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Sample records for controlling film morphology

  1. Achieving Thin Films with Micro/Nano-Scale Controllable Morphology by Glancing Angle Deposition Technique

    Institute of Scientific and Technical Information of China (English)

    JIANG Shao-Ji; WANG Chao-Yi; TANG Ji-Jia; HU Lin-Xin

    2008-01-01

    @@ We demonstrate that thin films with micro/nanometre controllable morphology can be fabricated by the glancing angle deposition (GLAD) technique which is a physical vapour deposition technique.In this technique, there are parameters which determine the morphology of the thin films: the incident angle, ratio of the deposition rate with respect to the substrate rotation rate, nature of the material being deposited, etc.We fabricate the morphology of column, pillar, helices, zigzag and study the parameters which determine morphology by given some examples of SEM.

  2. Structure and Morphology Control in Thin Films of Conjugated Polymers for an Improved Charge Transport

    OpenAIRE

    Haiyang Wang; Yaozhuo Xu; Xinhong Yu; Rubo Xing; Jiangang Liu; Yanchun Han

    2013-01-01

    The morphological and structural features of the conjugated polymer films play an important role in the charge transport and the final performance of organic optoelectronics devices [such as organic thin-film transistor (OTFT) and organic photovoltaic cell (OPV), etc.] in terms of crystallinity, packing of polymer chains and connection between crystal domains. This review will discuss how the conjugated polymer solidify into, for instance, thin-film structures, and how to control the molecula...

  3. Structure and Morphology Control in Thin Films of Conjugated Polymers for an Improved Charge Transport

    OpenAIRE

    Haiyang Wang; Yaozhuo Xu; Xinhong Yu; Rubo Xing; Jiangang Liu; Yanchun Han

    2013-01-01

    The morphological and structural features of the conjugated polymer films play an important role in the charge transport and the final performance of organic optoelectronics devices [such as organic thin-film transistor (OTFT) and organic photovoltaic cell (OPV), etc.] in terms of crystallinity, packing of polymer chains and connection between crystal domains. This review will discuss how the conjugated polymer solidify into, for instance, thin-film structures, and how to control the molecula...

  4. Structure and Morphology Control in Thin Films of Conjugated Polymers for an Improved Charge Transport

    Directory of Open Access Journals (Sweden)

    Haiyang Wang

    2013-11-01

    Full Text Available The morphological and structural features of the conjugated polymer films play an important role in the charge transport and the final performance of organic optoelectronics devices [such as organic thin-film transistor (OTFT and organic photovoltaic cell (OPV, etc.] in terms of crystallinity, packing of polymer chains and connection between crystal domains. This review will discuss how the conjugated polymer solidify into, for instance, thin-film structures, and how to control the molecular arrangement of such functional polymer architectures by controlling the polymer chain rigidity, polymer solution aggregation, suitable processing procedures, etc. These basic elements in intrinsic properties and processing strategy described here would be helpful to understand the correlation between morphology and charge transport properties and guide the preparation of efficient functional conjugated polymer films correspondingly.

  5. Simultaneous phase and morphology controllable synthesis of copper selenide films by microwave-assisted nonaqueous approach

    Science.gov (United States)

    Li, Jing; Fa, Wenjun; Li, Yasi; Zhao, Hongxiao; Gao, Yuanhao; Zheng, Zhi

    2013-02-01

    Copper selenide films with different phase and morphology were synthesized on copper substrate through controlling reaction solvent by microwave-assisted nonaqueous approach. The films were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The result showed that the pure films could be obtained using cyclohexyl alcohol or benzyl alcohol as solvent. The cubic Cu2-xSe dendrites were synthesized in cyclohexyl alcohol reaction system and hexagonal CuSe flaky crystals were obtained with benzyl alcohol as solvent.

  6. Morphology Control of Copolymer Thin Films by Nanoparticles

    OpenAIRE

    Shagolsem, Lenin Singh

    2014-01-01

    Diblock-Copolymers (DBCs), created by covalently joining two chemically distinct polymer blocks, spontaneously form various nanoscale morphologies such as lamellae, cylinders, spheres, etc. due to the chemical incompatibility of its constituent blocks. This effect is called microphase separation in the literature. Because of this self-organizing property DBCs find applications in many areas e.g. in creating selective membranes, and in polymer based modern electronic devices like organic photo...

  7. Highly Uniform Thin-Film Transistors Printed on Flexible Plastic Films with Morphology-Controlled Carbon Nanotube Network Channels

    Science.gov (United States)

    Numata, Hideaki; Ihara, Kazuki; Saito, Takeshi; Endoh, Hiroyuki; Nihey, Fumiyuki

    2012-05-01

    Carbon nanotube (CNT) transistor arrays were fabricated on plastic films by printing. All the device elements were directly patterned by maskless printing without any additional patterning process, and minimum materials were used. During fabrication, the morphology of the CNT random network was controlled by an adsorption mechanism on the surface to be printed, which resulted in excellent and uniform electrical properties. The field-effect mobility was further improved by post-treatment to modify the morphology of the CNT network. These results are promising for realizing printed electronics integrated with CNT transistors.

