythiophene]:poly[styrene sulfonate] (ITO/PEDOT:PSS)/P3HT:CIS:graphene/LiF/aluminum. It was observed that after annealing at 120°C for 15 min a typical device containing 0.005 % w/w of graphene shows the best performance with a PCE of 1.3%, an open-circuit voltage of 0.44V, a short-circuit current density of 7.6 mA/cm2, and a fill factor of 0.39. It is observed that the thermal annealing considerably enhances the efficiency of solar cells. However, an annealing at higher temperature such as at 140°C results in a decrease in the device efficiency.

  2. Annealing effects on strain and stress sensitivity of polymer optical fibre based sensors

    DEFF Research Database (Denmark)

    Pospori, A.; Marques, C. A. F.; Zubel, M. G.

    2016-01-01

    The annealing effects on strain and stress sensitivity of polymer optical fibre Bragg grating sensors after their photoinscription are investigated. PMMA optical fibre based Bragg grating sensors are first photo-inscribed and then they were placed into hot water for annealing. Strain, stress...... and force sensitivity measurements are taken before and after annealing. Parameters such as annealing time and annealing temperature are investigated. The change of the fibre diameter due to water absorption and the annealing process is also considered. The results show that annealing the polymer optical...

  3. Effect of annealing atmosphere on microstructure, optical and ...

    Indian Academy of Sciences (India)

    61

    Effect of annealing atmosphere on microstructure, optical and electronic properties of spray pyrolysed ... gap energies of ZnO and ZnS lead to an unfavourable electronic properties for Zn(O,S), when used as buffer layer in ..... absorption coefficient (α) of the films was determined from the relationship, α = −. 1 d ln. T. (1−R)2.

  4. Thermal annealing behavior of deep levels in Rh-doped n-type MOVPE GaAs

    Energy Technology Data Exchange (ETDEWEB)

    Naz, Nazir A., E-mail: nazir_phys@yahoo.co [Semiconductor Physics Laboratory, Department of Physics, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Department of Applied Physics, Federal Urdu University of Arts, Science and Technology, G-7/1, Islamabad (Pakistan); Qurashi, Umar S.; Zafar Iqbal, M. [Semiconductor Physics Laboratory, Department of Physics, Quaid-i-Azam University, Islamabad 45320 (Pakistan)

    2009-12-15

    We report the results of isochronal annealing study of deep levels in Rh-doped n-type GaAs grown by metal-organic vapor phase epitaxy (MOVPE). Deep level transient spectroscopy (DLTS) technique has been employed to study the effects of annealing on deep levels in Rh-doped p{sup +}nn{sup +} junction samples. A majority-carrier emitting band of deep levels along with a high temperature peak (RhE1), corresponding to deep level energy position E{sub c}-0.92 eV and a minority-carrier emitting band of deep levels are identified with Rh-impurity prior to thermal annealing of our samples. In addition to these Rh-related deep levels, the well-known native defect EL2 at E{sub c}-0.79 eV is observed in majority-carrier emission spectra and two inadvertent deep-level defects, H1 at E{sub v}+0.09 eV and H3 at E{sub v}+0.93 eV, usually observed in reference (without Rh) samples, are also detected in the minority-carrier emission spectra of Rh-doped samples. At least one level is found to be introduced at E{sub c}-0.13 eV in Rh-doped samples at about the same temperature position as the level E(A)1, observed in reference samples, as a result of isochronal annealing, while the other two levels observed in reference samples could not be seen in annealed Rh-doped samples. Data on the annealing behavior and other characteristics of both Rh-related bands of deep levels observed in majority- and minority-carrier emission DLTS spectra, as well as for the high temperature Rh-related electron-emission peak, are presented. Possible interpretations of these results for the nature and structure of the different deep-level defects are discussed.

  5. Interrogating the Effects of Radiation Damage Annealing on Helium Diffusion Kinetics in Apatite

    Science.gov (United States)

    Willett, C. D.; Fox, M.; Shuster, D. L.

    2015-12-01

    Apatite (U-Th)/He thermochronology is commonly used to study landscape evolution and potential links between climate, erosion and tectonics. The technique relies on a quantitative understanding of (i) helium diffusion kinetics in apatite, (ii) an evolving 4He concentration, (iii) accumulating damage to the crystal lattice caused by radioactive decay[1], and (iv) the thermal annealing of such damage[2],[3], which are each functions of both time and temperature. Uncertainty in existing models of helium diffusion kinetics has resulted in conflicting conclusions, especially in settings involving burial heating through geologic time. The effects of alpha recoil damage annealing are currently assumed to follow the kinetics of fission track annealing (e.g., reference [3]), although this assumption is difficult to fully validate. Here, we present results of modeling exercises and a suite of experiments designed to interrogate the effects of damage annealing on He diffusivity in apatite that are independent of empirical calibrations of fission track annealing. We use the existing experimental results for Durango apatite[2] to develop and calibrate a new function that predicts the effects of annealing temperature and duration on measured diffusivity. We also present a suite of experiments conducted on apatite from Sierra Nevada, CA granite to establish whether apatites with different chemical compositions have the same behavior as Durango apatite. Crystals were heated under vacuum to temperatures between 250 and 500°C for 1, 10, or 100 hours. The samples were then irradiated with ~220 MeV protons to produce spallogenic 3He, the diffusant then used in step-heating diffusion experiments. We compare the results of these experiments and model calibrations to existing models. Citations: [1]Shuster, D., Flowers R., and Farley K., (2006), EPSL 249(3-4), 148-161; [2]Shuster, D. and Farley, K., (2009), GCA 73 (1), 6183-6196; [3]Flowers, R., Ketcham, R., Shuster, D. and Farley, K

  6. Electrical and structural properties of (Pd/Au) Schottky contact to as grown and rapid thermally annealed GaN grown by MBE

    Energy Technology Data Exchange (ETDEWEB)

    Nirwal, Varun Singh, E-mail: varun.nirwal30@gmail.com; Singh, Joginder; Gautam, Khyati; Peta, Koteswara Rao [Department of Electronic Science, University of Delhi South Campus, Benito Juarez Road, New Delhi-110021 (India)

    2016-05-06

    We studied effect of thermally annealed GaN surface on the electrical and structural properties of (Pd/Au) Schottky contact to Ga-polar GaN grown by molecular beam epitaxy on Si substrate. Current voltage (I-V) measurement was used to study electrical properties while X-ray diffraction (XRD) measurement was used to study structural properties. The Schottky barrier height calculated using I-V characteristics was 0.59 eV for (Pd/Au) Schottky contact on as grown GaN, which increased to 0.73 eV for the Schottky contact fabricated on 700 °C annealed GaN film. The reverse bias leakage current at -1 V was also significantly reduced from 6.42×10{sup −5} A to 7.31×10{sup −7} A after annealing. The value of series resistance (Rs) was extracted from Cheung method and the value of R{sub s} decreased from 373 Ω to 172 Ω after annealing. XRD results revealed the formation of gallide phases at the interface of (Pd/Au) and GaN for annealed sample, which could be the reason for improvement in the electrical properties of Schottky contact after annealing.

  7. Thermal annealing of lattice-matched InGaAs/InAlAs Quantum-Cascade Lasers

    Science.gov (United States)

    Mathonnière, Sylvain; Semtsiv, M. P.; Ted Masselink, W.

    2017-11-01

    We describe the evolution of optical power, threshold current, and emission wavelength of a lattice-matched InGaAs/InAlAs Quantum-Cascade Laser (QCL) emitting at 13 μm grown by gas-source molecular-beam epitaxy under thermal annealing. Pieces from the same 2-in wafer were annealed at 600 °C, 650 °C, or 700 °C for 1 h; one control piece remained unannealed. No change in threshold current and emission wavelength was observed. The slope efficiency and maximum emission power increase for the 600 °C anneal, but higher annealing temperatures resulted in degraded performance. This result stands in contrast with the observation that strain-compensated structures cannot withstand annealing temperature of 600 °C. Useful information for post-growth processing steps and the role of interface roughness in QCL performance are obtained.

  8. Exploratory Study of Irradiation, Annealing, and Reirradiation Effects on American and Russian Reactor Pressure Vessel Steels

    Energy Technology Data Exchange (ETDEWEB)

    Chernobaeva, A.A., Kryukov, A.M., Nikolaev, Y.A., Korolev, Y.N. [Russian Research Centre Kurchatov Inst., Moscow (Russian Federation)], Sokolov, M.A., Nanstad, R.K. [Oak Ridge National Lab., TN (United States)

    1997-12-31

    One of the options to mitigate the effects of irradiation on reactor pressure vessels (RPVS) is to thermally anneal them to restore the toughness properties that have been degraded by neutron irradiation. even though a postirradiation anneal may be deemed successful, a critical aspect of continued RPV operation is the rate of embrittlement upon reirradiation. There are insufficient data available to allow for verification models of reirradiation embrittlement or for the development of a reliable predictive methodology. This is especially true in the case of fracture toughness data. Under the U.S.-Russia Joint Coordinating Committee for Civilian Nuclear Reactor Safety (JCCCNRS), Working Group 3 on Radiation Embrittlement, Structural Integrity, and Life Extension of Reactor Vessels and Supports agreed to conduct a comparative study of annealing and reirradiation effects on RPV steels. The working group agreed that each side would irradiate, anneal, reirradiate (if feasible), and test two materials of the other; so far, only charpy impact and tensile specimens have been included. Oak Ridge National Laboratory (ornl) conducted such a program (irradiation and annealing) with two weld metals representative of VVER-440 AND VVER-1000 RPVS, while the Russian Research Center-Kurchatov Institute (RRC-KI) conducted a program (irradiation,annealing, reirradiation, and reannealing) with Heavy-Section Steel Technology (HSST) program plate 02 and Heavy-Section Steel Irradiation (HSSI) program weld 73w. The results for each material from each laboratory are compared with those from the other laboratory. the ORNL experiments with the VVER welds included irradiation to about 1 x 10 (exp 19) N/SQ CM ({gt}1 MeV), while the RRC-KI experiments with the U.S. materials included irradiations from about 2 to 18 X 10 (exp 19) N/SQ CM ({gt}1 MeV).

  9. Evolution of the microstructure, residual stresses, and mechanical properties of W-Si-N coatings after thermal annealing

    NARCIS (Netherlands)

    Cavaleiro, A; Marques, AP; Fernandes, JV; Carvalho, NJM; De Hosson, JT

    W-Si-N films were deposited by reactive sputtering in a Ar + N-2 atmosphere from a W target encrusted with different number of Si pieces and followed by a thermal annealing at increasing temperatures up to 900 degrees C. Three iron-based substrates with different thermal expansion coefficients, in

  10. Rapid thermal annealing of YBaCuO films on Si and SiO/sub 2/ substrates

    Energy Technology Data Exchange (ETDEWEB)

    Aslam, M.; Soltis, R.E.; Logothetis, E.M.; Ager, R.; Mikkor, M.; Win, W.; Chen, J.T.; Wenger, L.E.

    1988-07-11

    A very rapid thermal annealing technique has been employed on sputter-deposited YBaCuO films. After an O/sub 2/ anneal (with or without a N/sub 2/ preanneal) at temperatures as high as 920 /sup 0/C for 8--12 s, films on (100)Si and on SiO/sub 2/ /Si substrates exhibited superconductivity onsets above 95 K and zero resistance in the range 40--66 K.

  11. Effects of annealing conditions on the dielectric properties of solution-processed Al2O3 layers for indium-zinc-tin-oxide thin-film transistors.

    Science.gov (United States)

    Kim, Yong-Hoon; Kim, Kwang-Ho; Park, Sung Kyu

    2013-11-01

    In this paper, the effects of annealing conditions on the dielectric properties of solution-processed aluminum oxide (Al2O3) layers for indium-zinc-tin-oxide (IZTO) thin-film transistors (TFTs) have been investigated. The dielectric properties of Al2O3 layers such as leakage current density and dielectric strength were largely affected by their annealing conditions. In particular, oxygen partial pressure in rapid thermal annealing, and the temperature profile of hot plate annealing had profound effects on the dielectric properties. From a refractive index analysis, the enhanced dielectric properties of Al2O3 gate dielectrics can be attributed to higher film density depending on the annealing conditions. With the low-temperature-annealed Al2O3 gate dielectric at 350 degrees C, solution-processed IZTO TFTs with a field-effect mobility of approximately 2.2 cm2/Vs were successfully fabricated.

  12. Optical characteristics of GaAsSb alloy after rapid thermal annealing

    Science.gov (United States)

    Gao, Xian; Zhao, Fenghuan; Fang, Xuan; Tang, Jilong; Fang, Dan; Wang, Dengkui; Wang, Xiaohua; Wei, Zhipeng; Chen, Rui

    2017-11-01

    GaAsSb ternary alloy is a promising material for application in infrared optoelectronic devices. In this letter, the investigation of carrier recombination in the as-grown and rapid thermal annealing (RTA) treated GaAsSb samples has been carried out. It was found that after thermal treatment the emission of the GaAsSb material was enhanced and could be maintained up to room temperature. These phenomena can be ascribed to the decrease of non-radiative combination defects in the GaAsSb sample, which implies an improved crystal quality. Moreover, the localized exciton-longitudinal optical phonon interaction is slightly increased after RTA treatment. It is suggested that the interaction depends strongly on the localized states, and the photoluminescence emission intensity can be significantly increased after suitable RTA treatment. Promoting better optical emission in GaAsSb is very useful for its practical application.

  13. Annealing effect on structural and optical properties of chemical bath deposited MnS thin film

    Energy Technology Data Exchange (ETDEWEB)

    Ulutas, Cemal, E-mail: cemalulutas@hakkari.edu.tr [Faculty of Education, Hakkari Universty, 30000, Hakkari (Turkey); Gumus, Cebrail [Faculty of Science and Letters, Cukurova University, 01330, Adana (Turkey)

    2016-03-25

    MnS thin film was prepared by the chemical bath deposition (CBD) method on commercial microscope glass substrate deposited at 30 °C. The as-deposited film was given thermal annealing treatment in air atmosphere at various temperatures (150, 300 and 450 °C) for 1 h. The MnS thin film was characterized by using X-ray diffraction (XRD), UV-vis spectrophotometer and Hall effect measurement system. The effect of annealing temperature on the structural, electrical and optical properties such as optical constants of refractive index (n) and energy band gap (E{sub g}) of the film was determined. XRD measurements reveal that the film is crystallized in the wurtzite phase and changed to tetragonal Mn{sub 3}O{sub 4} phase after being annealed at 300 °C. The energy band gap of film decreased from 3.69 eV to 3.21 eV based on the annealing temperature.

  14. The effect of thermal and vapor annealing treatments on the self-assembly of TiO{sub 2} /PS-b-PMMA nanocomposites generated via the sol-gel process

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, J; Tercjak, A; Garcia, I; Mondragon, I [' Materials-Technologies' Group, Departamento IngenierIa Quimica y Medio Ambiente, Escuela Politecnica, Universidad PaIs Vasco/Euskal Herriko Unibertsitatea, Plaza Europa 1, E-20018 Donostia-San Sebastian (Spain)], E-mail: inaki.mondragon@ehu.es

    2009-06-03

    Polystyrene-block-poly(methyl methacrylate) (SMMA) block copolymer has been used as a structure-directing agent for generating TiO{sub 2} /SMMA nanocomposites via the sol-gel process using a hydrophobic surfactant. The aim of the work has been focused on the preparation of well-defined nanostructured composites based on the self-assembling capability of the block copolymer using two different annealing methods: thermal- and solvent-induced microphase separation. The addition of different amounts of nanoparticles caused strong variations in the self-assembled morphology of the TiO{sub 2} /SMMA nanocomposites with respect to the block copolymer, as observed by atomic force microscopy (AFM). To verify the confinement of the nanoparticles in the PMMA block 3D AFM images and corresponding AFM profiles have also been reported. UV light irradiation of the nanocomposite films provoked the removal of the organic matrix and consequently led to an array of TiO{sub 2} nanoparticles on the substrate surface.

  15. The effect of annealing temperature on the electrical characterization of Co/n type GaP Schottky diode

    Energy Technology Data Exchange (ETDEWEB)

    Orak, İ., E-mail: ikramorak@gmail.com [Vocational School of Health Services, Bingöl University, 12000 Bingöl (Turkey); Ejderha, K. [Vocational School of Technical Sciences, Bingöl University, 12000 Bingöl (Turkey); Sönmez, E. [Department of Physics, Kazim Karabekir Education Faculty, Atatürk University, Erzurum 25240 (Turkey); Alanyalıoğlu, M. [Faculty of Science, Department of Chemistry, 25240 Erzurum (Turkey); Turut, A. [Faculty of Sciences, Department of Engineering Physics, Istanbul Medeniyet University, 34730 Istanbul (Turkey)

    2015-01-15

    The Co/n-GaP nano-Schottky diodes have been fabricated to investigate effect of annealing temperature on the characteristics of the device. DC Magnetron sputtering technique has been used for Co metallic contact. The samples have been annealed for three minutes at 400 °C and 600 °C. XRD analyzes of the devices subjected to thermal annealing process have been investigated. Surface images have been taken with atomic force microscopy (AFM) in order to examine the morphology of the surface of the metal layer before and after the annealing the sample. The current–voltage (I–V) measurements taken at room temperature have shown that the ideality factor and series resistance decrease with the increasing annealing temperature. The ideality factor was found to be 1.02 for sample annealed at 400 °C. Before and after annealing, depending on the temperature measurement, the capacitance–frequency (C–f), and conductance–frequency (G–f) have been measured, and graphs have been plotted.

  16. Thermal, quantum and simulated quantum annealing: analytical comparisons for simple models

    OpenAIRE

    Bapst, Victor; Semerjian, Guilhem

    2015-01-01

    We study various annealing dynamics, both classical and quantum, for simple mean-field models and explain how to describe their behavior in the thermodynamic limit in terms of differential equations. In particular we emphasize the differences between quantum annealing (i.e. evolution with Schr\\"odinger equation) and simulated quantum annealing (i.e. annealing of a Quantum Monte Carlo simulation).

  17. Effect of annealing over optoelectronic properties of graphene based transparent electrodes

    Science.gov (United States)

    Yadav, Shriniwas; Kaur, Inderpreet

    2016-04-01

    Graphene, an atom-thick two dimensional graphitic material have led various fundamental breakthroughs in the field of science and technology. Due to their exceptional optical, physical and electrical properties, graphene based transparent electrodes have shown several applications in organic light emitting diodes, solar cells and thin film transistors. Here, we are presenting effect of annealing over optoelectronic properties of graphene based transparent electrodes. Graphene based transparent electrodes have been prepared by wet chemical approach over glass substrates. After fabrication, these electrodes tested for optical transmittance in visible region. Sheet resistance was measured using four probe method. Effect of thermal annealing at 200 °C was studied over optical and electrical performance of these electrodes. Optoelectronic performance was judged from ratio of direct current conductivity to optical conductivity (σdc/σopt) as a figure of merit for transparent conductors. The fabricated electrodes display good optical and electrical properties. Such electrodes can be alternatives for doped metal oxide based transparent electrodes.

  18. Quantum Annealing and Quantum Fluctuation Effect in Frustrated Ising Systems

    OpenAIRE

    Tanaka, Shu; Tamura, Ryo

    2012-01-01

    Quantum annealing method has been widely attracted attention in statistical physics and information science since it is expected to be a powerful method to obtain the best solution of optimization problem as well as simulated annealing. The quantum annealing method was incubated in quantum statistical physics. This is an alternative method of the simulated annealing which is well-adopted for many optimization problems. In the simulated annealing, we obtain a solution of optimization problem b...

  19. Bandgap-Tuning in Triple-Chalcogenophene Polymer Films by Thermal Annealing.

    Science.gov (United States)

    González, Daniel Moseguí; Raftopoulos, Konstantinos N; He, Gang; Papadakis, Christine M; Brown, Alex; Rivard, Eric; Müller-Buschbaum, Peter

    2017-06-01

    The authors study adjustable bandgap properties of the novel triple chalcogenophene-based polymer poly-(3-hexyl-2(3-(4-hexylthiophene-2-yl)-4,5-butylselenophene-1-yl)-5-(4,5-butyltellurophene-1-yl)thiophene) through a combination of morphological, spectroscopic, and computational techniques. The bandgap can be tuned after polymerization by means of mild temperature annealing, which will allow for a partnership with a broader range of donor/acceptor molecules, a property that makes it potentially suitable for organic photovoltaic implementation. The bandgap is modified by selection of the annealing temperatures, and the process is arguably related to the aggregation of tellurophene units, as similar effects are observed in polytellurophenes. Moreover, adequate chemistry engineering ensures easy solution processability and attainment of homogeneous films, which is also essential for applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Investigation of Near-Surface Defects Induced by Spike Rapid Thermal Annealing in c-SILICON Solar Cells

    Science.gov (United States)

    Liu, Guodong; Ren, Pan; Zhang, Dayong; Wang, Weiping; Li, Jianfeng

    2016-01-01

    The defects induced by a spike rapid thermal annealing (RTA) process in crystalline silicon (c-Si) solar cells were investigated by the photoluminescence (PL) technique and the transmission electron microscopy (TEM), respectively. Dislocation defects were found to form in the near-surface junction region of the monocrystalline Si solar cell after a spike RTA process was performed at 1100∘C. Photo J-V characteristics were measured on the Si solar cell before and after the spike RTA treatments to reveal the effects of defects on the Si cell performances. In addition, the Silvaco device simulation program was used to study the effects of defects density on the cell performances by fitting the experimental data of RTA-treated cells. The results demonstrate that there was an obvious degradation in the Si solar cell performances when the defect density after the spike RTA treatment was above 1×1013cm-3.

  1. The effect of annealing temperature on the optical properties of a ruthenium complex thin film

    Energy Technology Data Exchange (ETDEWEB)

    Ocakoglu, Kasim, E-mail: kasim.ocakoglu@mersin.edu.tr [Advanced Technology Research & Application Center, Mersin University, TR-33343, Yenisehir, Mersin (Turkey); Department of Energy Systems Engineering, Faculty of Technology, Mersin University, TR-33480 Mersin (Turkey); Okur, Salih, E-mail: salih.okur@ikc.edu.tr [Department of Materials Science and Engineering, Faculty of Engineering and Architecture, Izmir Katip Celebi University, Izmir (Turkey); Aydin, Hasan [Izmir Institute of Technology, Department of Material Science and Engineering, Gulbahce Campus, 35430, Urla, Izmir (Turkey); Emen, Fatih Mehmet [Faculty of Arts and Sciences, Department of Chemistry, Mehmet Akif Ersoy University, TR-15030 Burdur (Turkey)

    2016-08-01

    The stability of the optical parameters of a ruthenium polypyridyl complex (Ru-PC K314) film under varying annealing temperatures between 278 K and 673 K was investigated. The ruthenium polypyridyl complex thin film was prepared on a quartz substrate by drop casting technique. The transmission of the film was recorded by using Ultraviolet/Visible/Near Infrared spectrophotometer and the optical band gap energy of the as-deposited film was determined around 2.20 eV. The optical parameters such as refractive index, extinction coefficient, and dielectric constant of the film were determined and the annealing effect on these parameters was investigated. The results show that Ru PC K314 film is quite stable up to 595 K, and the rate of the optical band gap energy change was found to be 5.23 × 10{sup −5} eV/K. Furthermore, the thermal analysis studies were carried out in the range 298–673 K. The Differential Thermal Analysis/Thermal Gravimmetry/Differantial Thermal Gravimmetry curves show that the decomposition is incomplete in the temperature range 298–673 K. Ru-PC K314 is thermally stable up to 387 K. The decomposition starts at 387 K with elimination of functional groups such as CO{sub 2}, CO molecules and SO{sub 3}H group was eliminated between 614 K and 666 K. - Highlights: • Optical parameters of a ruthenium polypyridyl complex film under varying annealing temperatures • The film is quite stable up to 573 K. • The rate of change of optical energy gap was obtained as 5.23 × 10{sup −5} eV/K.

  2. Rapid Thermal Annealing for Solution Synthesis of Transparent Conducting Aluminum Zinc Oxide Thin Films

    Science.gov (United States)

    Ullah, Sana; De Matteis, Fabio; Davoli, Ivan

    2017-11-01

    Transparent conducting oxide films with optimized dopant molar ratio have been prepared with limited pre- and postdeposition annealing duration of 10 min. Multiple aluminum zinc oxide (AZO) layers were spin-coated on ordinary glass substrates. The predeposition consolidation temperature and dopant molar ratio were optimized for electrical conductivity and optical transparency. Next, a group of films were deposited on Corning glass substrates from precursor solutions with the optimized dopant ratio, followed by postdeposition rapid thermal annealing (RTA) at different temperatures and in controlled environments. The lowest resistivity of 10.1 × 10-3 Ω cm was obtained for films receiving RTA at 600°C for 10 min each in vacuum then in N2-5%H2 environment, while resistivity of 20.3 × 10-3 Ω cm was obtained for films subjected to RTA directly in N2-5%H2. Optical measurements revealed average total transmittance of about 85% in the visible region. A direct allowed transition bandgap was determined based on the absorption edge with a value slightly above 3.0 eV, within the typical range for semiconductors. RTA resulted in desorption of oxygen with enhanced carrier concentration and crystallinity, which increased the carrier mobility with decreased bulk resistivity while maintaining the required optical transparency.

  3. Impact of Thermal Annealing on Organic Photovoltaic Cells Using Regioisomeric Donor-Acceptor-Acceptor Molecules.

    Science.gov (United States)

    Zhang, Tao; Han, Han; Zou, Yunlong; Lee, Ying-Chi; Oshima, Hiroya; Wong, Ken-Tsung; Holmes, Russell J

    2017-08-02

    We report a promising set of donor-acceptor-acceptor (D-A-A) electron-donor materials based on coplanar thieno[3,2-b]/[2,3-b]indole, benzo[c][1,2,5]thiadiazole, and dicyanovinylene, which are found to show broadband absorption with high extinction coefficients. The role of the regioisomeric electron-donating thienoindole moiety on the physical and structural properties is examined. Bulk heterojunction (BHJ) organic photovoltaic cells (OPVs) based on the thieno[2,3-b]indole-based electron donor NTU-2, using C70 as an electron acceptor, show a champion power conversion efficiency of 5.2% under AM 1.5G solar simulated illumination. This efficiency is limited by a low fill factor (FF), as has previously been the case in D-A-A systems. In order to identify the origin of the limited FF, further insight into donor layer charge-transport behavior is realized by examining planar heterojunction OPVs, with emphasis on the evolution of film morphology with thermal annealing. Compared to as-deposited OPVs that exhibit insufficient donor crystallinity, crystalline OPVs based on annealed thin films show an increase in the short-circuit current density, FF, and power conversion efficiency. These results suggest that that the crystallization of D-A-A molecules might not be realized spontaneously at room temperature and that further processing is needed to realize efficient charge transport in these materials.

  4. Effects of hydroxyl-functionalization and sub-Tg thermal annealing on high pressure pure- and mixed-gas CO2/CH4 separation by polyimide membranes based on 6FDA and triptycene-containing dianhydrides

    KAUST Repository

    Swaidan, Raja

    2015-02-01

    A sub-Tg thermally-annealed (250°C, 24h) ultra-microporous PIM-polyimide bearing a 9,10-diisopropyl-triptycene contortion center and hydroxyl-functionalized diamine (2,2-bis(3-amino-4-hydroxyphenyl)-hexafluoropropane, APAF) exhibited plasticization resistance up to 50bar for a 1:1 CO2/CH4 feed mixture, with a 9-fold higher CO2 permeability (30Barrer) and 2-fold increase in CO2/CH4 permselectivity (~50) over conventional dense cellulose acetate membranes at 10bar CO2 partial pressure. Interestingly, mixed-gas CO2/CH4 permselectivities were 10-20% higher than those evaluated under pure-gas conditions due to reduction of mixed-gas CH4 permeability by co-permeation of CO2. Gas transport, physisorption and fluorescence studies indicated a sieving pore-structure engaged in inter-chain charge transfer complexes (CTCs), similar to that of low-free-volume 6FDA-APAF polyimide. The isosteric heat of adsorption of CO2 as well as CO2/CH4 solubility selectivities varied negligibly upon replacement of OH with CH3 but CTC formation was hindered, CO2 sorption increased, CO2 permeability increased ~3-fold, CO2/CH4 permselectivity dropped to ~30 and CH4 mixed-gas co-permeation increased. These results suggest that hydroxyl-functionalization did not cause preferential polymer-gas interactions but primarily elicited diffusion-dominated changes owing to a tightened microstructure more resistant to CO2-induced dilations. Solution-processable hydroxyl-functionalized PIM-type polyimides provide a new platform of advanced materials that unites the high selectivities of low-free-volume polymers with the high permeabilities of PIM-type materials particularly for natural gas sweetening applications.

  5. Thermal annealing behaviour of deep levels in as-grown p-type MOCVD GaAs

    Energy Technology Data Exchange (ETDEWEB)

    Naz, Nazir A., E-mail: nazir_phys@yahoo.co [Semiconductor Physics Laboratory, Department of Physics, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Department of Applied Physics, Federal Urdu University of Arts, Science and technology, G-7/1, Islamabad (Pakistan); Qurashi, Umar S.; Zafar Iqbal, M. [Semiconductor Physics Laboratory, Department of Physics, Quaid-i-Azam University, Islamabad 45320 (Pakistan)

    2009-12-15

    Thermal annealing behaviour of deep levels in p-GaAs grown by metal-organic chemical-vapor deposition (MOCVD) has been studied by deep level transient spectroscopy (DLTS) technique. Thermal annealing is found to introduce at least six new defects, four majority-carrier emitting deep levels, situated at E{sub v}+0.11, E{sub v}+0.27, E{sub v}+0.44 and E{sub v}+0.89 eV in the bandgap, and two minority-carrier emitting defects, at E{sub c}-0.49 eV and E{sub c}-0.99 eV. The minority-carrier emitting band of deep levels around approx100 K in the as-grown material has also been found to resolve into two distinct peaks corresponding to deep levels at E{sub c}-0.16 eV and E{sub c}-0.21 eV, upon isochronal annealing. Four of the annealed-in defects at E{sub v}+0.27, E{sub v}+0.44, E{sub c}-0.16 eV and E{sub c}-0.49 eV are identified with previously reported deep levels, while the other four defects cannot be identified with any of the deep levels reported in the literature. Data on the annealing behavior and other characteristics of these annealed-in levels are presented. The thermal annealing behavior of the both inadvertent levels observed at E{sub v}+0.55 eV and E{sub v}+0.96 eV suggests that these levels are most likely related to arsenic antisite, As{sub Ga}, defects.

  6. The striking influence of rapid thermal annealing on InGaAsP grown by MBE: material and photovoltaic device

    Science.gov (United States)

    Ji, Lian; Tan, Ming; Ding, Chao; Honda, Kazuki; Harasawa, Ryo; Yasue, Yuya; Wu, Yuanyuan; Dai, Pan; Tackeuchi, Atsushi; Bian, Lifeng; Lu, Shulong; Yang, Hui

    2017-01-01

    Rapid thermal annealing (RTA) has been performed on InGaAsP solar cells with the bandgap energy of 1 eV grown by molecular beam epitaxy. With the employment of RTA under an optimized condition, the open voltage was increased from 0.45 to 0.5 V and the photoelectric conversion efficiency was increased from 11.87-13.2%, respectively, which was attributed to the crystal quality improvement of p-type InGaAsP and therefore a reduced recombination current inside depletion region. The integral photoluminescence (PL) intensity of p-type InGaAsP increased to 166 times after annealing at 800 °C and its PL decay time increased by one order of magnitude. While the changes of nominally undoped and n-doped InGaAsP were negligible. The different behaviors of the effect of RTA on InGaAsP of different doping types were attributed to the highly mobile "activator" - beryllium (Be) atom in p-type InGaAsP.

  7. A Thermally Annealed Mach-Zehnder Interferometer for High Temperature Measurement

    Directory of Open Access Journals (Sweden)

    Zhongyao Feng

    2014-08-01

    Full Text Available An in-fiber Mach-Zehnder interferometer (MZI for high temperature measurement is proposed and experimentally demonstrated. The device is constructed of a piece of thin-core fiber (TCF sandwiched between two short sections of multimode fiber (MMF, i.e., a MMF-TCF-MMF structure. A well-defined interference spectrum is obtained owing to the core-mismatch, and the interference dips are sensitive to the ambient temperature. The experimental results show that the proposed interferometer is capable of high temperature measurement up to 875 °C with a sensitivity of 92 pm/°C over repeated measurements. The explored wavelength drop point may limit the measurement range, which can be improved by repeated thermal annealing.

  8. A thermally annealed Mach-Zehnder interferometer for high temperature measurement.

    Science.gov (United States)

    Feng, Zhongyao; Li, Jiacheng; Qiao, Xueguang; Li, Ling; Yang, Hangzhou; Hu, Manli

    2014-08-04

    An in-fiber Mach-Zehnder interferometer (MZI) for high temperature measurement is proposed and experimentally demonstrated. The device is constructed of a piece of thin-core fiber (TCF) sandwiched between two short sections of multimode fiber (MMF), i.e., a MMF-TCF-MMF structure. A well-defined interference spectrum is obtained owing to the core-mismatch, and the interference dips are sensitive to the ambient temperature. The experimental results show that the proposed interferometer is capable of high temperature measurement up to 875 °C with a sensitivity of 92 pm/°C over repeated measurements. The explored wavelength drop point may limit the measurement range, which can be improved by repeated thermal annealing.

  9. Studies of thermal annealing and dope composition on the enhancement of separation performance cellulose acetate membrane for brackish water treatment from Jepara

    Directory of Open Access Journals (Sweden)

    Tutuk Djoko Kusworo

    2014-08-01

    Full Text Available Membrane is an alternative technology of water treatment with filtration principle that is being widely developed and used for water treatment. The main objective of this study was to make an asymmetric membrane using cellulose acetate polymer and study the effect of additive and annealing treatment on the morphology structure and performance of cellulose acetate membranes in brackish water treatment. Asymmetric membranes for brackish water treatment were casted using a casting machine process from dope solutions containing cellulose acetates and acetone as a solvent. Membranes was prepared by phase inversion method  with variation of polyethylene glycol (PEG concentration of 1 and 5 wt% and with thermal annealing at 60 oC in 10 seconds and without thermal annealing behavior. Membrane characterization consists of calculation of membrane flux and rejection with brackish water as a feed from Jepara. The research concluded that asymmetric cellulose acetate membrane can be made by dry/wet phase inversion method. The more added concentration of PEG will be resulted the larger pore of membrane. Meanwhile the higher temperature and the longer time of annealing treatment, the skin layer of membrane become denser. Membrane with the composition of 18 wt% cellulose acetate, 5 wt% PEG, 1 wt% distilled water, with heat treatment at temperature of 60 oC for 10 seconds is obtained optimal performance.

  10. Effect of prolonged annealing on the performance of coaxial Ge gamma-ray detectors

    NARCIS (Netherlands)

    Owens, A.; Brandenburg, S.; Buis, E. -J.; Kozorezov, A. G.; Kraft, S.; Ostendorf, R. W.; Quarati, F.

    The effects of prolonged annealing at elevated temperatures have been investigated in a 53 cm(3) closed-end coaxial high purity germanium detector in the reverse electrode configuration. The detector was multiply annealed at 100 degrees C in block periods of 7 days. After each anneal cycle it was

  11. Activated Carbon Fibers "Thickly Overgrown" by Ag Nanohair Through Self-Assembly and Rapid Thermal Annealing

    Science.gov (United States)

    Yan, Xuefeng; Xu, Sijun; Wang, Qiang; Fan, Xuerong

    2017-11-01

    Anisotropic nanomaterial-modified carbon fibers attract increasing attention because of their superior properties over traditional ones. In this study, activated carbon fibers (ACFs) "thickly overgrown" by Ag nanohair were prepared through self-assembly and rapid thermal annealing. Viscose fibers with well-dispersed silver nanoparticles (AgNPs) on surfaces were first prepared through self-assembly of hyperbranched poly(amino-amine) (HBPAA)-capped AgNPs on viscose surfaces. HBPAA endowed the AgNP surfaces with negative charges and abundant amino groups, allowing AgNPs to monodispersively self-assemble to fiber surfaces. Ag nanohair-grown ACFs were prepared by sequential pre-oxidation and carbonization. Because the carbonization furnace was open-ended, ACFs are immediately transferrable to the outside of the furnace. Therefore, the Ag liquid adsorbed by ACF pores squeezed out to form Ag nanowires through thermal contraction. FESEM characterization indicated that Ag nanohairs stood on ACF surface and grew from ACF caps. XPS and XRD characterization showed that Ag successfully assembled to fiber surfaces and retained its metallic state even after high-temperature carbonization. TG analysis suggested that Ag nanohair-grown ACFs maintained their excellent thermal stabilities. Finally, the fabricated ACFs showed excellent and durable antibacterial activities, and the developed method may provide a potential strategy for preparing metal nanowire-grown ACFs.

  12. Activated Carbon Fibers "Thickly Overgrown" by Ag Nanohair Through Self-Assembly and Rapid Thermal Annealing.

    Science.gov (United States)

    Yan, Xuefeng; Xu, Sijun; Wang, Qiang; Fan, Xuerong

    2017-11-09

    Anisotropic nanomaterial-modified carbon fibers attract increasing attention because of their superior properties over traditional ones. In this study, activated carbon fibers (ACFs) "thickly overgrown" by Ag nanohair were prepared through self-assembly and rapid thermal annealing. Viscose fibers with well-dispersed silver nanoparticles (AgNPs) on surfaces were first prepared through self-assembly of hyperbranched poly(amino-amine) (HBPAA)-capped AgNPs on viscose surfaces. HBPAA endowed the AgNP surfaces with negative charges and abundant amino groups, allowing AgNPs to monodispersively self-assemble to fiber surfaces. Ag nanohair-grown ACFs were prepared by sequential pre-oxidation and carbonization. Because the carbonization furnace was open-ended, ACFs are immediately transferrable to the outside of the furnace. Therefore, the Ag liquid adsorbed by ACF pores squeezed out to form Ag nanowires through thermal contraction. FESEM characterization indicated that Ag nanohairs stood on ACF surface and grew from ACF caps. XPS and XRD characterization showed that Ag successfully assembled to fiber surfaces and retained its metallic state even after high-temperature carbonization. TG analysis suggested that Ag nanohair-grown ACFs maintained their excellent thermal stabilities. Finally, the fabricated ACFs showed excellent and durable antibacterial activities, and the developed method may provide a potential strategy for preparing metal nanowire-grown ACFs.

  13. Fabrication of Ohmic contact on semi-insulating 4H-SiC substrate by laser thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Yue; Lu, Wu-yue; Wang, Tao; Chen, Zhi-zhan, E-mail: zzchen@shnu.edu.cn [Department of Physics, Shanghai Normal University, 100 Guilin Road, Shanghai 200234 (China)

    2016-06-14

    The Ni contact layer was deposited on semi-insulating 4H-SiC substrate by magnetron sputtering. The as-deposited samples were treated by rapid thermal annealing (RTA) and KrF excimer laser thermal annealing (LTA), respectively. The RTA annealed sample is rectifying while the LTA sample is Ohmic. The specific contact resistance (ρ{sub c}) is 1.97 × 10{sup −3} Ω·cm{sup 2}, which was determined by the circular transmission line model. High resolution transmission electron microscopy morphologies and selected area electron diffraction patterns demonstrate that the 3C-SiC transition zone is formed in the near-interface region of the SiC after the as-deposited sample is treated by LTA, which is responsible for the Ohmic contact formation in the semi-insulating 4H-SiC.

  14. Irradiation, Annealing, and Reirradiation Effects on American and Russian Reactor Pressure Vessel Steels

    Energy Technology Data Exchange (ETDEWEB)

    Chernobaeva, A.A.; Korolev, Y.N.; Nanstad, R.K.; Nikolaev, Y.A.; Sokolov, M.A.

    1998-06-16

    One of the options to mitigate the effects of irradiation on reactor pressure vessels (RPVs) is to thermally anneal them to restore the toughness properties that have been degraded by neutron irradiation. Even though a postirradiation anneal may be deemed successful, a critical aspect of continued RPV operation is the rate of embrittlement upon reirradiation. There are insufficient data available to allow for verification of available models of reirradiation embrittlement or for the development of a reliable predictive methodology. This is especially true in the case of fracture toughness data. Under the U.S.-Russia Joint Coordinating Committee for Civilian Nuclear Reactor Safety (JCCCNRS), Working Group 3 on Radiation Embrittlement, Structural Integrity, and Life Extension of Reactor Vessels and Supports agreed to conduct a comparative study of annealing and reirradiation effects on RPV steels. The Working Group agreed that each side would irradiate, anneal, reirradiate (if feasible ), and test two materials of the other. Charpy V-notch (CVN) and tensile specimens were included. Oak Ridge National Laboratory (ORNL) conducted such a program (irradiation and annealing, including static fracture toughness) with two weld metals representative of VVER-440 and VVER-1000 RPVs, while the Russian Research Center-Kurchatov Institute (RRC-KI) conducted a program (irradiation, annealing, reirradiation, and reannealing) with Heavy-Section Steel Technology (HSST) Program Plate 02 and Heavy-Section Steel Irradiation (HSSI) Program Weld 73W. The results for each material from each laboratory are compared with those from the other laboratory. The ORNL experiments with the VVER welds included irradiation to about 1 x 10{sup 19} n/cm{sup 2} (>1 MeV), while the RRC-KI experiments with the U.S. materials included irradiations from about 2 to 18 x 10{sup 19} n/cm{sup 2} (>l MeV). In both cases, irradiations were conducted at {approximately}290 C and annealing treatments were conducted

  15. The effect of humidity on annealing of polymer optical fibre bragg gratings

    DEFF Research Database (Denmark)

    Woyessa, Getinet; Nielsen, Kristian; Bang, Ole

    2015-01-01

    The effect of humidity on annealing of PMMA based microstructured polymer optical fiber (mPOF) Bragg gratings is studied. Polymer optical fibers (POFs) are annealed in order to release stress formed during the fabrication process. Un-annealed fibers will have high hysteresis and low sensitivity...... to humidity, particularly when operated at high temperature. Typically annealing of PMMA POFs is done at 80oC in an oven with no humidity control and therefor at low humidity. The response to humidity of PMMA FBGs annealed at different levels of humidity at the same temperature has also been studied. PMMA...... FBGs annealed at high humidity have response with no hysteresis and an improved sensitivity which are independent of temperature compared to FBGs annealed at the same temperature but at lower humidity. In addition, PMMA FBG annealed at high humidity showed a permanent blue shift more than 200nm, which...

  16. In situ transmission electron microscopy analyses of thermally annealed self catalyzed GaAs nanowires grown by molecular beam epitaxy

    DEFF Research Database (Denmark)

    Ambrosini, S.; Wagner, Jakob Birkedal; Booth, Tim

    2011-01-01

    Self catalyzed GaAs nanowires grown on Si-treated GaAs substrates were studied with a transmission electron microscope before and after annealing at 600◦C. At room temperature the nanowires have a zincblende structure and are locally characterized by a high density of rotational twins and stackin...... faults. Selected area diffraction patterns and high-resolution transmission electron microscopy images show that nanowires undergo structural modifications upon annealing, suggesting a decrease of defect density following the thermal treatment....

  17. Magnetic Characteristics of Mn-Implanted GaN Nanorods Followed by Thermal Annealing

    Directory of Open Access Journals (Sweden)

    Im Taek Yoon

    2012-01-01

    Full Text Available We have investigated the magnetic and optical properties of dislocation-free vertical GaN nanorods with diameters of 150 nm grown on (111 Si substrates by radio-frequency plasma-assisted molecular-beam epitaxy followed by Mn ion implantation and annealing. The GaN nanorods are fully relaxed and have a very good crystal quality characterized by extremely strong and narrow photoluminescence excitonic lines near 3.47 eV. For GaMnN nanorods, it can be concluded that the ferromagnetic property of GaMnN nanorod with a Curie temperature over 300 K is associated with the formation of Mn4Si7 magnetic phase which results from the effects of magnetic and structural disorder introduced by a random incorporation and inhomogeneous distribution of Mn atoms in the porous layer between the nanorods that form precipitates in the Si substrate before or during the annealing step amongst the GaN nanorods.

  18. Effect of air annealing on structural and magnetic properties of Ni/NiO nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Nadeem, K., E-mail: kashif.nadeem@iiu.edu.pk [Nanomagnetism and Nanotechnology Laboratory, International Islamic University, Islamabad (Pakistan); Ullah, Asmat; Mushtaq, M.; Kamran, M.; Hussain, S.S. [Nanomagnetism and Nanotechnology Laboratory, International Islamic University, Islamabad (Pakistan); Mumtaz, M. [Materials Research Laboratory, Department of Physics, International Islamic University, Islamabad (Pakistan)

    2016-11-01

    We reported systematic study on structural and magnetic properties of nickel/nickel oxide (Ni/NiO) nanoparticles annealed under air atmosphere at different temperatures in the range 400–800 °C. The XRD spectra revealed two phases such as Ni and NiO. The average crystallite size increases with increasing annealing temperature. A phase diagram was developed between two phases versus annealing temperature using XRD analysis. At lower annealing temperatures, Ni phase is dominant which does not easily undergo oxidation to form NiO. The NiO phase increases with increasing annealing temperature. FTIR spectroscopy revealed an increase in the NiO phase content at higher annealing temperature, which is in agreement with the XRD analysis. SEM images showed that nanoparticles are well separated at lower annealing temperatures but get agglomerated at higher annealing temperatures. The ferromagnetic (FM) Ni phase content and saturation magnetization (M{sub s}) showed nearly the same trend with increasing annealing temperature. The nanoparticles annealed at 500 °C and 800 °C revealed highest and lowest M{sub s} values, respectively, which is in accordance with the XRD phase diagram. Coercivity showed an overall decreasing trend with increasing annealing temperature due to decreased concentration of FM Ni phase and increasing average crystallite size. All these measurements indicate that the structural and magnetic properties of Ni/NiO nanoparticles are strongly influenced by the annealing temperature. - Highlights: • Air annealing effects on structural and magnetic properties of Ni/NiO nanoparticles have been studied. • The XRD spectra revealed two phases such as Ni and NiO. • A phase diagram was developed between two phases versus annealing temperature using XRD analysis. • The magnetic properties are well governed by ferromagnetic Ni phase.

  19. Rapid thermal annealing of sputter-deposited ZnO:Al films for microcrystalline Si thin-film solar cells

    Directory of Open Access Journals (Sweden)

    Hanajiri T.

    2012-06-01

    Full Text Available Rapid thermal annealing of sputter-deposited ZnO and Al-doped ZnO (AZO films with and without an amorphous silicon (a-Si capping layer was investigated using a radio-frequency (rf argon thermal plasma jet of argon at atmospheric pressure. The resistivity of bare ZnO films on glass decreased from 108 to 104–105 Ω cm at maximum surface temperatures Tmaxs above 650 °C, whereas the resistivity increased from 10-4 to 10-3–10-2Ω cm for bare AZO films. On the other hand, the resistivity of AZO films with a 30-nm-thick a-Si capping layer remained below 10-4Ω cm, even after TPJ annealing at a Tmax of 825 °C. The film crystallization of both AZO and a-Si layers was promoted without the formation of an intermixing layer. Additionally, the crystallization of phosphorous- and boron-doped a-Si layers at the sample surface was promoted, compared to that of intrinsic a-Si under the identical plasma annealing conditions. The TPJ annealing of n+-a-Si/textured AZO was applied for single junction n-i-p microcrystalline Si thin-film solar cells.

  20. Thermal annealing behavior of niobium-implanted {alpha}-Al{sub 2}O{sub 3} under reducing environment

    Energy Technology Data Exchange (ETDEWEB)

    Zeng Jianer; Naramoto, Hiroshi; Aoki, Yasushi; Yamamoto, Shunya; Gan Mingle; Takeshita, Hidefumi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    1997-03-01

    Thermal annealing behavior is studied in {alpha}-Al{sub 2}O{sub 3} implanted with {sup 93}Nb{sup +} using RBS/channeling technique and optical absorption spectrometry. The samples with <0001> and <112-bar0> orientations are implanted with 300 keV and 400 keV {sup 93}Nb{sup +} ions. Thermal annealing under reducing environment (Ar+3%H{sub 2}) is employed in the temperature range from 600 to 1000degC to explore unusual materials phase. The annealing up to 1000degC for an hour does not show any essential change in RBS/channeling spectra in two kinds of samples but the significant decrease in the visible region is observed in optical absorption spectra. After annealing at 1000degC for 10 hours, the recovery of the lattice damage is detected by RBS/channeling analysis especially in (112-bar0) sample. In the optical absorption spectra, new absorption envelope appears in the ultraviolet region. The results are related to the formation of niobium metal fine particles, and the sharp distribution is realized especially in (0001) sample. (author)

  1. Interdiffusion and growth of chromium silicide at the interface of Cr/Si(As) system during rapid thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Benkherbache, H. [Universite de M' Sila, (28000) M' Sila (Algeria); Merabet, A., E-mail: merabet_abdelali@yahoo.f [Laboratoire Physique et Mecanique des Materiaux Metalliques, Departement d' O.M.P., Faculte des Sciences de l' Ingenieur, Universite de Setif, (19000) Setif (Algeria)

    2010-02-26

    In this work, the solid-state reaction between a thin film of chromium and silicon has been studied using Rutherford backscattering spectroscopy, X-ray diffraction and the sheet resistance measurements. The thickness of 100 nm chromium layer has been deposited by electronic bombardment on Si (100) substrates, part of them had previously been implanted with arsenic ions of 10{sup 15} at/cm{sup 2} doses and an energy of 100 keV. The samples were heat treated under rapid thermal annealing at 500 {sup o}C for time intervals ranging from 15 to 60 s. The rapid thermal annealing leads to a reaction at the interface Cr/Si inducing the formation and the growth of the unique silicide CrSi{sub 2}, but no other phase can be detected. For samples implanted with arsenic, the saturation value of the sheet resistance is approximately 1.5 times higher than for the non-implanted case.

  2. Characterization of a rapid thermal anneal TiNxOy/TiSi2 contact barrier

    Science.gov (United States)

    Ho, V. Q.

    1989-07-01

    In this paper, the physical and electrical properties of a TiNxOy/TiSi2 dual layer contact barrier are reported. The TiNxOy/TiSi2 barrier was formed by rapidly annealing a Ti thin film on Si in an N2 ambient. During this process, the Ti film surface reacts with N2 to form a TiNxOy skin layer and the bulk of the Ti film reacts with Si to form an underlying TiSi2 layer. The influences of rapid thermal anneal (RTA) conditions on the TiNxOy layer were investigated by varying the RTA temperature from 600 to 1100° C and cycle duration from 30 to 100 s. It is found that the resulting TiNxOy and TiSi2 layer thicknesses are dependent on RTA temperature and the starting Ti thickness. For a starting Ti thickness of 500Å, 150Å thick TiNxOy and 800Å thick TiSi2 are obtained after an RTA at 900° C for 30 s. The TiNxOy thickness is limited by a fast diffusion of Si into Ti to form TiSi2. When a Ti film is deposited on SiO2, Ti starts to react with SiO2 from 600° C and a significant reduction of the SiO2 thickness is observed after an RTA at 900° C. The resulting layer is composed of a surface TiNxOy layer followed by a complex layer of titanium oxide and titanium suicide. In addition, when Ti is depos-ited on TiSi2, thicker TiNxOy and TiSi2 layers are obtained after RTA. This is because the TiSi2 layer retards the diffusion of Si from the underlying substrate into the Ti layer. NMOSFETs were fabricated using the TiNxOy/TiSi2 as a contact barrier formed by RTA at 900° C for 30 s and a significant reduction of contact resistance was obtained. In addition, electromigration test at a high current density indicated that a significant improvement in mean time to failure (MTF) has been obtained with the barrier.

  3. Effects of High-Temperature Annealing in Air on Hi-Nicalon Fiber-Reinforced Celsian Matrix Composites

    Science.gov (United States)

    Bansal, Narottam P.

    2008-01-01

    BN/SiC-coated Hi-Nicalon fiber-reinforced celsian matrix composites (CMC) were annealed for 100 h in air at various temperatures to 1200 C, followed by flexural strength measurements at room temperature. Values of yield stress and strain, ultimate strength, and composite modulus remain almost unchanged for samples annealed up to 1100 C. A thin porous layer formed on the surface of the 1100 C annealed sample and its density decreased from 3.09 to 2.90 g/cu cm. The specimen annealed at 1200 C gained 0.43 wt%, was severely deformed, and was covered with a porous layer of thick shiny glaze which could be easily peeled off. Some gas bubbles were also present on the surface. This surface layer consisted of elongated crystals of monoclinic celsian and some amorphous phase(s). The fibers in this surface ply of the CMC had broken into small pieces. The fiber-matrix interface strength was characterized through fiber push-in technique. Values of debond stress, alpha(sub d), and frictional sliding stress, tau(sub f), for the as-fabricated CMC were 0.31+/-0.14 GPa and 10.4+/-3.1 MPa, respectively. These values compared with 0.53+/-0.47 GPa and 8.33+/-1.72 MPa for the fibers in the interior of the 1200 C annealed sample, indicating hardly any change in fiber-matrix interface strength. The effects of thermal aging on microstructure were investigated using scanning electron microscopy. Only the surface ply of the 1200 C annealed specimens had degraded from oxidation whereas the bulk interior part of the CMC was unaffected. A mechanism is proposed explaining the various steps involved during the degradation of the CMC on annealing in air at 1200 C.

  4. Effect of temperature and post-deposition annealing on Schottky barrier characterization of Bromoindium phthalocyanine/aluminum interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Azim-Araghi, M.E.; Sahebi, R., E-mail: ramezan.sahebi@yahoo.com

    2014-01-15

    To investigate DC electrical properties and Schottky barrier characterization between BrInPc/Al interfaces, some thin films of BrInPc in sandwich form were prepared with Al electrodes. J–V characterization showed ohmic behavior at lower voltages upto 0.3 V followed by Schottky emission conduction mechanism at higher voltages. In the Schottky region two different slopes in the plot of ln (J) against V{sup 1/2} were observed and two different values of Schottky barrier height was determined for these regions. To investigate the effect of temperature on Schottky barrier behavior between BrInPc and aluminum interface, we studied the J–V characteristics of devices at the temperature range of 298–373 K. By increasing the temperature, the width of Schottky depletion region decreased and the Schottky barrier height increased, and at temperatures higher than 333 K the dominant conduction mechanism changed to Poole–Frenkel type. For annealed samples at 373 K and 423 K, the Schottky barrier height increased as the result of thermal annealing and increasing annealing temperature. The width of the Schottky depletion region decreased by annealing and increasing the annealing temperature.

  5. Effect of annealing temperature on the properties of pulsed magnetron sputtered nanocrystalline Ag:SnO{sub 2} films

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, A. Sivasankar [SEG-CEMUC, Department of Mechanical Engineering, University of Coimbra, 3030-788 Coimbra (Portugal); Division of Advanced Materials Engineering, Kongju National University, Budaedong, Cheonan City (Korea, Republic of); Figueiredo, N.M. [SEG-CEMUC, Department of Mechanical Engineering, University of Coimbra, 3030-788 Coimbra (Portugal); Cho, H.C.; Lee, K.S. [Division of Advanced Materials Engineering, Kongju National University, Budaedong, Cheonan City (Korea, Republic of); Cavaleiro, A., E-mail: albano.cavaleiro@dem.uc.pt [SEG-CEMUC, Department of Mechanical Engineering, University of Coimbra, 3030-788 Coimbra (Portugal)

    2012-04-16

    Highlights: Black-Right-Pointing-Pointer The nanocrystalline Ag:SnO{sub 2} films were prepared by pulsed direct current magnetron sputtering. Black-Right-Pointing-Pointer After annealing, the homogeneity and smoothness of the films was improved. Black-Right-Pointing-Pointer The as deposited films exhibited the highest optical transmittance of 95% with band gap of 3.23 eV. Black-Right-Pointing-Pointer The low electrical resistivity of 0.007 {Omega} cm was obtained at annealing temperature of 500 Degree-Sign C. - Abstract: Ag doped SnO{sub 2} (Ag:SnO{sub 2}) films were prepared on glass substrates by pulsed dc magnetron sputtering. The effect of thermal annealing treatments on the physical properties of the films was investigated. Several analytical techniques such as X-ray diffraction, electron probe microanalysis, scanning electron microscopy, atomic force microscopy, four-point probe and double beam spectrophotometer were used to examine the changes in structural, compositional, surface morphology, electrical and optical properties. XRD results showed that the films were grown with (1 1 0) preferential orientation with an average grain size in the range from 4.8 to 8.9 nm. The smoothness of the films increased with annealing temperature. The films annealed at 500 Degree-Sign C presented an electrical resistivity of 0.007 {Omega} cm. The as deposited films exhibited the highest optical transmittance of 95% with band gap of 3.23 eV.

  6. Implantation and annealing effects in molecular organic films

    CERN Document Server

    Pakhomov, G L; Shashkin, V I; Tura, J M; Ribo, J M; Ottaviano, L

    2002-01-01

    Ion implantation and annealing effects on the surface of phthalocyanine thin films have been studied by means of atomic force microscopy and electron spectroscopy for chemical analysis. Both the topology and the chemical composition of the surface are affected by irradiation. The influence of the irradiation dose is shown. The chemical degradation of the layer results mainly in the decrease of atomic concentration of nitrogen and chlorine, and in the increase of atomic concentration of oxygen. At highest dose, carbonization becomes important. Furthermore, N 1s, C 1s and Cl 2p core levels testify that the formation of new chemical species occurs in implanted pthalocyanine films. All these processes are modified by subsequent heat treatment in different ways, depending on the applied implantation fluence.

  7. Effect of heat moisture treatment and annealing on physicochemical ...

    African Journals Online (AJOL)

    Red sorghum starch was physically modified by annealing and heat moisture treatment. The swelling power and solubility increased with increasing temperature range (60-90°), while annealing and heatmoisture treatment decreased swelling power and solubility of starch. Solubility and swelling were pH dependent with ...

  8. Effect of Annealing Processes on Cu-Zr Alloy Film for Copper Metallization

    Science.gov (United States)

    Wang, Ying; Li, Fu-yin; Tang, Bin-han

    2017-10-01

    The effect of two different annealing processes on the microstructure and barrier-forming ability of Cu-Zr alloy films has been investigated. Cu-Zr alloy films were deposited directly onto SiO2/Si substrates via direct current magnetron sputtering and subsequently annealed by the vacuum annealing process (VAP) or rapid annealing process under argon atmosphere at temperatures 350°C, 450°C, and 550°C. Then, the microstructure, interface characteristics, and electrical properties of the samples were measured. After annealing, the samples showed a preferential (111) crystal orientation, independent of the annealing process. After two annealing methods, Zr aggregated at the Cu-Zr/SiO2 interface and no serious interdiffusion occurred between Cu and Si. The leakage current measurements revealed that the samples annealed by VAP show a higher reliability. According to the results, the vacuum annealing has better barrier performance than the rapid annealing when used for the fabrication of Cu-based interconnects.

  9. Nickel oxide films by thermal annealing of ion-beam-sputtered Ni: Structure and electro-optical properties

    Czech Academy of Sciences Publication Activity Database

    Horák, Pavel; Remeš, Zdeněk; Bejšovec, Václav; Vacík, Jiří; Daniš, S.; Kormunda, M.

    2017-01-01

    Roč. 640, č. 10 (2017), s. 52-59 ISSN 0040-6090 R&D Projects: GA ČR(CZ) GBP108/12/G108; GA ČR(CZ) GA14-05053S; GA MŠk LM2015056 Institutional support: RVO:61389005 ; RVO:68378271 Keywords : NiO * ion beam sputtering * thermal annealing * nuclear analytical methods * optical properties Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.879, year: 2016

  10. Electrode Materials, Thermal Annealing Sequences, and Lateral/Vertical Phase Separation of Polymer Solar Cells from Multiscale Molecular Simulations

    KAUST Repository

    Lee, Cheng-Kuang

    2014-12-10

    © 2014 American Chemical Society. The nanomorphologies of the bulk heterojunction (BHJ) layer of polymer solar cells are extremely sensitive to the electrode materials and thermal annealing conditions. In this work, the correlations of electrode materials, thermal annealing sequences, and resultant BHJ nanomorphological details of P3HT:PCBM BHJ polymer solar cell are studied by a series of large-scale, coarse-grained (CG) molecular simulations of system comprised of PEDOT:PSS/P3HT:PCBM/Al layers. Simulations are performed for various configurations of electrode materials as well as processing temperature. The complex CG molecular data are characterized using a novel extension of our graph-based framework to quantify morphology and establish a link between morphology and processing conditions. Our analysis indicates that vertical phase segregation of P3HT:PCBM blend strongly depends on the electrode material and thermal annealing schedule. A thin P3HT-rich film is formed on the top, regardless of bottom electrode material, when the BHJ layer is exposed to the free surface during thermal annealing. In addition, preferential segregation of P3HT chains and PCBM molecules toward PEDOT:PSS and Al electrodes, respectively, is observed. Detailed morphology analysis indicated that, surprisingly, vertical phase segregation does not affect the connectivity of donor/acceptor domains with respective electrodes. However, the formation of P3HT/PCBM depletion zones next to the P3HT/PCBM-rich zones can be a potential bottleneck for electron/hole transport due to increase in transport pathway length. Analysis in terms of fraction of intra- and interchain charge transports revealed that processing schedule affects the average vertical orientation of polymer chains, which may be crucial for enhanced charge transport, nongeminate recombination, and charge collection. The present study establishes a more detailed link between processing and morphology by combining multiscale molecular

  11. Application of fast thermal annealing to ferrites treatment; Application du recuit thermique rapide au traitement des ferrites

    Energy Technology Data Exchange (ETDEWEB)

    Legros, R.

    1995-12-31

    Annealing of magneto-optic memory disks require very fast treatment not to damage glass substrate. This article relates the optimisation of process and the choice of the most suitable alloy. Thermal rise time is linear for 15 s, then a 5 s constant 1273 degree Kelvin step is applied, and then a cooling phase starting at switching off the twelve 1 kw lamps. The most suitable alloy is the one containing manganese additions. (D.L.) 18 refs.

  12. Investigation of Annealing and Blend Concentration Effects of Organic Solar Cells Composed of Small Organic Dye and Fullerene Derivative

    OpenAIRE

    Yasser A. M. Ismail; Tetsuo Soga; Takashi Jimbo

    2011-01-01

    We have fabricated bulk heterojunction organic solar cells using coumarin 6 (C6) as a small organic dye, for light harvesting and electron donation, with fullerene derivative [6,6]-phenyl-C61 butyric acid methyl ester (PCBM), acting as an electron acceptor, by spin-coating technique. We have investigated thermal annealing and blend concentration effects on light harvesting, photocurrent, and performance parameters of the solar cells. In this work, we introduced an experimental method by which...

  13. Effect of annealing on graphene incorporated poly-(3-hexylthiophene):CuInS{sub 2} photovoltaic device

    Energy Technology Data Exchange (ETDEWEB)

    Kumari, Anita, E-mail: anita.20188@gmail.com; Dixit, Shiv Kumar [Department of Electronic Science, University of Delhi, South Campus, Benito Juarez Road, New Delhi-110021 (India); Singh, Inderpreet [Department of Electronic Science, University of Delhi, South Campus, Benito Juarez Road, New Delhi-110021, India and SGTB Khalsa College, University of Delhi, Delhi-110007 (India)

    2014-10-15

    The effect of thermal annealing on the power conversion efficiency (PCE) of poly(3-hexylthiophene) (P3HT):CuInS{sub 2} quantum dot:graphene photovoltaic device has been studied by analyzing optical characteristics of composite films and electrical characteristics of the device with structure indium tin oxide/poly[ethylene dioxythiophene]:poly[styrene sulfonate] (ITO/PEDOT:PSS)/P3HT:CIS:graphene/LiF/aluminum. It was observed that after annealing at 120°C for 15 min a typical device containing 0.005 % w/w of graphene shows the best performance with a PCE of 1.3%, an open-circuit voltage of 0.44V, a short-circuit current density of 7.6 mA/cm{sup 2}, and a fill factor of 0.39. It is observed that the thermal annealing considerably enhances the efficiency of solar cells. However, an annealing at higher temperature such as at 140°C results in a decrease in the device efficiency.

  14. Effects of casting and post casting annealing on xylene isomer transport properties of Torlon® 4000T films

    KAUST Repository

    Chafin, Raymond

    2010-07-01

    Procedures for Torlon® 4000T membrane formation were developed to provide attractive and repeatable xylene separation properties. Torlon® 4000T membrane films cast by our method were investigated in terms of thermally induced imidization, molecular weight enhancement, and solvent removal. After development of the Torlon® 4000T casting procedure, pervaporation of a xylene mixture (i.e. 30% para-xylene, 30% meta-xylene, 30% ortho-xylene, and 10% ethylbenzene) was performed in both Torlon® 4000T and post casting annealed Torlon® 4000T films. The xylene pervaporation in annealed Torlon® 4000T film at 200°C gave a permeability of 0.25 Barrer and a selectivity of 3.1 (para/ortho) and 2.1 (para/meta) respectively. A so-called " permeability collapse" reflecting an accelerated reduction in the free volume is consistent with significant temperature-induced changes in the films observed after thermal annealing at 300°C. This conditioning effect is induced by a combination of heat treatment and the presence of the interacting aromatic penetrants. Optical methods were used to verify that the density of annealed samples exposed to xylene for 5 days eventually increased, suggesting that the membrane is originally swollen upon initial xylene exposure, and then relaxes to a more densified, and more discriminating state. © 2010 Elsevier Ltd.

  15. Effects of annealing on self-assembled InAs quantum dots and wetting layer in GaAs matrix

    Energy Technology Data Exchange (ETDEWEB)

    Jasinski, J.; Babinski, A.; Bozek, R.; Szepielow, A.; Baranowski, J.M.

    2001-04-18

    Post-growth thermal annealing effects on InAs/GaAs quantum dots (QDs) near Stransky-Krastanow transformation were investigated. Self-assembled QDs of average size of about 10 nm were grown by metal organic vapour phase epitaxy. The photoluminescence (PL) due to emission from QDs as well as two peaks due to emission from the strained InAs wetting layer (WL) were observed in as-grown samples. Bimodal structure of the WL PL was attributed to WL regions of different thickness. There was almost no difference in the PL spectrum after 30 s annealing at 600 C. However, annealing at temperatures in the range between 700 C and 950 C resulted in quenching of the PL from QDs and the thinner WL. The PL peak from the new, thicker WL blue-shifted and narrowed with increasing annealing temperature. This behavior was in agreement with TEM observations. Complete dissolution of the QDs and substantial broadening of the WL was observed. All our results indicate that thermally induced modifications of the WL rather than QDs can be responsible for the blue-shift and narrowing of the PL peaks in structures containing InAs QDs.

  16. Effects of annealing on self-assembled InAs quantum dots and wetting layer in GaAs matrix

    Energy Technology Data Exchange (ETDEWEB)

    Jasinski, J.; Babinski, A.; Bozek, R.; Szepielow, A.; Baranowski, J.M.

    2001-04-18

    Post-growth thermal annealing effects on InAs/GaAs quantum dots (QDs) near Stransky-Krastanow transformation were investigated. Self-assembled QDs of average size of about 10 nm were grown by metal-organic vapor phase epitaxy. The photoluminescence (PL) due to emission from QDs as well as two peaks due to emission from the strained InAs wetting layer (WL) were observed in as-grown samples. Bimodal structure of the WL PL was attributed to WL regions of different thickness. There was almost no difference in the PL spectrum after 30 s annealing at 600 C. However, annealing at temperatures in the range between 700 C and 950 C resulted in quenching of the PL from QDs and the thinner WL. The PL peak from the new, thicker WL blue-shifted and narrowed with increasing annealing temperature. This behavior was in agreement with TEM observations. Complete dissolution of the QDs and substantial broadening of the WL was observed. All our results indicate that thermally induced modifications of the WL rather than QDs can be responsible for the blue-shift and narrowing of the PL peaks in structures containing InAs QDs.

  17. Effects of Annealing on TiN Thin Film Growth by DC Magnetron Sputtering

    Directory of Open Access Journals (Sweden)

    Azadeh Jafari

    2014-07-01

    Full Text Available We have reviewed the deposition of titanium nitride (TiN thin films on stainless steel substrates by a DC magnetron sputtering method and annealing at different annealing temperatures of 500, 600, and 700°C for 120 min in nitrogen/argon atmospheres. Effects of annealing temperatures on the structural and the optical properties of TiN films were investigated using X-ray diffraction (XRD, atomic force microscope (AFM, field emission scanning electron microscopy (FESEM, and UV-VIS spectrophotometer. Our experimental studies reveal that the annealing temperature appreciably affected the structures, crystallite sizes, and reflection of the films. By increasing the annealing temperature to 700°C crystallinity and reflection of the film increase. These results suggest that annealed TiN films can be good candidate for tokamak first wall due to their structural and optical properties.

  18. A Large-Area Nanoplasmonic Sensor Fabricated by Rapid Thermal Annealing Treatment for Label-Free and Multi-Point Immunoglobulin Sensing.

    Science.gov (United States)

    Lin, Hana Tzu-Han; Yang, Chuan-Kai; Lin, Chi-Chen; Wu, Albert Meng-Hsin; Wang, Lon A; Huang, Nien-Tsu

    2017-05-02

    Immunoglobulins are important biomarkers to evaluate the immune status or development of infectious diseases. To provide timely clinical treatments, it is important to continuously monitor the level of multiple immunoglobulins. Localized surface plasmon resonance (LSPR)-based nanoplasmonic sensors have been demonstrated for multiplex immunoglobulins detection. However, the sensor fabrication process is usually slow and complicated, so it is not accessible for large-area and batch fabrication. Herein, we report a large-area (2 cm × 2 cm) nanofabrication method using physical vapor deposition followed by a rapid thermal annealing treatment. To optimize the sensor performance, we systematically characterized three fabrication conditions, including (1) the deposition thickness; (2) the maximum annealing temperature, and (3) the annealing time. The corresponding absorbance spectrum profile and surface morphology of the nanostructures were observed by a UV-VIS spectrometer and atomic force microscopy. We then tested the sensitivity of the sensor using a glucose solution at different concentrations. The results showed that the sensor with 10 nm gold deposition thickness under 5-min 900 °C rapid thermal annealing can achieve the highest sensitivity (189 nm RIU-1). Finally, we integrated this nanoplasmonic sensor with a microchannel and a motorized stage to perform a 10-spot immunoglobulin detection in 50 min. Based on its real-time, dynamic and multi-point analyte detection capability, the nanoplasmonic sensor has the potential to be applied in high-throughput or multiplex immunoassay analysis, which would be beneficial for disease diagnosis or biomedical research in a simple and cost-effective platform.

  19. Study of annealing effects in In–Sb bilayer thin films

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 30; Issue 2. Study of annealing effects in In–Sb bilayer thin films. R K Mangal Y K Vijay. Thin Films Volume 30 Issue 2 April 2007 pp 117-121 ... shows mixing effect after annealing at 433 K for 1 h. This study confirms mixing of bilayer structure of semiconductor thin films.

  20. Investigations of rapid thermal annealing induced structural evolution of ZnO: Ge nanocomposite thin films via GISAXS

    Energy Technology Data Exchange (ETDEWEB)

    Ceylan, Abdullah, E-mail: aceylanabd@yahoo.com [Department of Physics Eng., Hacettepe University, Beytepe, 06800 Ankara (Turkey); Ozcan, Yusuf [Department of Electricity and Energy, Pamukkale University, Denizli (Turkey); Orujalipoor, Ilghar [Department of Nanotechnology and Nanomedicine, Hacettepe University, Beytepe, 06800 Ankara (Turkey); Huang, Yen-Chih; Jeng, U-Ser [National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu, Taiwan (China); Ide, Semra [Department of Physics Eng., Hacettepe University, Beytepe, 06800 Ankara (Turkey); Department of Nanotechnology and Nanomedicine, Hacettepe University, Beytepe, 06800 Ankara (Turkey)

    2016-06-07

    In this work, we present in depth structural investigations of nanocomposite ZnO: Ge thin films by utilizing a state of the art grazing incidence small angle x-ray spectroscopy (GISAXS) technique. The samples have been deposited by sequential r.f. and d.c. sputtering of ZnO and Ge thin film layers, respectively, on single crystal Si(100) substrates. Transformation of Ge layers into Ge nanoparticles (Ge-np) has been initiated by ex-situ rapid thermal annealing of asprepared thin film samples at 600 °C for 30, 60, and 90 s under forming gas atmosphere. A special attention has been paid on the effects of reactive and nonreactive growth of ZnO layers on the structural evolution of Ge-np. GISAXS analyses have been performed via cylindrical and spherical form factor calculations for different nanostructure types. Variations of the size, shape, and distributions of both ZnO and Ge nanostructures have been determined. It has been realized that GISAXS results are not only remarkably consistent with the electron microscopy observations but also provide additional information on the large scale size and shape distribution of the nanostructured components.

  1. Dependence of N incorporation into (Ga)InAsN QDs on Ga content probed by rapid thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Gargallo-Caballero, R.; Guzman, A.; Ulloa, J.M.; Hierro, A.; Calleja, E. [Instituto de Sistemas Optoelectronicos y Microtecnologia (ISOM) - Departamento de Ingenieria Electronica, ETSI Telecomunicacion, Universidad Politecnica de Madrid (Spain); Hopkinson, M. [Department of Electronic and Electrical Engineering, EPSRC National Centre for III-V Technologies, University of Sheffield (United Kingdom)

    2009-06-15

    In this letter we demonstrate that the N incorporation into (Ga)InAsN quantum dots (QDs), grown on GaAs (100) by radio-frequency (RF) plasma assisted molecular beam epitaxy (MBE), is enhanced as the Ga content increases up to 30% and decreases for Ga contents higher than 30%. Thus, this effect exhibits a maximum N incorporation with a Ga content of 30%. Two sets of (Ga)InAsN QDs samples have been grown under the same growth conditions but with different N contents in one of them and with different Ga concentration in the other set. Optical analysis using Photoluminescence (PL) measurements of the as-grown and post growth rapid thermal annealed samples have been performed. The experimental results show a clear increase of the blueshift with the N concentration as occurred in dilute nitride quantum well (QW) structures. PL peak emission wavelength as high as 1.55{mu}m has been obtained from QDs capped with GaAs. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Impacts of thermal annealing temperature on memory properties of charge trapping memory with NiO nano-pillars

    Science.gov (United States)

    Yan, Xiaobing; Yang, Tao; Jia, Xinlei; Zhao, Jianhui; Zhou, Zhenyu

    2017-03-01

    In this work, Au/SiO2/NiO/SiO2/Si structure charge trapping memory using NiO as the charge trapping layer was fabricated, and the impacts of the annealing temperature on the charge trapping memory performance were investigated in detail. The sample thermal annealed at 750 °C indicated a large memory window of 2.07 V under a low sweeping voltage of ± 5 V, which also has excellent charge retention properties with only small charge loss of ∼4.9% after more than 104 s retention. The high resolved transmission electron microscopy shows that the NiO films grew as nano-pillars structure. It is proposed that the excellent memory characteristics of the device are attributed to the inherent atomic defects and oxygen vacancies accumulated by the grain boundaries around NiO nano-pillars. Meanwhile the interface inter-diffusion formed by thermal annealing process is also an indispensable factor for the excellent memory characteristics of the device.

  3. Effect of annealing over optoelectronic properties of graphene based transparent electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, Shriniwas, E-mail: sniwas89@gmail.com; Kaur, Inderpreet, E-mail: inderpreety@yahoo.co.in [Academy of Scientific and Innovative Research- Central Scientific Instruments Organisation (AcSIR-CSIO), Sector-30C, Chandigarh (India); Council of Scientific and Industrial Research- Central Scientific Instruments Organisation (CSIR-CSIO), Sector-30C, Chandigarh (India)

    2016-04-13

    Graphene, an atom–thick two dimensional graphitic material have led various fundamental breakthroughs in the field of science and technology. Due to their exceptional optical, physical and electrical properties, graphene based transparent electrodes have shown several applications in organic light emitting diodes, solar cells and thin film transistors. Here, we are presenting effect of annealing over optoelectronic properties of graphene based transparent electrodes. Graphene based transparent electrodes have been prepared by wet chemical approach over glass substrates. After fabrication, these electrodes tested for optical transmittance in visible region. Sheet resistance was measured using four probe method. Effect of thermal annealing at 200 °C was studied over optical and electrical performance of these electrodes. Optoelectronic performance was judged from ratio of direct current conductivity to optical conductivity (σ{sub dc}/σ{sub opt}) as a figure of merit for transparent conductors. The fabricated electrodes display good optical and electrical properties. Such electrodes can be alternatives for doped metal oxide based transparent electrodes.

  4. Effect of cryo-rolling and annealing on microstructure and properties of commercially pure aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Rangaraju, Nikhil [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600 036 (India); Raghuram, T. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600 036 (India); Krishna, B. Vamsi [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600 036 (India)]. E-mail: vamsi23@yahoo.com; Rao, K. Prasad [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600 036 (India); Venugopal, P. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600 036 (India)

    2005-05-25

    Influence of cryo-rolling reduction and annealing of commercially pure (CP) Al is evaluated in four aspects: microstructure, mechanical properties, electrical conductivity and general corrosion. It is shown that by selecting optimal cryo-rolling reduction and subsequent annealing condition result in ultrafine grains in CP Al with good combination of high strength and ductility. Electrical conductivity of the cryo-rolled samples decreased due to increased number of the electron scattering centers (lattice defects and grain boundary area). However, optimization of cryo-rolling and annealing treatment could restore the conductivity coupled with high strength in CP Al. Corrosion behaviour of cryo-rolled CP Al improved after annealing treatment. High dissolution rate and low thermal stability of the ultrafine grain structure could override the anticipated advantage of uniform corrosion in ultrafine grain CP Al.

  5. Investigation of Annealing and Blend Concentration Effects of Organic Solar Cells Composed of Small Organic Dye and Fullerene Derivative

    Directory of Open Access Journals (Sweden)

    Yasser A. M. Ismail

    2011-01-01

    Full Text Available We have fabricated bulk heterojunction organic solar cells using coumarin 6 (C6 as a small organic dye, for light harvesting and electron donation, with fullerene derivative [6,6]-phenyl-C61 butyric acid methyl ester (PCBM, acting as an electron acceptor, by spin-coating technique. We have investigated thermal annealing and blend concentration effects on light harvesting, photocurrent, and performance parameters of the solar cells. In this work, we introduced an experimental method by which someone can easily detect the variation in the contact between active layer and cathode due to thermal annealing after cathode deposition. We have showed, in this work, unusual behavior of solar cell composed of small organic molecules under the influence of thermal annealing at different conditions. This behavior seemed uncommon for polymer solar cells. We try from this work to understand device physics and to locate a relationship between production parameters and performance parameters of the solar cell based on small organic molecules.

  6. Effects of different annealing atmospheres on the properties of cadmium sulfide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Yücel, E., E-mail: dr.ersinyucel@gmail.com [Department of Physics, Faculty of Arts and Sciences, Mustafa Kemal University, 31034 Hatay (Turkey); Kahraman, S. [Department of Metallurgy and Material Engineering, Faculty of Technology, Mustafa Kemal University, 31034 Hatay (Turkey); Güder, H.S. [Department of Physics, Faculty of Arts and Sciences, Mustafa Kemal University, 31034 Hatay (Turkey)

    2015-08-15

    Graphical abstract: The effects of different annealing atmospheres (air and sulfur) on the structural, morphological and optical properties of CdS thin films were studied at three different pH values. - Highlights: • Compactness and smoothness of the films were enhanced after sulfur annealing. • Micro-strain values of some films were improved after sulfur annealing. • Dislocation density values of some films were improved after sulfur annealing. • Band gap values of the films were improved after sulfur annealing. - Abstract: Cadmium sulfide (CdS) thin films were prepared on glass substrates by using chemical bath deposition (CBD) technique. The effects of different annealing atmospheres (air and sulfur) on the structural, morphological and optical properties of CdS thin films were studied at three different pH values. Compactness and smoothness of the films (especially for pH 10.5 and 11) enhanced after sulfur annealing. pH value of the precursor solution remarkably affected the roughness, uniformity and particle sizes of the films. Based on the analysis of X-ray diffraction (XRD) patterns of the films, micro-strain and dislocation density values of the sulfur-annealed films (pH 10.5 and 11) were found to be lower than those of air-annealed films. Air-annealed films (pH 10.5, 11 and 11.5) exhibited higher transmittance than sulfur-annealed films in the wavelength region of 550–800 nm. Optical band gap values of the films were found between 2.31 eV and 2.36 eV.

  7. The effect of irradiation, annealing temperature, and artificial aging on the oxidation, mechanical properties, and fracture mechanisms of UHMWPE.

    Science.gov (United States)

    Luisetto, Yannick; Wesslen, Bengt; Maurer, Frans; Lidgren, Lars

    2003-12-01

    UHMWPE crosslinked using Gamma radiation is believed to have improved wear properties, and this has been extensively studied during the past 10 years. Mechanical properties, oxidation, and wear properties of UHMWPE materials subjected to various thermal treatments have been investigated immediately after irradiation as well as after several years of aging. Nevertheless, the relationship between all these parameters is not yet fully understood. The aim of this study was to investigate the relationship between the thermal treatments that could be applied to irradiated UHMWPE [lower (gamma 60) or higher (gamma 150) than 140 degrees C, the melting temperature of the polymer] and the mechanical properties, the oxidation and the fracture behavior of the material. The effect of artificial aging on these properties was also investigated. This study concludes that immediately after the annealing, the mechanical properties (UTS and epsilon) of the irradiated and annealed material are improved compared with those of nonirradiated material. Although nonirradiated material has higher fracture toughness than irradiated and annealed materials, the materials break according to the same mechanism of fracture. After aging, no changes could be observed in any of the measured properties for nonirradiated material. On the other hand, important changes could be seen in both irradiated and annealed material after aging. Both UTS and epsilon decreased, much more so in the case of gamma 60. Furthermore, the aging induced a subsurface peak of oxidation in both irradiated and annealed materials, twice as intense for gamma 60 than for gamma 150. The mechanism of fracture of these materials changed drastically after aging, probably due to the presence of the oxidation peak, which seems to occur at a location where cracks initiate easily compared with the nonoxidized bulk of the material. In the case of gamma 60, it seems clear that a correlation between mechanical property, oxidation, and

  8. Nickel-Doped Ceria Nanoparticles: The Effect of Annealing on Room Temperature Ferromagnetism

    Directory of Open Access Journals (Sweden)

    Joseph C. Bear

    2015-08-01

    Full Text Available Nickel-doped cerium dioxide nanoparticles exhibit room temperature ferromagnetism due to high oxygen mobility within the doped CeO2 lattice. CeO2 is an excellent doping matrix as it can lose oxygen whilst retaining its structure. This leads to increased oxygen mobility within the fluorite CeO2 lattice, leading to the formation of Ce3+ and Ce4+ species and hence doped ceria shows a high propensity for numerous catalytic processes. Magnetic ceria are important in several applications from magnetic data storage devices to magnetically recoverable catalysts. We investigate the effect doping nickel into a CeO2 lattice has on the room temperature ferromagnetism in monodisperse cerium dioxide nanoparticles synthesised by the thermal decomposition of cerium(III and nickel(II oleate metal organic precursors before and after annealing. The composition of nanoparticles pre- and post-anneal were analysed using: TEM (transmission electron microscopy, XPS (X-ray photoelectron spectroscopy, EDS (energy-dispersive X-ray spectroscopy and XRD (X-ray diffraction. Optical and magnetic properties were also studied using UV/Visible spectroscopy and SQUID (superconducting interference device magnetometry respectively.

  9. Annealing effect on properties of transparent and conducting ZnO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Bouderbala, M. [Laboratoire de Microscopie Electronique et des Sciences des Materiaux, Departement de Physique, USTO, B.P. 1505, El-Mnaouer, 31000 Oran (Algeria)], E-mail: boudermstf@yahoo.fr; Hamzaoui, S.; Adnane, M.; Sahraoui, T.; Zerdali, M. [Laboratoire de Microscopie Electronique et des Sciences des Materiaux, Departement de Physique, USTO, B.P. 1505, El-Mnaouer, 31000 Oran (Algeria)

    2009-01-01

    This work presents the effect of postdeposition annealing on the structural, electrical and optical properties of undoped ZnO (zinc oxide) thin films, prepared by radio-frequency sputtering method. Two samples, 0.17 and 0.32 {mu}m-thick, were annealed in vacuum from room temperature to 350 deg. C while another 0.32 {mu}m-thick sample was annealed in air at 300 deg. C for 1 h. X-ray diffraction analysis revealed that all the films had a c-axis orientation of the wurtzite structure normal to the substrate. Electrical measurements showed that the resistivity of samples annealed in vacuum decreased gradually with the increase of annealing temperature. For the 0.32 {mu}m-thick sample, the gradual decrease of the resistivity was essentially due to a gradual increase in the mobility. On the other hand, the resistivity of the sample annealed in air increased strongly. The average transmission within the visible wavelength region for all films was higher than 80%. The band gap of samples annealed in vacuum increased whereas the band gap of the one annealed in air decreased. The main changes observed in all samples of this study were explained in terms of the effect of oxygen chemisorption and microstructural properties.

  10. Post Deposition Annealing Effects on Optical, Electrical and Morphological Studies of ZnTTBPc Thin Films

    Directory of Open Access Journals (Sweden)

    B. R. Rejitha

    2012-01-01

    Full Text Available Phthalocyanines (Pcs act as efficient absorbants of photons in the visible region, specifically between 600 and 700 nm. It will produce an excited triplet state. In this paper we report the annealing effects of optical, electrical and surface morphological properties of thermal evaporated Zinc-tetra-tert-butyl-29H, 31H phthalocyanine (ZnTTBPc thin films. The optical transmittance measurements were done in the visible region (400-800 nm and, films were found to be absorbing in nature. From spectral data the absorption coefficient α, dielectric constant ε and the extinction coefficient k were evaluated and, results discussed. Also the optical band gap of the material was estimated. The activation energies were measured. Scanning electron microscopic studies was carried out to determine surface uniformity of films.

  11. Annealing effect on threading dislocations in a GaN grown on Si substrate

    Science.gov (United States)

    Iwata, H.; Kobayashi, H.; Kamiya, T.; Kamei, R.; Saka, H.; Sawaki, N.; Irie, M.; Honda, Y.; Amano, H.

    2017-06-01

    Effect of rapid thermal annealing (RTA) on crystal defects in a GaN layer grown on a (111)Si substrate was investigated by photoluminescence (PL) and transmission electron microscopy (TEM) analyses. The PL spectra suggested that the density of gallium vacancy is not changed by the heat treatment up to 700 °C. In the TEM specimen, we had dislocation half loops generated by off-axis propagation of the threading dislocation. We found that the half-loop of c-type dislocation shrinks/moves by a repetitive RTA at 600-700 °C. In contrast, we could find no remarkable changes in the a-type or a+c-type dislocations.

  12. The influence of thermal annealing on structure and oxidation of iron nanowires

    Directory of Open Access Journals (Sweden)

    Krajewski Marcin

    2015-03-01

    Full Text Available Raman spectroscopy as well as Mössbauer spectroscopy were applied in order to study the phase composition of iron nanowires and its changes, caused by annealing in a neutral atmosphere at several temperatures ranging from 200°C to 800°C. As-prepared nanowires were manufactured via a simple chemical reduction in an external magnetic field. Both experimental techniques proved formation of the surface layer covered by crystalline iron oxides, with phase composition dependent on the annealing temperature (Ta. At higher Ta, hematite was the dominant phase in the nanowires.

  13. Instantons in Quantum Annealing: Thermally Assisted Tunneling Vs Quantum Monte Carlo Simulations

    Science.gov (United States)

    Jiang, Zhang; Smelyanskiy, Vadim N.; Boixo, Sergio; Isakov, Sergei V.; Neven, Hartmut; Mazzola, Guglielmo; Troyer, Matthias

    2015-01-01

    Recent numerical result (arXiv:1512.02206) from Google suggested that the D-Wave quantum annealer may have an asymptotic speed-up than simulated annealing, however, the asymptotic advantage disappears when it is compared to quantum Monte Carlo (a classical algorithm despite its name). We show analytically that the asymptotic scaling of quantum tunneling is exactly the same as the escape rate in quantum Monte Carlo for a class of problems. Thus, the Google result might be explained in our framework. We also found that the transition state in quantum Monte Carlo corresponds to the instanton solution in quantum tunneling problems, which is observed in numerical simulations.

  14. Effect of annealing temperature on the characteristics of ZnO thin films

    Science.gov (United States)

    Chen, Yi; Jyoti, Nayak; Hyun-U, Ko; Kim, Jaehwan

    2012-11-01

    Effect of annealing temperature on characteristics of sol-gel driven ZnO thin film spin-coated on Si substrate was studied. The UV-visible transmittance of the sol decreased with the increase of the aging time and drastically reduced after 20 days aging time. Granular shape of ZnO crystallites was observed on the surface of the films annealed at 550, 650, and 750 °C, and the crystallite size increased with the increase of the annealing temperature. Consequently nodular shape of crystallites was formed upon increasing the annealing temperature to 850 °C and above. The current-voltage characteristics of the Schottky diodes fabricated with ZnO thin films with various annealing temperatures were measured and analyzed. It is found that, ZnO films showed the Schottky characteristics up to 750 °C annealing temperature. The Schottky diode characteristics were diminished upon increasing the annealing temperature above 850 °C. XPS analysis suggested that the absence of oxygen atoms in its oxidized state in stoichiometric surrounding, might be responsible for the diminished forward current of the Schottky diode when annealed above 850 °C.

  15. Effect of annealing temperature on the stress and structural properties of Ge core fibre

    Science.gov (United States)

    Zhao, Ziwen; Cheng, Xueli; Xue, Fei; He, Ting; Wang, Tingyun

    2017-09-01

    Effect of annealing temperature on the stress and structural properties of a Ge core fibre via the molten core drawing (MCD) method is investigated using Raman spectroscopy, Scanning electronic microscopy (SEM), and X-ray diffraction. The experimental results showed that the Raman peak position of the Ge fibre shifted from 297.6 cm-1 to 300.5 cm-1, and the FWHM value decreased from 4.53 cm-1 to 4.31 cm-1, when the annealing is carried out at 700 °C, 800 °C, and 900 °C, respectively. For the Ge core annealed at 900 °C, an apparent crystal grain can be seen in the SEM image, and the diffraction peaks of the (3 3 1) plane are generated in the X-ray diffraction spectra. These results show that optimising the annealing temperature allows the release of the residual stress in the Ge core. When the Ge core fibre is annealed at 900 °C, it exhibits the lowest residual stress and the highest crystal quality, and the quality improvement relative to that of the sample annealed at 800 °C is significant. Hence, annealing at around 900 °C can greatly improve the quality of a Ge core fibre. Further performance improvement of the Ge core fibre by annealing techniques can be anticipated.

  16. Effect of annealing on In{2}S{3} thin films prepared by flash evaporation

    Science.gov (United States)

    Bouabid, K.; Ihlal, A.; Amira, Y.; Sdaq, A.; Outzourhit, A.; Nouet, G.

    2007-11-01

    In{2}S{3} thin films were deposited by flash evaporation of In{2}S{3 } powder. The effect of annealing in vacuum and under sulphur and oxygen atmosphere on the structural, compositional and optical properties of these films was investigated. X-ray diffraction studies reveal that the as-deposited films are amorphous. The formation of β -In{2}S{3} phase is obtained after annealing under vacuum at 693 K or under sulphur pressure at a lower annealing temperature (573 K). The EDAX analysis reveals that the sulphurized films are nearly stoichiometric and those annealed in vacuum are sulphur deficient. Optical transmission spectra showed a slight shift of the absorption edge towards lower wavelengths. The optical gap value varied between 2.4 and 3 eV as a function of the film thickness, the annealing temperature and the atmosphere ambient.

  17. Combined current-modulation annealing induced enhancement of giant magnetoimpedance effect of Co-rich amorphous microwires

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jingshun, E-mail: jingshun-liu@163.com, E-mail: faxiang.qin@gmail.com [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot 010051 (China); Qin, Faxiang, E-mail: jingshun-liu@163.com, E-mail: faxiang.qin@gmail.com [1D Nanomaterials Group, National Institute for Material Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Chen, Dongming; Shen, Hongxian; Wang, Huan; Xing, Dawei; Sun, Jianfei [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Phan, Manh-Huong [Department of Physics, University of South Florida, Tampa, Florida 33620 (United States)

    2014-05-07

    We report on a combined current-modulation annealing (CCMA) method, which integrates the optimized pulsed current (PC) and DC annealing techniques, for improving the giant magnetoimpedance (GMI) effect and its field sensitivity of Co-rich amorphous microwires. Relative to an as-prepared Co{sub 68.2}Fe{sub 4.3}B{sub 15}Si{sub 12.5} wire, CCMA is shown to remarkably improve the GMI response of the wire. At 10 MHz, the maximum GMI ratio and its field sensitivity of the as-prepared wire were, respectively, increased by 3.5 and 2.28 times when subjected to CCMA. CCMA increased atomic order orientation and circumferential permeability of the wire by the co-action of high-density pulsed magnetic field energy and thermal activation energy at a PC annealing stage, as well as the formation of uniform circular magnetic domains by a stable DC magnetic field at a DC annealing stage. The magnetic moment can overcome eddy-current damping or nail-sticked action in rotational magnetization, giving rise to a double-peak feature and wider working field range (up to ±2 Oe) at relatively higher frequency (f ≥ 1 MHz)

  18. Combined current-modulation annealing induced enhancement of giant magnetoimpedance effect of Co-rich amorphous microwires

    Science.gov (United States)

    Liu, Jingshun; Qin, Faxiang; Chen, Dongming; Shen, Hongxian; Wang, Huan; Xing, Dawei; Phan, Manh-Huong; Sun, Jianfei

    2014-05-01

    We report on a combined current-modulation annealing (CCMA) method, which integrates the optimized pulsed current (PC) and DC annealing techniques, for improving the giant magnetoimpedance (GMI) effect and its field sensitivity of Co-rich amorphous microwires. Relative to an as-prepared Co68.2Fe4.3B15Si12.5 wire, CCMA is shown to remarkably improve the GMI response of the wire. At 10 MHz, the maximum GMI ratio and its field sensitivity of the as-prepared wire were, respectively, increased by 3.5 and 2.28 times when subjected to CCMA. CCMA increased atomic order orientation and circumferential permeability of the wire by the co-action of high-density pulsed magnetic field energy and thermal activation energy at a PC annealing stage, as well as the formation of uniform circular magnetic domains by a stable DC magnetic field at a DC annealing stage. The magnetic moment can overcome eddy-current damping or nail-sticked action in rotational magnetization, giving rise to a double-peak feature and wider working field range (up to ±2 Oe) at relatively higher frequency (f ≥ 1 MHz).

  19. Effect of Annealing Process on the Properties of Ni(55%)Cr(40%)Si(5%) Thin-Film Resistors.

    Science.gov (United States)

    Cheng, Huan-Yi; Chen, Ying-Chung; Li, Pei-Jou; Yang, Cheng-Fu; Huang, Hong-Hsin

    2015-10-02

    Resistors in integrated circuits (ICs) are implemented using diffused methods fabricated in the base and emitter regions of bipolar transistor or in source/drain regions of CMOS. Deposition of thin films on the wafer surface is another choice to fabricate the thin-film resistors in ICs' applications. In this study, Ni(55%)Cr(40%)Si(5%) (abbreviated as NiCrSi) in wt % was used as the target and the sputtering method was used to deposit the thin-film resistors on Al2O3 substrates. NiCrSi thin-film resistors with different thicknesses of 30.8 nm~334.7 nm were obtained by controlling deposition time. After deposition, the thin-film resistors were annealed at 400 °C under different durations in N₂ atmosphere using the rapid thermal annealing (RTA) process. The sheet resistance of NiCrSi thin-film resistors was measured using the four-point-probe method from 25 °C to 125 °C, then the temperature coefficient of resistance could be obtained. We aim to show that resistivity of NiCrSi thin-film resistors decreased with increasing deposition time (thickness) and the annealing process had apparent effect on the sheet resistance and temperature coefficient of resistance. We also aim to show that the annealed NiCrSi thin-film resistors had a low temperature coefficient of resistance (TCR) between 0 ppm/°C and +50 ppm/°C.

  20. Effect of Austenite Stability on Microstructural Evolution and Tensile Properties in Intercritically Annealed Medium-Mn Lightweight Steels

    Science.gov (United States)

    Song, Hyejin; Sohn, Seok Su; Kwak, Jai-Hyun; Lee, Byeong-Joo; Lee, Sunghak

    2016-06-01

    The microstructural evolution with varying intercritical-annealing temperatures of medium-Mn ( α + γ) duplex lightweight steels and its effects on tensile properties were investigated in relation to the stability of austenite. The size and volume fraction of austenite grains increased as the annealing temperature increased from 1123 K to 1173 K (850 °C to 900 °C), which corresponded with the thermodynamic calculation data. When the annealing temperature increased further to 1223 K (950 °C), the size and volume fraction were reduced by the formation of athermal α'-martensite during the cooling because the thermal stability of austenite deteriorated as a result of the decrease in C and Mn contents. In order to obtain the best combination of strength and ductility by a transformation-induced plasticity (TRIP) mechanism, an appropriate mechanical stability of austenite was needed and could be achieved when fine austenite grains (size: 1.4 μm, volume fraction: 0.26) were homogenously distributed in the ferrite matrix, as in the 1123 K (850 °C)—annealed steel. This best combination was attributed to the requirement of sufficient deformation for TRIP and the formation of many deformation bands at ferrite grains in both austenite and ferrite bands. Since this medium-Mn lightweight steel has excellent tensile properties as well as reduced alloying costs and weight savings, it holds promise for new automotive applications.

  1. Analysis of Blockade in Charge Transport Across Polymeric Heterojunctions as a Function of Thermal Annealing: A Different Perspective

    Science.gov (United States)

    Rathi, Sonika; Chauhan, Gayatri; Gupta, Saral K.; Srivastava, Ritu; Singh, Amarjeet

    2017-02-01

    A blend of poly(3-hexylthiophene-2,5diyl) (P3HT) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) is popularly used as an active medium in polymeric solar devices. According to the most recent understanding, the blend is a three-phase system contrary to its earlier understanding of two-phase bicontinuous network. We have synthesized a P3HT-PCBM based layered heterostructure system by spin coating and thermal vacuum evaporations. Current density ( J) was measured as a function of applied electric field ( E) across the system bound between two metal electrodes. J- E relations were analyzed into the backdrop of space charge limited current model and Schottky model. The later was used to predict dc-dielectric constants from the linear slopes of ln ( J) versus E 1/2. The curves were not monotonously linear, but observe a knee-bend separating into two linear segments for each curve. Thermal annealing from 40°C to 80°C was used as an activation tool for driving changes in the internal morphology via inter-diffusion of polymers and current measurements were performed at room temperature after each annealing. At the last stage of annealing the two linear slopes were highly distinct. The presence of sharp knee-bend results in approximately 20 times jump in dielectric constant as a function of electric field. Such high jumps in dielectric constant illustrate the potential for switching applications and charge storage. The high dielectric constants can be understood in terms of space charge polarization due to isolated domains which hindrance to charge transport. The high dielectric constants were confirmed by another experiment of capacitance measurements of a different set of similar samples. A study of thermal evolution of internal morphology was also carried out using x-ray diffraction and scanning electron microscopy techniques to correlate the morphological changes with the transport properties.

  2. Study of annealing effects in Al–Sb bilayer thin films

    Indian Academy of Sciences (India)

    annealing and characterization of these films. 2. Experimental. 2.1 Sample preparation. The samples of Al–Sb were prepared by thermal evaporation method using Hind High Vacuum coating unit at a pressure of 10–5 torr. High purity aluminum (99⋅999%) and anti- mony powder (99⋅5%) were used. The glass substrates.

  3. Study of annealing effects in In–Sb bilayer thin films

    Indian Academy of Sciences (India)

    TECS

    was deposited by thermal evaporation method on ITO coated conducting glass substrates at room tempera- ture and a ... transmission spectra of as deposited and annealed films have been carried out at room temperature. The variation in optical ... pound semiconductor thin films, as it provides good control of composition ...

  4. Contacts realization by rapid thermal annealing in multicrystalline silicon solar cells with special emphasis on metal influence

    Energy Technology Data Exchange (ETDEWEB)

    El Omari, H.; Boyeaux, J.P.; Laugier, A. [Institut National des Sciences Appliquees de Lyon, Villeurbanne (France). Lab. de Physique de la Matiere

    1994-12-31

    To improve the quality of the screen printing contacts, the authors have previously shown the capability to sinter the screen printed contacts by Rapid Thermal Annealing (RTA) instead of commercial sintering; they have also noticed that the commonly used TiO{sub 2} coating deposited by spray enhances the quality of the contact either with classical annealing or RTA. The aim of the present work is to analyze the metal influence on either front or back contacts realization by RTA on Polix p type multicrystalline silicon subsequently phosphorus diffused. The screen printed contact was replaced by the chosen metal dot obtained by evaporation. The authors have studied: Al/TiO{sub 2}; Ag/Al/TiO{sub 2}; Cu/Al/TiO{sub 2}; Pt/Al/TiO{sub 2} and Cu/Cr/TiO{sub 2}. The RTA treatments were carried out at various temperatures and annealing time in an Ar ambience. The quality of the contacts are analyzed from I(V) characteristics, and possible diffusions of metallic species are characterized by SIMS experiments.

  5. Effect of annealing on phase transition in poly (vinylidene fluoride ...

    Indian Academy of Sciences (India)

    The -phase poly (vinylidene fluoride) (PVDF) films are usually prepared using dimethyl sulfoxide (DMSO) solvent, regardless of preparation temperature. Here we report the crystallization of both and -phase PVDF films by varying preparation temperature using DMSO solvent. The -phase PVDF films were annealed ...

  6. The effects of Mg incorporation and annealing temperature on the ...

    Indian Academy of Sciences (India)

    Antibacterial assay demonstrated that Mg-doped ZnO with 7% Mg content annealed at 400◦C had the strongest antibacterialactivity against {\\it Listeria monocytogenes} (98.7%). This study indicated that the inhibition rate of ZnO nanoparticles increased with the formation of granular structure and the decrease of ZnO size ...

  7. Effect of annealing process of iron powder on magnetic properties ...

    Indian Academy of Sciences (India)

    Administrator

    Abstract. Iron powder magnetic cores are used as soft magnetic rotors, in micro special motors such as BS brake motors, refrigerator compressor motors and brushless servo motors. Heat treatment of iron powder played an important role in the magnetic properties and loss of the motor cores. After the annealing process,.

  8. Effect of annealing process of iron powder on magnetic properties ...

    Indian Academy of Sciences (India)

    Iron powder magnetic cores are used as soft magnetic rotors, in micro special motors such as BS brake motors, refrigerator compressor motors and brushless servo motors. Heat treatment of iron powder played an important role in the magnetic properties and loss of the motor cores. After the annealing process, the cracks ...