  8. Morphology control of zinc oxide films via polysaccharide-mediated, low temperature, chemical bath deposition

    Directory of Open Access Journals (Sweden)

    Florian Waltz

    2015-03-01

    Full Text Available In this study we present a three-step process for the low-temperature chemical bath deposition of crystalline ZnO films on glass substrates. The process consists of a seeding step followed by two chemical bath deposition steps. In the second step (the first of the two bath deposition steps, a natural polysaccharide, namely hyaluronic acid, is used to manipulate the morphology of the films. Previous experiments revealed a strong influence of this polysaccharide on the formation of zinc oxide crystallites. The present work aims to transfer this gained knowledge to the formation of zinc oxide films. The influence of hyaluronic acid and the time of its addition on the morphology of the resulting ZnO film were investigated. By meticulous adjustment of the parameters in this step, the film morphology can be tailored to provide an optimal growth platform for the third step (a subsequent chemical bath deposition step. In this step, the film is covered by a dense layer of ZnO. This optimized procedure leads to ZnO films with a very high electrical conductivity, opening up interesting possibilities for applications of such films. The films were characterized by means of electron microscopy, X-ray diffraction and measurements of the electrical conductivity.

  9. High-performance perovskite light-emitting diodes via morphological control of perovskite films.

    Science.gov (United States)

    Yu, Jae Choul; Kim, Da Bin; Jung, Eui Dae; Lee, Bo Ram; Song, Myoung Hoon

    2016-04-07

    Solution-processable perovskite materials have garnered tremendous attention because of their excellent charge carrier mobility, possibility of a tunable optical bandgap, and high photoluminescence quantum efficiency (PLQE). In particular, the uniform morphology of a perovskite film is the most important factor in realizing perovskite light-emitting diodes (PeLEDs) with high efficiency and full-coverage electroluminescence (EL). In this study, we demonstrate highly efficient PeLEDs that contain a perovskite film with a uniform morphology by introducing HBr into the perovskite precursor. The introduction of HBr into the perovskite precursor results in a perovskite film with a uniform, continuous morphology because the HBr increases the solubility of the inorganic component in the perovskite precursor and reduces the crystallization rate of the perovskite film upon spin-coating. Moreover, PeLEDs fabricated using perovskite films with a uniform, continuous morphology, which were deposited using 6 vol% HBr in a dimethylformamide (DMF)/hydrobromic acid (HBr) cosolvent, exhibited full coverage of the green EL emission. Finally, the optimized PeLEDs fabricated with perovskite films deposited using the DMF/HBr cosolvent exhibited a maximum luminance of 3490 cd m(-2) (at 4.3 V) and a luminous efficiency of 0.43 cd A(-1) (at 4.3 V).

  10. Controlled morphologies and optical properties of ZnO films and their photocatalytic activities

    Energy Technology Data Exchange (ETDEWEB)

    Duan Jingjing [Key Laboratory for Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Ministry of Education, Nanjing 210094 (China); Liu Xiaoheng, E-mail: xhliu@mail.njust.edu.cn [Key Laboratory for Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Ministry of Education, Nanjing 210094 (China); Han Qiaofeng [Key Laboratory for Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Ministry of Education, Nanjing 210094 (China); Wang Xin, E-mail: wangx@mail.njust.edu.cn [Key Laboratory for Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Ministry of Education, Nanjing 210094 (China)

    2011-09-15

    Highlights: > Gelatin acts as a capping reagent in the morphology synthesis of ZnO films. > The microstructures of ZnO films are hexagonal prisms, plates and rose-like crystals. > The hexagonal prisms and rose-like films exhibit excellent photocatalytic activities. - Abstract: ZnO films with three different microstructures including hexagonal prisms, plates and rose-like twinned crystals were fabricated using chemical bath deposition with different concentration of gelatin. The growth mechanisms of ZnO films were discussed, and the gelatin played a vital role as a polyelectrolyte capping the formation of microstructures. The photoluminescence and Raman properties were found sensitive to the crystal morphologies of ZnO films. Significantly, the photodegradation efficiencies of methylene blue under UV light irradiation in the presence of ZnO films consisted of hexagonal prisms and rose-like twinned crystals were 95% and 96%, respectively. The excellent photocatalytic activities can be ascribed to the high oxygen vacancies concentration and high percentage of polar planes, and this result was important in addressing the origin of high photocatalytic activity.

  11. Controlling the morphology of thin titania films for applications in hybrid solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Rawolle, Monika; Ruderer, Matthias A.; Prams, Stefan; Zhong, Qi; Mueller-Buschbaum, Peter [TU Muenchen, Physik-Department LS E13, Garching (Germany); Memesa, Mine; Gutmann, Jochen S. [Max-Planck Institute for Polymer Research, Mainz (Germany)

    2010-07-01

    Nanostructured thin films of titania have a variety of applications. For applications in photovoltaics a high absorption coefficient and a large surface area are desirable. A sponge structure is a promising morphology for titania to meet these demands. Block copolymers can be used in a good-poor solvent pair induced phase separation process coupled with sol-gel chemistry to create structured titania films in a reproducible way. We use the amphiphilic diblock copolymer Poly(dimethyl siloxane)-block-methyl methacrylate poly(ethylene oxide)[PDMS-b-MA(PEO)] as templating agent. Different well defined mixing procedures of sol-gel components (Tetrahydrofuran, 2-Propanol, HCl and titania precursor in addition to the PDMS-b-MA(PEO)) of same weight fractions result in small changes in the morphology of the film. The thin films are prepared via spin-coating on silicon substrates. The surface structure is studied with SEM. Information on the morphology in the volume of the film is gained from GISAXS. The layer thickness and structure are studied with XRR, the optical properties with UV/Vis spectroscopy.

  12. Fabrication Of YSZ Thin Film By Electrochemical Deposition Method And The Effect Of The Pulsed Electrical Fields For Morphology Control

    Directory of Open Access Journals (Sweden)

    Fujita T.

    2015-06-01

    Full Text Available In this study, surface morphology control ions in a precursor solution and patterning the YSZ film has been carried out during deposition of thin film from a precursor solution by applying the electrical field for deposition and the pulsed electrical field. The precursor solution was mixed them of ZrO(NO34, Y(NO33-6H2O into deionized water, and then was controlled nearly pH3 by adding NH3(aq. The thin film was deposited on the glass substrate of the minus electrode side by applying the electrical field of 3.0 V for 20 min. In addition, another pulsed voltage was applied to the electrical field along the perdicular direction to the film deposition direction. After annealing samples at 773 K for 6 h in air, the film was crystallized and obtained YSZ film. In the limited condition, the linear patterns of YSZ films due to the frequency of the applied electrical field were observed. It is expected that ions in a precursor solution are controlled by applying the pulsed voltage and the YSZ film is patterned on the substrate.

  13. A simple route to morphology-controlled polydimethylsiloxane films based on particle-embedded elastomeric masters for enhanced superhydrophobicity.

    Science.gov (United States)

    Jeong, Dong-Wook; Kim, Seung-Jun; Park, Jong-Kweon; Kim, Soo-Hyung; Lee, Deug-Woo; Kim, Jong-Man

    2014-02-26

    We present a simple route for controlling the surface morphology of polydimethylsiloxane (PDMS) films based on a standard replica molding technique incorporating a microparticle-embedded elastomeric master for enhancing surface wetting properties. The elastomeric masters are simply prepared by embedding microparticles (MPs) firmly into a surface of PDMS substrates using an abrasive air-jetting (AAJ) that can be potentially scaled up to large-area fabrication. The surface geometries of the PDMS masters can be easily controlled by using MPs with different shape and size in the AAJ process, resulting in easy control of the surface morphologies and resultant wetting and optical properties of the PDMS films after replicating. The PDMS masters are found to be highly durable, enabling repeated use to produce superhydrophobic PDMS films with similar characteristics. In addition, the fabricated PDMS films retain almost constant properties even under repetitive compressing and stretching deformations thanks to the mechanical robustness enabled by their all-elastomeric architectures. We show that the fabricated PDMS surfaces can be potentially employed as self-cleaning films in glass-based applications, even with complex surfaces, owing to their enhanced wetting properties, fairly good optical transparency, and superior mechanical stability.

  14. Tuning Morphologies of Langmuir Polymer Films Through Controlled Relaxations of Non-Equilibrium States.

    Science.gov (United States)

    Chandran, Sivasurender; Dold, Stefanie; Buvignier, Amaury; Krannig, Kai-Steffen; Schlaad, Helmut; Reiter, Günter; Reiter, Renate

    2015-06-16

    Langmuir polymers films (LPFs) frequently form nonequilibrium states which are manifested in a decay of the surface pressure with time when the system is allowed to relax. Monitoring and manipulating the temporal evolution of these relaxations experimentally helps to shed light on the associated molecular reorganization processes. We present a systematic study based on different compression protocols and show how these reorganization processes impact the morphology of LPFs of poly(γ-benzyl-L-glutamate)(PBLG), visualized by means of atomic force microscopy. Upon continuous compression, a fibrillar morphology was formed with a surface decorated by squeezed-out islands. By contrast, stepwise compression promoted the formation of a fibrillar network with a bimodal distribution of fibril diameters, caused by merging of fibrils. Finally, isobaric compression induced in-plane compaction of the monolayer. We correlate these morphological observations with the kinetics of the corresponding relaxations, described best by a sum of two exponential functions with different time scales representing two molecular processes. We discuss the observed kinetics and the resulting morphologies in the context of nucleation and growth, characteristic for first-order phase transitions. Our results demonstrate that the preparation conditions of LPFs have tremendous impact on ordering of the molecules and hence various macroscopic properties of such films.