  9. Effect of Annealing, Stoichiometry, and Surface on Magnetism of (Pr,DyFeCoB Microparticles Ensemble

    Directory of Open Access Journals (Sweden)

    Kablov E.N.

    2017-09-01

    Full Text Available Magnetic properties of powder (Pr,DyFeCoB ferrimagnetic alloys and effects of annealing, surface states were analyzed. X-ray photoelectron spectroscopy and Mössbauer spectra of powders indicate the effect of surface states on phase composition and magnetic properties of the studied powder, if particles average size is smaller than 10 μm. Effect of stoichiometry on magnetic anisotropy was found. Thermal stability of anisotropy field was proved by replacement of Fe atoms with Co atoms.

  10. Chemical and electrical characterisation of the segregation of Al from a CuAl alloy (90%:10% wt) with thermal anneal

    Energy Technology Data Exchange (ETDEWEB)

    Byrne, C., E-mail: conor.byrne2@mail.dcu.ie [School of Physical Sciences, Dublin City University, Dublin 9 (Ireland); Brady, A.; Walsh, L.; McCoy, A.P.; Bogan, J. [School of Physical Sciences, Dublin City University, Dublin 9 (Ireland); McGlynn, E. [School of Physical Sciences, National Centre for Plasma Science and Technology, Dublin City University, Dublin 9 (Ireland); Rajani, K.V. [School of Electronic Engineering, Dublin City University, Dublin 9 (Ireland); Hughes, G. [School of Physical Sciences, Dublin City University, Dublin 9 (Ireland); School of Physical Sciences, National Centre for Plasma Science and Technology, Dublin City University, Dublin 9 (Ireland)

    2016-01-29

    A copper–aluminium (CuAl) alloy (90%:10% wt) has been investigated in relation to segregation of the alloying element Al, from the alloy bulk during vacuum anneal treatments. X-ray photoelectron spectroscopy (XPS) measurements were used to track the surface enrichment of Al segregating from the alloy bulk during in situ ultra-high vacuum anneals. Secondary ion mass spectroscopy (SIMS) indicates a build-up of Al at the surface of the annealed alloy relative to the bulk composition. Metal oxide semiconductor (MOS) CuAl/SiO{sub 2}/Si structures show a shift in flatband voltage upon thermal anneal consistent with the segregation of the Al to the alloy/SiO{sub 2} interface. Electrical four point probe measurements indicate that the segregation of Al from the alloy bulk following thermal annealing results in a decrease in film resistivity. X-ray diffraction data shows evidence for significant changes in crystal structure upon annealing, providing further evidence for expulsion of Al from the alloy bulk. - Highlights: • CuAl alloy (90%:Al 10% wt) deposited and vacuum annealed • XPS and SIMS data show segregation of Al from the alloy bulk. • Chemical changes seen indicate the reduction of Cu oxide and growth of Al Oxide. • Electrical measurements indicate a chemical change at the metal/SiO{sub 2} interface. • All data consistent with Cu diffusion barrier layer formed.

  11. Effects of gamma irradiation and post-irradiation annealing on carbon/epoxy UDC properties deduced by methods of local loading

    Science.gov (United States)

    Sekulic, Danijela; Stevanovic, M. M.

    2011-05-01

    Hardness and Young's modulus of the matrix and fibers in carbon/epoxy gamma irradiated and annealed composites were investigated using nanoindentation technique. The Vickers microhardness of the tested composites after irradiation and annealing was studied, as well. Gamma irradiation to various doses (5-27 MGy) of UDC plates, were followed by thermal treatments of irradiated coupons at 180 and 250 °C, in vacuum. The measured changes of nano and micro properties were correlated to glass transition temperatures, as well as the delamination toughness changes, determined earlier on the same material. The established irradiation and annealing effects on nanoindentation properties and Vickers mocrohardness were analyzed as a function of the matrix plasticity change. An attempt was made to assess the contribution of chain scission mechanism and the change in plasticity mechanism on the property changes from irradiation and subsequent thermal treatments.

  12. Metamorphosis of strain/stress on optical band gap energy of ZAO thin films via manipulation of thermal annealing process

    Energy Technology Data Exchange (ETDEWEB)

    Malek, M.F., E-mail: firz_solarzelle@yahoo.com [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); NANO-SciTech Centre (NST), Institute of Science (IOS), Universiti Teknologi MARA UiTM, 40450 Shah Alam, Selangor (Malaysia); Mamat, M.H. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Musa, M.Z. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM) Pulau Pinang, Jalan Permatang Pauh, 13500 Permatang Pauh, Pulau Pinang (Malaysia); Soga, T. [Department of Frontier Materials, Nagoya Institute of Technology (NITech), Nagoya 466-8555 (Japan); Rahman, S.A. [Low Dimensional Materials Research Centre (LDMRC), Department of Physics, Faculty of Science, Universiti Malaya (UM), 50603 Kuala Lumpur (Malaysia); Alrokayan, Salman A.H.; Khan, Haseeb A. [Department of Biochemistry, College of Science, King Saud University (KSU), Riyadh 11451 (Saudi Arabia); Rusop, M. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); NANO-SciTech Centre (NST), Institute of Science (IOS), Universiti Teknologi MARA UiTM, 40450 Shah Alam, Selangor (Malaysia)

    2015-04-15

    We report on the growth of Al-doped ZnO (ZAO) thin films prepared by the sol–gel technique associated with dip-coating onto Corning 7740 glass substrates. The influence of varying thermal annealing (T{sub a}) temperature on crystallisation behaviour, optical and electrical properties of ZAO films has been systematically investigated. All films are polycrystalline with a hexagonal wurtzite structure with a preferential orientation according to the direction 〈0 0 2〉. The metamorphosis of strain/stress effects in ZAO thin films has been investigated using X-ray diffraction. The as growth films have a large compressive stress of 0.55 GPa, which relaxed to 0.25 GPa as the T{sub a} was increased to 500 °C. Optical parameters such as optical transmittance, absorption coefficient, refractive index and optical band gap energy have been studied and discussed with respect to T{sub a}. All films exhibit a transmittance above 80–90% along the visible–NIR range up to 1500 nm and a sharp absorption onset below 400 nm corresponding to the fundamental absorption edge of ZnO. Experimental results show that the tensile stress in the films reveals an incline pattern with the optical band gap energy, while the compressive stress shows opposite relation. - Highlights: • Minimum stress of highly c-axis oriented ZAO was grown at suitable T{sub a} temperature. • The ZAO crystal orientation was influenced by strain/stress of the film. • Minimum stress/strain of ZAO film leads to lower defects. • Bandgap and defects were closely intertwined with strain/stress. • We report additional optical and electrical properties based on T{sub a} temperature.

  13. Annealing effects on the magnetic properties of a multifilamentary Cu-Nb composite

    Energy Technology Data Exchange (ETDEWEB)

    Sandim, M J R [Departamento de Engenharia de Materiais, FAENQUIL, CP 116, 12600-000, Lorena, SP (Brazil); Sandim, H R Z [Departamento de Engenharia de Materiais, FAENQUIL, CP 116, 12600-000, Lorena, SP (Brazil); Shigue, C Y [Departamento de Engenharia de Materiais, FAENQUIL, CP 116, 12600-000, Lorena, SP (Brazil); Filgueira, M [LAMAV, UENF, 28015-620, Campos dos Goytacazes, RJ (Brazil); Ghivelder, L [Instituto de Fisica, UFRJ, CP 68528, 21945-970, Rio de Janeiro, RJ (Brazil)

    2003-03-01

    In this paper, the annealing effects on the magnetic properties of a multifilamentary Cu-15vol%Nb composite were investigated. During vacuum annealing, noticeable changes take place in the microstructure, mostly the partial spheroidization and further coarsening of the niobium filaments. Results show that spheroidization becomes noticeable at about 700 deg. C and, even after annealing at severe conditions, e.g. 1050 deg C for 32 h, the continuity of the niobium-conducting path is partially preserved. The influence of these microstructural changes on the magnetic properties of the multifilamentary Cu-Nb composite conductor is discussed.

  14. Annealing effects on electrical, structural, and surface morphological properties of Ir/n-InGaN Schottky structures

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, V. Rajagopal; Padma, R.; Reddy, M.S.P. [Department of Physics, Sri Venkateswara University, Tirupati (India); Choi, C.J. [School of Semiconductor and Chemical Engineering, Semiconductor Physics Research Center (SPRC), Chonbuk National University, Jeonju (Korea, Republic of)

    2012-10-15

    The effects of thermal annealing on electrical and structural characteristics of iridium (Ir) Schottky contacts to n-type InGaN have been studied using current-voltage (I-V), capacitance-voltage (C-V), secondary ion mass spectrometer (SIMS), and X-ray diffraction (XRD) measurements. Measurements showed that the Schottky barrier height (SBH) of as-deposited sample is 0.79 eV (I-V) and 1.07 eV (C-V). It is observed that the barrier height increases to 0.85 eV (I-V) and 1.21 eV (C-V) after annealing at 300 C for 1 min in N{sub 2} ambient. However, it is found that the SBH slightly decreases when the contacts are annealed at 400 and 500 C and the corresponding values are 0.84 eV (I-V), 1.17 eV (C-V) for 400 C and 0.80 eV (I-V), 1.11 eV (C-V) for 500 C, respectively. Using Cheung's functions, the barrier height ({Phi}{sub b}), ideality factor (n), and series resistance (R{sub s}) are also calculated. From the above results, it is clear that the optimum annealing temperature for Ir Schottky contact is 300 C. SIMS and XRD results shows that the formation of gallide phases at Ir/n-InGaN interfaces could be the reason for variation in the SBHs upon annealing at elevated temperatures. Atomic force microscopy (AFM) results show that the overall surface morphology of Ir Schottky contacts on n-InGaN stays reasonably smooth. These results make Ir Schottky contacts attractive for high-temperature device applications. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Effect of annealing on properties of sputtered and nitrogen-implanted ZnO:Ga thin films

    Directory of Open Access Journals (Sweden)

    Vojs M.

    2012-07-01

    Full Text Available Thin films of gallium-doped zinc oxide (ZnO:Ga were deposited on Corning glass substrates by rf diode sputtering and then implanted with 180 keV nitrogen ions in the dose range of 1 × 1015 ÷ 2 × 1016 cm-2. After the ion implantation, the films were annealed under oxygen and nitrogen ambient, at different temperatures and time, and the effect on their microstructure, type and range of conductivity, and optical properties was investigated. Post-implantation annealing at 550 °C resulted in n-type conductivity films with the highest electron concentration of 1.4 × 1020 cm-3. It was found that the annealing parameters had a profound impact on the film’s properties. A p-type conductivity (a hole concentration of 2.8 × 1019 cm-3, mobility of 0.6 cm2/V s was observed in a sample implanted with 1 × 1016 cm-2 after a rapid thermal annealing (RTA in N2 at 400 °C. Optical transmittance of all films was >84% in the wavelength range of 390–1100 nm. The SIMS depth profile of the complex 30NO− ions reproduces well a Gaussian profile of ion implantation. XRD patterns reveal a polycrystalline structure of N-implanted ZnO:Ga films with a c-axis preferred orientation of the crystallites. Depending on the annealing conditions, the estimated crystallite size increased 25 ÷ 42 nm and average micro-strains decreased 1.19 × 10-2 ÷ 6.5 × 10-3 respectively.

  16. Thermal stability of RuO sub 2 -based bottom electrodes during various ambient annealings

    CERN Document Server

    Ahn, J H; Choi, G P; Choi, W Y; Kim, H G; Lee, W J; Yoon, S G

    1999-01-01

    RuO sub 2 thin films were prepared on SiO sub 2 /Si, TiN/SiO sub 2 /Si and Ru/poly-Si by using DC magnetron sputtering. The annealing of the RuO sub 2 -based bottom electrodes was performed in oxygen and argon ambients and in high vacuum in the temperature range of 400 .deg. C approx 800 .deg. C. In oxygen-ambient annealing, the surface morphology was drastically changed due to the evaporation of ruthenium dioxides in the form of RuO sub 3 and RuO sub 4. The RuO sub 2 thin film annealed in high vacuum was reduced to the Ru metal phase. Evaporation and reduction of the RuO sub 2 thin films could actually be observed during the deposition of (Ba,Sr)TiO sub 3 thin films. oxygen diffusion through the RuO sub 2 /diffusion barrier/poly-Si structures is also discussed

  17. Formation of ZnGa2O4 films by multilayer deposition and subsequent thermal annealing

    Science.gov (United States)

    Yan, Jin-Liang; Zhao, Yin-Nü; Li, Chao

    2014-04-01

    The Ga2O3/ZnO multilayer films are deposited on quartz substrates by magnetron sputtering, the thickness values of Ga2O3 layers are in a range of 19 nm-2.5 nm and the thickness of ZnO layer is a constant of 1 nm. Formation of spinel ZnGa2O4 film is achieved via the annealing of the Ga2O3/ZnO multilayer film. The influences of original Ga2O3 sublayer thickness on the optical and structural properties of Ga2O3/ZnO multilayer films and annealed films are studied. With the decrease of the thickness of Ga2O3 sublayer, the optical band-gap of Ga2O3/ZnO multilayer film decreases, the intensity of UV emission diminishes and the intensity of violet emission increases. The annealed film displays the enlarged optical band gap and the quenched violet emission. UV fluorescence bands are observed from Ga2O3 and ZnGa2O4.

  18. Effect of working pressure and annealing temperature on ...

    Indian Academy of Sciences (India)

    In this paper, Ba0.6Sr0.4TiO3 thin film has been deposited on the SiO2/Si substrate by the pulsed laser deposition (PLD) technique at three different oxygen working pressures of 100, 220 and 350 mTorr. Then the deposited thin films at 100 mTorr oxygen pressure were annealed for 50 min in oxygen ambient at three ...

  19. Effect of high heating rate on thermal decomposition behaviour of ...

    Indian Academy of Sciences (India)

    but rely on the concentration of hydrogen. The model ... first-order rate law. Lehmhus and Rausch (2004) have annealed TiH2 pow- der in air and argon. In argon, the powder does not develop a surface layer and as a result, a small amount of hydro- gen is lost ... rate effect on the thermal decomposition behaviour of TiH2.

  20. The effect of annealing on the elastoplastic and viscoelastic responses of isotactic polypropylene

    DEFF Research Database (Denmark)

    Drozdov, Aleksey D.; Christiansen, Jesper de Claville

    2002-01-01

    Observations are reported on isotactic polypropylene (i) in a series of tensile tests with a constant strain rate on specimens annealed for 24 h at various temperatures in the range from 110to 150 C, (ii) in two series of creep tests in the subyield region of deformations on samples not subjected...... to thermal treatment and on specimens annealed at 140 C, and (iii) in a series of tensile relaxation tests on non-annealed specimens. Constitutive equations are derived for the elastoplastic and non-linear viscoelastic responses of semicrystalline polymers. A polymer is treated as an equivalent transient...... equations for isothermal deformations with small strains are derived by using the laws of thermodynamics. Adjustable parameters in the stress–strain relations are found by fitting the experimental data. 2003 Elsevier Science B.V. All rights reserved....

  1. Effect of annealing temperature on structural, optical and electrical properties of hydrothermal assisted zinc oxide nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Narayanan, Guru Nisha; Sankar Ganesh, R.; Karthigeyan, A., E-mail: karthigeyan.a@ktr.srmuniv.ac.in

    2016-01-01

    Zinc oxide nanorods were grown employing a low cost hydrothermal method on microslide glass substrates pre-coated with ZnO seed layer. The as grown nanorods were annealed in air at 350 °C, 450 °C and 550 °C. The effect of annealing at different temperatures on morphology, structural, optical and electrical properties was investigated using field emission scanning electron microscopic, X-ray diffraction, UV–vis spectral, photoluminescence and electrical studies. The X-ray diffraction pattern of all the samples showed wurtzite structure preferentially oriented along the c-axis (0 0 2) direction. It was found that diameter of the nanorods increased with increasing of annealing temperature. The UV–vis absorption spectra showed a red shift from which it was inferred that the optical bandgap of the material decreases from 3.33 eV to 3.28 eV with increase in annealing temperature. Photoluminescence measurements showed increase in the UV emission intensity with respect to annealing temperature and also produced additional peaks attributed to defects and impurities. Annealing the ZnO nanorod structures at various temperatures evidently showed that the sample annealed at 550 °C acquired the lowest resistivity about 1.62 × 10{sup −4} Ω-cm. - Highlights: • ZnO nanorods were synthesized by hydrothermal method on microslide glass substrates. • Pre-deposited ZnO seeds were used. • Structural, optical and electrical properties of ZnO nanorods were studied. • Crystalline structure of ZnO nanorods was improved with increase in annealing temperature. • Resistivity decrease was observed with increase in the annealing temperature.

  2. Effect of Annealing on Nature of Corrosion Damages of Medium-nickel Austenitic Cast Iron

    Directory of Open Access Journals (Sweden)

    Medyński D.

    2017-09-01

    Full Text Available Within the presented research, effect of annealing on nature of corrosion damages of medium-nickel austenitic nodular cast iron castings, containing 5.5% to 10.3% Ni, was determined. Concentration of nickel, lower than in the Ni-Resist cast iron, was compensated with additions of other austenite-stabilising elements (manganese and copper. In consequence, raw castings with austenitic matrix structure and gravimetrically measured corrosion resistance increasing along with nickel equivalent value EquNi were obtained. Annealing of raw castings, aimed at obtaining nearly equilibrium structures, led to partial austenite-to-martensite transformation in the alloys with EquNi value of ca. 16%. However, corrosion resistance of the annealed alloys did not decrease in comparison to raw castings. Annealing of castings with EquNi value above 18% did not cause any structural changes, but resulted in higher corrosion resistance demonstrated by smaller depth of corrosion pits.

  3. Annealing effect on nano-ZnO powder studied from positron lifetime and optical absorption spectroscopy

    Science.gov (United States)

    Dutta, Sreetama; Chattopadhyay, S.; Jana, D.; Banerjee, A.; Manik, S.; Pradhan, S. K.; Sutradhar, Manas; Sarkar, A.

    2006-12-01

    Mechanical milling and subsequent annealing in air at temperatures between 210 and 1200°C have been carried out on high purity ZnO powder to study the defect generation and recovery in the material. Lowering of average grain size (from 76±1to22±0.5nm) as a result of milling has been estimated from the broadening of x-ray lines. Substantial grain growth in the milled sample occurs above 425°C annealing temperature. Positron annihilation lifetime (PAL) analysis of the samples shows a distinct decrease of the average lifetime of positrons very near the same temperature zone. As indicated from both x-ray diffraction (XRD) and PAL results, high temperature (>700°C) annealed samples have a better crystallinity (or lower defect concentration) than even the nonmilled ZnO. In contrast, the measured optical band gap of the samples (from absorption spectroscopy) does not confirm lowering of defects with high temperature annealing. Thermally generated defects at oxygen sites cause significant modification of the optical absorption; however, they are not efficient traps for positrons. Different thermal stages of generation and recovery of cationic as well as anionic defects in granular ZnO are discussed in the light of XRD, PAL, and optical absorption studies.

  4. Magnetic Characteristics of Mn-Implanted GaN Nanorods Followed by Thermal Annealing

    OpenAIRE

    Im Taek Yoon; Yoon Shon; Younghae Kwon; Park, Young S.; Chang Soo Park; Tae Won Kang

    2012-01-01

    We have investigated the magnetic and optical properties of dislocation-free vertical GaN nanorods with diameters of 150 nm grown on (111) Si substrates by radio-frequency plasma-assisted molecular-beam epitaxy followed by Mn ion implantation and annealing. The GaN nanorods are fully relaxed and have a very good crystal quality characterized by extremely strong and narrow photoluminescence excitonic lines near 3.47 eV. For GaMnN nanorods, it can be concluded that the ferromagnetic property of...

  5. Microstructural and Fractographic Characterization of a Thermally Embrittled Nuclear Grade Steel: Part I - Annealing

    Directory of Open Access Journals (Sweden)

    Tarpani José R.

    2002-01-01

    Full Text Available A nuclear reactor pressure vessel steel was submitted to different annealing heat treatments aimed at simulating neutron irradiation damage. The obtained microstructures were mechanically tested with subsequent metallographic and fractographic characterization. The relevant microstructural and fractographic aspects were employed in the interpretation of the mechanical behavior of the microstructures in both quasi-static (J-R curve and dynamic (Charpy impact loading regimes. A well defined relationship was determined between the elastic-plastic fracture toughness parameter J-integral and the Charpy impact energy for very most of the microstructures.

  6. Thermal Cycle Annealing and its Application to Arsenic-Ion Implanted HgCdTe

    Science.gov (United States)

    2014-06-26

    Bromine- Methanol , two methanol rinses followed by 45 seconds dip in the Benson etch and finally a de-ionized water rinse. Computer software was used...annealed sample into several smaller pieces and subjecting each piece to shallow or deeper Bromine- Methanol etch followed by only 20 seconds of the...Beam Epitaxy Grown HgCdTe/Si Layers," Journal of Electronic Materials, 2009. [7] T. Sasaki and N. Oda, "Dislocation reduction in HgCdTe on GaAs by

  7. Effect of annealing on the magnetic properties of ball milled NiO powders

    Energy Technology Data Exchange (ETDEWEB)

    Kisan, Bhagaban [Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781039 (India); Saravanan, P. [Defence Metallurgical Research laboratory, Hyderabad 500058 (India); Layek, Samar; Verma, H.C. [Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208016 (India); Hesp, David; Dhanak, Vinod [Department of Physics, University of Liverpool, Liverpool L69 3BX (United Kingdom); Krishnamurthy, Satheesh [Materials Engineering, The Open University, Milton Keynes MK7 6AA (United Kingdom); Perumal, A., E-mail: perumal@iitg.ernet.in [Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781039 (India)

    2015-06-15

    We report systematic investigations on structural and magnetic properties of nanosized NiO powders prepared by the ball milling process followed by systematic annealing at different temperatures. Both as-milled and annealed NiO powders exhibit face centered cubic structure, but average crystallite size decreases (increases) with increasing milling time (annealing temperature). Pure NiO exhibits antiferromagnetic nature, which transforms into ferromagnetic one with moderate moment at room temperature with decreasing crystallite size. The on-set of ferromagnetic behavior in the as-milled powders was observed at higher temperatures (>750 K) as compared to bulk Ni (~630 K). On the other hand, annealing of as-milled powders showed a large reduction in magnetic moment and the rate of decrease of moment strongly depends on the milling conditions. The observed properties are discussed on the basis of crystallite size variation, defect density, oxidation/reduction of Ni and interaction between uncompensated surfaces and particle core with lattice expansion. - Highlights: • Preparation of fine NiO powder using top-to-bottom approach using planetary ball mill. • Effect of milling on instituting room temperature ferromagnetism with size reduction. • Stability of ferromagnetic properties at high temperatures in milled NiO powders • Effect of annealing process on the structural properties of milled NiO powders. • Understanding the origin of ferromagnetism at 300 K in NiO powders through annealing.

  8. Tritium release from neutron irradiated beryllium: Kinetics, long-time annealing and effect or crack formation

    Energy Technology Data Exchange (ETDEWEB)

    Scaffidi-Argentina, F.; Werle, H. [Forschungszentrum Karlsruhe, (Germany)

    1995-09-01

    Since beryllium is considered as one of the best neutron multiplier materials in the blanket of the next generation fusion reactors, several studies have been started to evaluate its behaviour under irradiation during both operating and accidental conditions. Based on safety considerations, tritium produced in beryllium during neutron irradiation represents one important issue, therefore it is necessary to investigate tritium transport processes by using a comprehensive mathematical model and comparing its predictions with well characterized experimental tests. Because of the difficulties in extrapolating the short-time tritium release tests to a longer time scale, also long-time annealing experiments with beryllium samples from the SIBELIUS irradiation. have been carried out at the Forschungszentrum Karlsruhe. Samples were annealed up to 12 months at temperatures up to 650{degrees}C. The inventory after annealing was determined by heating the samples up to 1050{degrees}C with a He+0.1 vo1% H{sub 2} purge gas. Furthermore, in order to investigate the likely effects of cracks formation eventually causing a faster tritium release from beryllium, the behaviour of samples irradiated at low temperature (40-50{degrees}C) but up to very high fast neutron fluences (0.8-3.9{center_dot}10{sup 22} cm{sup -2}, E{sub n}{ge}1 MeV) in the BR2 reactor has been investigated. Tritium was released by heating the beryllium samples up to 1050{degrees}C and purging them with He+0.1 vo1% H{sub 2}. Tritium release from high-irradiated beryllium samples showed a much faster kinetics than from the low-irradiated ones, probably because of crack formation caused by thermal stresses in the brittle material and/or by helium bubbles migration. The obtained experimental data have been compared with predictions of the code ANFIBE with the goal to better understand the physical mechanisms governing tritium behaviour in beryllium and to assess the prediction capabilities of the code.

  9. Atmospheric pulsed laser deposition and thermal annealing of plasmonic silver nanoparticle films

    Science.gov (United States)

    Khan, T. M.; Mujawar, M. A.; Siewerska, K. E.; Pokle, A.; Donnelly, T.; McEvoy, N.; Duesberg, G. S.; Lunney, J. G.

    2017-11-01

    A new method for pulsed laser deposition of plasmonic silver nanoparticle (NP) films in flowing gas at atmospheric pressure is described. The ablation was done using an excimer laser at 248 nm. Fast optical imaging shows that the ablation plume is captured by the flowing gas, and is expected to form a NP aerosol, which is carried 5-20 mm to the substrate. The dependence of the deposition rate on laser fluence, gas flow velocity, and target-substrate distance was investigated using electron microscopy and absorption spectroscopy of the deposited films. The NP films were annealed in argon and hydrogen at 400 °C, and in air for temperatures in the range 200 °C-900 °C, leading to strong enhancement, and narrowing of the surface plasmon resonance. The films were used for surface enhanced Raman spectroscopy of a 10-5 molar solution of Rhodamine 6G; films annealed in air at 400 °C were five times more sensitive than the as-deposited films.

  10. ZnO films synthesized by thermal annealing of ZnSe/GaAs heterostructures

    Science.gov (United States)

    Maksimov, Oleg

    2008-03-01

    ZnO received much attention due to its potential application for the fabrication of ultraviolet light emitters and photodetectors. High crystalline quality films were grown using MBE, PLD, and CVD on Al2O3, GaN, SiC, and other substrates. However, further progress in this area is slowed down by the difficulties associated with doping ZnO p-type. Here, we report on the synthesis and doping of ZnO films using the annealing of MBE-grown ZnSe/GaAs heterostructures in the controlled environment. Se is displaced by oxygen through the reaction: 2ZnSe + 3O2-> 2ZnO + 2SO2. In addition, As migrating from the GaAs substrate into the ZnO layer, promotes p-type doping. While ZnGa2O4, ZnO2, and other second phases form as the result of high temperature annealing (>700^oC), stoichiometric ZnO films are obtained at moderate temperatures (˜500^oC). Films processed under optimized conditions exhibit sharp band edge emission, narrow rocking curve, and are comparable with the ZnO films grown on the GaAs substrates using other techniques. I would like to acknowledge support from the Office of Naval Research under grant N00014-06-1-1018.

  11. Quantum annealing with manufactured spins.

    Science.gov (United States)

    Johnson, M W; Amin, M H S; Gildert, S; Lanting, T; Hamze, F; Dickson, N; Harris, R; Berkley, A J; Johansson, J; Bunyk, P; Chapple, E M; Enderud, C; Hilton, J P; Karimi, K; Ladizinsky, E; Ladizinsky, N; Oh, T; Perminov, I; Rich, C; Thom, M C; Tolkacheva, E; Truncik, C J S; Uchaikin, S; Wang, J; Wilson, B; Rose, G

    2011-05-12

    Many interesting but practically intractable problems can be reduced to that of finding the ground state of a system of interacting spins; however, finding such a ground state remains computationally difficult. It is believed that the ground state of some naturally occurring spin systems can be effectively attained through a process called quantum annealing. If it could be harnessed, quantum annealing might improve on known methods for solving certain types of problem. However, physical investigation of quantum annealing has been largely confined to microscopic spins in condensed-matter systems. Here we use quantum annealing to find the ground state of an artificial Ising spin system comprising an array of eight superconducting flux quantum bits with programmable spin-spin couplings. We observe a clear signature of quantum annealing, distinguishable from classical thermal annealing through the temperature dependence of the time at which the system dynamics freezes. Our implementation can be configured in situ to realize a wide variety of different spin networks, each of which can be monitored as it moves towards a low-energy configuration. This programmable artificial spin network bridges the gap between the theoretical study of ideal isolated spin networks and the experimental investigation of bulk magnetic samples. Moreover, with an increased number of spins, such a system may provide a practical physical means to implement a quantum algorithm, possibly allowing more-effective approaches to solving certain classes of hard combinatorial optimization problems.

  12. XPS study of surface chemistry of tungsten carbides nanopowders produced through DC thermal plasma/hydrogen annealing process

    Science.gov (United States)

    Krasovskii, Pavel V.; Malinovskaya, Olga S.; Samokhin, Andrey V.; Blagoveshchenskiy, Yury V.; Kazakov, Valery А.; Ashmarin, Artem А.

    2015-06-01

    X-ray photoelectron spectroscopy (XPS) has been employed to characterize the surface composition and bonding of the tungsten carbides nanopowders produced through a DC thermal plasma/hydrogen annealing process. The XPS results were complemented with those from Raman spectroscopy, high-resolution transmission electron microscopy, and evolved gas analysis. The products of the DC plasma synthesis are the high-surface-area multicarbide mixtures composed mainly of crystalline WC1-x and W2C. The materials are contaminated with a pyrolitic carbonaceous deposit which forms ∼1 nm thick graphitic overlayers on the nanoparticles' surface. The underlying carbides are not oxidized in ambient air, and show no interfacial compounds underneath the graphitic overlayers. When annealed in hydrogen, the multicarbide mixtures undergo transformation into the single-phase WC nanopowders with an average particle size of 50-60 nm. The surface of the passivated and air-exposed WC nanopowders is stabilized by an ultrathin, no more than 0.5 nm in thickness, chemically heterogeneous overlayer, involving graphitic, carbon-to-oxygen, and WO3 bonding. Oxygen presents at coverages above a monolayer preferentially in the bonding configurations with carbon. The surface segregations of carbon are normally observed, even when the bulk content of carbon is below the stoichiometric level.

  13. Non-thermal alloyed ohmic contact process of GaN-based HEMTs by pulsed laser annealing

    Science.gov (United States)

    Tzou, An-Jye; Hsieh, Dan-Hua; Chen, Szu-Hung; Li, Zhen-Yu; Chang, Chun-Yen; Kuo, Hao-Chung

    2016-05-01

    We have demonstrated Si implantation incorporation into GaN HEMTs with a non-alloyed ohmic contact process. We optimized the power density of pulsed laser annealing to activate implanted Si dopants without a thermal metallization process. The experimental results show that the GaN surface will be reformed under the high power density of the illumination conditions. It provides a smooth surface for following contact engineering and leads to comparable contact resistance. The transmission line model (TLM) measurement shows a lower contact resistance to 6.8 × 10-7 Ω · cm2 via non-alloyed contact technology with significantly improved surface morphology of the contact metals. DC measurement of HEMTs shows better current and on-resistance. The on-resistance could be decreased from 2.18 to 1.74 mΩ-cm2 as we produce a lower contact resistance. Pulsed laser annealing also results in lower gate leakage and smaller dispersion under a pulse I-V measurement, which implies that the density of the surface state is improved.

  14. Growth Mechanism and Surface Structure of Ge Nanocrystals Prepared by Thermal Annealing of Cosputtered GeSiO Ternary Precursor

    Directory of Open Access Journals (Sweden)

    Bo Zhang

    2014-01-01

    Full Text Available Ge nanocrystals (Ge-ncs embedded in a SiO2 superlattice structure were prepared by magnetron cosputtering and postdeposition annealing. The formation of spherical nanocrystals was confirmed by transmission electron microscopy and their growth process was studied by a combination of spectroscopic techniques. The crystallinity volume fraction of Ge component was found to increase with crystallite size, but its overall low values indicated a coexistence of crystalline and noncrystalline phases. A reduction of Ge-O species was observed in the superlattice during thermal annealing, accompanied by a transition from oxygen-deficient silicon oxide to silicon dioxide. A growth mechanism involving phase separation of Ge suboxides (GeOx was then proposed to explain these findings and supplement the existing growth models for Ge-ncs in SiO2 films. Further analysis of the bonding structure of Ge atoms suggested that Ge-ncs are likely to have a core-shell structure with an amorphous-like surface layer, which is composed of GeSiO ternary complex. The surface layer thickness was extracted to be a few angstroms and equivalent to several atomic layer thicknesses.

  15. The effect of annealing on the nonlinear viscoelastic response of isotactic polypropylene

    DEFF Research Database (Denmark)

    Drozdov, Aleksey D.; Christiansen, Jesper de Claville

    2002-01-01

    Three series of tensile relaxation tests are performed on isotactic polypropylene at room temperature in the vicinity of the yield point. In the first series of experiments, injection-molded samples are used without thermal pre-treatment. In the second and third series. the specimens are annealed...... at 130°C for 4 and 24 hours, respectively. Constitutive equations are derived for the time-dependent response of semicrystalline polymers at isothermal loading with small strains. A polymer is treated as an equivalent temporary network of macromolecules bridged by junctions (physical cross...... spectrum (characterized by the distribution of MRs with various potential energies) is independent of mechanical factors, but is altered at annealing. For specimens not subjected to thermal treatment, the growth of longitudinal strain does not affect the volume fraction of active MRs and the attempt rate...

  16. Effect of annealing on pulse laser deposition grown copper oxide thin film

    Science.gov (United States)

    Mistry, Vaibhavi H.; Mistry, Bhaumik V.; Modi, B. P.; Joshi, U. S.

    2017-05-01

    Cuprous oxide (Cu2O) is a promising non-toxic and low cost semiconductor with potential applications in photovoltaic devices and sensor applications. Copper oxide thin films were prepared on glass substrate by pulse laser deposition. The effects of annealing on the structural, optical and electrical properties of copper oxide thin films were studied. The films were annealed in air for different temperature ranging from 200 to 450 °C. X-ray diffraction patterns reveals that the films as-deposited and annealed at 200 and 250 °C are of cuprite structure with composition Cu2O. Annealing at 300 °C and above converts these films to CuO phase. The atomic force microscopy results show that both the phase has nanocrystalline and particle size of the films is increasing with increase in annealing temperature. The conversion from Cu2O to CuO phase was confirmed by a shift in the optical band gap from 2.20 eV to 1.74 eV. The annealing conditions play a major role in the structural properties of copper oxide thin films.

  17. Enhanced Photoelectrochemical Behavior of H-TiO2 Nanorods Hydrogenated by Controlled and Local Rapid Thermal Annealing.

    Science.gov (United States)

    Wang, Xiaodan; Estradé, Sonia; Lin, Yuanjing; Yu, Feng; Lopez-Conesa, Lluis; Zhou, Hao; Gurram, Sanjeev Kumar; Peiró, Francesca; Fan, Zhiyong; Shen, Hao; Schaefer, Lothar; Braeuer, Guenter; Waag, Andreas

    2017-12-01

    Recently, colored H-doped TiO2 (H-TiO2) has demonstrated enhanced photoelectrochemical (PEC) performance due to its unique crystalline core-disordered shell nanostructures and consequent enhanced conduction behaviors between the core-shell homo-interfaces. Although various hydrogenation approaches to obtain H-TiO2 have been developed, such as high temperature hydrogen furnace tube annealing, high pressure hydrogen annealing, hydrogen-plasma assisted reaction, aluminum reduction and electrochemical reduction etc., there is still a lack of a hydrogenation approach in a controlled manner where all processing parameters (temperature, time and hydrogen flux) were precisely controlled in order to improve the PEC performance of H-TiO2 and understand the physical insight of enhanced PEC performance. Here, we report for the first time a controlled and local rapid thermal annealing (RTA) approach to prepare hydrogenated core-shell H-TiO2 nanorods grown on F:SnO2 (FTO) substrate in order to address the degradation issue of FTO in the typical TiO2 nanorods/FTO system observed in the conventional non-RTA treated approaches. Without the FTO degradation in the RTA approach, we systematically studied the intrinsic relationship between the annealing temperature, structural, optical, and photoelectrochemical properties in order to understand the role of the disordered shell on the improved photoelectrochemical behavior of H-TiO2 nanorods. Our investigation shows that the improvement of PEC performance could be attributed to (i) band gap narrowing from 3.0 to 2.9 eV; (ii) improved optical absorption in the visible range induced by the three-dimensional (3D) morphology and rough surface of the disordered shell; (iii) increased proper donor density; (iv) enhanced electron-hole separation and injection efficiency due to the formation of disordered shell after hydrogenation. The RTA approach developed here can be used as a suitable hydrogenation process for TiO2 nanorods/FTO system for

  18. Effects of field annealing on Gilbert damping of polycrystalline CoFe thin films

    Science.gov (United States)

    Zhou, Jing; Chen, Shaohai; Lin, Weinan; Qin, Qing; Liu, Liang; He, Shikun; Chen, Jingsheng

    2017-11-01

    The effects of annealing and magnetic field annealing on the Gilbert damping constant of polycrystalline CoFe thin films were investigated. Angle dependent ferromagnetic resonance (FMR) demonstrates that an in-plane (IP) anisotropy is developed by field annealing which dramatically reduces the effective Gilbert damping constant. An inverse relation between effective IP anisotropic field and effective damping is shown by FMR measurement in cryogenic environment. This relation is further confirmed in bilayer films of IrMn/CoFe where a strong in-plane unidirectional anisotropy is developed. A large effective IP anisotropic field is possibly associated with a smaller distribution of local fields which reduces the FMR linewidths and subsequently effective damping.

  19. Evolution of free volume in ultrasoft magnetic FeZrN films during thermal annealing

    NARCIS (Netherlands)

    Chechenin, NG; van Veen, A; Schut, H; Chezan, AR; Boerma, DO; Vystavel, T; De Hosson, JTM; DeHaven, PW; Field, DP; Harkness, SD; Sutliff, JA; Szpunar, JA; Tang, L; Thomson, T; Vaudin, MD

    2002-01-01

    The thermal stability of nanocrystalline ultra-soft magnetic (Fe98Zr2)(1-x)N-x films with x=0.10-0.25 was studied using high-resolution transmission electron microscopy (HRTEM), positron beam analysis (PBA) and thermal desorption spectrometry (TDS). The results demonstrate that grain growth during

  20. The effect of different annealing temperatures on tin and cadmium telluride phases obtained by a modified chemical route

    Energy Technology Data Exchange (ETDEWEB)

    Mesquita, Anderson Fuzer [Departamento de Química, CCE, Universidade Federal do Espírito Santo, Campus Goiabeiras, 29075-910 Vitória, Espírito Santo (Brazil); Porto, Arilza de Oliveira, E-mail: arilzaporto@yahoo.com.br [Departamento de Química, ICEx, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais (Brazil); Magela de Lima, Geraldo [Departamento de Química, ICEx, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais (Brazil); Paniago, Roberto [Departamento de Física, ICEx, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais (Brazil); Ardisson, José Domingos [Centro de Desenvolvimento da Tecnologia Nuclear, CDTN/CNEN, Belo Horizonte, Minas Gerais (Brazil)

    2012-11-15

    Graphical abstract: Display Omitted Highlights: ► Synthesis of cadmium and tin telluride. ► Chemical route to obtain pure crystalline cadmium and tin telluride. ► Effect of the annealing temperature on the crystalline phases. ► Removal of tin oxide as side product through thermal treatment. -- Abstract: In this work tin and cadmium telluride were prepared by a modification of a chemical route reported in the literature to obtain metallacycles formed by oxidative addition of tin-tellurium bonds to platinum (II). Through this procedure it was possible to obtain tin and cadmium telluride. X-ray diffraction and X-ray photoelectron spectroscopy were used to identify the crystalline phases obtained as well as the presence of side products. In the case of tin telluride it was identified potassium chloride, metallic tellurium and tin oxide as contaminants. The tin oxidation states were also monitored by {sup 119}Sn Mössbauer spectroscopy. The annealing in hydrogen atmosphere was chosen as a strategy to reduce the tin oxide and promote its reaction with the excess of tellurium present in the medium. The evolution of this tin oxide phase was studied through the annealing of the sample at different temperatures. Cadmium telluride was obtained with high degree of purity (98.5% relative weight fraction) according to the Rietveld refinement of X-ray diffraction data. The modified procedure showed to be very effective to obtain amorphous tin and cadmium telluride and the annealing at 450 °C has proven to be useful to reduce the amount of oxide produced as side product.

  1. Hydrophobic switching nature of methylcellulose ultra-thin films: thickness and annealing effects

    Energy Technology Data Exchange (ETDEWEB)

    Innis-Samson, Vallerie Ann; Sakurai, Kenji, E-mail: sakurai@yuhgiri.nims.go.jp [University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577 (Japan)

    2011-11-02

    We have studied the thermosensitive property of methylcellulose (MC) thin films supported on Si substrate by static sessile drop contact angle measurements, and their surface properties and thin film structure by x-ray reflectivity (XRR) and atomic force microscopy (AFM) techniques. From the static sessile drop contact angle measurements, the MC thin films showed the characteristic hydrophilic-to-hydrophobic transition at {approx}70 {sup 0}C, which is the lower critical solution temperature of the bulk solution volume phase separation transition. For films with thickness d {<=} R{sub g}, the onset of such a transition is affected by the film thickness while very thick films, d >> R{sub g}, yielded higher contact angles. Annealing the MC thin films with thicknesses {approx}200 A (near the radius of gyration, R{sub g}, of the polymer) below the bulk glass transition temperature (T{sub g} {approx} 195 deg. C) would not change the hydrophobic switch nature of the film but annealing 'at' and above the bulk T{sub g} would change its surface property. From surface topography images by AFM, there were no significant changes in either the roughness or the film texture before and after annealing. With XRR data, we were able to determine that such changes in the surface properties are highly correlated to the film thickness changes after the annealing process. This study, we believe, is the first to examine the thermal annealing affects on the thermal response function of a thermoresponsive polymer and is important for researching how to tailor the hydrophobic switching property of MC thin films for future sensing applications. (paper)

  2. Correlation between Pd metal thickness and thermally stable perpendicular magnetic anisotropy features in [Co/Pd]n multilayers at annealing temperatures up to 500 °C

    Directory of Open Access Journals (Sweden)

    Gwang Guk An

    2015-02-01

    Full Text Available We examine highly stable perpendicular magnetic anisotropy (PMA features of [Co/Pd]10 multilayers (MLs versus Pd thickness at various ex-situ annealing temperatures. Thermally stable PMA characteristics were observed up to 500 °C, confirming the suitability of these systems for industrial applications at this temperature. Experimental observations suggest that the choice of equivalent Co and Pd layer thicknesses in a ML configuration ensures thermally stable PMA features, even at higher annealing temperatures. X-ray diffraction patterns and cross-sectional transmission electron microscopy images were obtained to determine thickness, post-annealing PMA behavior, and to explore the structural features that govern these findings.

  3. Structural Reorganization of CNC in Injection-Molded CNC/PBAT Materials under Thermal Annealing.

    Science.gov (United States)

    Mariano, Marcos; El Kissi, Nadia; Dufresne, Alain

    2016-10-04

    Composite materials were prepared by extrusion and injection molding from polybutyrate adipate terephthalate (PBAT) and high aspect ratio cellulose nanocrystals (CNCs) extracted from capim dourado fibers. Three CNC contents were used, corresponding to 0.5, 1, and 2 times the theoretical percolation threshold. Small-amplitude oscillary shear (SAOS) experiments show that as the CNC content increases, a more elastic behavior is observed but no percolating network can form within the polymeric matrix as a result of the high shear rates involved during the injection-molding process. Annealing of the samples at 170 °C was performed, and the possible reorganization of the nanofiller was investigated. This reorganization was further elucidated using 2D-SAOS and creep experiments.

  4. Effect Of Low-Temperature Annealing On The Properties Of Ni-P Amorphous Alloys Deposited Via Electroless Plating

    Directory of Open Access Journals (Sweden)

    Zhao Guanlin

    2015-06-01

    Full Text Available Amorphous Ni-P alloys were prepared via electroless plating and annealing at 200°C at different times to obtain different microstructures. The effects of low-temperature annealing on the properties of amorphous Ni-P alloys were studied. The local atomic structure of the annealed amorphous Ni-P alloys was analyzed by calculating the atomic pair distribution function from their X-ray diffraction patterns. The results indicate that the properties of the annealed amorphous Ni-P alloys are closely related to the order atomic cluster size. However, these annealed Ni-P alloys maintained their amorphous structure at different annealing times. The variation in microhardness is in agreement with the change in cluster size. By contrast, the corrosion resistance of the annealed alloys in 3.5 wt% NaCl solution increases with the decrease in order cluster size.

  5. Effect of RF power and annealing on chemical bonding and morphology of a-CN{sub x} thin films as humidity sensor

    Energy Technology Data Exchange (ETDEWEB)

    Aziz, N. F. H; Hussain, N. S. Mohamed; Awang, R. [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia); Ritikos, R.; Kamal, S. A. A. [Low Dimensional Materials Research Centre, Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2013-11-27

    Amorphous carbon nitride (a-CN{sub x}) thin films were deposited using radio frequency plasma enhanced chemical vapor deposition (rf-PECVD) technique. A set of a-CN{sub x} thin films were prepared using pure methane (CH{sub 4}) gas diluted with nitrogen (N{sub 2}) gas. The rf power was varied at 50, 60, 70, 80, 90 and 100 W. These films were then annealed at 400 °C in a quartz tube furnace in argon (Ar) gas. The effects of rf power and thermal annealing on the chemical bonding and morphology of these samples were studied. Surface profilometer was used to measure film thickness. Fourier transform infra-red spectroscopy (FTIR) and Field emission scanning electron microscopy (FESEM) measurements were used to determine their chemical bonding and morphology respectively. The deposition rate of the films increased constantly with increasing rf power up to 80W, before decreasing with further increase in rf power. Fourier transform infra-red spectroscopy (FTIR) studies showed a systematic change in the spectra and revealed three main peaks included C-N, C=N, C=C and C≡N triple bond. C=N and C≡N bonds decreased with increased C-N bonds after thermal annealing process. The FESEM images showed that the structure is porous for as-deposited and covered by granule-like grain structure after thermal annealing process was done. The resistance of the a-CN{sub x} thin film changed from 23.765 kΩ to 5.845 kΩ in the relative humidity range of 5 to 92 % and the film shows a good response and repeatability as a humidity sensing materials. This work showed that rf power and thermal annealing has significant effects on the chemical bonding and surface morphology of the a-CN{sub x} films and but yield films which are potential candidate as humidity sensor device.

  6. Effect of annealing on structural and optical properties of Cu{sub 2}ZnSnS{sub 4} thin films grown by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Surgina, G.D., E-mail: silvereye@bk.ru [National Research Nuclear University “Moscow Engineering Physics Institute”, Moscow 115409 (Russian Federation); Moscow Institute of Physics and Technology, Dolgoprudny, Moscow region 141700 (Russian Federation); Nevolin, V.N. [National Research Nuclear University “Moscow Engineering Physics Institute”, Moscow 115409 (Russian Federation); P.N. Lebedev Physical Institute of the Russian Academy of Sciences, Moscow 119991 (Russian Federation); Sipaylo, I.P.; Teterin, P.E. [National Research Nuclear University “Moscow Engineering Physics Institute”, Moscow 115409 (Russian Federation); Medvedeva, S.S. [Immanuel Kant Baltic Federal University, Kaliningrad 236041 (Russian Federation); Lebedinsky, Yu.Yu.; Zenkevich, A.V. [National Research Nuclear University “Moscow Engineering Physics Institute”, Moscow 115409 (Russian Federation); Moscow Institute of Physics and Technology, Dolgoprudny, Moscow region 141700 (Russian Federation)

    2015-11-02

    In this work, we compare the effect of different types of thermal annealing on the morphological, structural and optical properties of Cu{sub 2}ZnSnS{sub 4} (CZTS) thin films grown by reactive Pulsed Laser Deposition in H{sub 2}S flow. Rutherford backscattering spectrometry, atomic force microscopy, X-ray diffraction, Raman spectroscopy and optical spectrophotometry data reveal dramatic increase of the band gap and the crystallite size without the formation of secondary phases upon annealing in N{sub 2} at the optimized conditions. - Highlights: • Cu{sub 2}ZnSnS{sub 4} (CZTS) thin films were grown at room temperature. • Reactive Pulsed Laser Deposition in H{sub 2}S flow was used as a growth method. • Effect of annealing conditions on CZTS structural and optical properties is revealed. • Both the grain size and the band gap of CZTS film increase following the annealing. • Annealing in N{sub 2} effectively inhibits the formation of Sn{sub x}S secondary phases.

  7. Effect of annealing on the mechanical and scratch properties of BCN films obtained by magnetron sputtering deposition

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Shuyan, E-mail: xsynefu@126.com [Key Laboratory of Forest Sustainable Management and Environmental Microorganism Engineering of Heilongjiang Province, Northeast Forestry University, Harbin 150040 (China); Ma, Xinxin [School of Material Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Wen, Huiying [Key Laboratory of Forest Sustainable Management and Environmental Microorganism Engineering of Heilongjiang Province, Northeast Forestry University, Harbin 150040 (China); Tang, Guangze [School of Material Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Li, Chunwei [Key Laboratory of Forest Sustainable Management and Environmental Microorganism Engineering of Heilongjiang Province, Northeast Forestry University, Harbin 150040 (China)

    2014-09-15

    Highlights: • The amorphous BCN films were annealed at different temperatures under vacuum condition. • The order degree increases with the annealing temperature increasing, and the films do not decompose even the annealing temperature rise to 1000 °C. • The nano-hardness and modulus of the films decrease with the increasing of annealing temperatures. • The critical load of BCN films is not affected by the annealing temperature, and the films have good interfacial adhesion. • The scratch resistance properties of BCN film are improved by annealing at 600 °C. - Abstract: Boron-carbon-nitride (BCN) films have been fabricated by direct current unbalanced magnetron sputtering. Boron carbide/graphite compound and a mixture of nitrogen and argon are used as target and carrier gas, respectively, during BCN synthesis. The obtained BCN films are annealed at different temperatures under vacuum condition. The effect of annealing temperature on the structure, mechanical properties and scratch behavior of the BCN films has been investigated. The results indicate that no decomposition products are found even the BCN films are annealed at 1000 °C. The hardness and elastic modulus of the films decrease with the increase of annealing temperatures. The BCN film annealed at 600 °C has the strongest scratch resistance. The friction coefficient of all BCN films is in range of 0.05 to 0.15.

  8. Influence of homo-buffer layers and post-deposition rapid thermal annealing upon atomic layer deposition grown ZnO at 100 °C with three-pulsed precursors per growth cycle

    Science.gov (United States)

    Cheng, Yung-Chen; Yuan, Kai-Yun; Chen, Miin-Jang

    2017-10-01

    ZnO main epilayers are deposited with three-pulsed precursors in every growth cycle at 100 °C on various thicknesses of 300 °C-grown homo-buffer layers by atomic layer deposition (ALD) on sapphire substrate. Samples are treated without and with post-deposition rapid thermal annealing (RTA). Two different annealing temperatures 300 and 1000 °C are utilized in the ambience of oxygen for 5 min. Extremely low background electron concentration 8.4 × 1014 cm-3, high electron mobility 62.1 cm2/V s, and pronounced enhancement of near bandgap edge photoluminescence (PL) are achieved for ZnO main epilayer with sufficient thickness of buffer layer (200 ALD cycles) and post-deposition RTA at 1000 °C. Effective block and remove of thermally unstable mobile defects and other crystal lattice imperfections are the agents of quality promotion of ZnO thin film.