  15. Morphology control in thin films of PS:PLA homopolymer blends by dip-coating deposition

    Science.gov (United States)

    Vital, Alexane; Vayer, Marylène; Tillocher, Thomas; Dussart, Rémi; Boufnichel, Mohamed; Sinturel, Christophe

    2017-01-01

    In this work, smooth polymer films of PS, PLA and their blends, with thicknesses ranging from 20 nm up to 400 nm and very few defects on the surface were obtained by dip-coating. In contrast to the process of spin-coating which is conventionally used to prepare thin films of polymer blends, we showed that depending on the deposition parameters (withdrawal speed and geometry of the reservoir), various morphologies such as layered films and laterally phase-separated domains could be formed for a given blend/solvent pair, offering much more opportunities compared to the spin-coating process. This diversity of morphologies was explained by considering the superposition of different phenomena such as phase separation process, dewetting and vitrification in which parameters such as the drying time, the compatibility of the polymer/solvent pairs and the affinity of the polymer towards the interfaces were suspected to play a significant role. For that purpose, the process of dip-coating was examined within the capillary and the draining regimes (for low and high withdrawal speed respectively) in order to get a full description of the thickness variation and evaporation rate as a function of the deposition parameters.

  16. Optimization of synthesis protocols to control the nanostructure and the morphology of metal oxide thin films for memristive applications

    Energy Technology Data Exchange (ETDEWEB)

    Baldi, G., E-mail: giacomo.baldi@cnr.it; Bosi, M.; Attolini, G.; Berzina, T.; Mosca, R.; Ponraj, J. S.; Iannotta, S. [IMEM-CNR Institute, Parco Area delle Scienze 37/A, I-43124 Parma (Italy); Giusti, G.; Nozar, P.; Toccoli, T.; Verucchi, R. [IMEM-CNR Institute, Via alla Cascata 56/C, Povo – I-38123 Trento (Italy); Collini, C.; Lorenzelli, L. [FBK Bruno Kessler Foundation, Via Sommarive 18, I-38123 Trento (Italy)

    2015-03-10

    We propose a multi-technique approach based on in-vacuum synthesis of metal oxides to optimize the memristive properties of devices that use a metal oxide thin film as insulating layer. Pulsed Microplasma Cluster Source (PMCS) is based on supersonic beams seeded by clusters of the metal oxide. Nanocrystalline TiO{sub 2} thin films can be grown at room temperature, controlling the oxide stoichiometry from titanium metal up to a significant oxygen excess. Pulsed Electron beam Deposition (PED) is suitable to grow crystalline thin films on large areas, a step towards producing device arrays with controlled morphology and stoichiometry. Atomic Layer Deposition (ALD) is a powerful technique to grow materials layer-by-layer, finely controlling the chemical and structural properties of the film up to thickness of 50-80 nm. We will present a few examples of metal-insulator-metal structures showing a pinched hysteresis loop in their current-voltage characteristic. The structure, stoichiometry and morphology of the metal oxide layer, either aluminum oxide or titanium dioxide, is investigated by means of scanning electron microscopy (SEM) and by Raman scattering.

  17. Control of crystal structure, morphology and optical properties of ceria films by post deposition annealing treatments

    Energy Technology Data Exchange (ETDEWEB)

    Eltayeb, Asmaa, E-mail: asmaa.eltayeb2@mail.dcu.ie [School of Electronic Engineering, National Centre for Plasma Science and Technology, Dublin City University, Glasnevin, Dublin 9 (Ireland); Vijayaraghavan, Rajani K. [School of Electronic Engineering, National Centre for Plasma Science and Technology, Dublin City University, Glasnevin, Dublin 9 (Ireland); McCoy, Anthony P. [School of Physical Sciences, Dublin City University, Glasnevin, Dublin 9 (Ireland); Cullen, Joseph [School of Physical Sciences, National Centre for Plasma Science and Technology, Dublin City University, Glasnevin, Dublin 9 (Ireland); Daniels, Stephen [School of Electronic Engineering, National Centre for Plasma Science and Technology, Dublin City University, Glasnevin, Dublin 9 (Ireland); McGlynn, Enda [School of Physical Sciences, National Centre for Plasma Science and Technology, Dublin City University, Glasnevin, Dublin 9 (Ireland)

    2016-03-31

    In this paper, the effects of post-deposition annealing temperature and atmosphere on the properties of pulsed DC magnetron sputtered ceria (CeO{sub 2}) thin films, including crystalline structure, grain size and shape and optical properties were investigated. Experimental results, obtained from X-ray diffraction (XRD), showed that the prepared films crystallised predominantly in the CeO{sub 2} cubic fluorite structure, although evidence of Ce{sub 2}O{sub 3} was also seen and this was quantified by a Rietveld refinement. The anneal temperature and oxygen content of the Ar/O{sub 2} annealing atmosphere both played important roles on the size and shape of the nanocrystals as determined by atomic force microscopy (AFM). The average grain size (determined by an AFM) as well as the out of plane coherence length (obtained from XRD) varied with increasing oxygen flow rate (OFR) in the annealing chamber. In addition, the shape of the grains seen in the AFM studies transformed from circular to triangular as the OFR was raised from 20 sccm to 30 sccm during an 800 °C thermal anneal. X-ray photoelectron spectroscopy was used to measure near-surface oxidation states of the thin-films with varying OFR in the annealing chamber. The bandgap energies were estimated from the ultra-violet and visible absorption spectra and low-temperature photoluminescence. An extracted bandgap value of 3.04 eV was determined for as-deposited CeO{sub 2} films and this value increased with increasing annealing temperatures. However, no difference was observed in bandgap energies with variation of annealing atmosphere. - Highlights: • Deposition of ceria thin films by pulsed DC magnetron sputtering • Effect of annealing temperature and gas ambient on film crystalline structure • Evidence for control of the film roughness and grain size and shape is achieved. • Investigation of the effect of post-deposition annealing on the film stoichiometry • Films showed blue shifts in bandgap energies

  18. Particle morphology as a control of permeation in polymer films obtained from MMA/nBA colloidal dispersions.

    Science.gov (United States)

    Lestage, David J; Urban, Marek W

    2004-07-20

    The combination of precision-controlled weight loss measurements and spectroscopic surface FT-IR analysis allowed us to identify unique behaviors of poly(methyl methacrylate) (p-MMA). When MMA and n-butyl acrylate (nBA) are polymerized into p-MMA and p-nBA homopolymer blends, MMA/nBA random copolymers, and p-MMA/p-nBA core-shell morphologies, a controlled mobility and stratification of low molecular weight components occurs in films formed from coalesced colloidal dispersions. Due to different affinities toward water, p-MMA and p-nBA are capable of releasing water at different rates, depending upon particle morphological features of initial dispersions. As coalescence progresses, water molecules are released from the high free volume p-nBA particles, whereas p-MMA retains water molecules for the longest time due to its hydrophilic nature. As a result, water losses at extended coalescence times are relatively small for p-MMA. MMA/nBA copolymer and p-MMA/p-nBA blends follow the same trends, although the magnitudes of changes are not as pronounced. The p-MMA/p-nBA core-shell behavior resembles that of p-nBA homopolymer, which is attributed to significantly lower content of the p-MMA component in particles. Annealing of coalesced colloidal films at elevated temperatures causes migration of SDOSS to the F-A interface, but for films containing primarily p-nBA, reverse diffusion back into the bulk is observed. These studies illustrate that the combination of different particle morphologies and temperatures leads to controllable permeation processes through polymeric films. Copyright 2004 American Chemical Society

  19. Impact of solvent additive on exciton dissociation in P3HT : EP-PDI blend film via controlling morphology

    Science.gov (United States)

    Yang, Xiao-Yu; Xu, Wei-Long; Zheng, Fei; Liu, Jian-Qiang; Hao, Xiao-Tao

    2016-06-01

    Suitable solvent additives provide an effective means to control the morphology of polymer blend films. In this work, we systematically investigate the impact of the solvent additive chloronaphthalene (CN) on the morphology of P3HT : EP-PDI blends. The optimum volume fraction of solvent additive CN was found to be 0.5 vol% by atom force microscopy and transmission electron microscopy. UV-visible absorption spectroscopy and grazing incidence x-ray diffraction indicate that the crystallinity of both the P3HT and EP-PDI domains significantly decreased in the blends with 0.5 vol% CN. Grazing incidence small-angle x-ray scattering results show that the size of the small EP-PDI aggregation decreases from 44-22 nm with the addition of CN. Time-resolved photoluminescence measurement reveals that the decreased EP-PDI domains give rise to increased donor-acceptor interfacial areas, which not only facilitate the exciton dissociation, but suppresses the formation of the EP-PDI intermolecular state.

  20. Efficiency Improvement of Heterojunction Polymer Photovoltaic Cells through Controlling the Morphology of the Polymer Film

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    1 Results Polymer photovoltaic cells, which provide clean and renewable energy sources, have gained more and more attention. Polymer photovoltaic cells have the advantage of low fabrication cost and high mechanical flexibility. Polymers can be processed through a solution process, so that a homogeneous polymer film could be readily prepared in a large area. Recently, the light-to-electricity conversion efficiency of the polymer photovoltaic cells was improved significantly[1-2]. Polymer donor and organi...

  1. Enhanced performance in hole transport material free perovskite solar cells via morphology control of PbI2 film by solvent treatment

    Science.gov (United States)

    Cheng, Nian; Liu, Pei; Bai, Sihang; Yu, Zhenhua; Liu, Wei; Guo, Shi-Shang; Zhao, Xing-Zhong

    2016-07-01

    The morphology of PbI2 film plays a critical role in determining the quality of the resultant CH3NH3PbI3 film and power conversion efficiency of CH3NH3PbI3 perovskite solar cell. Here, we propose a solvent treatment method in the two-step sequential deposition process to control the morphology of PbI2 film, which leads to enhanced power conversion efficiency. Hole transport material free perovskite solar cell is chosen as a paradigm to demonstrate this idea. Solvent (isopropanol, chlorobenzene, or ethanol) treated PbI2 films exhibit dendrite-like or flake-like morphologies, which facilitate more complete conversion of PbI2 to CH3NH3PbI3 perovskite in ambient atmosphere with a relative high humidity. Therefore, enhanced performance is obtained with the solvent treated PbI2 films. Average power conversion efficiency has been improved from 9.42% in the traditional two-step sequential deposition to 11.22% in solar cells derived from ethanol treated PbI2 films.