  9. A novel method for biopolymer surface nanostructuring by platinum deposition and subsequent thermal annealing

    National Research Council Canada - National Science Library

    Slepička, Petr; Juřík, Petr; Kolská, Zdeňka; Malinský, Petr; Macková, Anna; Michaljaničová, Iva; Švorčík, Václav

    2012-01-01

    .... The surface properties of sputtered platinum layers on the biocompatible polymer poly(l-lactic acid) (PLLA) are presented. The influence of thermal treatment on surface morphology and electrical resistance and Pt distribution in ca...

  10. Effect of Annealing Process on the Properties of Ni(55%Cr(40%Si(5% Thin-Film Resistors

    Directory of Open Access Journals (Sweden)

    Huan-Yi Cheng

    2015-10-01

    Full Text Available Resistors in integrated circuits (ICs are implemented using diffused methods fabricated in the base and emitter regions of bipolar transistor or in source/drain regions of CMOS. Deposition of thin films on the wafer surface is another choice to fabricate the thin-film resistors in ICs’ applications. In this study, Ni(55%Cr(40%Si(5% (abbreviated as NiCrSi in wt % was used as the target and the sputtering method was used to deposit the thin-film resistors on Al2O3 substrates. NiCrSi thin-film resistors with different thicknesses of 30.8 nm~334.7 nm were obtained by controlling deposition time. After deposition, the thin-film resistors were annealed at 400 °C under different durations in N2 atmosphere using the rapid thermal annealing (RTA process. The sheet resistance of NiCrSi thin-film resistors was measured using the four-point-probe method from 25 °C to 125 °C, then the temperature coefficient of resistance could be obtained. We aim to show that resistivity of NiCrSi thin-film resistors decreased with increasing deposition time (thickness and the annealing process had apparent effect on the sheet resistance and temperature coefficient of resistance. We also aim to show that the annealed NiCrSi thin-film resistors had a low temperature coefficient of resistance (TCR between 0 ppm/°C and +50 ppm/°C.

  11. Effect of ambient atmosphere in the annealing of indium tin oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Steckl, A.J.; Mohammed, G.

    1980-07-01

    Isochronal annealing experiments on dc-sputtered indium tin oxide (ITO) films in inert (N/sub 2/), reducing (N/sub 2//H/sub 2/) and oxidizing atmospheres were cumulatively performed over the 50..-->..500..-->..50 /sup 0/C range. Three anneal regimes have been identified. In region I, T/sub A/=50..-->..200 /sup 0/C, crystallization occurs, resulting in a sharp drop in sheet resistance (R/sub s/) due to increasing mobility. T/sub A/approx. =200 /sup 0/C results in a minimum R/sub s/. In region II, 200..-->..500..-->..200 /sup 0/C, R/sub s/ is proportional to T/sub A/, increasing (decreasing) during the forward (reverse) anneal cycle. This behavior is apparently due to a temperature-dependent active oxygen concentration and its effect on the carrier concentration. In region III, 200..-->..50 /sup 0/C, R/sub s/ is constant with T/sub A/. Optical transmission and x-ray diffraction experiments were performed at 100 /sup 0/C intervals. Successive anneals tended to increase the transmission in the visible and near-UV regions and to decrease it in the near- and far-IR region. Strong evidence of the Burstein-Moss shift was observed and an extrapolated intrinsic band gap of 3.85 eV was determined. Free-carrier absorption over the 2--5-..mu..m regions was evident after the 200 /sup 0/C anneal for all ambients. From the x-ray data, no evidence of crystallinity was observed in the as-deposited case and for anneals up to 100 /sup 0/C. For anneals in the 300--500 /sup 0/C range, a grain size of the order of 600 A with an orientation normal to the (222) plane was observed for all ambients.

  12. Annealing effect on physical properties of evaporated molybdenum oxide thin films for ethanol sensing

    Energy Technology Data Exchange (ETDEWEB)

    Touihri, S., E-mail: s_touihri@yahoo.fr [Unité de Physique des Dispositifs a semi-conducteurs, Faculté des sciences de Tunis, Tunis El Manar University, 2092 Tunis (Tunisia); Arfaoui, A.; Tarchouna, Y. [Unité de Physique des Dispositifs a semi-conducteurs, Faculté des sciences de Tunis, Tunis El Manar University, 2092 Tunis (Tunisia); Labidi, A. [Laboratoire Matériaux, Molécules et Applications, IPEST, BP 51 La Marsa 2070, Tunis (Tunisia); Amlouk, M. [Unité de Physique des Dispositifs a semi-conducteurs, Faculté des sciences de Tunis, Tunis El Manar University, 2092 Tunis (Tunisia); Bernede, J.C. [LUNAM, Universite de Nantes, Moltech Anjou, CNRS, UMR 6200, FSTN, 2 Rue de la houssiniere, BP 92208, Nantes F-44322 (France)

    2017-02-01

    Highlights: • Thermally grown molybdenum oxide films are amorphous, oxygen deficient and gas sensing. • Air or vacuum annealing transforms them into a sub-stoichiometric MoO{sub 3−x} phase. • The samples annealed at 500 °C in oxygen were crystallized and identified as pure orthorhombic MoO{sub 3} phase. • The conduction process and sensing mechanism of MoO{sub 3-x} to ethanol have been studied. - Abstract: This paper deals with some physical investigations on molybdenum oxide thin films growing on glass substrates by the thermal evaporation method. These films have been subjected to an annealing process under vacuum, air and oxygen at various temperatures 673, 723 and 773 K. First, the physical properties of these layers were analyzed by means of X-ray diffraction, Raman spectroscopy, scanning electron microscopy (SEM) and optical measurements. These techniques have been used to investigate the oxygen index in MoO{sub x} properties during the heat treatment. Second, from the reflectance and transmittance optical measurements, it was found that the direct band gap energy value increased from 3.16 to 3.90 eV. Finally, the heat treatments reveal that the oxygen index varies in such molybdenum oxides showing noticeably sensitivity toward ethanol gas.

  13. The Effects of Annealing Temperatures on Composition and Strain in SixGe1−x Obtained by Melting Growth of Electrodeposited Ge on Si (100

    Directory of Open Access Journals (Sweden)

    Mastura Shafinaz Zainal Abidin

    2014-02-01

    Full Text Available The effects of annealing temperatures on composition and strain in SixGe1−x, obtained by rapid melting growth of electrodeposited Ge on Si (100 substrate were investigated. Here, a rapid melting process was performed at temperatures of 1000, 1050 and 1100 °C for 1 s. All annealed samples show single crystalline structure in (100 orientation. A significant appearance of Si-Ge vibration mode peak at ~400 cm−1 confirms the existence of Si-Ge intermixing due to out-diffusion of Si into Ge region. On a rapid melting process, Ge melts and reaches the thermal equilibrium in short time. Si at Ge/Si interface begins to dissolve once in contact with the molten Ge to produce Si-Ge intermixing. The Si fraction in Si-Ge intermixing was calculated by taking into account the intensity ratio of Ge-Ge and Si-Ge vibration mode peaks and was found to increase with the annealing temperatures. It is found that the strain turns from tensile to compressive as the annealing temperature increases. The Si fraction dependent thermal expansion coefficient of SixGe1−x is a possible cause to generate such strain behavior. The understanding of compositional and strain characteristics is important in Ge/Si heterostructure as these properties seem to give significant effects in device performance.

  14. Effect of annealing ambient on SnO2 thin film transistors

    Science.gov (United States)

    D. M., Priyadarshini; Mannam, Ramanjaneyulu; Rao, M. S. Ramachandra; DasGupta, Nandita

    2017-10-01

    In this study, the effect of annealing ambient on SnO2 thin film transistors (TFTs) is presented. Phase pure SnO2 films have been deposited using solution processed spin coating technique with SnCl2 as the precursor material. The films are annealed at 500 °C for 1 h in different annealing ambient conditions with varying N2:O2 ratio. Top gate, bottom contact TFTs have been fabricated with SnO2 as the channel layer, silicon as the gate, silicon dioxide as the dielectric and gold as the contact material. XRD patterns reveal the amorphous nature of films. AFM image shows that the spin coated films are pin-hole free with extremely smooth surface morphology. PL and XPS measurements reveal that with increase in N2% during annealing, the defects in the films increase. However, with increase in nitrogen concentration, the device performance improves, the threshold voltage shifts towards lower values and mobility increases, but very high N2% is not suitable for device operation, a 70% N2 + 30% O2 annealing ambient is found to be suitable with devices showing saturation mobility of 0.23 cm2V-1s-1 and threshold voltage of 6.8 V and on/off ratio of 106.

  15. Investigation of annealing temperature effect on magnetron sputtered cadmium sulfide thin film properties

    Science.gov (United States)

    Akbarnejad, E.; Ghorannevis, Z.; Abbasi, F.; Ghoranneviss, M.

    2017-03-01

    Cadmium sulfide (CdS) thin films are deposited on the fluorine doped tin oxide coated glass substrate using the radio frequency magnetron sputtering setup. The effects of annealing in air on the structural, morphological, and optical properties of CdS thin film are studied. Optimal annealing temperature is investigated by annealing the CdS thin film at different annealing temperatures of 300, 400, and 500 °C. Thin films of CdS are characterized by X-ray diffractometer analysis, field emission scanning electron microscopy, atomic force microscopy, UV-Vis-NIR spectrophotometer and four point probe. The as-grown CdS films are found to be polycrystalline in nature with a mixture of cubic and hexagonal phases. By increasing the annealing temperature to 500 °C, CdS film showed cubic phase, indicating the phase transition of CdS. It is found from physical characterizations that the heat treatment in air increased the mean grain size, the transmission, and the surface roughness of the CdS thin film, which are desired to the application in solar cells as a window layer material.

  16. Effect of annealing process on TiN/TiC bilayers grown by pulsed arc discharge

    Energy Technology Data Exchange (ETDEWEB)

    Ramos-Rivera, L., E-mail: lramosr@unal.edu.co [Laboratorio de Fisica del Plasma, Universidad Nacional de Colombia Sede Manizales, Km. 9 via al Aeropuerto Campus La Nubia (Colombia); Escobar, D.; Benavides-Palacios, V.; Arango, P.J.; Restrepo-Parra, E. [Laboratorio de Fisica del Plasma, Universidad Nacional de Colombia Sede Manizales, Km. 9 via al Aeropuerto Campus La Nubia (Colombia)

    2012-08-15

    In this work, a study of annealing process effect on TiN/TiC bilayer is presented. The annealing temperature was varied between room temperature and 500 Degree-Sign C. Materials were produced by the plasma-assisted pulsed vacuum arc discharge technique. In order to grow the films, a target of Ti with 99.9999% purity and stainless-steel 304 substrate were used. For the production of TiN layer, the reaction chamber was filled up with nitrogen gas until reaching 25 Pa and the discharge was performed at 310 V. The TiC layer was grown in a methane atmosphere at 30 Pa and 270 V. X-ray diffraction and X photoelectron spectroscopy were employed for studying the structure and chemical composition evolution during the annealing process. At 400 Degree-Sign C, TiO{sub 2} phase begun to appear and it was well observed at 500 Degree-Sign C. Crystallite size and microstrain was obtained as a function of the annealing temperature. XPS technique was employed for analyzing the bilayers before and after the annealing process. Narrow spectra of Ti2p, N1s and O1s were obtained, presenting TiO phases.

  17. Influence of thermal annealing and radiation enhanced diffusion processes on surface plasmon resonance of gold implanted dielectric matrices

    Science.gov (United States)

    Devi, Ksh. Devarani; Ojha, Sunil; Singh, Fouran

    2018-03-01

    Gold nanoparticles (AuNPs) embedded in fused silica and sapphire dielectric matrices were synthesized by Au ion implantation. Systematic investigations were carried out to study the influence of implantation dose, post annealing temperature, swift heavy ion (SHI) irradiation and radiation enhanced diffusion (RED). Rutherford Backscattering Spectrometry (RBS) measurements were carried out to quantify concentration and depth profile of Au present in the host matrices. X-ray diffraction (XRD) was employed to characterize AuNPs formation. As-implanted and post-annealed films were irradiated using 100 MeV Ag ions to investigate the effect of electronic energy deposition on size and shape of NPs, which is estimated indirectly by the peak shape analysis of surface plasmon resonance (SPR). The effect of volume fraction of Au and their redistribution is also reported. A strong absorption in near infra red region is also noticed and understood by the formation of percolated NPs in dielectric matrices. It is quite clear from these results that the effect of RED assisted Oswald ripening is much more pronounced than the conventional Oswald ripening for the growth of NPs in the case of silica host matrices. However for sapphire matrices, it seems that growth of NPs already completed during implantation and it may be attributed to the high diffusivity of Au in sapphire matrices during implantation process.

  18. Annealing effect on properties of BaWO4:Eu3+ phosphor thin films grown on glass substrates by radio-frequency magnetron sputtering

    Science.gov (United States)

    Cho, Shinho

    2018-02-01

    The effects of the rapid thermal annealing (RTA) temperature on the properties of BaWO4:Eu3+ phosphor thin films grown on glass substrates by radio-frequency magnetron sputtering were investigated. The deposited phosphor thin films were annealed at several RTA temperatures for 30 min. The experimental results show that the crystalline phase, surface morphology, transmittance, optical band gap, and photoluminescence intensity depended strongly on the RTA temperature. A preferential orientation along (112) plane and grains with an average size of 40 nm were observed for a thin film annealed at 400 °C. As the annealing temperature increased, the average transmittance in the wavelength range of 400-1100 nm gradually increased, reaching a maximum of 90.8% at 550 °C, where the highest optical band gap of 3.98 eV was obtained. The dominant emission spectra of the BaWO4:Eu3+ phosphor thin films under excitation at 323 nm, regardless of the RTA temperature, exhibited an emission band at 622 nm arising from the 5D0 → 7F2 transition of Eu3+ ions, indicating that the Eu3+ ions in the BaWO4 host lattice were located at sites without inversion symmetry. The results suggest that the optimum annealing temperature for fabricating highly luminescent red-emitting phosphor thin films is 500 °C.

  19. Annealing-induced effects on structural and optical properties of Cd1−xZnxS thin films for optoelectronic applications

    Directory of Open Access Journals (Sweden)

    Zakria M.

    2015-12-01

    Full Text Available Cd1−xZnxS thin films of variable compositions (x = 0.2, 0.4, 0.6, 0.8 were deposited on glass at room temperature by thermal evaporation process. The prepared samples were annealed at two different temperatures (300 °C, 400 °C for 1 hour in ambient air. The effects of post-annealing on the structural and optical characteristics were investigated using X-ray diffraction (XRD, spectrophotometry, and Raman spectroscopy (RS methods. XRD studies suggested that the annealed and as-deposited samples belong to wurtzite structure for all Zn concentrations with a preferential orientation along (002 plane. Spectrophotometry analysis of the samples revealed that the energy band gap decreased with annealing temperature. RS investigated different phonon bands and crystalline phases. Two longitudinal optical phonon modes (1-LO, 2-LO corresponding to monophase hexagonal structure were observed for all Cd1−xZnxS samples. The observed red-shift and anti-symmetrical nature of the 1-LO phonon mode can be associated with annealing, while the overall blue-shift, except for x ⩽ 0.6, was caused by the structural disorders in periodic Cd atomic sub-lattices and broken translational symmetry. The spectroscopic results were strengthened by the XRD studies and their results are consistent.

  20. The change of electric field and of some other insulating properties during isochronal annealing in thermally poled Ge-doped silica films

    DEFF Research Database (Denmark)

    Liu, Q.M.; Poumellec, B.; Braga, D.

    2005-01-01

    The secondary electron emission contrast between poled and unpoled regions in thermally poled Ge-doped silica films were measured according to different annealing temperatures and electron doses with electron acceleration energy of 5 keV. It is used for measuring the change on annealing of poling...... induced electric field and other insulating properties like electron traps population and conductivity in high field. Concerning the change of the contrast at low dose arising from the poling electric field, we show that this field begins to disappear at around 450 degrees C and is erased completely...

  1. Thickness-dependent crystallization on thermal anneal for titania/silica nm-layer composites deposited by ion beam sputter method.

    Science.gov (United States)

    Pan, Huang-Wei; Wang, Shun-Jin; Kuo, Ling-Chi; Chao, Shiuh; Principe, Maria; Pinto, Innocenzo M; DeSalvo, Riccardo

    2014-12-01

    Crystallization following thermal annealing of thin film stacks consisting of alternating nm-thick titania/silica layers was investigated. Several prototypes were designed, featuring a different number of titania/silica layer pairs, and different thicknesses (in the range from 4 to 40 nm, for the titania layers), but the same nominal refractive index (2.09) and optical thickness (a quarter of wavelength at 1064 nm). The prototypes were deposited by ion beam sputtering on silicon substrates. All prototypes were found to be amorphous as-deposited. Thermal annealing in air at progressive temperatures was subsequently performed. It was found that the titania layers eventually crystallized forming the anatase phase, while the silica layers remained always amorphous. However, progressively thinner layers exhibited progressively higher threshold temperatures for crystallization onset. Accordingly it can be expected that composites with thinner layers will be able to sustain higher annealing temperatures without crystallizing, and likely yielding better optical and mechanical properties for advanced coatings application. These results open the way to the use of materials like titania and hafnia, that crystallize easily under thermal anneal, but ARE otherwise promising candidate materials for HR coatings necessary for cryogenic 3rd generation laser interferometric gravitational wave detectors.

  2. Synthesis of stoichiometric Ca{sub 2}Fe{sub 2}O{sub 5} nanoparticles by high-energy ball milling and thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Amorim, B.F.; Morales, M.A.; Bohn, F.; Carriço, A.S. [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil); Medeiros, S.N. de, E-mail: sndemedeiros@gmail.com [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil); Dantas, A.L. [Departamento de Física, Universidade do Estado do Rio Grande do Norte, 59610-210 Mossoró, RN (Brazil)

    2016-05-01

    We report the synthesis of Ca{sub 2}Fe{sub 2}O{sub 5} nanoparticles by high-energy ball milling and thermal annealing from α-Fe{sub 2}O{sub 3} and CaCO{sub 3}. Magnetization measurements, Mössbauer and X-ray spectra reveal that annealing at high temperatures leads to better quality samples. Our results indicate nanoparticles produced by 10 h high-energy ball milling and thermal annealing for 2 h at 1100 °C achieve improved stoichiometry and the full weak ferromagnetic signal of Ca{sub 2}Fe{sub 2}O{sub 5}. Samples annealed at lower temperatures show departure from stoichiometry, with a higher occupancy of Fe{sup 3+} in octahedral sites, and a reduced magnetization. Thermal relaxation for temperatures in the 700–1100 °C range is well represented by a Néel model, assuming a random orientation of the weak ferromagnetic moment of the Ca{sub 2}Fe{sub 2}O{sub 5} nanoparticles.

  3. Effect of annealing on bulk heterojunction organic solar cells based on copper phthalocyanine and perylene derivative

    KAUST Repository

    Kim, Inho

    2012-02-01

    We investigated the effects of annealing on device performances of bulk heterojunction organic solar cells based on copper phthalocyanine (CuPc) and N,N′-3,4,9,10-perylenetetracarboxylic diimide (PTCDI-C6). Blended films of CuPc and PTCDI-C6 with annealing at elevated temperature were characterized by measuring optical absorption, photoluminescence, and X-ray diffraction. Enhanced molecular ordering and increments in domain sizes of donor and acceptor for the blended films were observed, and their influences on device performances were discussed. Annealing led to substantial improvements in photocurrent owing to enhanced molecular ordering and formation of percolation pathways. © 2011 Elsevier B.V. All rights reserved.

  4. Effect of annealing atmosphere on optic-electric properties of Zn O thin films

    Energy Technology Data Exchange (ETDEWEB)

    Bueno, C. [Benemerita Universidad Autonoma de Puebla, Facultad de Ingenieria, Blvd. Valsequillo y Av. San Claudio s/n, 72570 Puebla (Mexico); Pacio, M.; Juarez, H. [Benemerita Universidad Autonoma de Puebla, Posgrado en Dispositivos Semiconductores, Av. San Claudio y 14 Sur, 72450 Puebla (Mexico); Osorio, E. [Universidad de Quinta Roo, Blvd. Bahia s/n, esquina Ignacio Comonfort, El Bosque, 77019 Chetumal, Quintana Roo (Mexico); Perez, R., E-mail: cba3009@gmail.com [Benemerita Universidad Autonoma de Puebla, Facultad de Ingenieria Quimica, Av. San Claudio y 18 Sur, 72570 Puebla (Mexico)

    2017-11-01

    In this work the study of structural, morphologic characteristics, optical and electrical properties of the thin films of Zn O in temperatures and annealing atmospheres different was realized. The films were obtained by the sol-gel method, utilizing zinc acetate dihydrate as the precursor, monoethanolamine (Mea) as a stabilizing agent and 2-methoxyethanol as a solvent and deposited by spin-coating. The films were crystallized at 600, 800 and 1000 degrees Celsius in oxygen and nitrogen atmospheres. The results obtained by XRD, Sem, photoluminescence and Hall effects of the Zn O films were related and depend strongly on the temperature and atmosphere annealing. (Author)

  5. DOE`s annealing prototype demonstration projects

    Energy Technology Data Exchange (ETDEWEB)

    Warren, J.; Nakos, J.; Rochau, G.

    1997-02-01

    One of the challenges U.S. utilities face in addressing technical issues associated with the aging of nuclear power plants is the long-term effect of plant operation on reactor pressure vessels (RPVs). As a nuclear plant operates, its RPV is exposed to neutrons. For certain plants, this neutron exposure can cause embrittlement of some of the RPV welds which can shorten the useful life of the RPV. This RPV embrittlement issue has the potential to affect the continued operation of a number of operating U.S. pressurized water reactor (PWR) plants. However, RPV material properties affected by long-term irradiation are recoverable through a thermal annealing treatment of the RPV. Although a dozen Russian-designed RPVs and several U.S. military vessels have been successfully annealed, U.S. utilities have stated that a successful annealing demonstration of a U.S. RPV is a prerequisite for annealing a licensed U.S. nuclear power plant. In May 1995, the Department of Energy`s Sandia National Laboratories awarded two cost-shared contracts to evaluate the feasibility of annealing U.S. licensed plants by conducting an anneal of an installed RPV using two different heating technologies. The contracts were awarded to the American Society of Mechanical Engineers (ASME) Center for Research and Technology Development (CRTD) and MPR Associates (MPR). The ASME team completed its annealing prototype demonstration in July 1996, using an indirect gas furnace at the uncompleted Public Service of Indiana`s Marble Hill nuclear power plant. The MPR team`s annealing prototype demonstration was scheduled to be completed in early 1997, using a direct heat electrical furnace at the uncompleted Consumers Power Company`s nuclear power plant at Midland, Michigan. This paper describes the Department`s annealing prototype demonstration goals and objectives; the tasks, deliverables, and results to date for each annealing prototype demonstration; and the remaining annealing technology challenges.

  6. Structural stability of hydrogenated amorphous carbon overcoats used in heat-assisted magnetic recording investigated by rapid thermal annealing

    KAUST Repository

    Wang, N.

    2013-01-01

    Ultrathin amorphous carbon (a-C) films are extensively used as protective overcoats of magnetic recording media. Increasing demands for even higher storage densities have necessitated the development of new storage technologies, such as heat-assisted magnetic recording (HAMR), which uses laser-assisted heating to record data on high-stability media that can store single bits in extremely small areas (∼1 Tbit/in.2). Because HAMR relies on locally changing the coercivity of the magnetic medium by raising the temperature above the Curie temperature for data to be stored by the magnetic write field, it raises a concern about the structural stability of the ultrathin a-C film. In this study, rapid thermal annealing (RTA) experiments were performed to examine the thermal stability of ultrathin hydrogenated amorphous carbon (a-C:H) films deposited by plasma-enhanced chemical vapor deposition. Structural changes in the a-C:H films caused by RTA were investigated by x-ray photoelectron spectroscopy, Raman spectroscopy, x-ray reflectivity, and conductive atomic force microscopy. The results show that the films exhibit thermal stability up to a maximum temperature in the range of 400-450 °C. Heating above this critical temperature leads to hydrogen depletion and sp 2 clustering. The critical temperature determined by the results of this study represents an upper bound of the temperature rise due to laser heating in HAMR hard-disk drives and the Curie temperature of magnetic materials used in HAMR hard disks. © 2013 American Institute of Physics.

  7. A Laboratory to Demonstrate the Effect of Thermal History on Semicrystalline Polymers Using Rapid Scanning Rate Differential Scanning Calorimetry

    Science.gov (United States)

    Badrinarayanan, Prashanth; Kessler, Michael R.

    2010-01-01

    A detailed understanding of the effect of thermal history on the thermal properties of semicrystalline polymers is essential for materials scientists and engineers. In this article, we describe a materials science laboratory to demonstrate the effect of parameters such as heating rate and isothermal annealing conditions on the thermal behavior of…

  8. Effect of doping and annealing on the physical properties of ZnO:Mg ...

    Indian Academy of Sciences (India)

    Abstract. Well-dispersed undoped and Mg-doped ZnO nanoparticles with different doping con- centrations at various annealing temperatures are synthesized using basic chemical solution method without any capping agent. To understand the effect of Mg doping and heat treatment on the structure and optical response of ...

  9. Effect of doping and annealing on the physical properties of ZnO: Mg ...

    Indian Academy of Sciences (India)

    Well-dispersed undoped and Mg-doped ZnO nanoparticles with different doping concentrations at various annealing temperatures are synthesized using basic chemical solution method without any capping agent. To understand the effect of Mg doping and heat treatment on the structure and optical response of the ...

  10. Effect of Doping Phosphorescent Material and Annealing Treatment on the Performance of Polymer Solar Cells

    Directory of Open Access Journals (Sweden)

    Zixuan Wang

    2013-01-01

    Full Text Available A series of polymer solar cells (PSCs with P3HT:PCBM or P3HT:PCBM:Ir(btpy3 blend films as the active layer were fabricated under the same conditions. Effects of phosphorescent material Ir(btpy3 doping concentration and annealing temperature on the performance of PSCs were investigated. The short-circuit current density (Jsc and open-circuit voltage (Voc are increased by adopting P3HT:PCBM:Ir(btpy3 blend films as the active layer when the cells do not undergo annealing treatment. The increased Jsc should be attributed to the increase of photon harvesting induced by doping phosphorescent material Ir(btpy3 and the effective energy transfer from Ir(btpy3 to P3HT. The effective energy transfer from Ir(btpy3 to P3HT was demonstrated by time-resolved photoluminescence (PL spectra. The increased Voc is due to the photovoltaic effect between Ir(btpy3 and PCBM. The power conversion efficiency (PCE of PSCs with P3HT:PCBM as the active layer is increased from 0.19% to 1.49% by annealing treatment at 140°C for 10 minutes. The PCE of PSCs with P3HT:PCBM:Ir(btpy3 as the active layer is increased from 0.49% to 0.95% by annealing treatment at lower temperature at 100°C for 10 minutes.

  11. CrCuAgN PVD nanocomposite coatings: Effects of annealing on coating morphology and nanostructure

    Science.gov (United States)

    Liu, Xingguang; Iamvasant, Chanon; Liu, Chang; Matthews, Allan; Leyland, Adrian

    2017-01-01

    CrCuAgN PVD nanocomposite coatings were produced using pulsed DC unbalanced magnetron sputtering. This investigation focuses on the effects of post-coat annealing on the surface morphology, phase composition and nanostructure of such coatings. In coatings with nitrogen contents up to 16 at.%, chromium exists as metallic Cr with N in supersaturated solid solution, even after 300 °C and 500 °C post-coat annealing. Annealing at 300 °C did not obviously change the phase composition of both nitrogen-free and nitrogen-containing coatings; however, 500 °C annealing resulted in significant transformation of the nitrogen-containing coatings. The formation of Ag aggregates relates to the (Cu + Ag)/Cr atomic ratio (threshold around 0.2), whereas the formation of Cu aggregates relates to the (Cu + Ag + N)/Cr atomic ratio (threshold around 0.5). The primary annealing-induced changes were reduced solubility of Cu, Ag and N in Cr, and the composition altering from a mixed ultra-fine nanocrystalline and partly amorphous phase constitution to a coarser, but still largely nanocrystalline structure. It was also found that, with sufficient Cu content (>12 at.%), annealing at a moderately high temperature (e.g. 500 °C) leads to transportation of both Cu and Ag (even at relatively low concentrations of Ag, ≤3 at.%) from inside the coating to the coating surface, which resulted in significant reductions in friction coefficient, by over 50% compared to that of the substrate (from 0.31 to 0.14 with a hemispherical diamond indenter, and from 0.83 to 0.40 with an alumina ball counterface, respectively). Results indicate that the addition of both Cu and Ag (in appropriate concentrations) to nitrogen-containing chromium is a viable strategy for the development of 'self-replenishing' silver-containing thin film architectures for temperature-dependent solid lubrication requirements or antimicrobial coating applications.

  12. Effects of excimer laser annealing on low-temperature solution based indium-zinc-oxide thin film transistor fabrication

    OpenAIRE

    Chen,Chao-Nan; Huang, Jung-Jie

    2015-01-01

    A Solution Based Indium-Zinc-Oxide thin-film transistor (TFT) with a field-effect mobility of 0.58 cm2/Vs, a threshold voltage of 2.84 V by using pulse laser annealing processes. Indium-zinc-oxide (IZO) films with a low process temperature were deposited by sol-gel solution based method and KrF excimer laser annealing (wavelength of 248 nm). Solution based indium-zinc-oxide (IZO) films usually needs high temperature about 500 °C post annealing in a oven. KrF excimer laser annealing shows adva...

  13. Comprehensive study of the surface morphology evolution induced by thermal annealing in single-crystalline ZnO films and ZnO bulks

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, N.; Oh, D. C. [Hoseo University, Asan (Korea, Republic of); Ko, H. J. [Korea Photonics Technology Institute, Gwangju (Korea, Republic of); Lim, D. S.; Hong, S. K. [Chungnam National University, Daejeon (Korea, Republic of); Yao, T. [Tohoku University, Sendai (Japan)

    2012-11-15

    We report on the evolution of the surface morphology induced by thermal annealing in N{sub 2} ambient over a wide temperature range of 500 - 1200 .deg. C in single-crystalline ZnO films and ZnO bulks. The surface morphology is seriously changed by the annealing temperature, and the evolution can be categorized into three regions: island growth, island agglomeration, and pit formation. Island growth at low temperatures below 700 .deg. C, is ascribed to the atomic migration to reduce surface energy, which causes surface roughening. Island agglomeration at intermediate temperatures of 700 - 900 .deg. C is ascribed to the migration and the evaporation of surface atoms, which causes surface flattening. Pit formation at high temperatures above 900 .deg. C is ascribed to the atomic evaporation by high vapor pressure, which causes surface destruction. On the other hand, the bulk lattice is continuously improved with increasing annealing temperature in the temperature regions before the surface-destruction region, which is attributed to the reduction in the numbers of point and line defects caused by recrystallization. As a result, the best surface morphology and the best bulk lattice are obtained at an annealing temperature of 900 .deg. C. The common surface-morphology evolution of ZnO films and ZnO bulks with increasing annealing temperature can be summarized using the three steps of surface roughening by island growth, surface flattening by island agglomeration, and surface destruction by pit formation.

  14. The Synthesis and Structural Properties of Crystalline Silicon Quantum Dots upon Thermal Annealing of Hydrogenated Amorphous Si-Rich Silicon Carbide Films

    Science.gov (United States)

    Wen, Guozhi; Zeng, Xiangbin; Li, Xianghu

    2016-08-01

    Silicon quantum dots (QDs) embedded in non-stoichiometric hydrogenated silicon carbide (SiC:H) thin films have been successfully synthesized by plasma-enhanced chemical vapor deposition and post-annealing. The chemical composition analyses have been carried out by x-ray photoelectron spectroscopy (XPS). The bonding configurations have been deduced from Fourier transform infrared absorption measurements (FTIR). The evolution of microstructure with temperature has been characterized by glancing incident x-ray diffraction (XRD) and Raman diffraction spectroscopy. XPS and FTIR show that it is in Si-rich feature and there are a few hydrogenated silicon clusters in the as-grown sample. XRD and Raman diffraction spectroscopy show that it is in amorphous for the as-grown sample, while crystalline silicon QDs have been synthesized in the 900°C annealed sample. Silicon atoms precipitation from the SiC matrix or silicon phase transition from amorphous SiC is enhanced with annealing temperature increase. The average sizes of silicon QDs are about 5.1 nm and 5.6 nm, the number densities are as high as 1.7 × 1012 cm-2 and 3.2 × 1012 cm-2, and the crystalline volume fractions are about 58.3% and 61.3% for the 900°C and 1050°C annealed samples, respectively. These structural properties analyses provide an understanding about the synthesis of silicon QDs upon thermal annealing for applications in next generation optoelectronic and photovoltaic devices.

  15. The effect of annealing on the time-dependent behavior of isotactic polypropylene at finite strains

    DEFF Research Database (Denmark)

    Drozdov, Aleksey D.; Christiansen, Jesper de Claville

    2002-01-01

    Four series of tensile relaxation tests are performed on isotactic polypropylene at elongations up to the necking point. In the first series of experiments, injection-molded samples are used without thermal pre-treatment. In the other series, the specimens are annealed for 24 h prior to testing...... with elongation ratio driven by the release of constrained amorphous phase induced by fragmentation of lamellae. In the sub-critical region of deformation (relatively small strains), the growth of the concentration of active meso-regions is associated with breakage of subsidiary (thin) lamellae developed...

  16. Annealing effects on the electrical resistivity of AuAl thin films alloys

    Energy Technology Data Exchange (ETDEWEB)

    Maldonado, R.D., E-mail: rubdoming@live.com.mx [Centro de Investigacion y de Estudios Avanzados del IPN Unidad Merida, Depto. de Fisica Aplicada, Km. 6 Antigua Carretera a Progreso 97310, Merida, Yucatan (Mexico); Oliva, A.I.; Corona, J.E. [Centro de Investigacion y de Estudios Avanzados del IPN Unidad Merida, Depto. de Fisica Aplicada, Km. 6 Antigua Carretera a Progreso 97310, Merida, Yucatan (Mexico)

    2009-08-15

    Au/Al bilayer (50-250-nm thickness) thin films were deposited by thermal evaporation on p-type silicon (1 0 0) substrates. The formed Au/Al/Si systems were annealed from room temperature (RT) to 400 deg. C to form AuAl/Si alloys. Two groups of AuAl alloys were analyzed. The first group was prepared as a function of the atomic concentration and the second group was prepared as a function of thickness. The morphology and crystalline structure of the alloys were analyzed by AFM and X-ray diffraction techniques, respectively. The electrical resistivities of the AuAl alloys were measured by the four-probe technique. The first group of thin AuAl alloys presented segregations as a consequence of the annealing treatment and the atomic concentration; meanwhile, the electrical resistivity showed abrupt changes as a consequence of changing the atomic concentration. In the second group a monotonically increment in the grain size was found meanwhile for thickness below 100 nm the electrical resistivity presented important differences as compared with the before annealing process.

  17. Topotaxial growth of α-Fe{sub 2}O{sub 3} nanowires on iron substrate in thermal annealing method

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Himanshu, E-mail: himsri@rrcat.gov.in; Srivastava, A. K.; Babu, Mahendra; Rai, Sanjay; Ganguli, Tapas [Indus Synchrotrons Utilization Division, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India)

    2016-06-28

    A detail cross-sectional transmission electron microscopy of as-grown α-Fe{sub 2}O{sub 3} nanowire sample, synthesized on iron substrate by thermal annealing method, was carried out to understand the mechanism of growth in this system. Iron undergoes sequential oxidation to form a layered structure of Fe/FeO/Fe{sub 3}O{sub 4}/α-Fe{sub 2}O{sub 3}. α-Fe{sub 2}O{sub 3} nanowires grow on to the top of α-Fe{sub 2}O{sub 3} layer. It was found that subsequent oxide layers grow topotaxially on the grains of iron, which results in a direct orientation relationship between the α-Fe{sub 2}O{sub 3} nanowire and the parent grain of iron. The results also showed that the grains of α-Fe{sub 2}O{sub 3} layer, which were uniquely oriented in [110] direction, undergo highly anisotropic growth to form the nanowire. This anisotropic growth occurs at a twin interface, given by (−11−1), in the α-Fe{sub 2}O{sub 3} layer. It was concluded that the growth at twin interface could be the main driving factor for such anisotropic growth. These observations are not only helpful in understanding the growth mechanism of α-Fe{sub 2}O{sub 3} nanowires, but it also demonstrates a way of patterning the nanowires by controlling the texture of iron substrate.

  18. Thermal annealing dynamics of carbon-coated LiFePO4 nanoparticles studied by in-situ analysis

    Science.gov (United States)

    Krumeich, Frank; Waser, Oliver; Pratsinis, Sotiris E.

    2016-10-01

    The thermal behavior of core-shell carbon-coated lithium iron phosphate (LiFePO4-C) nanoparticles made by flame spray pyrolysis (FSP) during annealing was investigated by in-situ transmission electron microscopy (TEM), in-situ X-ray powder diffraction (XRD) as well as ex-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Crystallization of the initially glassy LiFePO4-C nanoparticles starts at quite low temperatures (T=400 °C), forming single crystals inside the confinement of the carbon shell. Upon increasing the temperature to T≥700 °C, LiFePO4 starts to diffuse through the carbon shell resulting in cavities inside the mostly intact carbon shell. By increasing the temperature further to T≥800 °C, the initial core-shell morphology converts into open carbon shells (flakes and cenospheres) and bulky LiFePO4 particles (diameter in the range 300-400 nm), in agreement with ex-situ experiments.

  19. Catalyst-free synthesis of nitrogen-doped graphene via thermal annealing graphite oxide with melamine and its excellent electrocatalysis.

    Science.gov (United States)

    Sheng, Zhen-Huan; Shao, Lin; Chen, Jing-Jing; Bao, Wen-Jing; Wang, Feng-Bin; Xia, Xing-Hua

    2011-06-28

    The electronic and chemical properties of graphene can be modulated by chemical doping foreign atoms and functional moieties. The general approach to the synthesis of nitrogen-doped graphene (NG), such as chemical vapor deposition (CVD) performed in gas phases, requires transitional metal catalysts which could contaminate the resultant products and thus affect their properties. In this paper, we propose a facile, catalyst-free thermal annealing approach for large-scale synthesis of NG using low-cost industrial material melamine as the nitrogen source. This approach can completely avoid the contamination of transition metal catalysts, and thus the intrinsic catalytic performance of pure NGs can be investigated. Detailed X-ray photoelectron spectrum analysis of the resultant products shows that the atomic percentage of nitrogen in doped graphene samples can be adjusted up to 10.1%. Such a high doping level has not been reported previously. High-resolution N1s spectra reveal that the as-made NG mainly contains pyridine-like nitrogen atoms. Electrochemical characterizations clearly demonstrate excellent electrocatalytic activity of NG toward the oxygen reduction reaction (ORR) in alkaline electrolytes, which is independent of nitrogen doping level. The present catalyst-free approach opens up the possibility for the synthesis of NG in gram-scale for electronic devices and cathodic materials for fuel cells and biosensors.

  20. Synthesis and kinetics studies of poly(styrene-b-vinylmethylsiloxane) and its thin film ordering by thermal and solvent annealing

    Science.gov (United States)

    Chatterjee, Sourav; Uddin, Md Fakar; Lwoya, Baraka; Albert, Julie N. L.

    Nano-structured thin film materials are important materials that find uses in templating and membrane applications. Block copolymers (BCP) have gained considerable attention for next-generation lithographic masks due to their self-assemble into morphologies with periodic sub 20 nm feature sizes with high regularity and reproducibility. A novel synthetic block copolymer of poly(styrene-b-vinylmethylsiloxane) (PS-b-PVMS) was synthesized. Like poly(styrene-b-dimethylsiloxane), this polymer has a high Flory Huggins interaction parameter between blocks to minimize feature size. Furthermore, incorporation of the vinyl side group provides an opportunity for post-polymerization chemical modification to manipulate the interaction parameter or impart functionality for various applications. Synthesis and kinetic studies of PS-b-PVMS as well as PS and PVMS homopolymers will be presented. All polymers are well characterized by proton NMR and GPC. As proof of concept, we show that block copolymers having different block fractions self-assemble into the expected nanostructures (lamellae, cylinders, spheres). Thin film studies also will be presented showing how the ordering of PS-b-PVMS is affected by different solvent and thermal annealing conditions.

  1. Colloidal CdSe/Cu3P/CdSe nanocrystal heterostructures and their evolution upon thermal annealing.

    Science.gov (United States)

    De Trizio, Luca; De Donato, Francesco; Casu, Alberto; Genovese, Alessandro; Falqui, Andrea; Povia, Mauro; Manna, Liberato

    2013-05-28

    We report the synthesis of colloidal CdSe/Cu(3)P/CdSe nanocrystal heterostructures grown from hexagonal Cu(3)P platelets as templates. One type of heterostructure was a sort of "coral", formed by vertical pillars of CdSe grown preferentially on both basal facets of a Cu(3)P platelet and at its edges. Another type of heterostructure had a "sandwich" type of architecture, formed by two thick, epitaxial CdSe layers encasing the original Cu(3)P platelet. When the sandwiches were annealed under vacuum up to 450 °C, sublimation of P and Cd species with concomitant interdiffusion of Cu and Se species was observed by in situ HR- and EFTEM analyses. These processes transformed the starting sandwiches into Cu2Se nanoplatelets. Under the same conditions, both the pristine (uncoated) Cu(3)P platelets and a control sample made of isolated CdSe nanocrystals were stable. Therefore, the thermal instability of the sandwiches under vacuum might be explained by the diffusion of Cu species from Cu(3)P cores into CdSe domains, which triggered sublimation of Cd, as well as out-diffusion of P species and their partial sublimation, together with the overall transformation of the sandwiches into Cu(2)Se nanocrystals. A similar fate was followed by the coral-like structures. These CdSe/Cu(3)P/CdSe nanocrystals are therefore an example of a nanostructure that is thermally unstable, despite its separate components showing to be stable under the same conditions.

  2. Effect of annealing on natural calcitic crystals-A thermostimulated luminescence (TSL) study

    Energy Technology Data Exchange (ETDEWEB)

    Ponnusamy, V., E-mail: ponnu@mitindia.edu [Department of Physics, Division of Applied Sciences and Humanities, M.I.T. Campus, Anna University, Chennai 600044, Tamilnadu (India); Ramasamy, V. [Department of Physics, Annamalai University, Annamalainagar 608002, Tamilnadu (India); Jose, M.T. [Radiological Safety Division, IGCAR, Kalpakkam, Tamilnadu (India); Anandalakshmi, K. [Department of Physics, Annamalai University, Annamalainagar 608002, Tamilnadu (India)

    2012-04-15

    The quality crystals (Calcitic limestone) were selected using the UV-visible methylene blue adsorption method. The thermostimulated luminescence (TSL) glow curve characteristics of six well crystallized limestone samples were analyzed. The glow curves of unannealed sample show only one peak in the range 320-330 Degree-Sign C. The sample irradiated with a gamma dose of 100 Gy shows two additional peaks in the range of 113-125 Degree-Sign C and 242-260 Degree-Sign C when recorded with linear heating rate of 10 Degree-Sign C/s. The annealed sample also shows the same trend as that of irradiated sample. Annealing treatment above 250 Degree-Sign C increases the sensitivity of all TSL peaks except 320 Degree-Sign C. On the other hand, annealing at 750 Degree-Sign C caused a collapse in the TSL sensitivity. The enhancement in TSL sensitivity was found to depend on the annealing temperature and time. Annealing treatment at 650 Degree-Sign C for 4 h followed by quenching in air is the optimum condition for TSL sensitization. The response to gamma irradiation is linear in the range from 0.5 Gy to 10{sup 4} Gy. The emission spectra of all the samples show an emission at around 610 nm but with different intensities for each TSL peak. With reference to earlier work, it may be assumed that the recombination site always involves Mn{sup 2+} ions. The observation made through infra-red (IR) and X-ray diffraction (XRD) studies with thermal treatment shows the structural changes of calcite from D{sub 3h} to C{sub s} symmetry at 750 Degree-Sign C. The Thermogravimetric-Differential Thermal Analysis (TG-DTA) analysis shows the calcite gets disordered at 760 Degree-Sign C. Hence, the collapse in the TSL sensitivity at 750 Degree-Sign C is due to structural change or structural disorderedness. - Highlights: Black-Right-Pointing-Pointer Normally, the synthetic material was used as radiation dosimeter but the natural material can also be used for the same application. Black

  3. CrCuAgN PVD nanocomposite coatings: Effects of annealing on coating morphology and nanostructure

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xingguang, E-mail: xingguangliu1@gmail.com [Department of Materials Science and Engineering, Sir Robert Hadfield Building, The University of Sheffield, Mappin Street, Sheffield, S1 3JD (United Kingdom); Iamvasant, Chanon, E-mail: ciamvasant1@sheffield.ac.uk [Department of Materials Science and Engineering, Sir Robert Hadfield Building, The University of Sheffield, Mappin Street, Sheffield, S1 3JD (United Kingdom); Liu, Chang, E-mail: chang.liu@sheffield.ac.uk [Department of Materials Science and Engineering, Sir Robert Hadfield Building, The University of Sheffield, Mappin Street, Sheffield, S1 3JD (United Kingdom); Matthews, Allan, E-mail: allan.matthews@manchester.ac.uk [Pariser Building - B24 ICAM, School of Materials, The University of Manchester, Manchester, M13 9PL (United Kingdom); Leyland, Adrian, E-mail: a.leyland@sheffield.ac.uk [Department of Materials Science and Engineering, Sir Robert Hadfield Building, The University of Sheffield, Mappin Street, Sheffield, S1 3JD (United Kingdom)

    2017-01-15

    Highlights: • Coatings with nitrogen content up to 16 at.% exhibit a metallic Cr solid solution, even after post-coat annealing at 300 °C and 500 °C. • At higher N/Cr atomic ratios (approaching Cr{sub 2}N stoichiometry), chromium was still inclined to exist in solid solution with nitrogen, rather than as a ceramic nitride phase, even after annealing at 500 °C. • Transportation of Cu and Ag to the surface depends on annealing temperature, annealing duration, nitrogen concentration and ‘global’ Cu + Ag concentration. • Incorporation of copper appears to be a powerful strategy to enhance Ag mobility at low concentration (∼3 at.% Ag in this study) under moderately high service temperature. • A significant decrease in friction coefficient was obtained at room temperature after annealing, or during sliding wear testing at elevated temperature. - Abstract: CrCuAgN PVD nanocomposite coatings were produced using pulsed DC unbalanced magnetron sputtering. This investigation focuses on the effects of post-coat annealing on the surface morphology, phase composition and nanostructure of such coatings. In coatings with nitrogen contents up to 16 at.%, chromium exists as metallic Cr with N in supersaturated solid solution, even after 300 °C and 500 °C post-coat annealing. Annealing at 300 °C did not obviously change the phase composition of both nitrogen-free and nitrogen-containing coatings; however, 500 °C annealing resulted in significant transformation of the nitrogen-containing coatings. The formation of Ag aggregates relates to the (Cu + Ag)/Cr atomic ratio (threshold around 0.2), whereas the formation of Cu aggregates relates to the (Cu + Ag + N)/Cr atomic ratio (threshold around 0.5). The primary annealing-induced changes were reduced solubility of Cu, Ag and N in Cr, and the composition altering from a mixed ultra-fine nanocrystalline and partly amorphous phase constitution to a coarser, but still largely nanocrystalline structure. It was also

  4. Temperature annealing effect on structural and optical properties of ZnO thin films prepared by sol-gel method

    Directory of Open Access Journals (Sweden)

    Elamal Bouzit S.

    2013-09-01

    Full Text Available ZnO thin films have been synthesized by sol-gel method. The effect of the annealing temperature on the morphological, structural and optical properties of the ZnO thin films was investigated. A good crystllinity and good transmittance in the visible spectrum was obtained at the annealing temperature of 400°C.

  5. Effect of Annealing on the Microstructure of Rapidly Solidified Foils of Alloy Bi50Sn35In15

    Science.gov (United States)

    Shepelevich, V. G.; Shcherbachenko, L. P.

    2016-07-01

    The effect of annealing on the microstructure of foils of alloy Bi50Sn35In15 is studied. It is shown that prolongation of the annealing time is accompanied by coarsening of the structure, which reduces the specific surface of the interfaces virtually without changing the volume fractions of the phases.

  6. Rapid flash annealing of thermally reactive copolymers in a roll-to-roll process for polymer solar cells

    DEFF Research Database (Denmark)

    Helgesen, Martin; Carlé, Jon Eggert; Andreasen, Birgitta

    2012-01-01

    intensity pulsed light, delivered by a commercial photonic sintering system. Thermally labile ester groups are positioned on the DTZ unit of the copolymer that can be eliminated thermally for enhanced photochemical stability and advantages in terms of processing (solubility/insolubility switching......Light induced thermocleaving of a thermally reactive copolymer based on dithienylthiazolo[5,4-d]thiazole (DTZ) and silolodithiophene (SDT) in contact with the heat sensitive substrate the heat sensitive substrate polyethyleneterphthalate (PET) was effectively demonstrated with the use of high...

  7. Annealing effect on the electron spin dynamics in heavily Mn-doped (Ga,Mn)As

    Energy Technology Data Exchange (ETDEWEB)

    Yue, Han; Chen, Lin; Gao, Haixia; Zhao, Jianhua; Zhang, Xinhui [Institute of Semiconductors, Chinese Academy of Sciences, Beijing (China)

    2014-05-15

    A temperature- and photo-excitation-density-dependent electron spin dephasing process has been studied by time-resolved magneto-optical Kerr effect (TR-MOKE) measurements for heavily-doped (Ga,Mn)As after appropriate annealing treatment. Unlike the as-grown (Ga,Mn)As in which s-d scattering is dominant for spin dephasing at low temperature, the exchange scattering induced by Mn ions is efficiently suppressed after annealing. For annealed (Ga,Mn)As, the p-d exchange coupling proves to be important for the electron spin dephasing process. Moreover, the Coulomb scattering arising from the weakly-localized holes and Mn impurities is revealed to play an important role in the electron spin dephasing after annealing. Our results demonstrate that the impurity induced disorder plays a significant role in the electron spin-dephasing process in (Ga,Mn)As when Mn is over doped by as much as 15%, which is a critical issue that needs to be considered to achieve high-quality (Ga,Mn)As thin films with a higher Curie temperature T{sub C} and better functionality.

  8. Effect of complexing agent and annealing atmosphere on properties of nanocrystalline ZnS thin films.

    Science.gov (United States)

    Shin, Seung Wook; Oh, Hyun Pil; Pawar, S M; Moon, Jong-Ha; Kim, Jin Hyeok

    2010-05-01

    The nanocrystalline Zinc Sulfide (ZnS) thin films were prepared on glass substrates by chemical bath deposition (CBD) method using aqueous solutions of zinc acetate, thiourea and tri-sodium citrate in alkaline medium at 80 degrees C. The tri-sodium citrate acts as a complexing agent. The effects of complexing agent and annealing atmosphere (95%N2 + 5%H2S) on structural, morphological and optical properties of ZnS thin films were studied using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and optical absorption. XRD study revealed that single phase ZnS powder was formed in the solution with tri-sodium citrate, however, ZnS and ZnO mixed phase powder was formed in the solution without tri-sodium citrate. The films deposited with trisodium citrate showed ZnS with hexagonal wurtzite phase. However, annealed film in (N2 + H2S) atmosphere showed cubic (zincblende) phase. FE-SEM images show that grain size of as-deposited and annealed ZnS films are about 20 nm and 50 nm, respectively. Optical absorption study showed that the films have moderate optical transmission from 65% to 75% in the visible region and the optical band gap energy of as-deposited ZnS film is 3.91 eV and it decreases to 3.73 eV after annealing.