  2. Improvement of Light Extraction Efficiency in Flip-Chip Light Emitting Diodes on SiC Substrate via Transparent Haze Films with Morphology-Controlled Collapsed Alumina Nanorods.

    Science.gov (United States)

    Baek, Seunghwa; Kang, Gumin; Shin, Dongheok; Bae, Kyuyoung; Kim, Yong Hyun; Kim, Kyoungsik

    2016-01-13

    We demonstrate GaN-based flip-chip light emitting diodes (FC-LEDs) on SiC substrate achieving high extraction efficiency by simply attaching the optically transparent haze films consisting of collapsed alumina nanorods. Through controlled etching time of alumina nanorods, we obtain four types of films that have different morphologies with different optical transmittance and haze properties. We show that the light output power of the FC-LEDs with film, which has 95.6% transmittance and 62.7% haze, increases by 20.4% in comparison to the bare LEDs. The angular radiation pattern of the LEDs also follows the Lambertian emission pattern without deteriorating the electrical properties of the device. The improvement of light extraction is mainly attributed to the reduced total internal reflection (TIR) via efficient out-coupling of guided light from SiC substrate to air by collapsed alumina nanorod structures in the film. The high transparency of film and reduced Fresnel reflection via graded refractive index transition between the film and SiC substrate also contribute to the extraction enhancement of the device. We systematically investigate the influence of haze film's geometrical or optical properties on the extraction efficiency of FC-LEDs, and this study will provide a novel approach to enhance the performance of various optoelectronic devices.

  3. Electrical domain morphologies in compositionally graded ferroelectric films.

    Science.gov (United States)

    Okatan, M B; Roytburd, A L; Nagarajan, V; Alpay, S P

    2012-01-18

    We present a nonlinear thermodynamic formalism coupled with an electrostatic analysis of uniaxial n-layered compositionally graded heteroepitaxial ferroelectric films and extend this formalism to continuously graded ferroelectric films. We show that the domain morphology and its subsequent evolution in the presence of an electric field are determined by the spontaneous polarisation of the film induced through the compositional grading. The results for compositionally graded epitaxial (001) (Ba,Sr)TiO(3) and (001) Pb(Zr,Ti)O(3) films on (001)SrTiO(3) demonstrate that, while the domain morphologies in these two films are different in appearance, the dielectric displacement and the dielectric permittivity of such graded ferroelectric films exhibit a strong nonlinear behaviour which results in a high dielectric tunability. These findings indicate that it is possible to design specific domain structures that will yield desirable dielectric properties by controlling the strength of the compositional grading in the films.

  4. Atomic force microscopy investigation of the kinetic growth mechanisms of sputtered nanostructured Au film on mica: towards a nanoscale morphology control

    Directory of Open Access Journals (Sweden)

    Torrisi Vanna

    2011-01-01

    Full Text Available Abstract The study of surface morphology of Au deposited on mica is crucial for the fabrication of flat Au films for applications in biological, electronic, and optical devices. The understanding of the growth mechanisms of Au on mica allows to tune the process parameters to obtain ultra-flat film as suitable platform for anchoring self-assembling monolayers, molecules, nanotubes, and nanoparticles. Furthermore, atomically flat Au substrates are ideal for imaging adsorbate layers using scanning probe microscopy techniques. The control of these mechanisms is a prerequisite for control of the film nano- and micro-structure to obtain materials with desired morphological properties. We report on an atomic force microscopy (AFM study of the morphology evolution of Au film deposited on mica by room-temperature sputtering as a function of subsequent annealing processes. Starting from an Au continuous film on the mica substrate, the AFM technique allowed us to observe nucleation and growth of Au clusters when annealing process is performed in the 573-773 K temperature range and 900-3600 s time range. The evolution of the clusters size was quantified allowing us to evaluate the growth exponent 〈z〉 = 1.88 ± 0.06. Furthermore, we observed that the late stage of cluster growth is accompanied by the formation of circular depletion zones around the largest clusters. From the quantification of the evolution of the size of these zones, the Au surface diffusion coefficient was evaluated in D ( T   =   [ ( 7 . 42   ×   1 0 − 13   ±   ( 5 . 94   ×   1 0 − 14   m 2 /s ] exp ( − ( 0.33 ± 0.04   eV k T . These quantitative data and their correlation with existing theoretical models elucidate the kinetic growth mechanisms of the sputtered Au on mica. As a consequence we acquired a methodology to control the morphological characteristics of the Au film simply controlling the annealing temperature and time.

  5. Morphological Optimization of Perovskite Thin Films via Dynamic Zone Annealing

    Science.gov (United States)

    Sun, Yan; Wang, Kai; Gong, Xiong; Karim, Alamgir

    2015-03-01

    Organolead Halide Perovskites have been proved to be excellent candidates for application in low-cost high-efficient solar cells owing to their superior desired optical and electrical properties, as well as compatibility with low-temperature solution-processed manufacturing. However, most perovskites applications in photovoltaics require high quality perovskite films. Although tremendous works on tuning perovskite film morphology have been reported previously, it is still a challenge to realize high quality perovskite film with controllable film uniformity and surface coverage, neither the mechanisms in the formation of perovskite. To address the issues above, here we demonstrate the effect of Dynamic Zone Annealing (DZA) on perovskite morphologies, which is proved as an efficient method to control the structure and morphology in crystalline polymer and block copolymers. Via applying the DZA method, the mechanism in perovskite film formation is studied. Furthermore, by optimizing DZA parameter such as maximum temperature, temperature gradient and zone velocity to control dendritic morphology and the grain growth, enhanced device performance was realized eventually. Equal contribution.