  9. Research of acceptor impurity thermal activation in GaN: Mg epitaxial layers

    Directory of Open Access Journals (Sweden)

    Aleksandr V. Mazalov

    2016-06-01

    The effect of thermal annealing of GaN:Mg layers on acceptor impurity activation has been investigated. Hole concentration increased and mobility decreased with an increase in thermal annealing temperature. The sample annealed at 1000 °C demonstrated the lowest value of resistivity. Rapid thermal annealing (annealing with high heating speed considerably improved the efficiency of Mg activation in the GaN layers. The optimum time of annealing at 1000 °C has been determined. The hole concentration increased by up to 4 times compared to specimens after conventional annealing.

  10. High temperature annealing effects on deep-level defects in a high purity semi-insulating 4H-SiC substrate

    Science.gov (United States)

    Iwamoto, Naoya; Azarov, Alexander; Ohshima, Takeshi; Moe, Anne Marie M.; Svensson, Bengt G.

    2015-07-01

    Effects of high-temperature annealing on deep-level defects in a high-purity semi-insulating 4H silicon carbide substrate have been studied by employing current-voltage, capacitance-voltage, junction spectroscopy, and chemical impurity analysis measurements. Secondary ion mass spectrometry data reveal that the substrate contains boron with concentration in the mid 1015 cm-3 range, while other impurities including nitrogen, aluminum, titanium, vanadium and chromium are below their detection limits (typically ˜1014 cm-3). Schottky barrier diodes fabricated on substrates annealed at 1400-1700 °C exhibit metal/p-type semiconductor behavior with a current rectification of up to 8 orders of magnitude at bias voltages of ±3 V. With increasing annealing temperature, the series resistance of the Schottky barrier diodes decreases, and the net acceptor concentration in the substrates increases approaching the chemical boron content. Admittance spectroscopy results unveil the presence of shallow boron acceptors and deep-level defects with levels in lower half of the bandgap. After the 1400 °C annealing, the boron acceptor still remains strongly compensated at room temperature by deep donor-like levels located close to mid-gap. However, the latter decrease in concentration with increasing annealing temperature and after 1700 °C, the boron acceptor is essentially uncompensated. Hence, the deep donors are decisive for the semi-insulating properties of the substrates, and their thermal evolution limits the thermal budget for device processing. The origin of the deep donors is not well-established, but substantial evidence supporting an assignment to carbon vacancies is presented.

  11. Effect of oxidation and annealing temperature on optical and ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 37; Issue 3. Effect of oxidation and ... Keywords. SnO2 thin films; optical properties; optical bandgap; Urbach energy; surface roughness; XRD. ... The effect of oxidation temperature on the optical and structural properties of SnO2 films were investigated. Higher ...

  12. Effect of Annealing Temperature on Microstructure and Mechanical Properties of Hot-Dip Galvanizing DP600 Steel

    Science.gov (United States)

    Hai-yan, Sun; Zhi-li, Liu; Yang, Xu; Jian-qiang, Shi; Lian-xuan, Wang

    Hot-dip galvanizing dual phase steel DP600 steel grade with low Si was produced by steel plant and experiments by simulating galvanizing thermal history. The microstructure was observed and analyzed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The effect of different annealing temperatures on the microstructure and mechanical properties of dual-phase steel was also discussed. The experimental results show that the dual-phase steel possesses excellent strength and elongation that match EN10346 600MPa standards. The microstructure is ferrite and martensite. TEM micrograph shows that white ferrite with black martensite islands inlay with a diameter of around 1um and the content of 14 18%. The volume will expand and phase changing take the form of shear transformation when ferrite converted to martensite. So there are high density dislocations in ferrite crystalline grain near martensite. The martensite content growing will be obvious along with annealing temperature going up. But the tendency will be weak when temperature high.

  13. Optical properties of planar waveguides on ZnWO₄ formed by carbon and helium ion implantation and effects of annealing.

    Science.gov (United States)

    Zhao, Jin-Hua; Liu, Tao; Guo, Sha-Sha; Guan, Jing; Wang, Xue-Lin

    2010-08-30

    We report on the optical properties of ZnWO(4) planar waveguides created by ion implantation, and the effect annealing has on these structures. Planar optical waveguides in ZnWO(4) crystals are fabricated by 5.0 MeV carbon ion implantation with a fluence of 1 × 10(15) ions/cm(2) or 500 keV helium ion implantation with the a fluence of 1 × 10(16) ions/cm(2). The thermal stability was investigated by 60 minute annealing cycles at different temperatures ranging from 260°C to 550°C in air. The guided modes were measured by a model 2010 prism coupler at wavelengths of 633 nm and 1539 nm. The reflectivity calculation method (RCM) was applied to simulate the refractive index profile in these waveguides. The near-field light intensity profiles were measured using the end-face coupling method. The absorption spectra show that the implantation processes have almost no influence on the visible band absorption.

  14. Annealing effect on elastic, magnetic and magnetoelastic properties of CoFeB thin films on polymer substrate

    Science.gov (United States)

    Zighem, F.; Faurie, D.; Belmeguenai, M.; Girodon-Boulandet, N.; Gabor, M. S.; Djemia, P.

    2017-11-01

    We have studied the magnetomechanical properties of Co20 Fe60 B20 thin films deposited on polyimide substrate. Particularly, we studied the effect of annealing in the accessible temperature range (0-375 °C) allowed by the polymer substrate. Complementary techniques have been used to characterize the elastic, magnetic and magnetoelastic properties of annealed samples (Brillouin light scattering and tensile tests combined with in situ ferromagnetic resonance). Below 200 °C, no significant evolutions of the properties have been found excepted the magnetic damping parameter. In contrast, above 200 °C, strong variations are observed (+15% for Young’s modulus, -40% for magnetostriction coefficient and  +500% for the uniaxial magnetic anisotropy field). This is in correlation with the x-ray diffraction peak sharpening observed in the studied thin films. This is most probably due to exceeding of the glass transition temperature of the thin film. The complete data analysis allowed an estimation of the thermal stability of Co20 Fe60 B20 alloy thin films.

  15. Effect of the Annealing Temperature on the Structure and Magnetic Properties of 2% Si Steel

    Directory of Open Access Journals (Sweden)

    Cunha Marco A. da

    2002-01-01

    Full Text Available To study the effect of the annealing temperature on the structure and magnetic properties of a 2%Si non-oriented steel cold rolled samples were submitted to final annealing in the temperature range of 540 °C to 980 °C in hydrogen atmosphere. The samples had received cold rolling reduction of 75% to a final thickness of 0.50 mm. Recovery and recrystallization resulted in significant improvement of magnetic properties, with decrease of iron loss (W1.5 and increase of polarisation (J50 and relative permeability (µ1.5. On further grain growth, after recrystallization, there was simultaneous decrease of iron loss, polarisation and relative permeability. Texture evolution on grain growth accounts for the observed decrease of J50 and µ1.5. The beneficial effect of increasing grain size on core loss overcomes the detrimental effect of texture resulting in decrease of W1.5.

  16. Improved thermal and strain performance of annealed polymer optical fiber Bragg gratings

    DEFF Research Database (Denmark)

    Yuan, Scott Wu; Stefani, Alessio; Bache, Morten

    2011-01-01

    We report on a detailed study of the inscription and characterization of fiber Bragg gratings (FBGs) in commercial step index polymer optical fibers (POFs). Through the growth dynamics of the gratings, we identify the effect of UV-induced heating during the grating inscription. We found that FBGs...

  17. TiO2 films annealing temperature-dependent properties in terms of the Amlouk-Boubaker opto-thermal expansivity ψAB

    Science.gov (United States)

    Amlouk, A.; Boubaker, K.; El Mir, L.; Amlouk, M.

    2011-02-01

    In this study, TiO2 films were grown at room temperature by sol-gel process using titanium (IV)-isopropylat as precursor. XRD, EDS and MEB analyses proved that an eventual annealing treatment caused the TiO2 amorphous phase to shift to a crystalline anatase phase. Optical measurements were carried out via absorbance spectra in 500-2500 nm wavelength domain. From these optical measurements, the temperature-dependent conjoint optical and thermal properties were deduced using the Amlouk-Boubaker opto-thermal expansivity ψAB.

  18. Fabrication of a Cu(InGaSe2 Thin Film Photovoltaic Absorber by Rapid Thermal Annealing of CuGa/In Precursors Coated with a Se Layer

    Directory of Open Access Journals (Sweden)

    Chun-Yao Hsu

    2013-01-01

    Full Text Available Cu(InGaSe2 (CIGS thin film absorbers are prepared using sputtering and selenization processes. The CuGa/In precursors are selenized during rapid thermal annealing (RTA, by the deposition of a Se layer on them. This work investigates the effect of the Cu content in precursors on the structural and electrical properties of the absorber. Using X-ray diffraction, field emission scanning electron microscopy, Raman spectroscopy, and Hall effect measurement, it is found that the CIGS thin films produced exhibit facetted grains and a single chalcopyrite phase with a preferred orientation along the (1 1 2 plane. A Cu-poor precursor with a Cu/( ratio of 0.75 demonstrates a higher resistance, due to an increase in the grain boundary scattering and a reduced carrier lifetime. A Cu-rich precursor with a Cu/( ratio of 1.15 exhibits an inappropriate second phase ( in the absorber. However, the precursor with a Cu/( ratio of 0.95 exhibits larger grains and lower resistance, which is suitable for its application to solar cells. The deposition of this precursor on Mo-coated soda lime glass substrate and further RTA causes the formation of a MoSe2 layer at the interface of the Mo and CIGS.

  19. ZnO nanorod arrays prepared by chemical bath deposition combined with rapid thermal annealing: structural, photoluminescence and field emission characteristics

    Science.gov (United States)

    Chen, Hung-Wei; Yang, Hsi-Wen; He, Hsin-Min; Lee, Yi-Mu

    2016-01-01

    ZnO nanorod arrays were prepared by low temperature chemical bath deposition (CBD) combined with rapid thermal annealing (RTA) under different ambient conditions. The structure and morphology of the synthesized ZnO have been characterized by field-emission scanning electron microscopy (FESEM) and x-ray diffraction (XRD). The obtained ZnO samples are highly crystalline with a hexagonal wurtzite phase and also display well-aligned array structure. A pronounced effect on increased nanorod length was found for the RTA-treated ZnO as compared to the as-grown ZnO. Analysis of XRD indicates that the (0 0 2) feature peak of the as-grown ZnO was shifted towards a lower angle as compared to the peaks of RTA-treated ZnO samples due to the reduction of tensile strain along the c-axis by RTA. Photoluminescence (PL) studies reveal that the ZnO nanorod arrays receiving RTA in an O2 environment have the sharpest UV emission band and greatest intensity ratio of near band-edge emission (NBE) to deep level emission (DLE). Additionally, the effects of RTA on the field emission properties were evaluated. The results demonstrate that RTA an O2 environment can lower the turn-on field and improve the field enhancement factor. The stability of the field emission current was also tested for 4 h.

  20. Deformation and thermal histories of ordinary chondrites: Evidence for post-deformation annealing and syn-metamorphic shock

    Science.gov (United States)

    Ruzicka, Alex; Hugo, Richard; Hutson, Melinda

    2015-08-01

    We show that olivine microstructures in seven metamorphosed ordinary chondrites of different groups studied with optical and transmission electron microscopy can be used to evaluate the post-deformation cooling setting of the meteorites, and to discriminate between collisions affecting cold and warm parent bodies. The L6 chondrites Park (shock stage S1), Bruderheim (S4), Leedey (S4), and Morrow County (S5) were affected by variable shock deformation followed by relatively rapid cooling, and probably cooled as fragments liberated by impact in near-surface settings. In contrast, Kernouvé (H6 S1), Portales Valley (H6/7 S1), and MIL 99301 (LL6 S1) appear to have cooled slowly after shock, probably by deep burial in warm materials. In these chondrites, post-deformation annealing lowered apparent optical strain levels in olivine. Additionally, Kernouvé, Morrow County, Park, MIL 99301, and possibly Portales Valley, show evidence for having been deformed at an elevated temperature (⩾800-1000 °C). The high temperatures for Morrow County can be explained by dynamic heating during intense shock, but Kernouvé, Park, and MIL 99301 were probably shocked while the H, L and LL parent bodies were warm, during early, endogenically-driven thermal metamorphism. Thus, whereas the S4 and S5 chondrites experienced purely shock-induced heating and cooling, all the S1 chondrites examined show evidence for static heating consistent with either syn-metamorphic shock (Kernouvé, MIL 99301, Park), post-deformation burial in warm materials (Kernouvé, MIL 99301, Portales Valley), or both. The results show the pitfalls in relying on optical shock classification alone to infer an absence of shock and to construct cooling stratigraphy models for parent bodies. Moreover, they provide support for the idea that "secondary" metamorphic and "tertiary" shock processes overlapped in time shortly after the accretion of chondritic planetesimals, and that impacts into warm asteroidal bodies were

  1. Electrical, optical, and photoluminescence properties of ZnO films subjected to thermal annealing and treatment in hydrogen plasma

    Energy Technology Data Exchange (ETDEWEB)

    Abdullin, Kh. A.; Gabdullin, M. T. [al-Farabi Kazakh National University, National Nanotechnology Laboratory of Open Type (Kazakhstan); Gritsenko, L. V. [Kazakh National Technical Research University (Kazakhstan); Ismailov, D. V.; Kalkozova, Zh. K. [al-Farabi Kazakh National University, National Nanotechnology Laboratory of Open Type (Kazakhstan); Kumekov, S. E., E-mail: skumekov@mail.ru; Mukash, Zh. O. [Kazakh National Technical Research University (Kazakhstan); Sazonov, A. Yu. [200 University Avenue West, University of Waterloo (Canada); Terukov, E. I. [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation)

    2016-08-15

    The photoluminescence and optical absorption spectra and electrical properties of ZnO films grown by the metal–organic chemical vapor deposition and hydrothermal techniques, subjected to heat treatments and plasma treatment in a hydrogen atmosphere, are studied. It is shown that the adsorption of oxygen at grain boundaries upon annealing in an oxidizing atmosphere determines the electrical properties of the films. Vacuum annealing improves the electrical properties of the samples after degradation induced by annealing in air. Treatment in hydrogen plasma passivates surface states at the grain boundaries. The intrinsic photoluminescence intensity after plasma treatment is higher in the case of increased amounts of oxygen adsorbed at grain surfaces upon annealing in air. Surface states involving oxygen and hydrogen atoms are responsible for the high-intensity intrinsic photoluminescence band.

  2. Unique effects of thermal and pressure histories on glass hardness: Structural and topological origin

    Science.gov (United States)

    Smedskjaer, Morten M.; Bauchy, Mathieu; Mauro, John C.; Rzoska, Sylwester J.; Bockowski, Michal

    2015-10-01

    The properties of glass are determined not only by temperature, pressure, and composition, but also by their complete thermal and pressure histories. Here, we show that glasses of identical composition produced through thermal annealing and through quenching from elevated pressure can result in samples with identical density and mean interatomic distances, yet different bond angle distributions, medium-range structures, and, thus, macroscopic properties. We demonstrate that hardness is higher when the density increase is obtained through thermal annealing rather than through pressure-quenching. Molecular dynamics simulations reveal that this arises because pressure-quenching has a larger effect on medium-range order, while annealing has a larger effect on short-range structures (sharper bond angle distribution), which ultimately determine hardness according to bond constraint theory. Our work could open a new avenue towards industrially useful glasses that are identical in terms of composition and density, but with differences in thermodynamic, mechanical, and rheological properties due to unique structural characteristics.

  3. Hardness and microstructural response to thermal annealing of irradiated ASTM A533B class 1 plate steel

    Energy Technology Data Exchange (ETDEWEB)

    Reinhart, D.E. [SMS Concast, Inc., Pittsburgh, PA (United States); Kumar, A.S. [Univ. of Missouri, Rolla, MO (United States); Gelles, D.S.; Hamilton, M.L. [Pacific Northwest Lab., Richland, WA (United States); Rosinski, S.T. [Electric Power Research Inst., Charlotte, NC (United States)

    1999-10-01

    Hardness measurements were used to determine the post-irradiation annealing response of A533B class 1 plate steel irradiated to a fluence of 1 {times} 10{sup 19} n/cm{sup 2} (E > 1 MeV) at 150 C. Rockwell hardness measurements indicated that the material had hardened by 6.6 points on the B scale after irradiation. The irradiation induced hardness increase was associated with a decrease in upper shelf energy from 63.4 J to 5-1.8 J and a temperature shift in the Charpy curve at the 41 J level from 115 C to 215 C. Specimens were annealed after irradiation at temperatures of 343 C (650 F), 399 C (750 F), and 454 C (850 F) for durations of up to one week (168 h). Hardness measurements were made to chart recovery of hardness as a function of time and temperature. Specimens annealed at the highest temperature 454 C recovered the fastest, fully recovering within 144 h. Specimens annealed at 399 C recovered completely within 168 h. Specimens annealed at the lowest temperature, 343 C recovered only {approximately}70% after 168 h of annealing. After neutron irradiation, a new feature of black spot damage was found to be superimposed on the unirradiated microstructure. The density of black spots was found to vary from 2.3 {times} 10{sup 15}/cm{sup 3} to 1.1 {times} 10{sup 16}/cm{sup 3} with an average diameter of 2.85 nm. Following annealing at 454 C for 24 h the black spot damage was completely annealed out. It was concluded that the black spot damage was responsible for 70% of the irradiation-induced hardness.

  4. Electrical annealing of severely deformed copper: microstructure and hardness

    Science.gov (United States)

    Nobakht, Saeed; Kazeminezhad, Mohsen

    2017-10-01

    Commercial pure copper sheets were severely deformed after primary annealing to a strain magnitude of 2.32 through constrained groove pressing. After induction of an electrical current, the sheets were heated for 0.5, 1, 2, or 3 s up to maximum temperatures of 150, 200, 250, or 300°C. To compare the annealing process in the current-carrying system with that in the current-free system, four other samples were heated to 300°C at holding times of 60, 90, 120, or 150 s in a salt bath. The microstructural evolution and hardness values of the samples were then investigated. The results generally indicated that induction of an electrical current could accelerate the recrystallization process by decreasing the thermodynamic barriers for nucleation. In other words, the current effect, in addition to the thermal effect, enhanced the diffusion rate and dislocation climb velocity. During the primary stages of recrystallization, the grown nuclei of electrically annealed samples showed greater numbers and a more homogeneous distribution than those of the samples annealed in the salt bath. In the fully recrystallized condition, the grain size of electrically annealed samples was smaller than that of conventionally annealed samples. The hardness values and metallographic images obtained indicate that, unlike the conventional annealing process, which promotes restoration phenomena with increasing heating time, the electrical annealing process does not necessarily promote these phenomena. This difference is hypothesized to stem from conflicts between thermal and athermal effects during recrystallization.

  5. Effect of Postdeposition Annealing on the Structural, Electrical, and Optical Properties of DC Magnetron Sputtered Ta2O5 Films

    Directory of Open Access Journals (Sweden)

    S. Uthanna

    2007-12-01

    Full Text Available Thin films of tantalum oxide were formed on quartz and silicon (111 substrates kept at room temperature (303 K by reactive sputtering of tantalum target in the presence of mixture of oxygen and argon gases. The as-deposited films were annealed in air for an hour in the temperature range 673–873 K. The films were characterized by studying structural, dielectric, electrical, and optical properties. The as-deposited films were amorphous in nature. As the annealing temperature increased to 673 K, the films were transformed into polycrystalline. Electrical characteristics of as-deposited and annealed Ta2O5 thin films were compared. The thermal annealing reduced the leakage current density and increased the dielectric constant. The optical transmittance of the films increased with the increase of annealing temperature. The as-deposited films showed the optical band gap of 4.38 eV. It increased to 4.44 eV with the increase of annealing temperature to 873 K. The as-deposited films showed the low value (1.89 of refractive index and it increased to 2.15 when annealed at 873 K. The increase of refractive index with annealing temperature was due to the increase in the packing density and crystallinity of the films.

  6. Ozone-exposure and annealing effects on graphene-on-SiO2 transistors

    Science.gov (United States)

    Zhang, E. X.; Newaz, A. K. M.; Wang, B.; Zhang, C. X.; Fleetwood, D. M.; Bolotin, K. I.; Schrimpf, R. D.; Pantelides, S. T.; Alles, M. L.

    2012-09-01

    We employ resistance measurements and Raman spectroscopy to investigate the effects of UV ozone (UVO) exposure and Ar annealing on graphene-on-SiO2 transistors. Shorter UVO exposures lead to oxygen adsorption and doping; longer exposures lead to significant defect generation and then to etching. Elevated-temperature Ar annealing following UVO exposure leads to local defect healing, as shown by the evolution of the characteristic Raman D- and G-peaks. In striking contrast, the overall graphene transistor resistance increases significantly due to void formation. Density functional calculations show that carbon-oxygen reactions lead to efficient consumption and release of C atoms (as CO or CO2) under conditions of high surface oxygen concentration.

  7. Localized Electrothermal Annealing with Nanowatt Power for a Silicon Nanowire Field-Effect Transistor.

    Science.gov (United States)

    Park, Jun-Young; Lee, Byung-Hyun; Lee, Geon-Beom; Bae, Hagyoul; Choi, Yang-Kyu

    2018-02-07

    This work investigates localized electrothermal annealing (ETA) with extremely low power consumption. The proposed method utilizes, for the first time, tunneling-current-induced Joule heat in a p-i-n diode, consisting of p-type, intrinsic, and n-type semiconductors. The consumed power used for dopant control is the lowest value ever reported. A metal-oxide-semiconductor field-effect transistor (MOSFET) composed of a p-i-n silicon nanowire, which is a substructure of a tunneling FET (TFET), was fabricated and utilized as a test platform to examine the annealing behaviors. A more than 2-fold increase in the on-state (I ON ) current was achieved using the ETA. Simulations are conducted to investigate the location of the hot spot and how its change in heat profile activates the dopants.

  8. The Effect of Annealing on Nanothick Indium Tin Oxide Transparent Conductive Films for Touch Sensors

    Directory of Open Access Journals (Sweden)

    Shih-Hao Chan

    2015-01-01

    Full Text Available This study aims to discuss the sheet resistance of ultrathin indium tin oxide (ITO transparent conductive films during the postannealing treatment. The thickness of the ultrathin ITO films is 20 nm. They are prepared on B270 glass substrates at room temperature by a direct-current pulsed magnetron sputtering system. Ultrathin ITO films with high sheet resistance are commonly used for touch panel applications. As the annealing temperature is increased, the structure of the ultrathin ITO film changes from amorphous to polycrystalline. The crystalline of ultrathin ITO films becomes stronger with an increase of annealing temperature, which further leads to the effect of enhanced Hall mobility. A postannealing treatment in an atmosphere can enhance the optical transmittance owing to the filling of oxygen vacancies, but the sheet resistance rises sharply. However, a higher annealing temperature, above 250°C, results in a decrease in the sheet resistance of ultrathin ITO films, because more Sn ions become an effective dopant. An optimum sheet resistance of 336 Ω/sqr was obtained for ultrathin ITO films at 400°C with an average optical transmittance of 86.8% for touch sensor applications.

  9. Effects of Annealing Time on the Performance of OTFT on Glass with ZrO2 as Gate Dielectric

    Directory of Open Access Journals (Sweden)

    W. M. Tang

    2012-01-01

    Full Text Available Copper phthalocyanine-based organic thin-film transistors (OTFTs with zirconium oxide (ZrO2 as gate dielectric have been fabricated on glass substrates. The gate dielectric is annealed in N2 at different durations (5, 15, 40, and 60 min to investigate the effects of annealing time on the electrical properties of the OTFTs. Experimental results show that the longer the annealing time for the OTFT, the better the performance. Among the devices studied, OTFTs with gate dielectric annealed at 350°C in N2 for 60 min exhibit the best device performance. They have a small threshold voltage of −0.58 V, a low subthreshold slope of 0.8 V/decade, and a low off-state current of 0.73 nA. These characteristics demonstrate that the fabricated device is suitable for low-voltage and low-power operations. When compared with the TFT samples annealed for 5 min, the ones annealed for 60 min have 20% higher mobility and nearly two times smaller the subthreshold slope and off-state current. The extended annealing can effectively reduce the defects in the high-k film and produces a better insulator/organic interface. This results in lower amount of carrier scattering and larger CuPc grains for carrier transport.

  10. Silicon nanocrystals in SiN{sub x}/SiO{sub 2} hetero-superlattices: The loss of size control after thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Zelenina, A., E-mail: anastasia.zelenina@imtek.uni-freiburg.de; Zacharias, M. [Faculty of Engineering, IMTEK, Albert-Ludwigs-University Freiburg, Georges-Köhler-Allee 103, Freiburg 79110 (Germany); Sarikov, A. [Faculty of Engineering, IMTEK, Albert-Ludwigs-University Freiburg, Georges-Köhler-Allee 103, Freiburg 79110 (Germany); V. Lashkarev Institute of Semiconductor Physics NAS Ukraine, 45 Nauki Avenue, Kiev 03028 (Ukraine); Zhigunov, D. M. [Faculty of Physics, M.V. Lomonosov Moscow State University, Leninskie Gory 1, Moscow 119991 (Russian Federation); Weiss, C. [Fraunhofer-Institut für Solare Energiesysteme ISE, Heidenhofstr. 2, Freiburg 79110 (Germany); Zakharov, N.; Werner, P. [Max-Planck-Institute of Microstructure Physics, Weinberg 2, Halle 06120 (Germany); López-Conesa, L.; Peiró, F. [MIND-IN2UB, Departament d' Electrònica, Universitat de Barcelona, C/Martí i Franquès, 1, Barcelona 08028 (Spain); Estradé, S. [MIND-IN2UB, Departament d' Electrònica, Universitat de Barcelona, C/Martí i Franquès, 1, Barcelona 08028 (Spain); CCiT, Scientific and Technical Centers, Universitat de Barcelona, C/Lluís Solé i Sabaris 1, Barcelona 08028 (Spain); Dyakov, S. A. [Optics and Photonics, School of Information and Communication Technology, Royal Institute of Technology (KTH), Electrum 229, Kista SE-16440 (Sweden)

    2014-06-28

    Superlattices containing 3 nm thick silicon rich silicon nitride sublayers and 3 nm and 10 nm thick SiO{sub 2} barriers were prepared by plasma enhanced chemical vapor deposition. Despite the as-prepared samples represented a well-kept multilayer structure with smooth interfaces, the high temperature annealing resulted in the total destruction of multilayer structure in the samples containing 3 nm SiO{sub 2} barriers. Energy-filtered transmission electron microscopy images of these samples indicated a silicon nanoclusters formation with sizes of 2.5–12.5 nm, which were randomly distributed within the structure. Although in the sample with 10 nm SiO{sub 2} barriers some fragments of the multilayer structure could be still observed after thermal annealing, nevertheless, the formation of large nanocrystals with diameters up to 10 nm was confirmed by dark field transmission electron microscopy. Thus, in contrast to the previously published results, the expected size control of silicon nanocrystals was lost. According to the FTIR results, the thermal annealing of SiN{sub x}/SiO{sub 2} superlattices led to the formation of silicon nanocrystals in mostly oxynitride matrix. Annealed samples demonstrated a photoluminescence peak at 885 nm related to the luminescence of silicon nanocrystals, as confirmed by time-resolved photoluminescence measurements. The loss of nanocrystals size control is discussed in terms of the migration of oxygen atoms from the SiO{sub 2} barriers into the silicon rich silicon nitride sublayers. A thermodynamic mechanism responsible for this process is proposed. According to this mechanism, the driving force for the oxygen migration is the gain in the configuration entropy related to the relative arrangements of oxygen and nitrogen atoms.

  11. Impact of ink synthesis on processing of inkjet-printed silicon nanoparticle thin films: A comparison of Rapid Thermal Annealing and photonic sintering

    Energy Technology Data Exchange (ETDEWEB)

    Drahi, E.; Blayac, S. [Centre Microélectronique de Provence/Ecole Nationale Supérieure des Mines de Saint Etienne, 880, avenue de Mimet Gardanne, 13541 (France); Borbely, A. [Science des Matériaux et des Structures/Ecole Nationale Supérieure des Mines de Saint Etienne, 158, cours Fauriel Saint Etienne Cedex 2, 42023 (France); Benaben, P. [Centre Microélectronique de Provence/Ecole Nationale Supérieure des Mines de Saint Etienne, 880, avenue de Mimet Gardanne, 13541 (France)

    2015-01-01

    Inkjet printing has a high potential for cost reduction in solar cell and thermoelectric industry. This study demonstrates that silicon thin films can be produced by inkjet-printing of silicon nanoparticles followed by subsequent drying and annealing steps. Ink formulation is crucial for the sintering of the silicon nanoparticles and control of the microstructure at low temperature. Upon heating, the microstructure is modified from porous layer made of juxtaposed silicon nanoparticles to denser layer with coarser grains. This evolution is monitored by scanning electron microscopy and by micro-Raman spectroscopy, which offer a fast and precise characterization of the microstructure and chemical composition of thin films. Above a threshold temperature of 800 °C cracks appear within thin film and substrate because of the stress induced by the oxidation of the surface. An innovative sintering method, photonic annealing, is studied in order to reduce both oxidation and stress in the thin films as well as reducing processing time. Evolution of the thermal conductivity is performed by micro-Raman spectroscopy and can be tailored in a large range between ~ 1 and ~ 100 W·m{sup −1}·K{sup −1} depending on the sintering method and atmosphere. Therefore control of the microstructure evolution with applied annealing process allows tailoring of both microstructure and thermal conductivity of the silicon thin films. - Highlights: • Impact of ink synthesis on sintering (Si nanoparticle surface chemistry) • Photonic annealing of inkjet printed Si nanoparticles • Micro-Raman spectroscopy and X-Ray Diffraction for thin film characterization.

  12. The Effect of Solution Annealing on the Microstructural Behavior of Alloy 22 Welds

    Energy Technology Data Exchange (ETDEWEB)

    El-Dasher, B S; Edgecumbe, T S; Torres, S G

    2005-05-06

    Multi-pass gas tungsten arc welds of Alloy 22 were subjected to solution annealing durations of 20 minutes, 24 hours, 72 hours and 1 week at temperatures of 1075, 1121, 1200, and 1300 C. The specimens were studied in cross section by secondary electron microscopy to determine the effect of solution annealing on tetrahedrally close packed (TCP) precipitate stability. Electron backscatter diffraction mapping was also performed on all of the specimens to determine the recrystallization behavior of the welds. It was found that complete TCP precipitate dissolution occurs after solution annealing at 1075 C and 1121 C for 24 hours, and at 1200 C and 1300 C for durations of 20 minutes. Regions of most rapid recrystallization were correlated to the regions of lowest solute content and highest residual tensile stresses. Texture analysis indicated that while the columnar dendrites originally present in the weld grew with a <001> orientation in the transverse direction (opposite the heat flow direction), the recrystallized grains adopt a <101> orientation in the transverse direction when recrystallization and TCP phase dissolution occur simultaneously.

  13. Effect of annealing on the structure and optical properties of InGaAs/GaAs quantum dots

    DEFF Research Database (Denmark)

    Xu, Zhangcheng; Leosson, Kristjan; Birkedal, Dan

    2002-01-01

    We report the effect of annealing on self-assembled InGaAs/GaAs quantum dots, as investigated by means of resonant photoluminescence (PL), resonant Raman scattering, polarization dependent PL, and high resolution X-ray diffraction.......We report the effect of annealing on self-assembled InGaAs/GaAs quantum dots, as investigated by means of resonant photoluminescence (PL), resonant Raman scattering, polarization dependent PL, and high resolution X-ray diffraction....

  14. Enhanced propylene/propane separation by thermal annealing of an intrinsically microporous Hydroxyl-functionalized polyimide membrane

    KAUST Repository

    Swaidan, Ramy Jawdat

    2015-08-06

    Effective separation of propylene/propane is vital to the chemical industry where C3H6 is used as feedstock for a variety of important chemicals. The purity requirements are currently met with cryogenic distillation, which is an extremely energy-intensive process. Hybrid arrangements incorporating highly selective membranes (α>20) have been proposed to “debottleneck” the process and potentially improve the economics. Selective and permeable membranes can be obtained by the design of polymers of intrinsic microporosity (PIMs). In this work, a 250 °C annealed polyimide (PIM-6FDA-OH) membrane produced among the highest reported pure-gas C3H6/C3H8 selectivity of 30 for a solution-processable polymer to date. The high selectivity resulted from enhanced diffusivity selectivity due to the formation of inter-chain charge-transfer-complexes. Although there were some inevitable losses in selectivity under 50:50 mixed-gas feed conditions due to competitive sorption, relatively high selectivities were preserved due to enhanced plasticization resistance.

  15. Thermal annealing behavior of nano-size metal-oxide particles synthesized by ion implantation in Fe-Cr alloy

    Science.gov (United States)

    Zheng, C.; Gentils, A.; Ribis, J.; Borodin, V. A.; Descoins, M.; Mangelinck, D.; Dalle, F.; Arnal, B.; Delauche, L.

    2017-05-01

    Oxide dispersion strengthened (ODS) steels are promising structural materials for the next generation nuclear reactors, as well as fusion facilities. The detailed understanding of the mechanisms involved in the precipitation of nano-oxides during ODS steel production would strongly contribute to the improvement of the mechanical properties and the optimization of manufacturing of ODS steels, with a potentially strong economic impact for their industrialization. A useful tool for the experimental study of nano-oxide precipitation is ion implantation, a technique that is widely used to synthesize precipitate nanostructures in well-controlled conditions. Earlier, we have demonstrated the feasibility of synthesizing aluminum-oxide particles in the high purity Fe-10Cr alloy by consecutive implantation with Al and O ions at room temperature. This paper describes the effects of high-temperature annealing after the ion implantation stage on the development of the aluminum based oxide nanoparticle system. Using transmission electron microscopy and atom probe tomography experiments, we demonstrate that post-implantation heat treatment induces the growth of the nano-sized oxides in the implanted region and nucleation of new oxide precipitates behind the implantation zone as a result of the diffusion driven broadening of implant profiles. A tentative scenario for the development of metal-oxide nano-particles at both ion implantation and heat treatment stages is suggested based on the experimental observations.

  16. Annealing effects on the structure and magnetic properties of Ni/Ti multilayers

    Science.gov (United States)

    Sella, C.; Maˆaza, M.; Kaabouchi, M.; El Monkade, S.; Miloche, M.; Lassri, H.

    1993-03-01

    Interfaces of Ni-Ti multilayers deposited by dc triode sputtering under high purity conditions (base pressure 10 -7 Torr plus getter-sputtering) and their thermal evolution are studied. This was achieved by combining high energy electron diffraction, secondary ion mass spectrometry and magnetometry. The study shows the existence of a non-magnetic interfacial amorphous layer due to interdiffusion over very short distances during deposition. A marked asymmetry between the two sides of a given layer is observed, due to interfacial contamination of Ti by C and O acting as a diffusion barrier. Annealing treatments yield an increase in amorphization and finally crystallization of the interfacial amorphous phase to a NiTi stable phase.

  17. Effect of Post-Deposition Annealing on RF-Sputtered Catalyst-Free Grown ZnO Nanostructures

    Science.gov (United States)

    Srivastava, Amit; Kumar, Naresh

    2017-08-01

    Catalyst-free zinc oxide (ZnO) nano-structures were synthesized on silicon (100) substrate by radio frequency sputtering. The as-deposited films were post-annealed at 200°C, 400°C, 600°C, and 800°C. The effects of annealing temperature on the structural, morphological and optical properties of these nanostructures were investigated using x-ray diffraction (XRD), atomic force microscopy (AFM) and spectroscopic ellipsometry. XRD showed c-axis-oriented growth with the increase in crystallinity at the higher annealing temperature of these ZnO nanostructures. The crystallite size calculated using Scherrer's formula in the XRD data was found to increase with the annealing temperature. AFM images confirmed the growth of grains at higher annealing temperatures. Optical band gaps of these ZnO nanostructures were calculated using reflectance spectra in the ultraviolet-visible region and found to decrease from 3.19 eV to 3.09 eV as the annealing temperature increased from 200°C to 800°C. The decrease in band gap may be attributed to the decrease in oxygen vacancies at higher annealing temperatures and may be useful for different applications.

  18. Effect of annealing temperature and time on microstructure and mechanical properties of high Cr ferritic casting steel

    Science.gov (United States)

    Suo, Z. Y.; Fu, L. M.; Zhang, R. N.; Wang, Y. J.; Shan, A. D.

    2017-09-01

    A new-type of high Cr ferrite cast steel was designed and investigated. Effects of annealing temperature and time on the microstructure and mechanical properties of the high Cr ferrite cast steel were studied. The results show that the microstructures of the as-cast and annealing steels are composed of ferrite and (Cr•Fe)23C6 carbide. The morphology of carbides is from long rod and the continuous network to crystal precipitation for the steels with increasing of annealing temperature and time. The impact toughness is slightly increased from 6 J/cm2 to 8 J/cm2 when the annealing temperature increases from 1180 ℃ to 1200 ℃. But the hardness is about HB 200 and no obvious differences between the as-cast and annealing steels. The most suitable annealing temperature and time are 1200 ℃ and 5 h, respectively. The wear resistance of the high Cr ferrite cast steel is increased and improved with annealing temperature and holding time at 260 ℃. The wear mechanism is changed from abrasion wear to abrasive and adhesive wear. The good wear-resistant of the high Cr ferrite cast steel is mainly attributed to the fine uniformly dispersed carbides.

  19. Effects of air annealing on the optical, electrical, and structural properties of nanostructured ZnS/Au/ZnS films

    Energy Technology Data Exchange (ETDEWEB)

    Ghorashi, S.M.B. [Atomic and Molecular Group, Faculty of Physics, Yazd University, Yazd (Iran, Islamic Republic of); Behjat, A., E-mail: abehjat@yazduni.ac.ir [Atomic and Molecular Group, Faculty of Physics, Yazd University, Yazd (Iran, Islamic Republic of); Neghabi, M.; Mirjalili, G. [Atomic and Molecular Group, Faculty of Physics, Yazd University, Yazd (Iran, Islamic Republic of)

    2010-12-15

    In this paper, transparent conductive ZnS/Au/ZnS nano-multilayer films have been designed and the optimum thickness of gold and zinc sulfide layers are calculated. The conductive transparent ZnS/Au/ZnS nano-multilayer structure with optimized thickness have also been fabricated on a glass substrate by thermal evaporation and have been annealed in air at different temperatures. The electrical, optical and structural properties of the films such as electrical resistivity, optical transmittance, grain size have been obtained. X-ray diffraction patterns show that increase in annealing temperature increases the crystallinity of the structures. Moreover, Scanning electron microscope images of the samples show that the grain sizes become larger by increasing the annealing temperature which is in consistence with the X-ray diffraction analysis.

  20. Effect of annealing temperature on magnetic property of Si{sub 1-x}Cr{sub x} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Wenyong; Guo Liping, E-mail: guolp@whu.edu.cn; Peng Guoliang; Li Tiecheng; Feng Shixuan; Zhou Zhongpo; Peng Ting; Quan Zuci

    2011-11-01

    Polycrystalline Si{sub 1-x}Cr{sub x} thin films have been prepared by magnetron sputtering followed by rapid thermal annealing (RTA) for crystallization. RTA was performed at 800 Degree-Sign C for 5 min, 1200 Degree-Sign C for 30 s and 1200 Degree-Sign C for 2 min, in a N{sub 2} flow. The magnetic hysteresis loops were observed at room temperature in all the samples except for RTA at 800 Degree-Sign C for 5 min, and the annealing caused the decrease of saturation magnetization relative to the as-grown film. X-ray diffraction spectra and Raman spectra showed that the annealing process lead the deposited amorphous film to be crystallized and CrSi{sub 2} phase formed. The magnetism of the films was determined by the competition between crystallinity and precipitation of diamagnetic CrSi{sub 2} phase.

  1. Simulated Annealing Approach to the Temperature-Emissivity Separation Problem in Thermal Remote Sensing Part One: Mathematical Background

    CERN Document Server

    Morgan, John A

    2016-01-01

    The method of simulated annealing is adapted to the temperature-emissivity separation (TES) problem. A patch of surface at the bottom of the atmosphere is assumed to be a greybody emitter with spectral emissivity $\\epsilon(k)$ describable by a mixture of spectral endmembers. We prove that a simulated annealing search conducted according to a suitable schedule converges to a solution maximizing the $\\textit{A-Posteriori}$ probability that spectral radiance detected at the top of the atmosphere originates from a patch with stipulated $T$ and $\\epsilon(k)$. Any such solution will be nonunique. The average of a large number of simulated annealing solutions, however, converges almost surely to a unique Maximum A-Posteriori solution for $T$ and $\\epsilon(k)$. The limitation to a stipulated set of endmember emissivities may be relaxed by allowing the number of endmembers to grow without bound, and to be generic continuous functions of wavenumber with bounded first derivatives with respect to wavenumber.

  2. Modification of photosensing property of CdS–Bi{sub 2}S{sub 3} bi-layer by thermal annealing and swift heavy ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Shaikh, Shaheed U.; Siddiqui, Farha Y. [Thin Film and Nanotechnology Laboratory, Department of Physics (India); Department of Nanotechnology, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad 431004 (India); Singh, Fouran; Kulriya, Pawan K. [Inter University Accelerator Center, Aruna Asaf Ali Marg, New Delhi 110 067 (India); Phase, D.M. [UGC DAE Consortium for Scientific Research, Khandwa Road, Indore 452017 (India); Sharma, Ramphal, E-mail: ramphalsharma@yahoo.com [Thin Film and Nanotechnology Laboratory, Department of Physics (India); Department of Nanotechnology, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad 431004 (India)

    2016-02-01

    The CdS–Bi{sub 2}S{sub 3} bi-layer thin films have been deposited on Indium Tin Oxide (ITO) glass substrates at room temperature by Chemical Bath Deposition Technique (CBD) and bi-layer thin films were annealed in air atmosphere for 1 h at 250 {sup °}C. The air annealed sample was irradiated using Au{sup 9+} ions at the fluence 5 × 10{sup 11} ion/cm{sup 2} with 120 MeV energy. Effects of Swift Heavy Ion (SHI) irradiation on CdS–Bi{sub 2}S{sub 3} bi-layer thin films were studied. The results are explained on the basis annealing and high electronic excitation, using X-ray diffraction (XRD), Selective Electron Area Diffraction (SEAD), Atomic Force Microscopy (AFM), Raman Spectroscopy, UV spectroscopy and I–V characteristics. The photosensing property after illumination of visible light over the samples is studied. These as-deposited, annealed and irradiated bi-layer thin films are used to sense visible light at room temperature. - Graphical abstract: Schematic illustration of CdS–Bi{sub 2}S{sub 3} bi-layer thin film (a) As-deposited (b) Annealed (c) irradiated sample respectively (d) Model of bi-layer photosensor device (e) Graph of illumination intensity verses photosensitivity. - Highlights: • CdS–Bi{sub 2}S{sub 3} bi-layer thin film prepared at room temperature. • Irradiated using Au{sup 9+} ions at the fluence of 5 × 10{sup 11} ion/cm{sup 2} with 120 MeV energy. • Study of modification induced by irradiations. • Study of Photosensitivity after annealing and irradiation.

  3. Effects of Annealing on Electrical Characteristics and Current Transport Mechanisms of the Y/ p-GaN Schottky Diode

    Science.gov (United States)

    Reddy, V. Rajagopal; Asha, B.; Choi, Chel-Jong

    2016-07-01

    This study investigates the effects of annealing on the electrical properties and current transport mechanism of Y/ p-GaN Schottky barrier diodes (SBDs). We found no significant change in the surface morphology of the Y Schottky contacts during the annealing process. The Schottky barrier height (SBH) of the as-deposited Y/ p-GaN SBD was estimated to be 0.95 eV ( I- V)/1.19 eV ( C- V). The SBH increased upon annealing at 400°C and 500°C, and then decreased slightly with annealing at 600°C. Thus the maximum SBH of the Y/ p-GaN SBD was achieved at 500°C, with values of 1.01 eV ( I- V)/1.29 eV ( C- V). In addition, the SBH values were estimated by Cheung's, Norde, and Ψs- V plots and were found to be in good agreement with one another. Series resistance ( R S) values were also calculated by I- V, Cheung's, and Norde functions at different annealing temperatures, with results showing a decrease in the interface state density of the SBD with annealing at 500°C, followed by a slight increase upon annealing at 600°C. The forward-bias current transport mechanism of SBD was investigated by the log I-log V plot at different annealing temperatures. Our investigations revealed that the Poole-Frenkel emission mechanism dominated the reverse leakage current in Y/ p-GaN SBD at all annealing temperatures.

  4. Correlating the silicon surface passivation to the nanostructure of low-temperature a-Si:H after rapid thermal annealing

    Science.gov (United States)

    Macco, Bart; Melskens, Jimmy; Podraza, Nikolas J.; Arts, Karsten; Pugh, Christopher; Thomas, Owain; Kessels, Wilhelmus M. M.

    2017-07-01

    Using an inductively coupled plasma, hydrogenated amorphous silicon (a-Si:H) films have been prepared at very low temperatures (growth. The correlation between the a-Si:H nanostructure and the activation of a-Si:H/c-Si interface passivation, upon annealing, has been studied in detail. This yields a structural model that qualitatively describes the different processes that take place in the a-Si:H films during annealing. The presented experimental findings and insights can prove to be useful in the further development of very thin a-Si:H passivation layers for use in silicon heterojunction solar cells.

  5. Rapid thermal annealing of p-type silicon: Correlation between deep-level transient spectroscopy and lifetime measurements

    Science.gov (United States)

    Poggi, Antonella; Susi, Enrichetta; Bumuri, Maria Angela; Carotta, Maria Cristina

    1994-03-01

    The correlation between minority carrier lifetime and deep-level transient spectroscopy measurements was used in order to obtain more information about the mechanisms of defect formation and annealing in CS and FZ silicon during high temperature heating by lamp. Different energy levels induced by lamp annealings were detected: a good correlation with the lifetime behavior was observed of a donor at E(sub v) + 0.29 eV. No direct influence of the oxygen content was detected at 1050 C, while at 750 C a gettering action of oxygen aggregates can be hypothesized.

  6. Effect of high pressure sintering and annealing on microstructure and thermoelectric properties of nanocrystalline Bi2Te2.7Se0.3 doped with Gd

    Directory of Open Access Journals (Sweden)

    Ping Zou

    2014-06-01

    Full Text Available Bi2Te2.7Se0.3 of high performance doped with Gd bulk materials was prepared by a high pressure (6.0 GPa sintering (HPS method at 593 K, 633 K, 673 K and 693 K. The sample was then annealed for 36 h in a vacuum at 633 K. The phase composition, crystal structure and morphology of the sample were analyzed by X-ray diffraction and scanning electron microscopy. The electric conductivity, Seebeck coefficient, and thermal conductivity aspects of the sample were measured from 298 K to 473 K. The results show that high pressure sintering and the doping with Gd has a great effect on the crystal structure and the thermoelectric properties of the samples. The samples are consisted of nanoparticles before and after annealing, and these nanostructures have good stability at high temperature. HPS together with annealing can improve the TE properties of the sample by decreasing the thermal conductivity of the sample with nanostructures. The maximum ZT value of 0.74 was obtained at 423 K for the sample, which was sintered at 673 K and then annealed at 633 K for 36 h. Compared with the zone melting sample, it was increased by 85% at 423 K. Hence the temperature of the maximum of figure of merit was increased. The results can be applied to the field of thermoelectric power generation materials.

  7. Origin of a Raman scattering peak generated in single-walled carbon nanotubes by X-ray irradiation and subsequent thermal annealing

    Directory of Open Access Journals (Sweden)

    Toshiya Murakami

    2016-08-01

    Full Text Available We have found that a Raman scattering (RS peak around 1870 cm−1 was produced by the annealing of the X-ray irradiated film of single-walled carbon nanotubes (SWNTs at 450 oC. The intensity of 1870-cm−1 peak showed a maximum at the probe energy of 2.3 eV for the RS spectroscopy with various probe lasers. Both the peak position and the probe-energy dependence were almost identical to those of the one-dimensional carbon chains previously reported in multi-walled carbon nanotubes. Consequently, we concluded that the 1870-cm−1 peak found in the present study is attributed to carbon chains. The formation of carbon chains by the annealing at temperature lower than 500 oC is firstly reported by the present study. The carbon chains would be formed by aggregation of the interstitial carbons, which are formed as a counterpart of carbon vacancies by X-ray irradiation diffused on SWNT walls. The result indicates that the combination of X-ray irradiation and subsequent thermal annealing is a feasible tool for generating new nanostructures in SWNT.

  8. Origin of a Raman scattering peak generated in single-walled carbon nanotubes by X-ray irradiation and subsequent thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Murakami, Toshiya; Matsuda, Mitsuaki; Itoh, Chihiro, E-mail: citoh@sys.wakayama-u.ac.jp [Department of Materials Science, Wakayama University, 930 Sakaedani, Wakayama 640-8510 (Japan); Kisoda, Kenji [Department of Physics, Wakayama University, 930 Sakaedani, Wakayama 640-8510 (Japan)

    2016-08-15

    We have found that a Raman scattering (RS) peak around 1870 cm{sup −1} was produced by the annealing of the X-ray irradiated film of single-walled carbon nanotubes (SWNTs) at 450 {sup o}C. The intensity of 1870-cm{sup −1} peak showed a maximum at the probe energy of 2.3 eV for the RS spectroscopy with various probe lasers. Both the peak position and the probe-energy dependence were almost identical to those of the one-dimensional carbon chains previously reported in multi-walled carbon nanotubes. Consequently, we concluded that the 1870-cm{sup −1} peak found in the present study is attributed to carbon chains. The formation of carbon chains by the annealing at temperature lower than 500 {sup o}C is firstly reported by the present study. The carbon chains would be formed by aggregation of the interstitial carbons, which are formed as a counterpart of carbon vacancies by X-ray irradiation diffused on SWNT walls. The result indicates that the combination of X-ray irradiation and subsequent thermal annealing is a feasible tool for generating new nanostructures in SWNT.

  9. Effects of water and sawdust additives on thermal effusivity, thermal ...

    African Journals Online (AJOL)

    The effects of water and sawdust additives on the thermal effusivity (e), thermal conductivity (λ), and durability of cement-stabilized laterites were investigated. The thermal effusivity (e) and conductivity(λ) have direct influ-ence on heat transfer and thermal insulation in buildings, and the parameters were determined by hot ...