  6. Controlling morphology, mesoporosity, crystallinity, and photocatalytic activity of ordered mesoporous TiO{sub 2} films prepared at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Elgh, Björn; Yuan, Ning; Palmqvist, Anders E. C. [Applied Surface Chemistry, Department of Chemical and Biological Engineering, Chalmers University of Technology, SE 412 96 Göteborg (Sweden); Cho, Hae Sung; Terasaki, Osamu [Graduate School of EEWS (WCU), KAIST, Daejeon 305-701 (Korea, Republic of); Magerl, David; Philipp, Martine; Müller-Buschbaum, Peter [Lehrstuhl für Funktionelle Materialien, Physik-Department, Technische Universität München, 85748 Garching (Germany); Roth, Stephan V. [DESY, Notkestrasse 85, 22603 Hamburg (Germany); Yoon, Kyung Byung [Department of Chemistry, Sogang University, Seoul 121-742 (Korea, Republic of)

    2014-11-01

    Partly ordered mesoporous titania films with anatase crystallites incorporated into the pore walls were prepared at low temperature by spin-coating a microemulsion-based reaction solution. The effect of relative humidity employed during aging of the prepared films was studied using SEM, TEM, and grazing incidence small angle X-ray scattering to evaluate the mesoscopic order, porosity, and crystallinity of the films. The study shows unambiguously that crystal growth occurs mainly during storage of the films and proceeds at room temperature largely depending on relative humidity. Porosity, pore size, mesoscopic order, crystallinity, and photocatalytic activity of the films increased with relative humidity up to an optimum around 75%.

  7. Morphology and Thickness Control of Thin Copper Films Prepared by Electrochemical Deposition onto Mo-sputtered Stainless Steel Substrates

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Mi Kyung; Lee, Sang Min; Lee, Chi Woo [Korea Univ., Seoul (Korea, Republic of); Chae, Su Byeong; Yang, Jeom Sik [ILJIN Materials Co., Ltd., Seoul (Korea, Republic of)

    2012-12-15

    Electrodeposition of CIGS precursor films can be performed by using either single step or multistep process. Although Bhattacharya et al. have reported the development of a 15.4% efficiency CIGS cell by employing a single-bath electrochemical deposition following physical vapor deposition, no other laboratory has reproduced it. We succeeded in producing copper thin films suitable for industrial purpose. Work is in progress to find the mechanistic aspect of Cu film formation and the electrodeposition conditions of other elements (In, Ga, and Se) as well with high speed for commercialization of CIGS solar cells.

  8. Surface morphology of thin films polyoxadiazoles

    OpenAIRE

    J. Weszka; M.M. Szindler; M. Chwastek-Ogierman; BRUMA M.; P. Jarka; Tomiczek, B.

    2011-01-01

    urpose: The purpose of this paper was to analyse the surface morphology of thin films polyoxadiazoles. Design/methodology/approach: SSix different polymers which belong to the group of polyoxadiazoles were dissolved in the solvent NMP. Each of these polymer was deposited on a glass substrate and a spin coating method was applied with a spin speed of 1000, 2000 and 3000 rev/min. Changes in surface topography and roughness were observed. An atomic force microscope AFM Park System has been used....

  9. Film morphology and photophysics of polyfluorene

    Science.gov (United States)

    Cadby, A. J.; Lane, P. A.; Mellor, H.; Martin, S. J.; Grell, M.; Giebeler, C.; Bradley, D. D. C.; Wohlgenannt, M.; An, C.; Vardeny, Z. V.

    2000-12-01

    We have studied the interplay between photophysics and film morphology of poly(9,9-dioctyl)fluorene (PFO) using a variety of optical probes. Upon slowly warming a spin-cast PFO film from 80 to 300 K, a fraction of the sample is transformed into a different solid phase, the β phase. Absorption and electroabsorption measurements show that the β phase has more extended conjugation than the glassy phase. As a consequence, excited states of the β phase are redshifted and have higher polarizability. The photoinduced absorption spectrum of a glassy PFO film is dominated by triplet excitons, whereas both polarons and triplet excitons are seen in a sample containing a fraction of the β phase. The dependence of the photoinduced absorption and photocurrent upon the excitation wavelength shows that there is a clear link between polaron and triplet photogeneration.

  10. Thermal instability of DLC film surface morphology - an AFM study

    Science.gov (United States)

    Maheswaran, R.; Thiruvadigal, D. John; Gopalakrishnan, C.

    2012-06-01

    The surface morphology of the DLC film during thermal annealing at particular temperature above the graphitization temperature shows blistering and buckling and also delaminates from the substrate. The DLC film shows poor thermal stability at higher temperature.