  10. Effect of Batch Annealing Temperature on Microstructure and Resistance to Fish Scaling of Ultra-Low Carbon Enamel Steel

    Directory of Open Access Journals (Sweden)

    Zaiwang Liu

    2017-02-01

    Full Text Available In the present work, an ultra-low carbon enamel steel was batch annealed at different temperatures, and the effect of the batch annealing temperature on the microstructure and resistance to fish scaling was investigated by optical microscopy, transmission electron microscopy, and a hydrogen permeation test. The results show that the main precipitates in experimental steel are fine TiC and coarse Ti4C2S2 particles. The average sizes of both TiC and Ti4C2S2 increase with increasing the batch annealing temperature. The resistance to fish scaling decreases with increasing the annealing temperature, which is caused by the growth of ferrite grain and the coarsening of the TiC and Ti4C2S2 particles

  11. Effects of air annealing on the optical, electrical, and structural properties of indium-tin oxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Trejo-Cruz, C. [Cinvestav-Queretaro, Libramiento Norponiente 2000, Fracc. Real de Juriquilla, 76230 Queretaro (Mexico); Mendoza-Galvan, A., E-mail: amendoza@qro.cinvestav.m [Cinvestav-Queretaro, Libramiento Norponiente 2000, Fracc. Real de Juriquilla, 76230 Queretaro (Mexico); Lopez-Beltran, A.M. [Cinvestav-Queretaro, Libramiento Norponiente 2000, Fracc. Real de Juriquilla, 76230 Queretaro (Mexico); Facultad de Ciencias Quimico-Biologicas, Universidad Autonoma de Sinaloa, Ciudad Universitaria, 80010 Culiacan (Mexico); Gracia-Jimenez, M. [Instituto de Fisica, Benemerita Universidad Autonoma de Puebla, Av. San Claudio y 18 Sur, 72570 Puebla (Mexico)

    2009-06-30

    The effects of air annealing on the optical, electrical, and structural properties of indium-tin oxide thin films were investigated using spectroscopic ellipsometry in the UV-visible range, reflectance-transmittance spectra at normal incidence in the infrared range, electrical resistivity measurements, and X-ray diffraction. It was found that annealing at 300 {sup o}C produces an overall shift to lower photon energies of the optical constant spectra, which is related to the increase in electrical resistivity. The electrical measurements performed in the 25-300 K range show a metallic behavior with large residual resistivity, quantity that increases with annealing temperature and is closely related with the change in the relative intensity of the main diffraction peaks. Also it is shown that under certain conditions of film deposition onto indium-tin oxide, some of its properties can change in a similar way as in air-annealing processing.

  12. Effect of annealing temperature on the morphology and optical properties of PMMA films by spin-coating method

    Energy Technology Data Exchange (ETDEWEB)

    Aadila, A., E-mail: aadilaazizali@gmail.com; Afaah, A. N.; Asib, N. A. M. [NANO-SciTech Centre, Institute of Science, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia); Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia); Mohamed, R.; Rusop, M. [NANO-SciTech Centre, Institute of Science, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia); NANO-Electronic Centre, Faculty of Electrical Engineering, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia); Khusaimi, Z., E-mail: zurai142@salam.uitm.edu.my [NANO-SciTech Centre, Institute of Science, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia)

    2016-07-06

    Poly(methyl methacrylate) (PMMA) films were deposited on glass substrate by sol-gel spin-coating method. The films were annealed for 10 minutes in furnace at different annealing temperature of room temperature, 50, 100, 150 and 200 °C. The effect of annealing temperatures to the surface and optical properties of PMMA films spin-coated on the substrate were investigated by Atomic Force Microscope (AFM) and Ultraviolet-Visible (UV-Vis) Spectroscopy. It was observed in AFM analysis all the annealed films show excellent smooth surface with zero roughness. All the samples demonstrate a high transmittance of 80% in UV region as shown in UV-Vis measurement. Highly transparent films indicate the films are good optical properties and could be applied in various optical applications and also in non-linear optics.

  13. The effects of post-deposition annealing on the microstructure of electron-beam evaporated indium tin oxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Diniz, A.S.A.C.; Kiely, C.J. (Liverpool Univ. (United Kingdom)); Elfallal, I.; Pilkington, R.D.; Hill, A.E. (Salford Univ. (United Kingdom))

    1994-08-01

    ITO thin films have been produced by electron beam evaporation and submitted to a post-deposition annealing to study the effect of heat treatments on the optoelectronic characteristics of the films. The electrical and optical characteristics of the ITO thin films after annealing showed that high quality material can be prepared reproducibly with the transmission being largely controlled by annealing step in air and the electrical properties being improved by a subsequent anneal under a reducing atmosphere. In this paper we will report Transmission Electron Microscopy and X-ray Diffraction results on the microstructural evolution of the ITO films at each stage of fabrication process. These will be correlated with the electrical and optical characteristics of the films at each corresponding stage. (Author)

  14. CoFe Layers Thickness and Annealing Effect on the Magnetic Behavior of the CoFe/Cu Multilayer Nanowires

    Directory of Open Access Journals (Sweden)

    M. Ahmadzadeh

    2015-04-01

    Full Text Available CoFe/Cu multilayer nanowires were electrodeposited into anodic aluminum oxide templates prepared by a two-step mild anodization method, using the single-bath technique. Nanowires with 30 nm diameter and the definite lengths were obtained. The effect of CoFe layers thickness and annealing on the magnetic behavior of the multilayer nanowires was investigated. The layers thickness was controlled through the pulses numbers: 200, 260, 310,360 and 410 pulses were used to deposit the CoFe layers, while 300 pulse for the Cu layers. A certain increase in coercivity and squareness of CoFe/Cu multilayer nanowires observed with increasing the CoFe layer thickness and annealing improved the coercivity and decrease squareness of CoFe/Cu multilayer nanowires. First order reversal curves after annealed showed amount domains with soft magnetic phase, it also shows decreasing spreading of distribution function along the Hu axis after annealed

  15. The effect of annealing ambient on the characteristics of an indium-gallium-zinc oxide thin film transistor.

    Science.gov (United States)

    Park, Soyeon; Bang, Seokhwan; Lee, Seungjun; Park, Joohyun; Ko, Youngbin; Jeon, Hyeongtag

    2011-07-01

    In this study, the effects of different annealing conditions (air, O2, N2, vacuum) on the chemical and electrical characteristics of amorphous indium-gallium-zinc oxide (a-IGZO) thin film transistors (TFT) were investigated. The contact resistance and interface properties between the IGZO film and the gate dielectric improved after an annealing treatment. However, the chemical bonds in the IGZO bulk changed under various annealing atmospheres, which, in turn, altered the characteristics of the TFTs. The TFTs annealed in vacuum and N2 ambients exhibited undesired switching properties due to the high carrier concentration (>10(17) cm(-3)) of the IGZO active layer. In contrast, the IGZO TFTs annealed in air and oxygen ambients displayed clear transfer characteristics due to an adequately adjusted carrier concentration in the operating range of the TFT. Such an optimal carrier concentration arose through the stabilization of unstable chemical bonds in the IGZO film. With regard to device performance, the TFTs annealed in O2 and air exhibited saturation mobility values of 8.29 and 7.54 cm2/Vs, on-off ratios of 7.34 x 10(8) and 3.95 x 10(8), and subthreshold swing (SS) values of 0.23 and 0.19 V/decade, respectively. Therefore, proper annealing ambients contributed to internal modifications in the IGZO structure and led to an enhancement in the oxidation state of the metal. As a result, defects such as oxygen vacancies were eliminated. Oxygen annealing is thus effective for controlling the carrier concentration of the active layer, decreasing electron traps, and enhancing TFT performance.

  16. Thermal effects in supercapacitors

    CERN Document Server

    Xiong, Guoping; Fisher, Timothy S

    2015-01-01

    This Brief reviews contemporary research conducted in university and industry laboratories on thermal management in electrochemical energy storage systems (capacitors and batteries) that have been widely used as power sources in many practical applications, such as automobiles, hybrid transport, renewable energy installations, power backup and electronic devices. Placing a particular emphasis on supercapacitors, the authors discuss how supercapacitors, or ultra capacitors, are complementing and  replacing, batteries because of their faster power delivery, longer life cycle and higher coulombic efficiency, while providing higher energy density than conventional electrolytic capacitors. Recent advances in both macro- and micro capacitor technologies are covered. The work facilitates systematic understanding of thermal transport in such devices that can help develop better power management systems.

  17. Mesoscale Benchmark Demonstration Problem 1: Mesoscale Simulations of Intra-granular Fission Gas Bubbles in UO2 under Post-irradiation Thermal Annealing

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yulan; Hu, Shenyang Y.; Montgomery, Robert; Gao, Fei; Sun, Xin; Tonks, Michael; Biner, Bullent; Millet, Paul; Tikare, Veena; Radhakrishnan, Balasubramaniam; Andersson , David

    2012-04-11

    A study was conducted to evaluate the capabilities of different numerical methods used to represent microstructure behavior at the mesoscale for irradiated material using an idealized benchmark problem. The purpose of the mesoscale benchmark problem was to provide a common basis to assess several mesoscale methods with the objective of identifying the strengths and areas of improvement in the predictive modeling of microstructure evolution. In this work, mesoscale models (phase-field, Potts, and kinetic Monte Carlo) developed by PNNL, INL, SNL, and ORNL were used to calculate the evolution kinetics of intra-granular fission gas bubbles in UO2 fuel under post-irradiation thermal annealing conditions. The benchmark problem was constructed to include important microstructural evolution mechanisms on the kinetics of intra-granular fission gas bubble behavior such as the atomic diffusion of Xe atoms, U vacancies, and O vacancies, the effect of vacancy capture and emission from defects, and the elastic interaction of non-equilibrium gas bubbles. An idealized set of assumptions was imposed on the benchmark problem to simplify the mechanisms considered. The capability and numerical efficiency of different models are compared against selected experimental and simulation results. These comparisons find that the phase-field methods, by the nature of the free energy formulation, are able to represent a larger subset of the mechanisms influencing the intra-granular bubble growth and coarsening mechanisms in the idealized benchmark problem as compared to the Potts and kinetic Monte Carlo methods. It is recognized that the mesoscale benchmark problem as formulated does not specifically highlight the strengths of the discrete particle modeling used in the Potts and kinetic Monte Carlo methods. Future efforts are recommended to construct increasingly more complex mesoscale benchmark problems to further verify and validate the predictive capabilities of the mesoscale modeling

  18. Hysteresis in Lanthanide Zirconium Oxides Observed Using a Pulse CV Technique and including the Effect of High Temperature Annealing

    Directory of Open Access Journals (Sweden)

    Qifeng Lu

    2015-07-01

    Full Text Available A powerful characterization technique, pulse capacitance-voltage (CV technique, was used to investigate oxide traps before and after annealing for lanthanide zirconium oxide thin films deposited on n-type Si (111 substrates at 300 °C by liquid injection Atomic Layer Deposition (ALD. The results indicated that: (1 more traps were observed compared to the conventional capacitance-voltage characterization method in LaZrOx; (2 the time-dependent trapping/de-trapping was influenced by the edge time, width and peak-to-peak voltage of a gate voltage pulse. Post deposition annealing was performed at 700 °C, 800 °C and 900 °C in N2 ambient for 15 s to the samples with 200 ALD cycles. The effect of the high temperature annealing on oxide traps and leakage current were subsequently explored. It showed that more traps were generated after annealing with the trap density increasing from 1.41 × 1012 cm−2 for as-deposited sample to 4.55 × 1012 cm−2 for the 800 °C annealed one. In addition, the leakage current density increase from about 10−6 A/cm2 at Vg = +0.5 V for the as-deposited sample to 10−3 A/cm2 at Vg = +0.5 V for the 900 °C annealed one.

  19. The effect of annealing temperature on the magnetic anisotropy in Co ultrathin film on MgO(001) substrate

    Science.gov (United States)

    Zhang, Yong-Sheng; He, Wei; Tang, Jin; Ahmad, Syed Sheraz; Zhang, Wei; Li, Yan; Zhang, Xiang-Qun; Cheng, Zhao-Hua

    2017-05-01

    Co epitaxial thin films with 2.5nm thickness were prepared on single-crystal MgO(001) substrates and annealed at different temperatures. The contribution of each interface of the MgO/Co/Cu trilayer to the in-plane magnetic anisotropy (IMA) was studied by changing interfacial coupling through annealing. The structure was measured by low energy electron diffraction (LEED), and the magnetic properties were measured using the anisotropic magnetoresistance (AMR) measurements and the longitudinal Magneto-optical Kerr effect magnetometer (MOKE). We found that the magnetic anisotropy of the as-deposited one shows superposition of a two-fold symmetry with a weak four-fold contribution caused by the stress of the interface between Co/Cu, which is along the easy axis [-110]. After annealing at 200°C, the symmetry of magnetic anisotropy was changed from uniaxial magnetic anisotropy (UMA) into four-fold symmetry due to the significant increasing of four-fold magnetocrystalline anisotropy. When the films were annealed above 300°C, the damage of the MgO/Co interface additionally decreased the IMA to isotropy. Meanwhile, the coercivity raised from 45Oe (without annealing) to 1200Oe (annealed at 400°C) along the easy axis direction. Our experimental results prove that the Co/Cu interface and the MgO/Co interface play an essential role in manipulating the four-fold and the UMA in the system.

  20. The effect of annealing temperature on the magnetic anisotropy in Co ultrathin film on MgO(001 substrate

    Directory of Open Access Journals (Sweden)

    Yong-Sheng Zhang

    2017-05-01

    Full Text Available Co epitaxial thin films with 2.5nm thickness were prepared on single-crystal MgO(001 substrates and annealed at different temperatures. The contribution of each interface of the MgO/Co/Cu trilayer to the in-plane magnetic anisotropy (IMA was studied by changing interfacial coupling through annealing. The structure was measured by low energy electron diffraction (LEED, and the magnetic properties were measured using the anisotropic magnetoresistance (AMR measurements and the longitudinal Magneto-optical Kerr effect magnetometer (MOKE. We found that the magnetic anisotropy of the as-deposited one shows superposition of a two-fold symmetry with a weak four-fold contribution caused by the stress of the interface between Co/Cu, which is along the easy axis [-110]. After annealing at 200°C, the symmetry of magnetic anisotropy was changed from uniaxial magnetic anisotropy (UMA into four-fold symmetry due to the significant increasing of four-fold magnetocrystalline anisotropy. When the films were annealed above 300°C, the damage of the MgO/Co interface additionally decreased the IMA to isotropy. Meanwhile, the coercivity raised from 45Oe (without annealing to 1200Oe (annealed at 400°C along the easy axis direction. Our experimental results prove that the Co/Cu interface and the MgO/Co interface play an essential role in manipulating the four-fold and the UMA in the system.

  1. The effect of annealing on microstructure and cation distribution of NiFe{sub 2}O{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Cvejić, Ž., E-mail: zeljkac@uns.ac.rs [Department of Physics, Faculty of Sciences, University of Novi Sad, Trg D. Obradovića 4, 21000 Novi Sad (Serbia); Đurđić, E.; Ivković Ivandekić, G. [Department of Physics, Faculty of Sciences, University of Novi Sad, Trg D. Obradovića 4, 21000 Novi Sad (Serbia); Bajac, B. [Department of Materials Engineering, Faculty of Technology, University of Novi Sad, Bulevar Cara Lazara 1, 21000 Novi Sad (Serbia); Postolache, P.; Mitoseriu, L. [Faculty of Physics, University “Al. I. Cuza”, Bv. Carol I Nr 11, RO-Iasi 700506 (Romania); Srdić, V.V. [Department of Materials Engineering, Faculty of Technology, University of Novi Sad, Bulevar Cara Lazara 1, 21000 Novi Sad (Serbia); Rakić, S. [Department of Physics, Faculty of Sciences, University of Novi Sad, Trg D. Obradovića 4, 21000 Novi Sad (Serbia)

    2015-11-15

    Nickel ferrite nanopowder was synthesized using a co-precipitation method, and further annealed at three different temperatures of 500 °C, 750 °C and 900 °C. The effect of annealing process was explored on particle size, cation distribution and magnetic properties of NiFe{sub 2}O{sub 4}. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy and with the use of a vibrating sample magnetometer. The X-ray diffraction patterns at different annealing temperatures demonstrated the existence of only spinel phase of NiFe{sub 2}O{sub 4}. The results of Rietveld analysis showed that the sample annealed at 750 °C possesses inverse spinel structure, while the others have partially inverted spinel structure. The SEM analysis indicated a change of particle size and morphology at higher annealing temperature. The change in Raman modes was observed with the change of particle size and cation distribution. The highest value of the saturation magnetization (38 emu g{sup −1}) was obtained at annealing temperatures of 900 °C. - Highlights: • Nickel ferrite nanopowders were synthesized by the co-precipitation method. • The particle size, cation distribution and magnetic properties were explored. • The intensity of obtained Raman spectra is closely related to the grains size. • The magnetic saturation depends on the cation distribution and on a grain size.

  2. Correlation of Etch Pits and Dislocations in As-grown and Thermal Cycle-Annealed HgCdTe(211) Films

    Science.gov (United States)

    Vaghayenegar, M.; Jacobs, R. N.; Benson, J. D.; Stoltz, A. J.; Almeida, L. A.; Smith, David J.

    2017-08-01

    This paper reports observations of the different types of etch pits and dislocations present in thick HgCdTe (211) layers grown by molecular beam epitaxy on CdTe/Si (211) composite substrates. Dislocation analysis for as-grown and thermal cycle-annealed samples has been carried out using bright-field transmission electron microscopy. Triangular pits present in as-grown material are associated with a mixture of Frank partials and perfect dislocations, while pits with fish-eye shapes have perfect dislocations with 1/2[0\\bar{1}1] Burgers vector. The dislocations beneath skew pits are more complex as they have two different crystallographic directions, and are associated with a mixture of Shockley partials and perfect dislocations. Dislocation analysis of samples after thermal cycle annealing (TCA) shows that the majority of dislocations under the etch pits are short segments of perfect dislocations with 1/2[0\\bar{1}1] Burgers vector while the remainder are Shockley partials. The absence of fish-eye shape pits in TCA samples suggests that they are associated with mobile dislocations that have reacted during annealing, causing the overall etch pit density to be reduced. Very large pits with a density ˜2×103 cm-2 are observed in as-grown and TCA samples. These defects thread from within the CdTe buffer layer into the upper regions of the HgCdTe layers. Their depth in as-grown material is so large that it is not possible to locate and identify the underlying defects.

  3. Effects of getter annealing and codoping of iron and zinc in yttrium-barium cuprates

    Energy Technology Data Exchange (ETDEWEB)

    O' Brien, J.R.; Oesterreicher, H. (Univ. of California, San Diego, La Jolla, CA (United States)); Taylor, R.D. (Los Alamos National Lab., NM (United States). Physics Division)

    1994-09-01

    This study explores issues connected with the complex structural and electronic behavior of partly substituted YBa[sub 2](Cu[sup 1[minus]x[minus]z]Fe[sub x]Zn[sub z])[sub 3]O[sub y] when given special redox sequencing over varying times. For z = 0 and x = 0.03 conventional oxygenated slow cooling preparations (OP) yield tetragonal materials with [Tc][sub mid] = 59K. Getter annealing procedures using Gd to control the extent of reduction to y = 6.1 at 1000K for 4 days followed by reoxidation at 700K for 1 hour yield orthorhombic materials with [Tc][sub mid] = 68K and improved superconducting volume fractions. The results are in line with expectations for the presence of ordered atomic size Fe clusters with these reducing preparations (RP). This redox sequence also reduces the paramagnetic Curie temperature from [Theta][sub P] = [minus]35K to [Theta][sub P] = [minus]51K for z = 0, hinting at higher cluster Neel temperatures. When the getter annealed specimen is air annealed for prolonged times (50h) at 673K, a broader [Tc] transition develops and a slight decrease in the orthorhombic splitting is observed. This demonstrates that small rearrangements from properties of RP to OP are possible even at these low temperatures. Codoping to x = 0.03, z = 0.01 results in drastic reductions to [Tc][sub mid] = 31K for OP, beyond the one expected from individual contributions, while structural parameters do not change noticeably. This synergistic effects is also reflected in [Theta][sub P] and may have to do with a large proportion of Fe occupying the Cu(2) site. Results are discussed within models of inhomogeneous M distributions and oxygen chain order.

  4. Rolling and Annealing Effects on Microstructure and Hardness of Commercial 405 Stainless Steel

    Directory of Open Access Journals (Sweden)

    A.K. Jahja

    2007-07-01

    Full Text Available The "cold-rolling" experiments for several values of true strain namely 5 percent, 10 percent, and 15 percent respectively have been carried out on commercial SS-405 steel samples at 350oC; the as-rolled samples were cut into several pieces in size of 10 x 10 x 5 mm3, and some pieces were annealed to 550oC for 24 hours. All samples were then mounted and polished before etching in order to observe the grain boundaries. The microstructure observation on all samples was carried out by using optical microscope (MO, meanwhile X-ray diffraction technique was employed in order to support the identification of the existing phases and to verify changes with respect to crystal orientation; the hardness tests were carried out by using Vickers micro hardness tester. The microstructure observation supported by X-ray diffraction results shows that the phase grains of rolled sample tends to take the oblong-shape, accompanied by a preferred orientation predominantly inclined toward the (110 plane. The microhardness testing results show that there has been an increase in the hardness of the as-rolled samples; Mainly because of the nearly negligible thickness of the original sample (being only 5 mm in size, the 15 percent as-rolled samples exhibits only a slight reduction in hardness compared to the 10 percent as-rolled samples; The main cause of this effect is the movement of some dislocations infiltrating the surface resulting in the reduction of the inner-stress in the bulk of the samples. In the rolled-annealed samples there is a very significant reduction in hardness compared to the as-rolled samples. Here the main cause is the recrystallization process taking place during annealing, which tends to significantly reduce the dislocations.

  5. Optimization of the contact resistance in the interface structure of n-type Al/a-SiC:H by thermal annealing for optoelectronics applications

    Energy Technology Data Exchange (ETDEWEB)

    Ambrosio, Roberto; Mireles, Jose Jr. [Technology and Engineering Institute, Ciudad Juarez University UACJ, Av. Del Charro 450N, 32310, Chihuahua (Mexico); Torres, Alfonso; Zuniga, Carlos; Moreno, Mario [National Institute for Astrophysics Optics and Electronics INAOE, Luis E. Erro 1, PO Box 51 and 216, 7200, Puebla (Mexico)

    2010-07-15

    The presented work meets the requirements for integration of amorphous silicon carbon films with silicon technology in order to obtain a complete optoelectronic system such as light emitting diodes and its electronic readout circuits. The key enabler for this integration scheme is the low temperature of deposition of a-SiC:H films and an ohmic behavior in the interface metal/a-SiC:H. In this work, the optimization of the interface Al/a-SiC:H films are performed by means of thermal annealing timing. The a-SiC:H films were deposited by enhanced chemical vapor deposition from CH{sub 4}/SiH{sub 4} and C{sub 2}H{sub 2}/SiH{sub 4} mixtures. The structural and optical properties of the deposited films are presented. An implantation phosphorous dose was used for doping before fabrication of patterned aluminum contacts. The implanted films were electrically characterized by the transfer length method (TLM) measuring a sheet resistance value as low as 171 M{omega}/square. The Schottky behavior was improved to ohmic behavior after several hours in thermal annealing treatments at 350 C, which allows to obtain a reasonable contact resistance values in the range from 8.6 to 26.8 k{omega}. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  6. Ion-beam mixed ultra-thin cobalt suicide (CoSi2) films by cobalt sputtering and rapid thermal annealing

    Science.gov (United States)

    Kal, S.; Kasko, I.; Ryssel, H.

    1995-10-01

    The influence of ion-beam mixing on ultra-thin cobalt silicide (CoSi2) formation was investigated by characterizing the ion-beam mixed and unmixed CoSi2 films. A Ge+ ion-implantation through the Co film prior to silicidation causes an interface mixing of the cobalt film with the silicon substrate and results in improved silicide-to-silicon interface roughness. Rapid thermal annealing was used to form Ge+ ion mixed and unmixed thin CoSi2 layer from 10 nm sputter deposited Co film. The silicide films were characterized by secondary neutral mass spectroscopy, x-ray diffraction, tunneling electron microscopy (TEM), Rutherford backscattering, and sheet resistance measurements. The experi-mental results indicate that the final rapid thermal annealing temperature should not exceed 800°C for thin (films reveals that Ge+ ion mixing (45 keV, 1 × 1015 cm-2) produces homogeneous silicide with smooth silicide-to-silicon interface.

  7. Effects on external quantum efficiency of electrochemically constructed n-ZnO/p-Cu2O photovoltaic device by annealing

    Science.gov (United States)

    Khoo, Pei Loon; Kikkawa, Yuuki; Shinagawa, Tsutomu; Izaki, Masanobu

    2017-07-01

    Cuprous oxide (Cu2O), a terrestrial abundant, low cost, nontoxic, intrinsically p-type oxide semiconductor with bandgap energy of about 2eV, has recently received increasing attention as a light absorbing layer in solar cells. However, the performances of electrochemically constructed Cu2O solar devices are poor compared to the theoretical power conversion efficiency. This research was conducted focusing on the EQE performance, which is closely related to the short circuit current of a solar device. ZnO/Cu2O-PV-devices were constructed electrochemically with 3-electrode cell on Ga:ZnO/SLG substrates; ZnO layers were deposited from an aqueous solution of 8 mmolL-1 zinc nitrate hexahydrate at 63°C, 0.01 Coulomb cm-2, and -0.8V, while Cu2O layers were deposited from aqueous solution containing 0.4 molL-1 copper (II) acetate monohydrate (pH12.5), at 40°C, 1.5 Coulomb cm-2, and -0.4V. Devices were then annealed under different temperatures of 150°C, 200°C, 250°C, and 300°C for 60 minutes with a Rapid Thermal Anneal furnace (RTA). The EQE of the devices were measured with a spectral sensitivity device and compared to the non-annealed device. Further studies were made such as morphology observation of the films by FE-SEM and measurements of X-ray diffraction patterns. Annealed samples showed improved maximum EQE at 150-200°C of annealing, indicating that EQE above 90% can be achieved, proving the validity of EQE improvement via low temperature annealing method for thin film Cu2O photovoltaic devices.

  8. Effects of annealing and pulse plating on soft magnetic properties of electroplated Fe-Ni films

    Directory of Open Access Journals (Sweden)

    T. Yanai

    2016-05-01

    Full Text Available We have already reported that Fe-Ni films prepared in citric-acid-based plating baths show good soft magnetic properties. In this paper, we investigated the effect of the grain size of the Fe-Ni crystalline phase in the films on magnetic properties, and employed an annealing and a pulse plating method in order to vary the grain size. The coercivity of the annealed Fe-Ni films at 600 °C shows large value, and good correlation between the grain growth and the coercivity was observed. The pulse plating enables us to reduce the grain size of the as-plated Fe-Ni films compared with the DC plating method, and we realized smooth surface and low coercivity of the Fe-Ni films using the pulse plating method. From these results, we confirmed the importance of the reduction in the grain size, and concluded that a pulse plating is an effective method to improve the good soft magnetic properties for our previously-reported Fe-Ni films.

  9. The effects of annealing and irradiation on the sensitivity and superlinearity properties of the 110{sup o}C thermoluminescence peak of quartz

    Energy Technology Data Exchange (ETDEWEB)

    Polymeris, George [Archaeometry Laboratory, Cultural and Educational Technology Institute, Tsimiski 58, 67100-Xanthi (Greece); Nuclear Physics Laboratory, Aristotle University of Thessaloniki, 54124-Thessaloniki (Greece); Kitis, George [Nuclear Physics Laboratory, Aristotle University of Thessaloniki, 54124-Thessaloniki (Greece); Pagonis, Vasilis [Physics Department, McDaniel College, Westminster, MD 21157 (United States)]. E-mail: vpagonis@mcdaniel.edu

    2006-05-15

    Quartz samples which undergo heating and irradiation treatments exhibit changes in their sensitivity to irradiation, as well as in their TL dose response. These changes of thermoluminescence (TL) sensitivity and superlinearity of the 110 deg. C TL peak of quartz have been the subject of several experimental and theoretical studies, because they form the basis of the predose technique for dating ceramics and for accident dosimetry. In an effort to separate experimentally the effects of irradiation and annealing on the predose effect, three quartz samples of different origin were prepared under three different conditions: unannealed samples, samples annealed at 500 deg. C, and samples annealed at 900 deg. C. Complete TL versus dose and sensitivity S versus predose curves were obtained for the dose range of 0.1thermal or irradiation history of the quartz samples. The experimental data is consistent with the assumption that high-temperature anneals and/or high dose irradiation of the samples reduces the concentration of available competitor sites. The concentration of these competitor sites, as described by the Zimmerman model of quartz, is identified as the most important factor in causing the observed differences in predose behavior between quartz samples of different origin. Strong evidence in support of this competitor theory is provided by the estimated equivalent doses (EDs) for the three quartz samples.

  10. Effect of low temperature annealing on magneto-caloric effect of Ni–Mn–Sn–Al ferromagnetic shape memory alloy

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, Sandeep [Haldia Institute of Technology, Haldia 721657, West Bengal (India); LCMP, Department of Condensed Matter Physics and Material Sciences, S.N. Bose National Centre for Basic Sciences, JD Block, Salt Lake, Kolkata 700098 (India); Stern-Taulats, Enric; Mañosa, Lluís [Departament d’Estructura i Constituents de la Matèria, Facultat de Física, Universitat de Barcelona, 08028 Barcelona, Catalonia (Spain); Mukhopadhyay, P.K., E-mail: pkm@bose.res.in [LCMP, Department of Condensed Matter Physics and Material Sciences, S.N. Bose National Centre for Basic Sciences, JD Block, Salt Lake, Kolkata 700098 (India)

    2015-08-25

    Highlights: • Magnetic properties of the system changed after secondary heat treatment. • MCE was enhanced after Al was partially replaced with Sn in Ni–Mn–Al system. • Suitable heat treatment further increased overall MCE in the sample. • Change in magnetic properties occurred due to change in atomic ordering. - Abstract: We studied the effect of low temperature annealing on the atomic ordering and consequent changes in the magnetization and magnetocaloric effect of the sample. The annealing at lower temperatures initially decreased the magnetization and magnetocaloric effect in the sample, but at higher annealing temperatures both increased. The changes in magnetization and magnetocaloric effect arise from the change in atomic ordering. We have shown that post quenching heat treatment offers easy way of optimizing the alloy for magnetocaloric effect. In order to verify that there was no overestimation in the measurement of magnetocaloric effect we also performed an infield calorimetric measurements and compared them with those from the magnetization measurements. We did not find remarkable difference between them.

  11. The effect of magnetic annealing on crystallographic texture and magnetic properties of Fe-2.6% Si

    Energy Technology Data Exchange (ETDEWEB)

    Salih, M.Z., E-mail: mohammedzs2007@hotmail.com [Institut für Werkstoffkunde und Werkstofftechnik, TU Clausthal, Agricolastraße 6, D-38678 Clausthal-Zellerfeld (Germany); Uhlarz, M. [Dresden High Magnetic Field Laboratory (HLD), Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, D-01328 Dresden (Germany); Pyczak, F. [Instiute of Materials Research, Helmholtz-Zentrum Geesthacht, Max-Planck-Straße 1, D-21502 Geesthacht (Germany); Brokmeier, H.-G. [Institut für Werkstoffkunde und Werkstofftechnik, TU Clausthal, Agricolastraße 6, D-38678 Clausthal-Zellerfeld (Germany); Instiute of Materials Research, Helmholtz-Zentrum Geesthacht, Max-Planck-Straße 1, D-21502 Geesthacht (Germany); Weidenfeller, B. [Institut für Elektrochemie, Abteilung für Materialwissenschaft, Arnold-Sommerfeld-Straße 6, D-38678 Clausthal-Zellerfeld (Germany); Al-hamdany, N. [Institut für Werkstoffkunde und Werkstofftechnik, TU Clausthal, Agricolastraße 6, D-38678 Clausthal-Zellerfeld (Germany); Gan, W.M. [Instiute of Materials Research, Helmholtz-Zentrum Geesthacht, Max-Planck-Straße 1, D-21502 Geesthacht (Germany); Zhong, Z.Y. [Institut für Werkstoffkunde und Werkstofftechnik, TU Clausthal, Agricolastraße 6, D-38678 Clausthal-Zellerfeld (Germany); Schell, N. [Instiute of Materials Research, Helmholtz-Zentrum Geesthacht, Max-Planck-Straße 1, D-21502 Geesthacht (Germany)

    2015-05-01

    The effect of magnetic annealing on crystallographic texture, microstructure, defects density and magnetic properties of a Fe-2.6% Si steel has been analyzed. After two stage cold rolling (75% and 60% cold rolled) with intermediate annealing process at (600 °C/1 h) the sample annealed at 600 °C for one hour during which different magnetic field of 0, 7 and 14 T were applied has been investigated. The effect of defects density after cold rolling process on the recrystallization texture and magnetic properties was characterized. Heat treatments under a high external field of 14 T show a drastic improvement of the magnetic properties such as significantly increased permeability. Neutron diffraction measurements were preferred for measurement of the bulk sample texture so that sufficient grain statistics were obtained. Because of its small wavelength (0.05–0.2 Å) Synchrotron diffraction with high photon energy was used to evaluate the defects density by a modified Williamson–Hall plot. - Highlights: • We show the effect of the magnetic annealing after intermediate cold rolling on the crystallographic texture and magnetic properties. • Due the coarse grained we used Neutron diffraction for texture measurement. • We used hysteresis recorder to measure the magnetic properties. • The magnetic annealing leads to drastic improvements of the magnetic properties such as significantly increased permeability. • We show the effect of defect density on the crystallographic texture and magnetic properties.

  12. Effect of annealing procedure on the bonding of ceramic to cobalt-chromium alloys fabricated by rapid prototyping.

    Science.gov (United States)

    Tulga, Ayca

    2017-08-22

    An annealing procedure is a heat treatment process to improve the mechanical properties of cobalt-chromium (Co-Cr) alloys. However, information is lacking about the effect of the annealing process on the bonding ability of ceramic to Co-Cr alloys fabricated by rapid prototyping. The purpose of this in vitro study was to evaluate the effects of the fabrication techniques and the annealing procedure on the shear bond strength of ceramic to Co-Cr alloys fabricated by different techniques. Ninety-six cylindrical specimens (10-mm diameter, 10-mm height) made of Co-Cr alloy were prepared by casting (C), milling (M), direct process powder-bed (LaserCUSING) with and without annealing (CL+, CL), and direct metal laser sintering (DMLS) with annealing (EL+) and without annealing (EL). After the application of ceramic to the metal specimens, the metal-ceramic bond strength was assessed using a shear force test at a crosshead speed of 0.5 mm/min. Shear bond strength values were statistically analyzed by 1-way ANOVA and Tukey multiple comparison tests (α=.05). Although statistically significant differences were found among the 3 groups (M, 29.87 ±2.06; EL, 38.92 ±2.04; and CL+, 40.93 ±2.21; P=.002), no significant differences were found among the others (P>.05). The debonding surfaces of all specimens exhibited mixed failure mode. These results showed that the direct process powder-bed method is promising in terms of metal-ceramic bonding ability. The manufacturing technique of Co-Cr alloys and the annealing process influence metal-ceramic bonding. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  13. Effect of the annealing temperature on dynamic and structural properties of Co2FeAl thin films

    Directory of Open Access Journals (Sweden)

    Belmeguenai M.

    2014-07-01

    Full Text Available 10 nm and 50 nm thick Co2FeAl (CFA thin films have been deposited on thermally oxidized Si(001 substrates by magnetron sputtering using a Tantalum cap layer and were then ex-situ annealed at 415°C, 515°C and 615°C during 15 minutes in vacuum. X-rays diffraction indicates that films CFA are polycrystalline and exhibit an in-plane isotropy growth. Ferromagnetic resonance measurements, using a microstrip line (MS-FMR, reveal a huge interfacial perpendicular magnetic anisotropy and small in-plane uniaxial anisotropy both annealing temperature-dependent. The MS-FMR data also allow concluding that the gyromagnetic factor remains constant and that the exchange stiffness constant increases with annealing temperature. Finally, the FMR linewidth decreases with increasing annealing temperature due to the enhancement of the chemical order, and allow deriving a very low intrinsic damping parameter (1.3×10−3 at 615°C.

  14. Effect of antireflection coating on the crystallization of amorphous silicon films by flash lamp annealing

    Science.gov (United States)

    Sonoda, Yuki; Ohdaira, Keisuke

    2017-04-01

    We succeed in decreasing the fluence of a flash-lamp pulse required for the crystallization of electron-beam (EB)-evaporated amorphous silicon (a-Si) films using silicon nitride (SiN x ) antireflection films. The antireflection effect of SiN x is confirmed not only when SiN x is placed on the surface of a-Si or flash lamp annealing (FLA) is performed from the film side, but also when SiN x is inserted between glass and a-Si and a flash pulse is supplied from the glass side. We also quantitatively confirm, by calculating flash-lamp pulse energies actually reaching a-Si films using reflectance spectra, that the reduction in the fluence of a flash-lamp pulse for the crystallization of a-Si films is due to the antireflection effect of SiN x .

  15. Effect of Post-annealing Processes on Filamentary-Based Resistive Switching Mechanism of Chromium Oxide Thin Films

    Science.gov (United States)

    Pham, Ngoc Kim; Ta, Kieu Hanh Thi; Tran, Vinh Cao; Le, Van Hieu; Le Nguyen, Bao Thu; Ju, Heong Kyu; Seetawan, Tosawat; Phan, Bach Thang

    2017-06-01

    The interrelation between microstructure of chromium oxide films (CrOx) and formation of silver (Ag) filament in Ag/CrOx/Pt devices has been investigated at various annealing temperatures. It is revealed that Cr2O3 phase is dominant at high annealing temperatures and different microstructures of the CrOx films exhibit different resistance switching characteristics. As-deposited CrOx films with amorphous structure show highly reliable and reproducible resistance switching due to an easy formation of thin Ag filaments. 300°C-annealed CrOx films with denser structure exhibit a fluctuating switching characteristics, relating to negative differential resistance (NDR) effect, in the first several tens of switching cycles, followed by a stable switching characteristics. On the contrary, the resistance switching is not observed in 500°C-annealed CrOx films due to presence of voids or pinholes created at high annealing temperature. The roles of NDR effect and voids/pinholes on resistance switching characteristics of CrOx thin films are also discussed.

  16. Annealing Effect on Photovoltaic Performance of CdSe Quantum-Dots-Sensitized TiO2 Nanorod Solar Cells

    Directory of Open Access Journals (Sweden)

    Yitan Li

    2012-01-01

    Full Text Available Large area rutile TiO2 nanorod arrays were grown on F:SnO2 (FTO conductive glass using a hydrothermal method at low temperature. CdSe quantum dots (QDs were deposited onto single-crystalline TiO2 nanorod arrays by a chemical bath deposition (CBD method to make a photoelectrode. The solar cell was assembled using a CdSe-TiO2 nanostructure as the photoanode and polysulfide solution as the electrolyte. The annealing effect on optical and photovoltaic properties of CdSe quantum-dots-sensitized TiO2 nanorod solar cells was studied systematically. A significant change of the morphology and a regular red shift of band gap of CdSe nanoparticles were observed after annealing treatment. At the same time, an improved photovoltaic performance was obtained for quantum-dots-sensitized solar cell using the annealed CdSe-TiO2 nanostructure electrode. The power conversion efficiency improved from 0.59% to 1.45% as a consequence of the annealing effect. This improvement can be explained by considering the changes in the morphology, the crystalline quality, and the optical properties caused by annealing treatment.

  17. Effect of Annealing Temperature on the Mechanical and Corrosion Behavior of a Newly Developed Novel Lean Duplex Stainless Steel

    Science.gov (United States)

    Guo, Yanjun; Hu, Jincheng; Li, Jin; Jiang, Laizhu; Liu, Tianwei; Wu, Yanping

    2014-01-01

    The effect of annealing temperature (1000–1150 °C) on the microstructure evolution, mechanical properties, and pitting corrosion behavior of a newly developed novel lean duplex stainless steel with 20.53Cr-3.45Mn-2.08Ni-0.17N-0.31Mo was studied by means of optical metallographic microscopy (OMM), scanning electron microscopy (SEM), magnetic force microscopy (MFM), scanning Kelvin probe force microscopy (SKPFM), energy dispersive X-ray spectroscopy (EDS), uniaxial tensile tests (UTT), and potentiostatic critical pitting temperature (CPT). The results showed that tensile and yield strength, as well as the pitting corrosion resistance, could be degraded with annealing temperature increasing from 1000 up to 1150 °C. Meanwhile, the elongation at break reached the maximum of 52.7% after annealing at 1050 °C due to the effect of martensite transformation induced plasticity (TRIP). The localized pitting attack preferentially occurred at ferrite phase, indicating that the ferrite phase had inferior pitting corrosion resistance as compared to the austenite phase. With increasing annealing temperature, the pitting resistance equivalent number (PREN) of ferrite phase dropped, while that of the austenite phase rose. Additionally, it was found that ferrite possessed a lower Volta potential than austenite phase. Moreover, the Volta potential difference between ferrite and austenite increased with the annealing temperature, which was well consistent with the difference of PREN. PMID:28788201

  18. Effects of magnetic annealing on structure and multiferroic properties of pure and dysprosium substituted BiFeO 3

    KAUST Repository

    Zhang, Shuxia

    2012-07-01

    In this work, the effects of magnetic annealing on crystal structure and multiferroic properties of BiFeO 3 and Bi 0.85Dy 0.15FeO 3 have been investigated. It is found that the X-ray diffraction patterns of pure BiFeO 3 samples are obviously broadened after magnetic annealing, whereas those of Bi 0.85Dy 0.15FeO 3 samples are almost unchanged. Magnetic field annealing did not affect the magnetic properties of these two kinds of samples much. However, ferroelectric properties of the two materials exhibited different behaviors after magnetic field annealing. For pure BiFeO 3 samples, the remnant polarizations (P r) are suppressed; in contrast, for Bi 0.85Dy 0.15FeO 3 samples, P r is greatly enhanced. Possible mechanisms for the effects of magnetic field annealing have been discussed. © 2012 Elsevier B.V. All rights reserved.

  19. Effect of Annealing Treatments on the Microstructure and Texture Development in API 5L X60 Microalloyed Pipeline Steel

    Science.gov (United States)

    Joodaki, R.; Alavi Zaree, S. R.; Gheisari, Kh.; Eskandari, M.

    2017-05-01

    Effect of annealing treatments at 600, 800, 1000 and 1200 °C on the microstructure, texture, grain boundary characteristic and recrystallization fraction of Nb-microalloyed X60 steel is evaluated by using x-ray diffraction and EBSD techniques. The results indicate that bimodal as-received microstructure is changed to a homogeneous equiaxed grain structure above annealing at 1000 °C. Macro-texture investigations depict that increasing annealing temperature results in considerable variation of texture intensity, especially at 1200 °C. Maximum intensity corresponds to {001}, Goss, copper texture components as well as near γ-fiber at 1200 °C. Recrystallization analysis shows that volume fraction of recrystallization noticeably is increased by annealing temperature at 1200 °C. Recrystallized grains are mainly oriented along γ-fiber, especially close to {111} texture component. Moreover, coincidence site lattice (CSL) analysis shows that the effect of annealing temperature on the volume fraction of Σ3 boundary is negligible.

  20. Effect of post annealing temperature on photonic bandgap of ZnO nanorods grown by chemical bath deposition

    Science.gov (United States)

    Lim, W. Q.; Sim, L. K.; Fazrina, N.; Maryam, W.

    2017-05-01

    Nanostructures with wide photonic bandgap grown at low cost are desirable for fabricating photonic devices in industrial scale. In this work, ZnO nanorods were grown on glass substrates in a two-step chemical bath deposition technique. The effects of annealing the structures post growth were investigated using Field Effect Scanning Electron Microscope (FESEM), X-Ray Diffraction (XRD) and UV-Vis spectroscopy. FESEM images showed hexagonal structures vertically grown with an increase in ZnO nanorod diameter with increasing temperature. XRD measurements on the other hand revealed a decrease in grain size for samples annealed at 600 °C, indicating increased crystallinity. Slight increase in size of the photonic bandgap, a region of zero light transmission, was observed with increasing annealing temperature. We attribute this increase in photonic band gap to the increase in nanorod diameter as well as in creased gaps in between nanorods and the increased crystallinity when samples are annealed at 600 °C. The ability to tune the photonic bandgap of low cost photonic devices and annealing at relatively low temperature of photonic device fabrication; essentially at the limit for cheap glass substrates; provides potential in making useful low cost integrated photonic devices.

  1. Effect of Annealing Temperature on the Mechanical and Corrosion Behavior of a Newly Developed Novel Lean Duplex Stainless Steel

    Directory of Open Access Journals (Sweden)

    Yanjun Guo

    2014-09-01

    Full Text Available The effect of annealing temperature (1000–1150 °C on the microstructure evolution, mechanical properties, and pitting corrosion behavior of a newly developed novel lean duplex stainless steel with 20.53Cr-3.45Mn-2.08Ni-0.17N-0.31Mo was studied by means of optical metallographic microscopy (OMM, scanning electron microscopy (SEM, magnetic force microscopy (MFM, scanning Kelvin probe force microscopy (SKPFM, energy dispersive X-ray spectroscopy (EDS, uniaxial tensile tests (UTT, and potentiostatic critical pitting temperature (CPT. The results showed that tensile and yield strength, as well as the pitting corrosion resistance, could be degraded with annealing temperature increasing from 1000 up to 1150 °C. Meanwhile, the elongation at break reached the maximum of 52.7% after annealing at 1050 °C due to the effect of martensite transformation induced plasticity (TRIP. The localized pitting attack preferentially occurred at ferrite phase, indicating that the ferrite phase had inferior pitting corrosion resistance as compared to the austenite phase. With increasing annealing temperature, the pitting resistance equivalent number (PREN of ferrite phase dropped, while that of the austenite phase rose. Additionally, it was found that ferrite possessed a lower Volta potential than austenite phase. Moreover, the Volta potential difference between ferrite and austenite increased with the annealing temperature, which was well consistent with the difference of PREN.

  2. Effect of Annealing Temperature on the Mechanical and Corrosion Behavior of a Newly Developed Novel Lean Duplex Stainless Steel.

    Science.gov (United States)

    Guo, Yanjun; Hu, Jincheng; Li, Jin; Jiang, Laizhu; Liu, Tianwei; Wu, Yanping

    2014-09-12

    The effect of annealing temperature (1000-1150 °C) on the microstructure evolution, mechanical properties, and pitting corrosion behavior of a newly developed novel lean duplex stainless steel with 20.53Cr-3.45Mn-2.08Ni-0.17N-0.31Mo was studied by means of optical metallographic microscopy (OMM), scanning electron microscopy (SEM), magnetic force microscopy (MFM), scanning Kelvin probe force microscopy (SKPFM), energy dispersive X-ray spectroscopy (EDS), uniaxial tensile tests (UTT), and potentiostatic critical pitting temperature (CPT). The results showed that tensile and yield strength, as well as the pitting corrosion resistance, could be degraded with annealing temperature increasing from 1000 up to 1150 °C. Meanwhile, the elongation at break reached the maximum of 52.7% after annealing at 1050 °C due to the effect of martensite transformation induced plasticity (TRIP). The localized pitting attack preferentially occurred at ferrite phase, indicating that the ferrite phase had inferior pitting corrosion resistance as compared to the austenite phase. With increasing annealing temperature, the pitting resistance equivalent number (PREN) of ferrite phase dropped, while that of the austenite phase rose. Additionally, it was found that ferrite possessed a lower Volta potential than austenite phase. Moreover, the Volta potential difference between ferrite and austenite increased with the annealing temperature, which was well consistent with the difference of PREN.

  3. In-situ thermal annealing of on-membrane silicon-on-insulator semiconductor-based devices after high gamma dose irradiation

    Science.gov (United States)

    Amor, S.; André, N.; Kilchytska, V.; Tounsi, F.; Mezghani, B.; Gérard, P.; Ali, Z.; Udrea, F.; Flandre, D.; Francis, L. A.

    2017-05-01

    In this paper, we investigate the recovery of some semiconductor-based components, such as N/P-type field-effect transistors (FETs) and a complementary metal-oxide-semiconductor (CMOS) inverter, after being exposed to a high total dose of gamma ray radiation. The employed method consists mainly of a rapid, low power and in situ annealing mitigation technique by silicon-on-insulator micro-hotplates. Due to the ionizing effect of the gamma irradiation, the threshold voltages showed an average shift of -580 mV for N-channel transistors, and -360 mV for P-MOSFETs. A 4 min double-cycle annealing of components with a heater temperature up to 465 °C, corresponding to a maximum power of 38 mW, ensured partial recovery but was not sufficient for full recovery. The degradation was completely recovered after the use of a built-in high temperature annealing process, up to 975 °C for 8 min corresponding to a maximum power of 112 mW, which restored the normal operating characteristics for all devices after their irradiation.

  4. Effects of Surface Treatment and Anneal Temperature on Poly(3-hexylthiophene) Infiltration in Zinc Oxide Nanorod Arrays

    Science.gov (United States)

    Wood, Taylor; Baker, Darick; Olson, Dana; Collins, Reuben; Furtak, Thomas

    2010-10-01

    The performance of a hybrid inorganic/organic photovoltaic cell is crucially dependent on the contact between the inorganic electron acceptor and the organic electron donor. In this study, we seek to optimize the infiltration and local polymer ordering of poly(3-hexylthiophene) (P3HT) into ZnO nanorod arrays through thermal annealing and chemical surface treatment. ZnO nanorods were grown on glass substrates and subsequently spin-coated with P3HT. Some of the nanorod arrays were chemically treated with ocadecyltriethoxysilane (OTES), phenyltriethoxysilane (PTES), and octadecanethiol (ODT) to form organic molecular layers on the rod surfaces. Samples were then thermally annealed at 150 and 220 C and characterized using UV-Vis spectrophotometry and electron microscopy. Our results revealed that while high-temperature annealing increases the amount of P3HT infiltration, it also destroys local polymer ordering and thus charge carrier mobility. Results from chemically-treated samples were largely inconclusive and merit further research. This material is based upon work supported by the National Science Foundation through Grant Nos. DMR-0820518 and DMR-0907409.

  5. Effect of heating rate on intercritical annealing of low-carbon cold-rolled steel

    Science.gov (United States)

    Thomas, Larrin

    A study was performed on the effect of heating rate on transformations during intercritical annealing of cold-rolled low-carbon sheet steels. Two sets of experiments were developed: 1) a series of alloys (1020, 1019M, 15B25) with two different cold reductions (nominally 40 and 60 pct) were heated at different rates and transformation temperatures were determined using analysis of dilatometry and metallography of intercritically annealed samples, allowing the study of the impact of composition and cold work on transformation behavior with different heating rates. 2) A cold-rolled C-Mn-Nb steel was tested with different heating rates selected for different degrees of recrystallization during austenite formation to test the impact of ferrite recrystallization on austenite formation. Heat treated samples were analyzed with SEM, EBSD, dilatometry, and microhardness to study the changes in transformation behavior. The results of this study were extended by adding step heating tests, heat treatments with an intercritical hold, and secondary ion mass spectrometry (SIMS) measurements of Mn distribution. Austenite transformation temperatures increased logarithmically with heating rate. Greater degrees of cold work led to reduced transformation temperatures across all heating rates because the energy of cold work increased the driving force for austenite formation. The relative effects of alloying additions on transformation temperatures remained with increasing heating rate. Rapid heating minimized ferrite recrystallization and pearlite spheroidization. Austenite formation occurred preferentially in recovered ferrite regions as opposed to recrystallized ferrite boundaries. Martensite was evenly distributed in slowly heated steels because austenite formed on recrystallized, equiaxed, ferrite boundaries. With rapid heating, austenite formed in directionally-oriented recovered ferrite which increased the degree of banding. The greatest degree of banding was found with

  6. Effects of Annealing on the Martensitic Transformation of Ni-Based Ferromagnetic Shape Memory Heusler Alloys and Nanoparticles

    Directory of Open Access Journals (Sweden)

    Tina Fichtner

    2015-03-01

    Full Text Available We report on the effects of annealing on the martensitic phase transformation in the Ni-based Heusler system: Mn50Ni40Sn10 and Mn50Ni41Sn9 powder and Co50Ni21Ga32 nanoparticles. For the powdered Mn50Ni40Sn10 and Mn50Ni41Sn9 alloys, structural and magnetic measurements reveal that post-annealing decreases the martensitic transformation temperatures and increases the transition hysteresis. This might be associated with a release of stress in the Mn50Ni40Sn10 and Mn50Ni41Sn9 alloys during the annealing process. However, in the case of Co50Ni21Ga32 nanoparticles, a reverse phenomenon is observed. X-ray diffraction analysis results reveal that the as-prepared Co50Ni21Ga32 nanoparticles do not show a martensitic phase at room temperature. Post-annealing followed by ice quenching, however, is found to trigger the formation of the martensitic phase. The presence of the martensitic transition is attributed to annealing-induced particle growth and the stress introduced during quenching.

  7. Thermal Annealing to Modulate the Shape Memory Behavior of a Biobased and Biocompatible Triblock Copolymer Scaffold in the Human Body Temperature Range.

    Science.gov (United States)

    Merlettini, Andrea; Gigli, Matteo; Ramella, Martina; Gualandi, Chiara; Soccio, Michelina; Boccafoschi, Francesca; Munari, Andrea; Lotti, Nadia; Focarete, Maria Letizia

    2017-08-14

    A biodegradable and biocompatible electrospun scaffold with shape memory behavior in the physiological temperature range is here presented. It was obtained starting from a specifically designed, biobased PLLA-based triblock copolymer, where the central block is poly(propylene azelate-co-propylene sebacate) (P(PAz60PSeb40)) random copolymer. Shape memory properties are determined by the contemporary presence of the low melting crystals of the P(PAz60PSeb40) block, acting as switching segment, and of the high melting crystal phase of PLLA blocks, acting as physical network. It is demonstrated that a straightforward annealing process applied to the crystal phase of the switching element gives the possibility to tune the shape recovery temperature from about 25 to 50 °C, without the need of varying the copolymer's chemical structure. The thermal annealing approach here presented can be thus considered a powerful strategy for "ad hoc" programming the same material for applications requiring different recovery temperatures. Fibroblast culture experiments demonstrated scaffold biocompatibility.

  8. Low temperature annealing effects on the performance of proton irradiated GaAs detectors

    Energy Technology Data Exchange (ETDEWEB)

    Vanni, P.; Nava, F.; Canali, C.; Castaldini, A.; Cavallini, A.; Polenta, L.; Lanzieri, C

    1999-08-01

    Semi-insulating, undoped, Liquid Encapsulated Czochralski (SI-U LEC) GaAs detectors have been irradiated with 24 GeV/c protons at the fluence of 5.6x10{sup 13} p/cm{sup 2}. The detector charge collection efficiency (CCE), for both electrons and holes is remarkably reduced after irradiation while the reverse current increases. The effect of annealing the detectors at temperatures ranging from 220 deg. C to 280 deg. C has been seen to reduce the reverse current and to increase the electron CCE, while the recovery of the hole CCE is negligible in irradiated detectors. Deep electron traps have been followed in their evolution with the heat treatment temperature by P-DLTS and C-V measurements. They recover by increasing the heat treatment temperature and this can explain the restoration observed in electron CCE.

  9. Thermal annealing and SHI irradiation induced modifications in sandwiched structured Carbon-gold-Carbon (a-C/Au/a-C) nanocomposite thin film

    Science.gov (United States)

    Singh, S. K.; Singhal, R.

    2017-09-01

    In the present work, we study the annealing and swift heavy ion (SHI) beam induced modifications in the optical and structural properties of sandwiched structured Carbon-gold-Carbon (a-C/Au/a-C) nanocomposite (NCs) thin films. The NCs thin films were synthesized by electron-beam evaporation technique at room temperature with ∼30 nm thickness for both carbon layer and ∼6 nm for gold layer. Gold-carbon NCs thin films were annealed in the presence of argon at a temperature of 500 °C, 600 °C and 750 °C. The NCs thin films were also irradiated with 90 MeV Ni ions beam with different ion fluences in the range from 3 × 1012, 6 × 1012 and 1 × 1013 ions/cm2. Surface plasmon resonance (SPR) of Au nanoparticles are not observed in the pristine film but, after annealing at temperature of 600 °C and 750 °C, it was clearly seen at ∼534 nm as confirmed by UV-visible absorption spectroscopy. 90 MeV Ni irradiated thin film at the fluence of 1 × 1013 ions/cm2 also show strong absorption band at ∼534 nm. The growth and size of Au nanoparticle for pristine and 90 MeV Ni ion irradiated thin film with fluence of 1 × 1013 ions/cm2, were estimated by Transmission electron microscopy (TEM) images with the bi-model distribution. The size of the gold nanoparticle (NPs) was found to be ∼4.5 nm for the pristine film and ∼5.4 nm for the irradiated film at a fluence of 1 × 1013 ions/cm2. The thickness and metal atomic fraction in carbon matrix were estimated by Rutherford backscattering spectroscopy (RBS). The effect of annealing as well as heavy ion irradiation on D and G band of carbon matrix were studied by Raman spectroscopy.

  10. Self-assembled plasmonic templates produced by microwave annealing: applications to surface-enhanced Raman scattering

    OpenAIRE

    Panagiotopoulos, NT; Kalfagiannis, N.; Vasilopoulos, KC; Pliatsikas, N; Kassavetis, S; Vourlias, G.; Karakassides, MA; Patsalas, P.

    2015-01-01

    Perhaps the simplest method for creating metal nanoparticles on a substrate is by driving their self-assembly with the thermal annealing of a thin metal film. By properly tuning the annealing parameters one hopes to discover a recipe that allows the pre-determined design of the NP arrangement. However, thermal treatment is known for detrimental effects and is not really the manufacturer's route of choice when it comes to large-scale applications. An alternative method is the use of microwave ...

  11. Effects of annealing temperature on nanomechanical and microstructural properties of Cu-doped In2O3 thin films

    Science.gov (United States)

    Jian, Sheng-Rui; Chen, Guo-Ju; Lee, Jyh-Wei

    2017-12-01

    In this study, the effects of post-annealing on the microstructural, surface morphological and nanomechanical properties of Cu-doped In2O3 (CIO) thin films were investigated using X-ray diffraction, scanning electron microscopy and nanoindentation techniques, respectively. The CIO thin films were deposited on the c-plane sapphire substrates at room temperature using the radio frequency magnetron sputtering system. Post-annealing was carried out at the temperatures of 750-950 °C, and resulted in progressive increase in the average grain size and improved crystallinity of CIO thin films. In addition, the hardness and Young's modulus of CIO thin films were measured by a nanoindenter equipped with a Berkovich diamond tip and operated with the continuous contact stiffness measurements mode. Results indicated that the values of hardness and Young's modulus of CIO thin films increased when the annealing temperature increased from 750 to 950 °C.

  12. Effect of air and nitrogen annealing on TiO2/Cu2O heterojunction photoelectrochemical solar cells

    Science.gov (United States)

    Pagare, Pavan K.; Kanade, K. G.; Torane, A. P.

    2017-10-01

    TiO2/Cu2O heterojunction solar cells have been successfully synthesized by an electrochemical route. The structural, morphological and optical properties of TiO2/Cu2O heterojunction solar cells were studied using x-ray diffraction, scanning electron microscopy and UV-vis spectroscopic techniques. The change in morphology is observed due to the effect of the annealing atmosphere on TiO2/Cu2O heterojunction. The surface morphological study shows truncated triangular and nanostar-like Cu2O material using air and nitrogen annealing. The oxidation state of TiO2 and Cu2O materials was studied by x-ray photoelectron spectroscopy. The J-V characteristics curve shows maximum 0.31% photoconversion efficiency of nitrogen-annealed TiO2/Cu2O heterojunction solar cells.

  13. Regular Organic Solar Cells with Efficiency over 10% and Promoted Stability by Ligand- and Thermal Annealing-Free Al-Doped ZnO Cathode Interlayer.

    Science.gov (United States)

    Liu, Xiaohui; Wang, Hai-Qiao; Li, Yaru; Gui, Zhenzhen; Ming, Shuaiqiang; Usman, Khurram; Zhang, Wenjun; Fang, Junfeng

    2017-08-01

    Landmark power conversion efficiency (PCE) over 10% has been accomplished in the past year for single-junction organic solar cell (OSCs), suggesting a promising potential application of this technology. However, most of the high efficient OSCs are based on inverted configuration. Regular structure OSCs with both high efficiency and good stability are still rarely reported to date. In this work, by utilizing a new designed ligand-free and non-thermal-annealing-treated Al-doped ZnO cathode interlayer, high efficiency and greatly improved stability are simultaneously realized in regular OSCs. The highest PCE of 10.14% is accomplished for single-junction regular OSCs with active blend of poly [[2,6'-4,8-di(5-ethylhexylthienyl)benzo[1,2-b;3,3-b]dithiophene][3-fluoro-2[(2-ethylhexyl)carbonyl]thieno [3,4-b]thiophenediyl

  14. Reflectance improvement by thermal annealing of sputtered Ag/ZnO back reflectors in a-Si:H thin film silicon solar cells

    DEFF Research Database (Denmark)

    Haug, Franz-Josef; Söderström, Karin; Pahud, Céline

    2011-01-01

    Silver can be used as the back contact and reflector in thin film silicon solar cells. When deposited on textured substrates, silver films often exhibit reduced reflectance due to absorption losses by the excitation of surface plasmon resonances. We show that thermal annealing of the silver back...... reflector increases its reflectance drastically. The process is performed at low temperature (150°C) to allow the use of plastic sheets such as polyethylene naphthalate and increases the efficiency of single junction amorphous solar cells dramatically. We present the best result obtained on a flexible...... substrate: a cell with 9.9% initial efficiency and 15.82 mA/cm2 in short circuit current is realized in n-i-p configuration. © 2011 Materials Research Society....

  15. Effect of graphene nanoplatelets on coefficient of thermal expansion of polyetherimide composite

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Huang, E-mail: huang.wu.84@gmail.com [Composite Materials and Structures Center, Michigan State University, East Lansing, MI 48864 (United States); Department of Chemical Engineering and Material Science, Michigan State University, East Lansing, MI 48864 (United States); Drzal, Lawrence T. [Composite Materials and Structures Center, Michigan State University, East Lansing, MI 48864 (United States); Department of Chemical Engineering and Material Science, Michigan State University, East Lansing, MI 48864 (United States)

    2014-07-01

    Thermal expansion is one of the major concerns for polymer composites. In this research, graphene nanoplatelets (GNPs) were added to polyetherimide (PEId) thermoplastic polymer in order to reduce the coefficient of thermal expansion (CTE) of the injection molded composite. First, the coefficient of linear thermal expansion (LTE) was measured in three directions in the anisotropic coupon: 0°, 90° and the out of plane Z direction. It is found that the GNP particles are very effective in terms of reducing the LTE in 0° direction due to high degree of alignment. After annealing above glass transition temperature, significant increase of 0° LTE and decrease of Z° LTE were observed. The bulk CTE was calculated by adding up the LTEs in all three directions and is found to be independent of annealing. Second, several models were applied to predict both CTE and LTE. It is found that Schapery's lower limit model fits the experimental CTE very well. Chow's model was applied for LTEs in three directions. The behavior of GNP-5/PEId composites is explained by the combination of Chow's model and morphology obtained by scanning electron microscope (SEM). - Highlights: • Coefficient of thermal expansion (CTE) of polymer composite is characterized. • Reduction of linear thermal expansion depends on filler orientation. • Filler orientation is characterized based on the location of the specimen. • Filler orientation is changed by annealing, causing subsequent change in CTE. • CTE and linear thermal expansion coefficient are modeled.

  16. Effect of Ag nanostructures and annealing process on the localized surface plasmon resonance properties of Ag-based AZO films

    Science.gov (United States)

    Jin, Jing; Hui, Chaoxian; Liu, Can; Shi, Weimin

    2017-08-01

    Ag nanoparticles were obtained in Ag/AZO and AZO/Ag/AZO films by magnetron sputtering method at room temperature with different deposition time. The morphology of Ag nanoparticles is strongly affected by the particle size, shape and distribution as well as annealing temperatures, which determine the optical response of films. The high quality of AZO film with better crystallinity can enhance the optical transmittance and a good coverage by AZO as top layer on Ag nanoparticles can also enhance the surface plasmon resonance (SPR) absorption of Ag in long wavelengths. The mechanisms involved in shifts and broadening of SPR peaks have been explained detailedly. The effect of annealing process on SPR of Ag and photoelectric properties of AZO/Ag/AZO films can be also discussed. It is shown that the SPR peak of 664 nm only appears in AZO/Ag (5 s)/AZO film and no SPR peaks are found in annealed AZO/Ag/AZO films. The AZO/Ag (20 s)/AZO film annealed at 300 °C shows a great figure of merit (F_{{TC}}) of 4.8 × 10-2 Ω-1 because of high visible optical average transmittance of 85% and low sheet resistance (R_{{S}}) of 4.1 Ω/sq. The overall results reveal that annealing process can improve the electrical property of film and may not be able to promote the SPR of Ag nanoparticles, especially when AZO top layer is added. The introduction of Ag nanoparticles in AZO/Ag/AZO films should be very effective for improving the SPR or photoelectric properties of films depending on deposition conditions and annealing process.

  17. Energy Band Diagram near the Interface of Aluminum Oxide on p-Si Fabricated by Atomic Layer Deposition without/with Rapid Thermal Cycle Annealing Determined by Capacitance-Voltage Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Satoh, N. [Department of Electrical Engineering, Kyoto University, Kyoto (Japan); Cesar, I.; Lamers, M.; Romijn, I.; Bakker, K.; Olson, C.; Oosterling Saynova, D.; Komatsu, Y.; Weeber, A. [ECN Solar Energy, Petten (Netherlands); Verbake, F.; Wiggers, M. [Philips Research, Eindhoven (Netherlands)

    2012-07-01

    We evaluated the fixed charge (Qf) and the interface state density (Dit) from the capacitance-voltage (C-V) measurement before and after rapid thermal cycle annealing (RTCA) using p-type silicon in which the passivation was performed with aluminum oxide (Al2O3) film by atomic layer deposition (ALD). From C-V measurement we obtained the surface potential (VS), accumulation and depletion width, and as a result, energy band diagrams were produced. It was determined that a barrier height of approximately 100 mV was induced by fixed negative charges in the Al2O3 layer near the interface to the p-type Si substrate. The field effect of the Al2O3 passivation layer created by RTCA strongly remains without depending on the gate voltage (VG)

  18. Annealing effects on the ferromagnetic resonance linewidths of sputter-deposited Fe{sub 100−x}Co{sub x}(001) thin films (x < 11)

    Energy Technology Data Exchange (ETDEWEB)

    Kusaoka, A.; Kimura, J.; Takahashi, Y., E-mail: takahasy@yz.yamagata-u.ac.jp; Inaba, N. [Graduate School of Science and Engineering, Yamagata University, Yonezawa, Yamagata 992-8510 (Japan); Kirino, F. [Graduate School of Fine Arts, Tokyo National University of Fine Arts and Music, Tokyo 110-8714 (Japan); Ohtake, M.; Futamoto, M. [Faculty of Science and Engineering, Chuo University, Tokyo 112-8551 (Japan)

    2015-05-07

    Effects of post-growth annealing on the magnetic damping of 3d transition alloy thin films were investigated. Fe{sub 100−x}Co{sub x} (x < 11 at. %) thin films were epitaxially deposited on GaAs(001) substrates by rf magnetron sputtering, and some of them were annealed without exposing to atmosphere. Electrical measurement showed that in-plane resistivity was smaller in the annealed films than in the as-deposited ones, indicating that the annealing mitigates crystalline imperfections and leads to reduced electron scattering rates. Magnetic damping was evaluated by the peak widths of ferromagnetic resonance (FMR) spectra obtained by a conventional Q-band spectrometer. Comparison of as-deposited and annealed specimens showed that the damping was decreased by annealing. Combined with the electrical and FMR measurements, these observations are consistent with the theoretical predictions that crystalline imperfections strongly influence the magnetic damping, both in intrinsic and extrinsic origins.

  19. Experimental determination of La{sub 2}O{sub 3} thermal conductivity and its application to the thermal analysis of a-Ge/La{sub 2}O{sub 3}/c-Si laser annealing

    Energy Technology Data Exchange (ETDEWEB)

    Fornarini, L. [Enea-Frascati, Via Enrico Fermi 45, I-00044 Frascati, Roma (Italy)], E-mail: fornarini@frascati.enea.it; Conde, J.C. [Dpto. Fisica Aplicada, E.T.S.I.I. University of Vigo, Lagoas Marcosende 9, E-36200 Vigo (Spain); Alvani, C. [Enea-Casaccia, S.P. Anguillarese 301, I-00100 Roma (Italy); Olevano, D. [Centro Sviluppo Materiali, Via di Castel Romano 100, I-00128 Roma (Italy); Chiussi, S. [Dpto. Fisica Aplicada, E.T.S.I.I. University of Vigo, Lagoas Marcosende 9, E-36200 Vigo (Spain)

    2008-09-01

    Rare earth oxides are emerging candidates for gate oxide films as they have high dielectric constants as well as promising crystal and electronic structures. Lanthanum oxide is one of them but, even if many of its properties are known, no data exist in literature on its thermal conductivity. In this work, La{sub 2}O{sub 3} thermal diffusivity has been measured by laser flash technique in the temperature range 300 K-1600 K and, from it, its thermal conductivity has been derived. Thermal diffusivity showed a decreasing trend from 2.7 * 10{sup -6} m{sup 2}/s to 0.7 * 10{sup -6} m{sup 2}/s while thermal conductivity decreases from 6 W/m/K to 2.1 W/m/K in the studied temperature range. Results have been applied to the thermal analysis of excimer laser annealing of La{sub 2}O{sub 3}/Si and a-Ge/La{sub 2}O{sub 3}/c-Si structures.

  20. Annealing effect on transport properties of Nd0.67Sr0.33MnO3 thin ...

    Indian Academy of Sciences (India)

    Annealing effect on transport properties of. Nd0.67Sr0.33MnO3 thin films. M PATTABIRAMAN a. , P MURUGARAJ a. , G RANGARAJAN a. , V PRASAD b. ,. S V SUBRAMANYAM b. , V S SASTRY c. , SANG-MO KOO d and K V RAO d. Department of Physics, Indian Institute of Technology, Chennai 600 036, India. Department ...

  1. Effect of shot peening coverage on fatigue limit in round bar of annealed medium carbon steel

    Energy Technology Data Exchange (ETDEWEB)

    Sakamoto, Junji; Lee, Yong Sung; Seong Kyun [Seoul National Univ., Seoul (Korea, Republic of)

    2014-09-15

    Shot peening is an effective and economical technique for improving the fatigue strength of metallic components by inducing compressive residual stress and hardening the layer near the surface. The effect is generally evaluated by main two parameters: coverage and peening intensity. However, the valuable coverage for improving the fatigue strength depends on the shape of the target material. In this study, the effect of coverage on fatigue limit in round bar of annealed medium carbon steel was experimentally studied. The fatigue limits for shot peened round bar specimens with 140-2300% coverage increased 14-25% by comparing those for non-peened round bar specimens. The valuable range of coverage was 280-560% in the used material and shot peening condition for improving the fatigue limit in short time. The result indicates that the valuable coverage of the round bar material is higher than full coverage to improve the fatigue limit of the material due to the effect of incident angle on round bar, even though the degree depends on the materials and shot peening conditions.

  2. Effect of Annealing on the Nanostructure Formation in Alkoxy Substituted Phthalocyanine Thin Films

    Directory of Open Access Journals (Sweden)

    Vinu. T. Vadakel

    2012-01-01

    Full Text Available Vacuum deposited 2,3,9,10,16,17,23,24-octakis (octyloxy phthalocyanine (H2PcOC8 thin films on glass substrates have exhibited a change on their surface morphology with the post deposition annealing temperature under normal atmosphere. These films have been characterized by optical absorptions and Scanning Electron Microscopy. SEM images also have shown nano-rod like structures for the samples annealed at different temperatures. The variation of optical band gap with annealing temperature is determined. The direct and allowed optical band gap energy has been evaluated from the α2 versus hυ plots. The electrical conductivity of the films at various heat treated samples are also studied. The activation energies are determined from the Arrhenius plots of lnσ versus 1000/T . It shows variation with the annealing temperature.

  3. Annealing and deposition effects of the chemical composition of silicon rich nitride

    DEFF Research Database (Denmark)

    Andersen, Karin Nordström; Svendsen, Winnie Edith; Stimpel-Lindner, T.

    2005-01-01

    Silicon-rich nitride, deposited by LPCVD, is a low stress amorphous material with a high refractive index. After deposition the silicon-rich nitride thin film is annealed at temperatures above 1100 oC to break N-H bonds, which have absorption peaks in the wavelength band important for optical...... telecommunication. However, silicon clustering appears in the thin films when annealing above 1150 oC. Clustering is undesirable in waveguide materials because the localized variations of the refractive index associated with the clusters lead to Raleigh scattering, which can cause significant propagation loss...... in optical waveguides. This means that the annealing temperature must be high enough to break the N-H bonds, but no so high as to produce clusters. Therefore, the process window for an annealing step lies between 1100 and 1150 oC. The chemical composition of amorphous silicon-rich nitride has been...

  4. Effect of annealing on the dielectric properties of PZN-PT-BT ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Wang Xiaoli; Chen Haydn

    2003-05-25

    The dielectric behaviors of Pb(Zn{sub 1/3}Nb{sub 2/3})O{sub 3}-PbTiO{sub 3}-BaTiO{sub 3} (PZN-PT-BT) ceramics of several compositions have been systematically studied in as-prepared (unannealed) condition as well as after annealing (at 880 deg. C for 16 h). The general trend seems to indicate that the annealed samples become more ferroelectric-like as opposed to relaxor type in the unannealed state. It also shows a shift of T{sub m}, the temperature at dielectric maximum, toward higher value after annealing. Both behaviors are composition dependent. X-ray diffraction patterns reveal changes of crystalline structure after annealing, which can be correlated to the accompanied changes in dielectric properties. Those experimental results may be understood using a model of paraelectric BZN nano-phase particles embedded in the PZN-PT-BT matrix.

  5. Effect of aging and annealing on perpendicular magnetic anisotropy of ultra-thin CoPt films

    Directory of Open Access Journals (Sweden)

    R. Hara

    2016-05-01

    Full Text Available The effect of aging and annealing on the magnetic properties of ultra-thin CoPt films with a Ru underlayer was investigated. For the 3 nm thick CoPt film aged in the air, the decrease of the saturation magnetic moment ms, the drastic increase of the perpendicular coercivity Hc⊥ and the perpendicular anisotropy were observed. This is because the surface layer of the CoPt film was oxidized and the bottom layer with high perpendicular anisotropy due to lattice distortion remained. For the annealed 3 nm thick CoPt film with a Pt protective layer, rising the annealing temperature Ta led to the decrease of ms, the decrease after increase of Hc⊥, and the decrease of the perpendicular squareness ratio S⊥ at Ta of 400 ∘C. The origins of effect of annealing were considered to be the grain boundary diffusion and the bulk diffusion of Ru and Pt into the CoPt film, and relaxation of the lattice distortion.

  6. Microstructure analysis of silicon nanocrystals formed from silicon rich oxide with high excess silicon: Annealing and doping effects

    Science.gov (United States)

    Nomoto, K.; Yang, T. C. J.; Ceguerra, A. V.; Zhang, T.; Lin, Z.; Breen, A.; Wu, L.; Puthen-Veettil, B.; Jia, X.; Conibeer, G.; Perez-Wurfl, I.; Ringer, S. P.

    2017-07-01

    Thin films consisting of silicon nanocrystals fabricated by high silicon content in silicon rich oxide show unique properties of decreasing resistivity and increasing light absorption while maintaining quantum confinement effects. With that said, the effect of the annealing temperature and doping element on the microscopic structure of silicon nanocrystals (Si NCs) and the film are still under research. In this study, individual intrinsic, boron-, and phosphorus-doped films are annealed at various temperatures, and their structural properties are analyzed via atom probe tomography together with glancing incidence x-ray diffraction, Raman spectroscopy (Raman), transmission electron microscopy (TEM), and energy filtered TEM. In addition, photoluminescence (PL) is performed and linked with their microstructural properties. The Si NC growth is confirmed at annealing temperatures of 1000 °C and 1100 °C. The microstructure of the Si NCs in the whole film is dramatically changed by increasing the annealing temperature from 1000 °C to 1100 °C. In addition, doping changes the arrangement of the Si NCs by assisting their penetration across the SiO2 barrier layers. This study helps to understand the relationship between the microscopic and macroscopic properties of the Si NC film, showing that the size and distribution of the Si NCs are correlated with the obtained PL profiles.

  7. Photovoltaic performance improvement in planar P3HT/CdS solar cells induced by structural, optical and electrical property modification in thermal annealed P3HT thin films

    Science.gov (United States)

    Cortina-Marrero, Hugo Jorge; Martínez-Alonso, Claudia; Hechavarría-Difur, Liliana; Hu, Hailin

    2013-07-01

    Bilayer hybrid solar cells were prepared by solution deposition of CdS thin films on conductive glass substrates (ITO), followed by spin-coating or drop-casting poly (3-hexylthiophene) (P3HT) solution on a CdS surface. After a slow drying process, the P3HT films of different thicknesses (from 100 to 725 nm) were annealed at temperatures (T1) from 110 to 190 °C, called pre-metal contact annealing. Then carbon paint was collocated on top of P3HT and gold was evaporated. The whole structure was annealed for the second time, called post-metal contact annealing, at temperature (T2) between 110 and 190 °C. The continuous increase of the (1 0 0) crystalline plane and the optical absorption coefficient of P3HT films with annealing temperatures indicates the improvement of molecular order inside the polymer films induced by the thermal annealing process. The better ordered P3HT films lead to lower series resistance and higher fill factor in the corresponding solar cells, suggesting the enlargement of charge carrier mobility in annealed P3HT films. On the other hand, the photovoltaic performance is also affected by T2 temperature; a low T2 improves the ohmic contact between P3HT and the metal contact to benefit the charge carrier extraction, whereas a high T2 may deteriorate that union. The same observation was obtained in CdS/P3HT solar cells with P3HT films of different thicknesses. The best energy conversion efficiency of 0.44% was obtained in CdS/P3HT cells with 305 nm thick P3HT annealed at T1 = 190 °C and T2 = 110 °C for 10 min each.

  8. Memory effects in annealed hybrid gold nanoparticles/block copolymer bilayers

    Directory of Open Access Journals (Sweden)

    Ruffino Francesco

    2011-01-01

    Full Text Available Abstract We report on the use of the self-organization process of sputtered gold nanoparticles on a self-assembled block copolymer film deposited by horizontal precipitation Langmuir-Blodgett (HP-LB method. The morphology and the phase-separation of a film of poly-n-butylacrylate-block-polyacrylic acid (PnBuA-b-PAA were studied at the nanometric scale by using atomic force microscopy (AFM and Time of Flight Secondary Ion Mass Spectrometry (TOF-SIMS. The templating capability of the PnBuA-b-PAA phase-separated film was studied by sputtering gold nanoparticles (NPs, forming a film of nanometric thickness. The effect of the polymer chain mobility onto the organization of gold nanoparticle layer was assessed by heating the obtained hybrid PnBuA-b-PAA/Au NPs bilayer at T >Tg. The nanoparticles' distribution onto the different copolymer domains was found strongly affected by the annealing treatment, showing a peculiar memory effect, which modifies the AFM phase response of the Au NPs layer onto the polar domains, without affecting their surfacial composition. The effect is discussed in terms of the peculiar morphological features induced by enhanced mobility of polymer chains on the Au NPs layer.

  9. Chemical Annealing of Zinc Tetraphenylporphyrin Films: Effects on Film Morphology and Organic Photovoltaic Performance

    KAUST Repository

    Trinh, Cong

    2012-07-10

    We present a chemical annealing process for organic thin films. In this process, a thin film of a molecular material, such as zinc tetraphenylporphyrin (ZnTPP), is exposed to a vapor of nitrogen-based ligand (e.g., pyrazine, pz, and triazine, tz), forming a film composed of the metal-ligand complex. Fast and quantitative formation of the complex leads to marked changes in the morphology and optical properties of the film. X-ray diffraction studies show that the chemical annealing process converts amorphous ZnTPP films to crystalline ZnTPP•ligand films, whose porphryin planes lie nearly parallel to the substrate (average deviation is 8° for the ZnTPP•pz film). Organic solar cells were prepared with ZnTPP donor and C 60 acceptor layers. Devices were prepared with and without chemical annealing of the ZnTPP layer with a pyrazine ligand. The devices with chemically annealed ZnTPP donor layer show an increase in short-circuit current (J SC) and fill factor (FF) relative to analogous unannealed devices, presumably because of enhanced exciton diffusion length and improved charge conductivity. The open circuit voltages (V OC) of the chemically annealed devices are lower than their unannealed counterpart because of enhanced polaron pair recombination at the donor/acceptor heterojunction. A net improvement of 5-20% in efficiency has been achieved, after chemical annealing of ZnTPP films with pyrazine. © 2012 American Chemical Society.

  10. Effect of annealing temperature on hardness, thickness and phase structure of carbonitrided 304 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    El-Hossary, F.M.; Negm, N.Z.; Khalil, S.M.; Abed El-Rahman, A.M.; Raaif, M. [Sohag University, Physics Department, Faculty of Science, Sohag (Egypt); Maendl, S. [Leibniz-Institute fuer Oberflaechenmodifizierung, Leipzig (Germany)

    2010-05-15

    Carbonitriding of AISI 304 austenitic stainless steel was performed at a plasma-processing power of 450 W using inductively coupled radio frequency (rf) plasma in a gas mixture of 50% N{sub 2} and 50% C{sub 2}H{sub 2}. The rate of carbonitriding, microhardness, phase structure of the compound layer, surface microstructure and cross-section morphology were studied before and after the annealing process. At the annealing temperature up to 800 C, the microhardness values of the compound zones decrease, while the associated values of the diffused zones increase. Little change was found in the thickness of the compound and diffused zones when the carbonitrided samples were annealed up to 400 C. However, at a higher annealing temperature, the thicknesses of both zones increase. The {gamma}-Fe austenite is the main crystalline phase that can be detected by X-ray diffraction. As the annealing temperature increases up to 500 C, X-ray spectra show {alpha}-Fe and Fe{sub 5}C{sub 2} phases. Nitrogen diffuses more deeply from the near surface to the interior of the treated sample as the annealing temperature increases up to 800 C and this might explain the extent of carbonitrided thickness and the enhanced microhardness of the diffused zone. (orig.)

  11. Effect of dose and post irradiation annealing in Ni implanted high entropy alloy FeCrCoNi using slow positron beam

    Energy Technology Data Exchange (ETDEWEB)

    Abhaya, S., E-mail: sab@igcar.gov.in; Rajaraman, R.; Kalavathi, S.; David, C.; Panigrahi, B.K.; Amarendra, G.

    2016-06-05

    Defect characterization of room temperature 1.5 MeV Ni ion implanted high entropy FeCrCoNi alloy for two fluences (1 × 10{sup 15} ions/cm{sup 2} and 5 × 10{sup 16} ions/cm{sup 2}) was carried out using the variable low energy positron beam. The FCC solid solution remains robust and stable under 100 dpa irradiation and high temperature annealing. The change in the defect sensitive S-parameter upon implantation reveals the presence of monovacancies for both the doses. The changes in the defect microstructure upon thermal annealing are found to be dose dependent. The high dose shows the formation of stable stacking fault tetrahedrons (SFT's) from the aggregates of monovacancies at higher annealing temperatures while the low dose shows the annealing of monovacancies with temperature. - Highlights: • Defect characterization of room temperature Ni implanted high entropy FeCrCoNi alloy carried out using the slow positron beam. • The FCC FeCrCoNi remains structurally stable under both irradiation and high temperature annealing. • Defect evolution upon thermal annealing is found to be dose dependent.

  12. The effect of annealing on the transformation and the microstructure of Mn{sub 1−x}Cr{sub x}CoGe alloys

    Energy Technology Data Exchange (ETDEWEB)

    Torrens-Serra, J., E-mail: j.torrens@uib.es [Departament de Física, Universitat de les Illes Balears, Cra. Valldemossa km 7.5, E-07122 Palma de Mallorca (Spain); Biffi, C.A. [Consiglio Nazionale delle Ricerche CNR—IENI, C.so P.Sposi 29, 23900 Lecco (Italy); Santamarta, R. [Departament de Física, Universitat de les Illes Balears, Cra. Valldemossa km 7.5, E-07122 Palma de Mallorca (Spain); Recarte, V.; Pérez-Landazábal, J.I. [Departamento de Física, Universidad Pública de Navarra, Campus de Arrosadía, E-31006 Pamplona (Spain); Tuissi, A. [Consiglio Nazionale delle Ricerche CNR—IENI, C.so P.Sposi 29, 23900 Lecco (Italy); Cesari, E. [Departament de Física, Universitat de les Illes Balears, Cra. Valldemossa km 7.5, E-07122 Palma de Mallorca (Spain)

    2014-07-01

    In this work the effect of different thermal treatments on the transformation behavior of Mn{sub 1−x}Cr{sub x}CoGe alloys, with x = 0.15 and 0.20 has been analyzed. The changes in the transformation temperatures have been studied by differential scanning calorimetry (DSC). The results show that the structural transition temperature depends on the previous annealing. However, under the same heat treatment no significant change is observed on the transformation temperatures when replacing Mn by Cr. The microstructural evolution has been monitored using in-situ X-ray diffraction and transmission electron microscopy. The effect of an applied magnetic field on the transformation has been explored by SQUID magnetometry. Two different magnetic transitions are found: a first order paramagnetic (PM) to ferromagnetic (FM) corresponding to the transformation observed by calorimetry and a re-entrant spin glass to ferromagnetic transition. - Highlights: • The annealing conditions determine the magnetostructural transition. • A laminar microstructure along preferential planes observed by TEM • A RSG to ferromagnetic transition at low temperatures is detected.

  13. Enabling n-type polycrystalline Ge junctionless FinFET of low thermal budget by in situ doping of channel and visible pulsed laser annealing

    Science.gov (United States)

    Huang, Wen-Hsien; Shieh, Jia-Min; Kao, Ming-Hsuan; Shen, Chang-Hong; Huang, Tzu-En; Wang, Hsing-Hsiang; Yang, Chih-Chao; Hsieh, Tung-Ying; Hsieh, Jin-Long; Yu, Peichen; Yeh, Wen-Kuan

    2017-02-01

    A low-thermal-budget n-type polycrystalline Ge (poly-Ge) channel that was prepared by plasma in-situ-doped nanocrystalline Ge (nc-Ge) and visible pulsed laser annealing exhibits a high electrically active concentration of 2 × 1019 cm-3 and a narrow Raman FWHM of 3.9 cm-1. Furthermore, the fabricated n-type poly-Ge junctionless FinFET (JL-FinFET) shows an I on/I off ratio of 6 × 104, V th of -0.3 V, and a subthreshold swing of 237 mV/dec at V d of 1 V and DIBL of 101 mV/V. The poly-Ge JL-FinFET with a high-aspect-ratio fin channel is less sensitive to V th roll-off and subthreshold-swing degradation as the gate length is scaled down to 50 nm. This low-thermal-budget JL-FinFET can be integrated into three-dimensional sequential-layer integration and flexible electronics.

  14. Cu(In,Ga)Se2 thin films annealed using a continuous wave Nd:YAG laser (λ0 = 532 nm): Effects of laser-annealing time

    Science.gov (United States)

    Yoo, Myoung Han; Ko, Pil Ju; Kim, Nam-Hoon; Lee, Hyun-Yong

    2017-12-01

    Preparation of Cu(In,Ga)Se2 (CIGS) thin films has continued to face problems related to the selenization of sputtered Cu-In-Ga precursors when using H2Se vapor in that the materials are highly toxic and the facilities extremely costly. Another obstacle facing the production of CIGS thin films has been the required annealing temperature, as it relates to the decomposition temperature of a typical flexible polymer substrate. A novel laser-annealing process for CIGS thin films, which does not involve the selenization process and which can be performed at a lower temperature, has been proposed. Following sputtering with a Cu0.9In0.7Ga0.3Se2 target, the laser-annealing of the CIGS thin film was performed using a continuous 532-nm Nd:YAG laser with an annealing time of 200 - 1000 s at a laser optical power of 2.75 W. CIGS chalcopyrite (112), (220/204), and (312/116) phases, with some weak diffraction peaks corresponding to the Cu-Se- or the In-Se-related phases, were successfully obtained for all the CIGS thin films that had been laser-annealed at 2.75 W. The lattice parameters, the d-spacing, the tetragonal distortion parameter, and the strain led to the crystallinity being worse and grain size being smaller at 600 s while better crystallinity was obtained at 200 and 800 s, which was closely related to the deviations from molecularity and stoichiometry, which were greatest at 600 s while the values exhibited near-stoichiometric compositions at 200 and 800 s. The band gaps of the laser-annealed CIGS thin films were within a range of 1.765 - 1.977 eV and depended on the internal stress. The mean absorbance of the laser-annealed CIGS thin films was within a range of 1.598 - 1.900, suggesting that approximately 97.47 - 98.74% of the incident photons in the visible spectral region were absorbed by this 400-nm film. The conductivity types exhibited the same deviations (Δ m > 0 and Δ s < 0) in all the laser-annealed CIGS thin films. After laser-annealing, the resistivity

  15. Inverse strain rate effect on cyclic stress response in annealed Zircaloy-2

    Science.gov (United States)

    Sudhakar Rao, G.; Verma, Preeti; Chakravartty, J. K.; Nudurupati, Saibaba; Mahobia, G. S.; Santhi Srinivas, N. C.; Singh, Vakil

    2015-02-01

    Low cycle fatigue behavior of annealed Zircaloy-2 was investigated at 300 and 400 °C at different strain amplitudes and strain rates of 10-2, 10-3, and 10-4 s-1. Cyclic stress response showed initial hardening with decreasing rate of hardening, followed by linear cyclic hardening and finally secondary hardening with increasing rate of hardening for low strain amplitudes at both the temperatures. The rate as well the degree of linear hardening and secondary hardening decreased with decrease in strain rate at 300 °C, however, there was inverse effect of strain rate on cyclic stress response at 400 °C and cyclic stress was increased with decrease in strain rate. The fatigue life decreased with decrease in strain rate at both the temperatures. The occurrence of linear cyclic hardening, inverse effect of strain rate on cyclic stress response and deterioration in fatigue life with decrease in strain rate may be attributed to dynamic strain aging phenomena resulting from enhanced interaction of dislocations with solutes. Fracture surfaces revealed distinct striations, secondary cracking, and oxidation with decrease in strain rate. Deformation substructure showed parallel dislocation lines and dislocation band structure at 300 °C. Persistent slip band wall structure and development of fine Corduroy structure was observed at 400 °C.

  16. Laser annealing effects of the Raman laser on nitrogen implanted glassy carbon

    Energy Technology Data Exchange (ETDEWEB)

    Barbara, D.; Prawer, S.; Jamieson, D.N. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1996-12-31

    Raman analysis is a popular method of investigating crystallite sizes, ordering and the types of bonds that exist in ion irradiated carbon materials, namely graphite, diamond and glassy carbon (G.C.). In particular Raman spectroscopy is used in determining the tetrahedral bonding required for the elusive and potentially important new material called carbon nitride. Carbon nitride, {beta}-C{sub 3}N{sub 4}, is predicted to exist in several forms. Forming the tetrahedral bond between C and N has proved troublesome bain of many experimenters. A proven method for synthesizing novel materials is ion implantation. Thus G.C. was implanted with N at low temperatures so that diffusion of the implanted N would be hindered. G.C. is a relatively hard, chemically inert, graphitic material. The opaque property of G.C. means that Raman spectroscopy will only give information about the structures that exist at the surface and near surface layers. It was decided, after observing conflicting Raman spectra at different laser powers, that an investigation of the laser annealing effects of the Raman laser on the N implanted G.C. was warranted. The results of the preliminary investigation of the effects of increasing the Raman laser power and determining a power density threshold for high dose N implanted G.C. are discussed. 4 refs., 4 figs.

  17. Effect of annealing on down-conversion properties of monoclinic Gd2O3:Er3+ nanophosphors.

    Science.gov (United States)

    Tamrakar, Raunak Kumar; Bisen, D P; Upadhyay, Kanchan

    2015-09-01

    Erbium-doped nano-sized Gd2O3 phosphor was prepared by a solution combustion method in the presence of urea as a fuel. The phosphor was characterized by X-ray diffractometry (XRD), Fourier transform infra-red spectroscopy, energy dispersive X-ray analysis (EDX) and transmission electron microscopy (TEM). The results of the XRD shows that the phosphor has a monoclinic phase, which was further confirmed by the TEM results. Particle size was calculated by the Debye-Scherrer formula. The erbium-doped Gd2O3 nanophosphor was revealed to have good down-conversion (DC) properties and the intensity of phosphor could be modified by annealing. The effects of annealing at 900°C on the particle size and luminescence properties were studied and compared with freshly prepared Gd2O3:Er(3+) nanoparticles. The average particle sizes were calculated as 8 and 20 nm for the freshly prepared samples and samples annealed at 900°C for 1 h, respectively. The results show that both freshly prepared and annealed Gd2O3:Er(3+) have monoclinic structure. Copyright © 2014 John Wiley & Sons, Ltd.

  18. Effects of annealing, acid and alcoholic beverages on Fe1+yTe0.6Se0.4

    Science.gov (United States)

    Sun, Y.; Taen, T.; Tsuchiya, Y.; Shi, Z. X.; Tamegai, T.

    2013-01-01

    We have systematically investigated and compared different methods to induce superconductivity in the iron chalcogenide Fe1+yTe0.6Se0.4, including annealing in a vacuum, N2, O2 and I2 atmospheres and immersing samples into acid and alcoholic beverages. Vacuum and N2 annealing are proved to be ineffective in inducing superconductivity in a Fe1+yTe0.6Se0.4 single crystal. Annealing in O2 and I2 and immersion in acid and alcoholic beverages can induce superconductivity by oxidizing the excess Fe in the sample. Superconductivity in O2 annealed samples is of a bulk nature, while I2, acid and alcoholic beverages can only induce superconductivity near the surface. By comparing the different effects of O2, I2, acid and alcoholic beverages we propose a scenario to explain how the superconductivity is induced in the non-superconducting as-grown Fe1+yTe0.6Se0.4.

  19. Effects of excimer laser annealing on low-temperature solution based indium-zinc-oxide thin film transistor fabrication

    Directory of Open Access Journals (Sweden)

    Chao-Nan Chen

    2015-04-01

    Full Text Available A Solution Based Indium-Zinc-Oxide thin-film transistor (TFT with a field-effect mobility of 0.58 cm2/Vs, a threshold voltage of 2.84 V by using pulse laser annealing processes. Indium-zinc-oxide (IZO films with a low process temperature were deposited by sol-gel solution based method and KrF excimer laser annealing (wavelength of 248 nm. Solution based indium-zinc-oxide (IZO films usually needs high temperature about 500 °C post annealing in a oven. KrF excimer laser annealing shows advantages of low temperature process, the less process time deceases to only few seconds was used to replace the high temperature process. IZO thin films suffering laser irradiation still keeps the amorphous film quality by transmission electron microscopy (TEM diffraction pattern analysis. It could be expected this technology to large-area flexible display, in the future.

  20. Effect of annealing on the structural, morphological and optical properties of Ga-doped ZnO nanoparticles by reflux precipitation method

    Science.gov (United States)

    Ungula, J.; Dejene, B. F.; Swart, H. C.

    Gallium-doped zinc oxide nanoparticles (GZO NPs) were synthesized using reflux precipitation method and annealed at temperatures ranging from 300 to 600 °C. X-ray diffraction study exhibited a highly crystalline GZO NPs with hexagonal wurtzite structure. The highest diffraction peak intensity was displayed by GZO NPs annealed at 300 °C. The crystallite size of the NPs increased from 12 to 25 nm with the increase in annealing temperature (AT) indicating the tendency of large grain growth in the nanoparticles due to annealing. SEM micrographs showed tiny hexagonal particles for unannealed samples which turned into bigger rods with increasing AT. Photoluminescence spectra displayed the highest excitonic peak luminescence for the sample annealed at 300 °C among its annealed counterparts. The minimum reflection was also observed for the sample annealed at 300 °C. The red shift in the UV emission with increasing particle size due to annealing closely followed the red shift in the band edge emission of the reflectance spectra, indicating that the two complement each other. The band gap of GZO NPs decreased from 3.3 to 3.1 eV with an increase in AT, implying that the optical properties of these materials were clearly affected by thermal annealing. We were able to produce better quality GZO NPs with high crystallinity, minimum lattice stress, and lowest % reflectance in both the visible and UV-Vis range at a relatively lower AT of 300 °C using the reflux method which, to the best of our knowledge, is less reported on to synthesize GZO NPs.

  1. The Effect of Core Configuration on Thermal Barrier Thermal Performance

    Science.gov (United States)

    DeMange, Jeffrey J.; Bott, Robert H.; Druesedow, Anne S.

    2015-01-01

    Thermal barriers and seals are integral components in the thermal protection systems (TPS) of nearly all aerospace vehicles. They are used to minimize heat transfer through interfaces and gaps and protect underlying temperature-sensitive components. The core insulation has a significant impact on both the thermal and mechanical properties of compliant thermal barriers. Proper selection of an appropriate core configuration to mitigate conductive, convective and radiative heat transfer through the thermal barrier is challenging. Additionally, optimization of the thermal barrier for thermal performance may have counteracting effects on mechanical performance. Experimental evaluations have been conducted to better understand the effect of insulation density on permeability and leakage performance, which can significantly impact the resistance to convective heat transfer. The effect of core density on mechanical performance was also previously investigated and will be reviewed. Simple thermal models were also developed to determine the impact of various core parameters on downstream temperatures. An extended understanding of these factors can improve the ability to design and implement these critical TPS components.

  2. Tailoring giant magnetoimpedance effect of Co-based microwires for optimum efficiency by self-designed square-wave pulse current annealing

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jingshun, E-mail: jingshun_liu@163.com [School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot 010051 (China); Du, Zhaoxin [School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot 010051 (China); Jiang, Sida; Shen, Hongxian [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Li, Ze [School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot 010051 (China); Xing, Dawei [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Ma, Wen [School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot 010051 (China); Sun, Jianfei [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2015-07-01

    Herein, we systematically studied the effect of a novel square-wave pulse current annealing (SPCA) on the magnetic properties and microstructure of Co-based melt-extracted amorphous wires, and efficiently tailored the related experimental parameters by using numerical calculation of transient temperature rise during SPCA process. We obtained the optimal SPCA treatment (at 50 Hz, with amplitude of 90 mA for 480 s) can remarkably enhance the GMI property of as-prepared wires. At 10 MHz, the maximum GMI ratio [ΔZ/Z{sub 0}]{sub max} and maxima response sensitivity ξ{sub max} of SPCA-treated wire increases to 202.60% and 305.74%/Oe, which is nearly two times and 1.5 times of 104.80% and 208.14%/Oe for as-cast wire, respectively. Especially, at 5 MHz, [ΔZ/Z{sub 0}]{sub max} of SPCA-treated wire increases to 185.81%, which is 2.5 times of 73.69% for as-cast wire, and ξ{sub max} of SPCA-treated wire increases to 346.65%/Oe by less than two times of 190.16%/Oe for as-cast wire. From mictrostructural perspective, the notably observed role of atomic order orientation regimes and circular magnetic domain during stress releasing or structural relaxation by the co-action of high-density pulse magnetic field energy and thermal activation energy determines the optimum efficiency of SPCA, further to enhance circumferential permeability. In conclusion, SPCA treatment is expected to effectively improve GMI property of microwires, which can be used as sensitive materials for potential sensor application in detecting weak magnetic field. - Highlights: • Annealing parameters are optimized by transient temperature rising calculation. • SPCA as a novel annealing treatment has larger GMI ratio and field sensitivity. • GMI effect is generally related to annealed microstructures identified by XRD. • Domain observed by MFM to explain the enhanced GMI property for SPCA-ed wires. • Results indicate SPCA-ed wires are useful for potential GMI sensor applications.

  3. Weak localization and percolation effects in annealed In2O3-ZnO thin films

    Directory of Open Access Journals (Sweden)

    B. Shinozaki

    2011-09-01

    Full Text Available We have investigated the temperature T and magnetic field H dependences of the sheet resistance R□ of thin (In2O30.975-(ZnO0.025 films with different resistivities and carrier densities prepared by postannealing in air at various annealing temperatures Ta. Regarding the magnetoconductance Δσ(H ≡ 1/R□(H − 1/R□(0 of films with large values of sheet resistance R□, agreement between weak localization theory and the data cannot be obtained for any value of the localization length L in (T=Dτ in (T, where D and τin are the diffusion constant and inelastic scattering time, respectively. Taking account of the inhomogeneous morphology confirmed by Scanning Electron Microscopy (SEM observation, we introduced the effective sheet resistance R□eff given by R□eff = α × R□meas., where the strength of reduction factor α is less than unit, α ⩽ 1. Using a suitable value of α(Ta, we successfully fitted the theory to data for Δσeff(H, T, regarding Lin2(T as a fitting parameter in the region 2.0 K⩽T ⩽ 50 K. It was confirmed that the rate 1/τin(T is given by the sum of the electron-electron and electron-phonon inelastic scattering rates.

  4. The effects of Mg incorporation and annealing temperature on the physicochemical properties and antibacterial activity against Listeria monocytogenes of ZnO nanoparticles

    Science.gov (United States)

    Shadan, Nima; Ziabari, Ali Abdolahzadeh; Meraat, Rafieh; Jalali, Kamyar Mazloum

    2017-02-01

    In this paper, Mg-doped ZnO nanoparticles were synthesized by the facile sol-gel method. The crystalline structure, characteristic absorption bands and morphology of the obtained Mg-doped ZnO nanoparticles were studied by XRD, FTIR and TEM. The thermal degradation behaviour of the samples was investigated by differential scanning calorimetry (DSC) and thermogravimetry (TG). The effect of Mg concentrations and annealing temperatures on the antibacterial properties of the obtained nanoparticles was investigated in detail. The results indicated that doping Mg ions into ZnO lattice could enhance its antibacterial activity. Antibacterial assay demonstrated that Mg-doped ZnO with 7% Mg content annealed at 400 ∘C had the strongest antibacterial activity against Listeria monocytogenes (98.7%). This study indicated that the inhibition rate of ZnO nanoparticles increased with the formation of granular structure and the decrease of ZnO size due to the doping of Mg ions into the ZnO lattice.

  5. Effect of Annealing Ambient on the Electrical and Optical Properties of Aluminum-Doped ZnO Films Produced via a Sol-Gel Process

    Science.gov (United States)

    Ho, Yung-Shou; Chen, Yi-Siou; Wu, Cheng-Heng

    2014-07-01

    In this study, aluminum-doped ZnO (AZO) thin films were prepared by a sol-gel with spin coating process. The AZO films were annealed by a two-step process. The films were first annealed in air or nitrogen at 500°C for 3 h, followed by annealing in three types of ambient, i.e., vacuum (10-3 Torr or 10-6 Torr) or forming gas (10% H2/90% N2), at 500°C for 4 h. The effect of the annealing ambient on the microstructure, electrical and optical properties of the AZO films was explored by x-ray diffraction, field-emission scanning electron microscopy, four-point probe sheet resistivity measurements, Hall voltage measurements, and ultraviolet-visible spectroscopy. The results showed that the size of AZO particulates in the films was determined mainly by the first annealing step. The films annealed in air in the first step were composed of larger AZO particulates than those annealed in nitrogen. The conductivities of the AZO films were significantly increased by the second annealing step. Second annealing in a high-vacuum system (10-6 Torr) led to the highest AZO film conductivity among the three ambients. Regardless of the various annealing processes, the films remained transparent under visible light and exhibited a sharp absorption edge in the ultraviolet region. The highest conductivity, i.e., 168 S cm-1, was obtained from films annealed first in air and then in vacuum of 10-6 Torr.

  6. Directed Self-Assembly of Polystyrene- b -poly(propylene carbonate) on Chemical Patterns via Thermal Annealing for Next Generation Lithography

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Guan-Wen [MOE Laboratory of; Wu, Guang-Peng [MOE Laboratory of; Chen, Xuanxuan [Institute for Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States; Xiong, Shisheng [Institute for Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States; Materials Science Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, United States; Arges, Christopher G. [Cain Department; Ji, Shengxiang [Key Laboratory of Polymer Ecomaterials,; Nealey, Paul F. [Institute for Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States; Materials Science Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, United States; Lu, Xiao-Bing [State Key Laboratory of; Darensbourg, Donald J. [Department of Chemistry, Texas A& amp,M University, 3255 TAMU, College Station, Texas 77843, United States; Xu, Zhi-Kang [MOE Laboratory of

    2017-01-23

    Directed self-assembly (DSA) of block copolymers (BCPs) combines advantages of conventional photolithography and polymeric materials and shows competence in semiconductors and data storage applications. Driven by the more integrated, much smaller and higher performance of the electronics, however, the industry standard polystyrene-block-poly(methyl methacrylate) (PS-b-PMM.A) in DSA strategy cannot meet the rapid development of lithography technology because its intrinsic limited Flory-Huggins interaction parameter (chi). Despite hundreds of block copolymers have been developed, these BCPs systems are usually subject to a trade-off between high chi and thermal treatment, resulting in incompatibility with the current nanomanufacturing fab processes. Here we discover that polystyrene-b-poly(propylene carbonate) (PS-b-PPC) is well qualified to fill key positions on DSA strategy for the next-generation lithography. The estimated chi-value for PS-b-PPC is 0.079, that is, two times greater than PS-b-PMMA (chi = 0.029 at 150 degrees C), while processing the ability to form perpendicular sub-10 nm morphologies (cylinder and lamellae) via the industry preferred thermal-treatment. DSA of lamellae forming PS-b-PPC on chemoepitaxial density multiplication demonstrates successful sub-10 nm long-range order features on large-area patterning for nanofabrication. Pattern transfer to the silicon substrate through industrial sequential infiltration synthesis is also implemented successfully. Compared with the previously reported methods to orientation control BCPs with high chi-value (including solvent annealing, neutral top-coats, and chemical modification), the easy preparation, high chi value, and etch selectivity while enduring thermal treatment demonstrates PS-b-PPC as a rare and valuable candidate for advancing the field of nanolithography.

  7. Annealing effects and DLTS study on NPN silicon bipolar junction transistors irradiated by heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chaoming; Li, Xingji, E-mail: lxj0218@hit.edu.cn; Yang, Jianqun; Rui, Erming

    2014-01-21

    Isochronal anneal sequences have been carried out on 3DG112 silicon NPN bipolar junction transistors (BJTs) irradiated with 20 MeV bromine (Br) heavy ions. The Gummel curve is utilized to characterize the annealing behavior of defects in both the emitter-base depletion region and the neutral base. We find that the base current (I{sub B}) decreases with the increasing annealing temperature, while the collector current (I{sub C}) remains invariable. The current gain varies slightly, when the annealing temperature (T{sub A}) is lower than 400 K, while varies rapidly at T{sub A}<450 K, and the current gain of the 3DG112 BJT annealing at 700 K almost restore to that of the pre-radiation transistor. Deep level transient spectroscopy (DLTS) data is used to assign the relative magnitude of each of the important defects. Based on the in situ electrical measurement and DLTS spectra, it is clear that the V{sub 2}(−/0)+V-P traps are the main contribution to the degradation of current gain after the 20 MeV Br ions irradiation. The V{sub 2}(−/0)+V-P peak has many of the characteristics expected for the current gain degradation.

  8. Annealing effects and DLTS study on NPN silicon bipolar junction transistors irradiated by heavy ions

    Science.gov (United States)

    Liu, Chaoming; Li, Xingji; Yang, Jianqun; Rui, Erming

    2014-01-01

    Isochronal anneal sequences have been carried out on 3DG112 silicon NPN bipolar junction transistors (BJTs) irradiated with 20 MeV bromine (Br) heavy ions. The Gummel curve is utilized to characterize the annealing behavior of defects in both the emitter-base depletion region and the neutral base. We find that the base current (IB) decreases with the increasing annealing temperature, while the collector current (IC) remains invariable. The current gain varies slightly, when the annealing temperature (TA) is lower than 400 K, while varies rapidly at TABJT annealing at 700 K almost restore to that of the pre-radiation transistor. Deep level transient spectroscopy (DLTS) data is used to assign the relative magnitude of each of the important defects. Based on the in situ electrical measurement and DLTS spectra, it is clear that the V2(-/0)+V-P traps are the main contribution to the degradation of current gain after the 20 MeV Br ions irradiation. The V2(-/0)+V-P peak has many of the characteristics expected for the current gain degradation.

  9. Annealing temperature effect on the properties of untreated and treated copper films with oxygen plasma

    Science.gov (United States)

    Hojabri, Alireza; Hajakbari, Fatemeh; Soltanpoor, Nasrin; Hedayati, Maryam Sadat

    2014-06-01

    In this work, the copper films were deposited on quartz substrates by DC magnetron sputtering method and then, the prepared films were annealed in air atmosphere at different annealing temperatures. Before annealing, some of the copper films, treated by oxygen plasma, for comparison of the results. The structural and morphological properties of the films have been investigated using X-ray diffraction (XRD), atomic force microscopy, and four point probe techniques. XRD results exhibited that the cuprous oxide phase changes to cupric oxide by enhancing of annealing temperatures. Also, oxygen plasma treatment can cause the better crystallinity for the prepared copper oxide films. The results confirm that oxygen plasma treatment, affected the crystal size, grain size, average roughness, sheet resistivity and strain of the films. The optical characteristics of the oxygen plasma treated films, such as refractive index, extinction coefficient and absorption coefficient were calculated by straight forward method proposed by Swanepoel using transmittance measurements. Moreover it was found that annealing temperature augmentation lead to decrease the optical band gap energy calculated using Tauc's relation from 2.45 to 1.80 eV.

  10. Positron annihilation spectroscopy study on annealing effect of CuO nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Jianjian; Wang, Jiaheng; Yang, Wei; Zhu, Zhejie; Wu, Yichu, E-mail: ycwu@whu.edu.cn [School of Physics and Technology, Hubei Key Laboratory of Nuclear Solid State Physics, Wuhan University (WHU), Wuhan (China)

    2016-03-15

    The microstructure and defects of CuO nanoparticles under isochronal annealing were investigated by positron annihilation spectroscopy (PAS), X-ray diffraction (XRD) and scanning electron microscope (SEM). XRD and SEM results indicated that the average grain sizes of CuO nanoparticles grew slowly below 800 °C, and then increased rapidly with the annealing temperature from 800 to 1000 °C. Positron lifetime analysis exhibited that positrons were mainly annihilated in mono-vacancies (V{sub Cu}, V{sub O}) and vacancy clusters when annealing from 200 to 800 °C. Furthermore, W-S plot of Doppler broadening spectra at different annealing temperatures found that the (W, S) points distributed on two different defect species, which suggested that V{sup −}{sub Cu} - V{sup +}{sub O} complexes were produced when the grains grew to bigger size after annealing above 800 °C, and positrons might annihilate at these complexes. (author)

  11. Embrittlement recovery due to annealing of reactor pressure vessel steels

    Energy Technology Data Exchange (ETDEWEB)

    Eason, E.D.; Wright, J.E.; Nelson, E.E. [Modeling and Computing Services, Boulder, CO (United States); Odette, G.R.; Mader, E.V. [Univ. of California, Santa Barbara, CA (United States)

    1996-03-01

    Embrittlement of reactor pressure vessels (RPVs) can be reduced by thermal annealing at temperatures higher than the normal operating conditions. Although such an annealing process has not been applied to any commercial plants in the United States, one US Army reactor, the BR3 plant in Belgium, and several plants in eastern Europe have been successfully annealed. All available Charpy annealing data were collected and analyzed in this project to develop quantitative models for estimating the recovery in 30 ft-lb (41 J) Charpy transition temperature and Charpy upper shelf energy over a range of potential annealing conditions. Pattern recognition, transformation analysis, residual studies, and the current understanding of the mechanisms involved in the annealing process were used to guide the selection of the most sensitive variables and correlating parameters and to determine the optimal functional forms for fitting the data. The resulting models were fitted by nonlinear least squares. The use of advanced tools, the larger data base now available, and insight from surrogate hardness data produced improved models for quantitative evaluation of the effects of annealing. The quality of models fitted in this project was evaluated by considering both the Charpy annealing data used for fitting and the surrogate hardness data base. The standard errors of the resulting recovery models relative to calibration data are comparable to the uncertainty in unirradiated Charpy data. This work also demonstrates that microhardness recovery is a good surrogate for transition temperature shift recovery and that there is a high level of consistency between the observed annealing trends and fundamental models of embrittlement and recovery processes.

  12. Effect of annealing process in TiO2 thin films: Structural, morphological, and optical properties

    Science.gov (United States)

    Dussan, A.; Bohórquez, A.; Quiroz, Heiddy P.

    2017-12-01

    This work presents a study of the structural, morphological, and optical properties of titanium dioxide thin films prepared via chemical bath deposition method, after being submitted to annealing processes varying the temperature from 373 to 723 K. The presence of the Rutile phase in all the samples was identified using X-ray diffraction measurements. When the annealing temperature increased to 723 K, the presence of the Anatase phase was observed. From scanning electron microscopy measurements, the formation of nanoflowers was also perceived; these flower-like structures are composed of nanorods of around ∼10 nm in length. With increasing annealing temperature, these structures disappear trans-forming into platelets distributed over the whole surface. A gap energy (Eg) of 3.0 eV was determined, and this value decreased to 2.98 eV after the temperature of T = 723 K was implemented, which is also where the Anatase phase was observed.

  13. Effects of annealing on mechanical behavior of Zr–Ti–Ni thin film metallic glasses

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chu-Shuan [Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Yiu, Pakman [Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Department of Physics and Materials Science, City University of Hong Kong, Kowloon, Hong Kong (China); Li, Chia-Lin; Chu, Jinn P. [Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Shek, Chan-Hung [Department of Physics and Materials Science, City University of Hong Kong, Kowloon, Hong Kong (China); Hsueh, Chun-Hway, E-mail: hsuehc@ntu.edu.tw [Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

    2014-07-01

    Zr{sub 46}Ti{sub 26}Ni{sub 28} thin film metallic glass was fabricated by radio frequency magnetron single target sputtering on Si and stainless steel substrates. The as-deposited film was found to be fully amorphous with high glass transition and crystallization temperatures of 466 °C and 502 °C, respectively. Its hardness progressively increased from 6.2 GPa to as high as 11.1 GPa when subjected to annealing near the glass-transition temperature at 450 °C. It was also of good adhesive strength and scratch resistance after the annealing treatment at 400 °C. Transmission electron microscopy results revealed annealing-induced nanocrystals that accounted for such superior mechanical properties. With the above unique properties, Zr–Ti–Ni thin film metallic glass has the potential for the fabrication of high strength micro parts and protective coating.

  14. Annealing temperature effect on the properties of mercury-doped TiO{sub 2} films prepared by sol-gel dip-coating technique

    Energy Technology Data Exchange (ETDEWEB)

    Mechiakh, R., E-mail: raouf_mechiakh@yahoo.fr [Departement de Medecine, Faculte de Medecine, Universite Hadj Lakhdar Batna, Batna (Algeria); Laboratoire de Photovoltaique de Semi-conducteurs et de Nanostructures, Centre de Recherche et des Technologies de l' Energie (CRTEn), BP. 95, Hammam-Lif 2050 (Tunisia); Ben Sedrine, N. [Laboratoire de Photovoltaique de Semi-conducteurs et de Nanostructures, Centre de Recherche et des Technologies de l' Energie (CRTEn), BP. 95, Hammam-Lif 2050 (Tunisia); Karyaoui, M. [Departement de Medecine, Faculte de Medecine, Universite Hadj Lakhdar Batna, Batna (Algeria); Laboratoire de Photovoltaique de Semi-conducteurs et de Nanostructures, Centre de Recherche et des Technologies de l' Energie (CRTEn), BP. 95, Hammam-Lif 2050 (Tunisia); Chtourou, R. [Laboratoire de Photovoltaique de Semi-conducteurs et de Nanostructures, Centre de Recherche et des Technologies de l' Energie (CRTEn), BP. 95, Hammam-Lif 2050 (Tunisia)

    2011-04-15

    This work presents the annealing temperature effect on the properties of mercury (Hg)-doped titanium dioxide (TiO{sub 2}). Thin films and polycrystalline powders have been prepared by sol-gel process. The structure, surface morphology and optical properties, as a function of the annealing temperature, have been studied by atomic force microscopy (AFM), Raman, reflectance and ellipsometric spectroscopies. In order to determine the transformation points, we have analyzed the xerogel-obtained powder by differential scanning calorimetry (DSC). Raman spectroscopy shows the crystalline anatase and rutile phases for the films annealed at 400 deg. C and 1000 deg. C respectively. The AFM surface morphology results indicate that the particle size increases from 14 to 57 nm by increasing the annealing temperature. The complex index and the optical band gap (E{sub g}) of the films were determined by the spectroscopic ellipsometry analysis. We have found that the optical band gap decreases by increasing the annealing temperature.

  15. Ni-Mn-Sn Heusler: milling and annealing effect on structural and magnetic properties

    Science.gov (United States)

    Popa, Florin; Florin Marinca, Traian; Florin Chicinaş, Horea; Isnard, Olivier; Chicinaş, Ionel

    2017-10-01

    Nanocrystalline Ni51Mn19Sn30 Heusler alloy was prepared in the form of powder by solid state reaction in a planetary ball mill under argon atmosphere. After 10 h of milling the samples exhibit a mixture of two phases: disordered Heusler structure and half-Heusler structure. The stability of the phases was studied and a transformation of the disordered Heusler phase into the ordered Heusler and Ni3Sn2 phase was observed after heat treatment. Magnetic properties strongly depend on the phases promoted during milling and annealing. The phase change after annealing leads to the increase of the sample’s magnetisation.

  16. Thermal stability of quaternary alloy (InAlGaAs)-capped InAs/GaAs multilayer quantum dot heterostructures with variation in growth rate, barrier thickness, seed quantum dot monolayer coverage, and post-growth annealing

    Energy Technology Data Exchange (ETDEWEB)

    Mandal, A.; Chakrabarti, S. [Indian Institute of Technology Bombay, Department of Electrical Engineering, Mumbai, Maharashtra (India); Verma, U. [Indian Institute of Technology Rajasthan, Department of Electrical Engineering, Jodhpur, Rajasthan (India)

    2013-10-15

    Strain-driven influences on the structural and optoelectronic properties of self-assembled InAs/GaAs multilayer quantum dot (MQD) heterostructures prompted our research into the growth of thermally stable MQD samples that were functional in an emission range technically favorable for communication lasers and intermediate band gap solar cells. We also studied parameter optimization by varying growth rate, capping layer thickness, seed quantum dot (QD) monolayer coverage, and post-growth annealing. A capping combination of InAlGaAs and i-GaAs was used. This combination helps in strain compensation, favors growth of multiple QD layers, functions as a strain-driven phase separation alloy, and helps increase QD stability. Photoluminescence results showed MQD sample emissions in the technologically significant range of 1.1-1.3 {mu}m. Post-growth annealing at high temperatures led to inter-diffusion of the constituent QD materials, generation of low minimum energy states, and greater carrier involvement in intermediate band gap structures, thereby showing that annealing is a suitable method for post-growth manipulation. For one MQD sample, the annealing temperature was found to affect structural and optoelectronic properties as well as the presence of intermediate energy states. Heterostructure stability at annealing temperatures up to 750 {sup circle} C was found for the other samples. Transmission electron microscopy and photoluminescence results supported these findings. (orig.)

  17. Population Annealing Monte Carlo for Frustrated Systems

    Science.gov (United States)

    Amey, Christopher; Machta, Jonathan

    Population annealing is a sequential Monte Carlo algorithm that efficiently simulates equilibrium systems with rough free energy landscapes such as spin glasses and glassy fluids. A large population of configurations is initially thermalized at high temperature and then cooled to low temperature according to an annealing schedule. The population is kept in thermal equilibrium at every annealing step via resampling configurations according to their Boltzmann weights. Population annealing is comparable to parallel tempering in terms of efficiency, but has several distinct and useful features. In this talk I will give an introduction to population annealing and present recent progress in understanding its equilibration properties and optimizing it for spin glasses. Results from large-scale population annealing simulations for the Ising spin glass in 3D and 4D will be presented. NSF Grant DMR-1507506.

  18. Degradation and annealing effects caused by oxygen in AlGaN/GaN high electron mobility transistors

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, R., E-mail: rong.jiang@vanderbilt.edu; Chen, J.; Duan, G. X.; Zhang, E. X.; Schrimpf, R. D. [Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, Tennesse 37235 (United States); Shen, X. [Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennesse 37235 (United States); Department of Physics and Materials Science, University of Memphis, Memphis, Tennesse 38152 (United States); Fleetwood, D. M. [Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, Tennesse 37235 (United States); Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennesse 37235 (United States); Kaun, S. W.; Kyle, E. C. H.; Speck, J. S. [Materials Department, University of California, Santa Barbara, California 93106 (United States); Pantelides, S. T. [Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennesse 37235 (United States); Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, Tennesse 37235 (United States)

    2016-07-11

    Hot-carrier degradation and room-temperature annealing effects are investigated in unpassivated ammonia-rich AlGaN/GaN high electron mobility transistors. Devices exhibit a fast recovery when annealed after hot carrier stress with all pins grounded. The recovered peak transconductance can exceed the original value, an effect that is not observed in control passivated samples. Density functional theory calculations suggest that dehydrogenation of pre-existing O{sub N}-H defects in AlGaN plays a significant role in the observed hot carrier degradation, and the resulting bare O{sub N} can naturally account for the “super-recovery” in the peak transconductance.

  19. Annealing temperature and barrier thickness effect on the structural and optical properties of silicon nanocrystals/SiO₂ superlattices

    Energy Technology Data Exchange (ETDEWEB)

    López-Vidrier, J., E-mail: jlopezv@el.ub.edu; Hernández, S.; López-Conesa, L.; Peiró, F.; Garrido, B. [MIND–IN2UB, Electronics Department, University of Barcelona, Martí i Franquès 1, E–08028 Barcelona (Spain); Hiller, D.; Gutsch, S.; Zacharias, M. [IMTEK, Faculty of Engineering, Albert-Ludwigs-University Freiburg, Georges-Köhler-Allee 103, D-79110 Freiburg (Germany); Estradé, S. [MIND–IN2UB, Electronics Department, University of Barcelona, Martí i Franquès 1, E–08028 Barcelona (Spain); TEM–MAT, CCiT–UB, Scientific and Technological Center - University of Barcelona, Solé i Sabarís 1, E–08028 Barcelona (Spain)

    2014-10-07

    The effect of the annealing temperature and the SiO₂ barrier thickness of silicon nanocrystal (NC)/SiO₂ superlattices (SLs) on their structural and optical properties is investigated. Energy-filtered transmission electron microscopy (TEM) revealed that the SL structure is maintained for annealing temperatures up to 1150 °C, with no variation on the nanostructure morphology for different SiO₂ barrier thicknesses. Nevertheless, annealing temperatures as high as 1250 °C promote diffusion of Si atoms into the SiO₂ barrier layers, which produces larger Si NCs and the loss of the NC size control expected from the SL approach. Complementary Raman scattering measurements corroborated these results for all the SiO₂ and Si-rich oxynitride layer thicknesses. In addition, we observed an increasing crystalline fraction up to 1250 °C, which is related to a decreasing contribution of the suboxide transition layer between Si NCs and the SiO₂ matrix due to the formation of larger NCs. Finally, photoluminescence measurements revealed that the emission of the superlattices exhibits a Gaussian-like lineshape with a maximum intensity after annealing at 1150 °C, indicating a high crystalline degree in good agreement with Raman results. Samples submitted to higher annealing temperatures display a progressive emission broadening, together with an increase in the central emission wavelength. Both effects are related to a progressive broadening of the size distribution with a larger mean size, in agreement with TEM observations. On the other hand, whereas the morphology of the Si NCs is unaffected by the SiO₂ barrier thickness, the emission properties are slightly modified. These observed modifications in the emission lineshape allow monitoring the precipitation process of Si NCs in a direct non-destructive way. All these experimental results evidence that an annealing temperature of 1150 °C and 1-nm SiO₂ barrier can be reached whilst preserving the SL structure, being

  20. Effect of annealing conditions on structural and luminescencent properties of Eu3+-doped Gd2Ti2O7 thin films

    Science.gov (United States)

    Antić, Željka; Prashanthi, K.; Ćulubrk, Sanja; Vuković, Katarina; Dramićanin, Miroslav D.; Thundat, Thomas

    2016-02-01

    Here we report on preparation of Eu3+-doped Gd2Ti2O7 pyrochlore luminescent thin films by pulsed laser deposition technique and their structural, morphological and optical characterization. The influence of annealing temperature and background gas (air vs. argon) on film photoluminescence is examined for the optimization of post-deposition annealing conditions. As-deposited amorphous films become pure pyrochlore crystalline after calcination at temperatures higher than 1000 °C. Atomic force microscopy showed increase in the grain size from ∼20 nm in the as-deposited to ∼60 nm in the crystalline sample annealed at 1100 °C. Scanning electron microscopy showed dense films with the uniform thickness of about 700 nm. Luminescence spectra of crystalline films were complex and composed of better resolved emission lines than in the amorphous sample. Emission spectra showed that symmetry of Eu3+ sites become disturbed in annealed films due to the extrinsic thermal stress. Films treated in argon displayed similar emission and excitation spectral features like air-treated ones, but with better resolved emission lines. Calculated quantum efficiency of emission showed that optimization of annealing conditions led to an enhancement of films luminescence. The highest quantum efficiency of emission and the longest lifetime is found for the sample annealed at 1100 °C in presence of argon.

  1. Temperature- and roughness- dependent permittivity of annealed/unannealed gold films.

    Science.gov (United States)

    Shen, Po-Ting; Sivan, Yonatan; Lin, Cheng-Wei; Liu, Hsiang-Lin; Chang, Chih-Wei; Chu, Shi-Wei

    2016-08-22

    Intrinsic absorption and subsequent heat generation have long been issues for metal-based plasmonics. Recently, thermo-plasmonics, which takes the advantage of such a thermal effect, is emerging as an important branch of plasmonics. However, although significant temperature increase is involved, characterization of metal permittivity at different temperatures and corresponding thermo-derivative are lacking. Here we measure gold permittivity from 300K to 570K, which the latter is enough for gold annealing. More than one order difference in thermo-derivative is revealed between annealed and unannealed films, resulting in a large variation of plasmonic properties. In addition, an unusual increase of imaginary permittivity after annealing is found. Both these effects can be attributed to the increased surface roughness incurred by annealing. Our results are valuable for characterizing extensively used unannealed nanoparticles, or annealed nanostructures, as building blocks in future thermo-nano-plasmonic systems.

  2. Ti-thickness-dependent electromigration resistance for Ti/Al-Cu-Si metallization with and without barrier rapid-thermal-anneal in an ammonia ambient

    Science.gov (United States)

    Fu, Kuan Y.; Kawasaki, Hisao; Olowolafe, Johnson O.; Pyle, Ronald E.

    1993-05-01

    The electromigration resistance for Al-Cu-Si alloy over a Ti underlayer as a function of the initial Ti thickness in the range of 0 angstroms - 1000 angstroms is investigated. After the Ti deposition, test structures have been divided into groups with and without a rapid thermal anneal (RTA) in an ammonia ambient to form a TiN barrier. The electromigration resistance of these barrier metallization systems, in general, increases with the initial Ti thickness, except when the initial Ti thickness is less than 600 angstroms for the RTA TiN/Al-Cu-Si system. A model is proposed to explain this electromigration characteristic as a function of the initial Ti thickness for these barrier metallization systems, with the support of texture analysis of the Al-alloy surface and stress measurements of barrier layers using X-ray diffraction and wafer curvature. This study highlights a direction of how a Ti-based barrier metallization system should be processed in order to optimize its electromigration resistance.

  3. UV-pretreatment- and near-infrared rapid thermal annealing-enhanced dehydrogenation for a-Si:H thin films at 400 °C

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Sanghyun [AP Systems Corp., 15-5 Dongtansandan 8-gil, Dongtanmyeon, Hwaseongsi, Gyeonggido 445-811 (Korea, Republic of); Dept. of Chem. and Biomol. Engng., Sogang Univ., 35 Baekbeomro, Mapogu, Seoul 121-742 (Korea, Republic of); Hwang, Chi-Sun [ETRI, 138 Gajeongro, Yuseonggu, Daejeon 305-350 (Korea, Republic of); Jeong, Pilseong; Lee, Sungyong [AP Systems Corp., 15-5 Dongtansandan 8-gil, Dongtanmyeon, Hwaseongsi, Gyeonggido 445-811 (Korea, Republic of); Lee, Kwang Soon, E-mail: kslee@sogang.ac.kr [Dept. of Chem. and Biomol. Engng., Sogang Univ., 35 Baekbeomro, Mapogu, Seoul 121-742 (Korea, Republic of)

    2016-01-01

    A new dehydrogenation processing method was developed for the low-temperature polysilicon process. This method can reduce both the process temperature and time through the combination of an ultraviolet pretreatment (UVP) process with near-infrared rapid thermal annealing (NIR-RTA). NIR-RTA using tungsten-halogen lamps was observed to reduce the dehydrogenation time by approximately two thirds and the temperature by approximately 20 °C compared to conventional furnace processing. The UVP process was able to lower the dehydrogenation temperature by a further 20 °C. Thus, the new dehydrogenation process, consisting of UVP followed by NIR-RTA, could achieve a hydrogen concentration of 1.97 at.% in 20 min at 360 °C. - Highlights: • An enhanced dehydrogenation process for flexible substrates as well as glass substrates is proposed.. • UV pretreatment and NIR-RTA are used.. • Temperature of the LTPS process for a-Si:H thin films could be reduced by 40 °C.. • Dehydrogenation time of the LTPS process could be reduced by 20 min..

  4. Effect of post-annealing on the plasma etching of graphene-coated-copper.

    Science.gov (United States)

    Hui, L S; Whiteway, E; Hilke, M; Turak, A

    2014-01-01

    High temperature deposition of graphene on Cu by chemical vapor deposition can be used to produce high quality films. However, these films tend to have a non-equilibrium structure, with relatively low graphene adhesion. In this study, samples of graphene grown on copper foils by high temperature CVD were post-deposition annealed at temperatures well below the critical temperature of Cu. Resistance to etching under plasma was examined to assess the mechanical robustness of the graphene on the Cu surface, analyzed using optical and Raman microscopies. We found a correlation between the post-annealing time and etching time for the complete removal of graphene from Cu. Etching rates, minimum etch times, and surface appearance were observed to vary depending on the etching plasma (air, oxygen or nitrogen). Oxygen plasmas were found to be the least aggressive, emphasizing the improved adhesion with post-annealing treatments. Our results imply that the etching of graphene on Cu, and hence the adhesion of graphene, can be controlled by proper annealing and choice of plasma gas.

  5. EFFECTS OF XE ION IRRADIATION AND SUBSEQUENT ANNEALING ON THE PROPERTIES OF MAGNESIUM-ALUMINATE SPINEL

    Energy Technology Data Exchange (ETDEWEB)

    I. AFANASYEV; ET AL

    2000-04-01

    Single crystals of magnesium-aluminate spinel MgAl{sub 2}O{sub 4} were irradiated with 340 keV Xe{sup 2} ions at {minus}173 C ({approximately} 100 K). A fluence of 1 x 10{sup 20} Xe/m{sup 2} created an amorphous layer at the surface of the samples. The samples were annealed for 1 h at different temperatures ranging from 130 C to 880 C. Recrystallization took place in the temperature interval between 610 C and 855 C. Transmission electron microscopy (TEM) images show two distinct layers near the surface: (1) a polycrystalline layer with columnar grain structure; and (2) a buried damaged layer epitaxial with the substrate. After annealing at 1100 C for 52 days, the profile of implanted Xe ions did not change, which means that Xe ions are not mobile in the spinel structure up to 1100 C. The thickness of the buried damaged layer decreased significantly in the 1100 C annealed sample comparing to the sample annealed for 1 h at 855 C.

  6. Page 1 Annealing effect in silk fibres 9 temperatures. This clearly ...

    Indian Academy of Sciences (India)

    This study shows that one can improve the strength of the pure Mysore silk fibres by annealing at 140°C for 7 h without loss of lustre of the silk fibres. Acknowledgement. The authors thank the Director, Central Sericulture Research and Training. Institute, Mysore, for providing samples and Dr I H Hall, UMIST, Manchester,.

  7. The Effects of Helium Bubble Microstructure on Ductility in Annealed and HERF 21Cr-6Ni-9Mn Stainless Steel

    Energy Technology Data Exchange (ETDEWEB)

    Tosten, M.H. [Westinghouse Savannah River Company, AIKEN, SC (United States); Morgan, M.J.

    1998-01-01

    This study examined the effects of microstructure on the ambient temperature embrittlement from hydrogen isotopes and decay helium in 21Cr-6Ni-9Mn stainless steel. Hydrogen and tritium-exposed 21Cr-6Ni-9Mn stainless steel tensile samples were pulled to failure and then characterized by transmission electron microscopy (TEM) and optical microscopy. This study determined that ductility differences between annealed and high-energy-rate-forged (HERF) stainless steel containing tritium and its decay product, helium, could be related to differences in the helium bubble microstructures. The HERF microstructures were more resistant to tritium-induced embrittlement than annealed microstructures because the high number density of helium bubbles on dislocations trap tritium within the matrix and away from the grain boundaries.

  8. Controlling Spatial Confinement Effects in La0.3Pr0.4Ca0.3MnO3 Microbridges via Post Ar and Air Annealing

    Science.gov (United States)

    Jeon, Jaechun; Jung, Jan; Chow, Kim H.

    2017-08-01

    We report the effects of post Ar and air annealing of La0.3Pr0.4Ca0.3MnO3 microbridges which do not initially show spatial confinement effects. The removal or addition of oxygen via the post annealing changes the sizes and distribution of the metallic and insulating phase domains within these films and can create spatial confinement effects such as percolation induced resistance jumps and tunneling magnetoresistance.

  9. Postdeposition Annealing Effect on Cu2ZnSnS4 Thin Films Grown at Different Substrate Temperature

    Directory of Open Access Journals (Sweden)

    Samia Ahmed Nadi

    2014-01-01

    Full Text Available Cu2ZnSnS4 (CZTS thin films were deposited on top of Molybdenum (Mo coated soda lime glass (SLG substrates using a single target rf magnetron sputtering technique. The sputtering parameters such as base pressure, working pressure, rf power, argon (Ar gas flow rate, and deposition time were kept consistent throughout the experiment. The effect of different substrate temperatures, for example, room temperature (RT, 300°C, 350°C, 370°C, 400°C, and 450°C, was analyzed by studying their structural, electrical, and optical properties. As-sputtered films were then annealed at 460°C. X-ray diffraction (XRD measurement revealed the structure to be kesterite with peak of (112 plane in both annealed and as-sputtered CZTS thin films. The crystallinity of the films improved with the increasing substrate temperature until 370°C. Secondary phases of MoS2, CuxMoSx, CuxSnSx, CuxS, and Cu6MoSnS8 (hemusite were also observed in the annealed CZTS films. Scanning electron microscopy (SEM shows crystallite size of deposited CZTS thin film to be proportionally related to deposition temperature. The highest surface roughness of 67.318 nm is observed by atomic force microscopy (AFM. The conductivity type of the films was found to be p-type by Hall effect measurement system.

  10. Effect of annealing and hydrogen plasma treatment on the luminescence and persistent photoconductivity of polycrystalline ZnO films

    Science.gov (United States)

    Abdullin, Kh. A.; Cicero, G.; Gritsenko, L. V.; Kumekov, S. E.; Markhabaeva, A. A.

    2017-06-01

    Photoluminescence (PL) and electrical properties of boron doped zinc oxide (ZnO) thin films, deposited by metalorganic chemical vapour deposition on a glass substrate, were investigated. The effects of annealing in air, as well as the influence of the radiofrequency—plasma treatment in hydrogen atmosphere, on the PL and electrical conductivity of the ZnO films were studied. A correlation between photoluminescence and electrical properties during annealing was observed. Hydrogen plasma treatment causes an increase in the carrier mobility and concentration and results in a very intensive near band edge emission (NBE). It was found that defects responsible for the dramatic increase in the intensity of NBE band in the hydrogen-treated ZnO films are hydrogen-related complexes formed near or at the surface of the samples. The intensity of NBE in hydrogen-treated samples decreases after aging in the dark, and, conversely, the NBE intensity increases under UV light illumination. This effect is fully reversible and depends on the gas atmosphere during the UV exposure and subsequent aging. It was proposed that the NBE band in the ZnO films annealed in the air and treated in hydrogen plasma emerges due to O-H complexes forming at zinc vacancy sites, n(O-H)-VZn.

  11. Oxygenation and air-annealing effects on the electronic properties of Cu(In,Ga)Se2 films and devices

    Science.gov (United States)

    Rau, U.; Braunger, D.; Herberholz, R.; Schock, H. W.; Guillemoles, J.-F.; Kronik, L.; Cahen, David

    1999-07-01

    Post-deposition air-annealing effects of Cu(In,Ga)Se2 based thin films and heterojunction solar cell devices are studied by photoelectron spectroscopy and admittance spectroscopy. Ultraviolet photoelectron spectroscopy reveals type inversion at the surface of the as-prepared films, which is eliminated after exposure of several minutes to air due to the passivation of surface Se deficiencies. X-ray photoelectron spectroscopy demonstrates that air annealing at 200 °C leads to a decreased Cu concentration at the film surface. Admittance spectroscopy of complete ZnO/CdS/Cu(In,Ga)Se2 heterojunction solar cells shows that the Cu(In,Ga)Se2 surface type inversion is restored by the chemical bath used for CdS deposition. Air annealing of the finished devices at 200 °C reduces the type inversion again due to defect passivation. Our results also show that oxygenation leads to a charge redistribution and to a significant compensation of the effective acceptor density in the bulk of the absorber. This is consistent with the release of Cu from the absorber surface and its redistribution in the bulk.

  12. Improvement on the electrical characteristics of Pd/HfO{sub 2}/6H-SiC MIS capacitors using post deposition annealing and post metallization annealing

    Energy Technology Data Exchange (ETDEWEB)

    Esakky, Papanasam, E-mail: papanasamte@gmail.com; Kailath, Binsu J

    2017-08-15

    Highlights: • Post deposition annealing (PDA) and post metallization annealing (PMA) on the electrical characteristics of Pd/HfO{sub 2}/6H-SiC MIS capacitors. • Post deposition N{sub 2}O plasma annealing inhibits crystallization of HfO{sub 2} during high temperature annealing. • Plasma annealing followed by RTA in N{sub 2} results in formation of hafnium silicate at the HfO{sub 2}-SiC interface. • PDA reduces interface state density (D{sub it}) and gate leakage current density (J{sub g}) by order. • PMA in forming gas for 40 min results in better passivation and reduces D{sub it} by two orders and J{sub g} by thrice. - Abstract: HfO{sub 2} as a gate dielectric enables high electric field operation of SiC MIS structure and as gas sensor HfO{sub 2}/SiC capacitors offer higher sensitivity than SiO{sub 2}/SiC capacitors. The issue of higher density of oxygen vacancies and associated higher leakage current necessitates better passivation of HfO{sub 2}/SiC interface. Effect of post deposition annealing in N{sub 2}O plasma and post metallization annealing in forming gas on the structural and electrical characteristics of Pd/HfO{sub 2}/SiC MIS capacitors are reported in this work. N{sub 2}O plasma annealing suppresses crystallization during high temperature annealing thereby improving the thermal stability and plasma annealing followed by rapid thermal annealing in N{sub 2} result in formation of Hf silicate at the HfO{sub 2}/SiC interface resulting in order of magnitude lower density of interface states and gate leakage current. Post metallization annealing in forming gas for 40 min reduces interface state density by two orders while gate leakage current density is reduced by thrice. Post deposition annealing in N{sub 2}O plasma and post metallization annealing in forming gas are observed to be effective passivation techniques improving the electrical characteristics of HfO{sub 2}/SiC capacitors.

  13. Impacts of excimer laser annealing on Ge epilayer on Si

    Science.gov (United States)

    Huang, Zhiwei; Mao, Yichen; Yi, Xiaohui; Lin, Guangyang; Li, Cheng; Chen, Songyan; Huang, Wei; Wang, Jianyuan

    2017-02-01

    The impacts of excimer laser annealing on the crystallinity of Ge epilayers on Si substrate grown by low- and high-temperature two-step approach in an ultra-high vacuum chemical vapor deposition system were investigated. The samples were treated by excimer laser annealing (ELA) at various laser power densities with the temperature above the melting point of Ge, while below that of Si, resulting in effective reduction of point defects and dislocations in the Ge layer with smooth surface. The full-width at half-maximum (FWHM) of X-ray diffraction patterns of the low-temperature Ge epilayer decreases with the increase in laser power density, indicating the crystalline improvement and negligible effect of Ge-Si intermixing during ELA processes. The short laser pulse time and large cooling rate cause quick melting and recrystallization of Ge epilayer on Si in the non-thermal equilibrium process, rendering tensile strain in Ge epilayer as calculated quantitatively with thermal mismatch between Si and Ge. The FWHM of X-ray diffraction patterns is significantly reduced for the two-step grown samples after treated by a combination of ELA and conventional furnace thermal annealing, indicating that the crystalline of Ge epilayer is improved more effectively with pre- annealing by excimer laser.

  14. Effect of Annealing on the Properties of Antimony Telluride Thin Films and Their Applications in CdTe Solar Cells

    Directory of Open Access Journals (Sweden)

    Zhouling Wang

    2014-01-01

    Full Text Available Antimony telluride alloy thin films were deposited at room temperature by using the vacuum coevaporation method. The films were annealed at different temperatures in N2 ambient, and then the compositional, structural, and electrical properties of antimony telluride thin films were characterized by X-ray fluorescence, X-ray diffraction, differential thermal analysis, and Hall measurements. The results indicate that single phase antimony telluride existed when the annealing temperature was higher than 488 K. All thin films exhibited p-type conductivity with high carrier concentrations. Cell performance was greatly improved when the antimony telluride thin films were used as the back contact layer for CdTe thin film solar cells. The dark current voltage and capacitance voltage measurements were performed to investigate the formation of the back contacts for the cells with or without Sb2Te3 buffer layers. CdTe solar cells with the buffer layers can reduce the series resistance and eliminate the reverse junction between CdTe and metal electrodes.

  15. Improved ground-state modulation characteristics in 1.3 μm InAs/GaAs quantum dot lasers by rapid thermal annealing

    Directory of Open Access Journals (Sweden)

    Ngo Chun

    2011-01-01

    Full Text Available Abstract We investigated the ground-state (GS modulation characteristics of 1.3 μm InAs/GaAs quantum dot (QD lasers that consist of either as-grown or annealed QDs. The choice of annealing conditions was determined from our recently reported results. With reference to the as-grown QD lasers, one obtains approximately 18% improvement in the modulation bandwidth from the annealed QD lasers. In addition, the modulation efficiency of the annealed QD lasers improves by approximately 45% as compared to the as-grown ones. The observed improvements are due to (1 the removal of defects which act as nonradiative recombination centers in the QD structure and (2 the reduction in the Auger-related recombination processes upon annealing.

  16. Laser annealing heals radiation damage in avalanche photodiodes

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Jin Gyu [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Electrical and Computer Engineering, Waterloo, ON (Canada); Anisimova, Elena; Higgins, Brendon L.; Bourgoin, Jean-Philippe [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada); Jennewein, Thomas [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada); Canadian Institute for Advanced Research, Quantum Information Science Program, Toronto, ON (Canada); Makarov, Vadim [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Electrical and Computer Engineering, Waterloo, ON (Canada); University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada)

    2017-12-15

    Avalanche photodiodes (APDs) are a practical option for space-based quantum communications requiring single-photon detection. However, radiation damage to APDs significantly increases their dark count rates and thus reduces their useful lifetimes in orbit. We show that high-power laser annealing of irradiated APDs of three different models (Excelitas C30902SH, Excelitas SLiK, and Laser Components SAP500S2) heals the radiation damage and several APDs are restored to typical pre-radiation dark count rates. Of nine samples we test, six APDs were thermally annealed in a previous experiment as another solution to mitigate the radiation damage. Laser annealing reduces the dark count rates further in all samples with the maximum dark count rate reduction factor varying between 5.3 and 758 when operating at -80 C. This indicates that laser annealing is a more effective method than thermal annealing. The illumination power to reach these reduction factors ranges from 0.8 to 1.6 W. Other photon detection characteristics, such as photon detection efficiency, timing jitter, and afterpulsing probability, fluctuate but the overall performance of quantum communications should be largely unaffected by these variations. These results herald a promising method to extend the lifetime of a quantum satellite equipped with APDs. (orig.)

  17. Effects of pre-irradiation annealing at high temperature on optical absorption and electron paramagnetic resonance of natural pumpellyite mineral

    Energy Technology Data Exchange (ETDEWEB)

    Javier-Ccallata, Henry, E-mail: henrysjc@gmail.com [Escuela de Ingeniería Electrónica y Telecomunicaciones, Universidad Alas Peruanas Filial Arequipa, Urb. D. A. Carrión G-14, J. L. Bustamante y Rivero, Arequipa (Peru); Laboratório de Sistemas Nanoestruturados, Departamento de Física, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina (Brazil); Filho, Luiz Tomaz [Departamento de Física Nuclear, Instituto de Física, Universidade de São Paulo, Rua do Matão, travessa R, 187, CEP 05508-900 São Paulo, SP (Brazil); Faculdade de Tecnologia e Ciências Exatas, Universidade São Judas Tadeu, Rua Taquari 546, São Paulo, SP (Brazil); Sartorelli, Maria L. [Laboratório de Sistemas Nanoestruturados, Departamento de Física, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina (Brazil); Watanabe, Shigueo [Departamento de Física Nuclear, Instituto de Física, Universidade de São Paulo, Rua do Matão, travessa R, 187, CEP 05508-900 São Paulo, SP (Brazil)

    2013-09-15

    Highlights: •Natural pumpellyite mineral presents superposition bands around 900 and 1060 nm due Fe{sup 2+}and Fe{sup 3+}. •High temperature annealing influences the EPR and OA spectra. •The behavior of EPR line for 800 and 900 °C can be attributed to forbidden dd transitions due the Fe{sup 3+}. -- Abstract: Natural silicate mineral of pumpellyite, Ca{sub 2}MgAl{sub 2}(SiO{sub 4})(Si{sub 2}O{sub 7})(OH){sub 2}·(H{sub 2}O), point group A2/m, has been studied concerning high temperature annealing and γ-radiation effects on Optical Absorption (OA) and Electron Paramagnetic Resonance (EPR) properties. Chemical analysis revealed that besides Si, Al, Ca and Mg, other oxides i.e., Fe, Mn, Na, K, Ti and P are present in the structure as impurities. OA measurements of natural and annealed pumpellyite revealed several bands in the visible region due to spin forbidden transitions of Fe{sup 2+} and Fe{sup 3+}. The behaviour of bands around 900 and 1060 nm, with pre-annealing and γ radiation dose, indicating a transition Fe{sup 2+} → e{sup −} + Fe{sup 3+}. On the other hand, EPR measurements reveal six lines of Mn{sup 2+}, and satellites due to hyperfine interaction, superimposed on the signal of Fe{sup 3+} around of g = 2. For heat treatment from 800 °C the signal grows significantly and for 900 °C a strong signal of Fe{sup 3+} hides all Mn{sup 2+} lines. The strong growth of this signal indicates that the transitions are due to Fe{sup 3+} dipole–dipole interactions.

  18. Effect of annealing on magnetic properties and structure of Fe-Ni based magnetic microwires

    Energy Technology Data Exchange (ETDEWEB)

    Zhukova, V. [Dpto. de Física de Materiales, Fac. Químicas, UPV/EHU, 20018 San Sebastian (Spain); Dpto. de Física Aplicada, EUPDS, UPV/EHU, 20018 San Sebastian (Spain); Korchuganova, O.A.; Aleev, A.A. [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), 115409 Moscow (Russian Federation); Tcherdyntsev, V.V.; Churyukanova, M. [National University of Science and Technology «MISIS», 119049 Moscow (Russian Federation); Medvedeva, E.V. [Institute of Electrophysics, Ural Branch, Russian Academy of Sciences 620016 Yekaterinburg (Russian Federation); Seils, S.; Wagner, J. [Karlsruhe Nano Micro Facility (KNMF), Karlsruhe Institute of Technology, 76131 Karlsruhe (Germany); Ipatov, M. [Dpto. de Física de Materiales, Fac. Químicas, UPV/EHU, 20018 San Sebastian (Spain); Dpto. de Física Aplicada, EUPDS, UPV/EHU, 20018 San Sebastian (Spain); Blanco, J.M. [Dpto. de Física Aplicada, EUPDS, UPV/EHU, 20018 San Sebastian (Spain); Kaloshkin, S.D. [National University of Science and Technology «MISIS», 119049 Moscow (Russian Federation); Aronin, A. [National University of Science and Technology «MISIS», 119049 Moscow (Russian Federation); Insitute of Solid State Physics, Moscow Region, 142432 Chernogolovka (Russian Federation); Abrosimova, G.; Orlova, N. [Insitute of Solid State Physics, Moscow Region, 142432 Chernogolovka (Russian Federation); and others

    2017-07-01

    Highlights: • High domain wall mobility of Fe-Ni-based microwires. • Enhancement of domain wall velocity and mobility in Fe-rich microwires after annealing. • Observation of areas enriched by Si and depleted by B after annealing. • Phase separation in annealed Fe-Ni based microwires in metallic nucleus and near the interface layer. - Abstract: We studied the magnetic properties and domain wall (DW) dynamics of Fe{sub 47.4}Ni{sub 26.6}Si{sub 11}B{sub 13}C{sub 2} and Fe{sub 77.5}Si{sub 7.5}B{sub 15} microwires. Both samples present rectangular hysteresis loop and fast magnetization switching. Considerable enhancement of DW velocity is observed in Fe{sub 77.5}Si{sub 7.5}B{sub 15}, while DW velocity of samples Fe{sub 47.4}Ni{sub 26.6}Si{sub 11}B{sub 13}C{sub 2} is less affected by annealing. The other difference is the magnetic field range of the linear region on dependence of domain wall velocity upon magnetic field: in Fe{sub 47.4}Ni{sub 26.6}Si{sub 11}B{sub 13}C{sub 2} sample is considerably shorter and drastically decreases after annealing. We discussed the influence of annealing on DW dynamics considering different magnetoelastic anisotropy of studied microwires and defects within the amorphous state in Fe{sub 47.4}Ni{sub 26.6}Si{sub 11}B{sub 13}C{sub 2}. Consequently we studied the structure of Fe{sub 47.4}Ni{sub 26.6}Si{sub 11}B{sub 13}C{sub 2} sample using X-ray diffraction and the atom probe tomography. The results obtained using the atom probe tomography supports the formation of the B-depleted and Si-enriched precipitates in the metallic nucleus of Fe-Ni based microwires.

  19. Effects of annealing temperature on the physicochemical, optical and photoelectrochemical properties of nanostructured hematite thin films prepared via electrodeposition method

    Energy Technology Data Exchange (ETDEWEB)

    Phuan, Yi Wen [School of Engineering, Chemical Engineering Discipline, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway 46150 Selangor DE (Malaysia); Chong, Meng Nan, E-mail: Chong.Meng.Nan@monash.edu [School of Engineering, Chemical Engineering Discipline, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway 46150 Selangor DE (Malaysia); Sustainable Water Alliance, Advanced Engineering Platform, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway 46150 Selangor DE (Malaysia); Zhu, Tao; Yong, Siek-Ting [School of Engineering, Chemical Engineering Discipline, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway 46150 Selangor DE (Malaysia); Chan, Eng Seng [School of Engineering, Chemical Engineering Discipline, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway 46150 Selangor DE (Malaysia); Sustainable Water Alliance, Advanced Engineering Platform, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway 46150 Selangor DE (Malaysia)

    2015-09-15

    Highlights: • Nanostructured hematite thin films were synthesized via electrodeposition method. • Effects of annealing on size, grain boundary and PEC properties were examined. • Photocurrents generation was enhanced when the thin films were annealed at 600 °C. • The highest photocurrent density of 1.6 mA/cm{sup 2} at 0.6 V vs Ag/AgCl was achieved. - Abstract: Hematite (α-Fe{sub 2}O{sub 3}) is a promising photoanode material for hydrogen production from photoelectrochemical (PEC) water splitting due to its wide abundance, narrow band-gap energy, efficient light absorption and high chemical stability under aqueous environment. The key challenge to the wider utilisation of nanostructured hematite-based photoanode in PEC water splitting, however, is limited by its low photo-assisted water oxidation caused by large overpotential in the nominal range of 0.5–0.6 V. The main aim of this study was to enhance the performance of hematite for photo-assisted water oxidation by optimising the annealing temperature used during the synthesis of nanostructured hematite thin films on fluorine-doped tin oxide (FTO)-based photoanodes prepared via the cathodic electrodeposition method. The resultant nanostructured hematite thin films were characterised using field emission-scanning electron microscopy (FE-SEM) coupled with energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), UV-visible spectroscopy and Fourier transform infrared spectroscopy (FTIR) for their elemental composition, average nanocrystallites size and morphology; phase and crystallinity; UV-absorptivity and band gap energy; and the functional groups, respectively. Results showed that the nanostructured hematite thin films possess good ordered nanocrystallites array and high crystallinity after annealing treatment at 400–600 °C. FE-SEM images illustrated an increase in the average hematite nanocrystallites size from 65 nm to 95 nm when the annealing temperature was varied from 400 °C to 600

  20. Effect of thermal treatment on the characteristics of iridium Schottky barrier diodes on n-Ge (1 0 0)

    Energy Technology Data Exchange (ETDEWEB)

    Chawanda, A., E-mail: albert.chawanda@up.ac.za [Department of Physics, University of Pretoria, 0002 (South Africa); Department of Physics, Midlands State University, Bag 9055, Gweru (Zimbabwe); Coelho, S.M.M.; Auret, F.D.; Mtangi, W. [Department of Physics, University of Pretoria, 0002 (South Africa); Nyamhere, C. [Department of Physics, Nelson Mandela Metropolitan University, Box 77000, Port Elizabeth 6031 (South Africa); Nel, J.M.; Diale, M. [Department of Physics, University of Pretoria, 0002 (South Africa)

    2012-02-05

    Highlights: Black-Right-Pointing-Pointer Ir/n-Ge (1 0 0) Schottky diodes were characterized using I-V, C-V and SEM techniques under various annealing conditions. Black-Right-Pointing-Pointer The variation of the electrical and structural properties can be due to effects phase transformation during annealing. Black-Right-Pointing-Pointer Thermal stability of these diodes is maintained up to 500 Degree-Sign C anneal. Black-Right-Pointing-Pointer SEM results depicts that the onset temperature for agglomeration in 20 nm Ir/n-Ge (1 0 0) system occurs between 600 and 700 Degree-Sign C. - Abstract: Iridium (Ir) Schottky barrier diodes were deposited on bulk grown (1 0 0) Sb-doped n-type germanium by using the electron beam deposition system. Electrical characterization of these contacts using current-voltage (I-V) and capacitance-voltage (C-V) measurements was performed under various annealing conditions. The variation of the electrical properties of these Schottky diodes can be attributed to combined effects of interfacial reaction and phase transformation during the annealing process. Thermal stability of the Ir/n-Ge (1 0 0) was observed up to annealing