  11. Morphological control of anodic crystalline TiO{sub 2} nanochannel films for use in size-selective photocatalytic decomposition of organic molecules

    Energy Technology Data Exchange (ETDEWEB)

    Tsuji, E., E-mail: e-tsuji@eng.hokudai.ac.jp [Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628 (Japan); Division of Materials Chemistry, Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628 (Japan); Taguchi, Y. [Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628 (Japan); Aoki, Y. [Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628 (Japan); Division of Materials Chemistry, Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628 (Japan); Hashimoto, T.; Skeldon, P.; Thompson, G.E. [Corrosion and Protection Centre, School of Materials, The University of Manchester, Manchester, M13 9PL England (United Kingdom); Habazaki, H. [Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628 (Japan); Division of Materials Chemistry, Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628 (Japan)

    2014-05-01

    Graphical abstract: - Highlights: • The crystalline TiO{sub 2} nanochannel films were formed by anodizing titanium at 20 V in glycerol electrolyte containing various amounts of K{sub 3}PO{sub 4}, K{sub 2}HPO{sub 4} and KH{sub 2}PO{sub 4} at 433 K. • The growth rate of the films increased with an increase in the basicity of the electrolyte, leading to highly ordered nanochannel structures (the pore size was as small as ∼10 nm). • Size-selective photocatalytic decomposition for small organic molecules was achieved by utilizing the highly ordered TiO{sub 2} nanochannel films. - Abstract: We report the size-selective photocatalytic decomposition of organic molecules using crystalline anodic TiO{sub 2} nanochannel films as the photocatalyst. The porous TiO{sub 2} films were formed by anodizing titanium at 20 V in glycerol electrolyte containing various amounts of K{sub 3}PO{sub 4}, K{sub 2}HPO{sub 4}, and KH{sub 2}PO{sub 4} at 433 K. Regardless of the electrolyte composition, the as-formed TiO{sub 2} films had a crystalline anatase structure. The basicity of the electrolyte markedly influenced the morphology of the TiO{sub 2} nanochannel films; more regular nanochannels developed with increasing basicity of the electrolyte. Because the diameter of the nanochannels in the films formed in a basic electrolyte was as small as ∼10 nm, the anodic TiO{sub 2} nanochannel films with a thickness of 5 μm revealed a selective photocatalytic decomposition of methylene blue (MB) in a mixture of MB and direct red 80 (DR) kept under UV irradiation. The importance of the diameter of the nanochannels and their uniformity for size-selective decomposition of organic molecules were investigated.

  12. Morphological Influence of Solution-Processed Zinc Oxide Films on Electrical Characteristics of Thin-Film Transistors

    Directory of Open Access Journals (Sweden)

    Hyeonju Lee

    2016-10-01

    Full Text Available We report on the morphological influence of solution-processed zinc oxide (ZnO semiconductor films on the electrical characteristics of ZnO thin-film transistors (TFTs. Different film morphologies were produced by controlling the spin-coating condition of a precursor solution, and the ZnO films were analyzed using atomic force microscopy, X-ray diffraction, X-ray photoemission spectroscopy, and Hall measurement. It is shown that ZnO TFTs have a superior performance in terms of the threshold voltage and field-effect mobility, when ZnO crystallites are more densely packed in the film. This is attributed to lower electrical resistivity and higher Hall mobility in a densely packed ZnO film. In the results of consecutive TFT operations, a positive shift in the threshold voltage occurred irrespective of the film morphology, but the morphological influence on the variation in the field-effect mobility was evident. The field-effect mobility in TFTs having a densely packed ZnO film increased continuously during consecutive TFT operations, which is in contrast to the mobility decrease observed in the less packed case. An analysis of the field-effect conductivities ascribes these results to the difference in energetic traps, which originate from structural defects in the ZnO films. Consequently, the morphological influence of solution-processed ZnO films on the TFT performance can be understood through the packing property of ZnO crystallites.

  13. Copper Phthalocyanine Thin Film Morphology Impact on Impedance Spectrum

    Science.gov (United States)

    Robinson, Kyle; Gredig, Thomas

    2012-11-01

    Copper phthlacyanine thin films play an important role as the active layer in gas sensors, organic solar cells, and organic field-effect transistors. The surface morphology of such thin films can be controlled via modification of thermal deposition parameters. Thin films were deposited onto platinum interdigitated electrodes for impedance measurements to study the effect of structure on charge transport. The average grain size increases and changes from α- and β-phase for samples deposited in the temperature range of 295-534 K. AC measurements in the temperature range of 295-385 K reveal relaxation peaks in the impedance spectra. From this spectrum, essential properties are retrieved, such as relaxation times and effective capacities, and correlated with the film morphology. Subject to both photo- and 5-day-dark current trials, photodecay rates are extracted via effective impedance circuit analysis using a phenomenological model that includes contributions from the grain boundary and the bulk part of the grain. Results indicate that the resistance contribution of low frequency relaxation peaks decrease while approaching the phase transition temperature, and vice versa for capacitance. We attribute the low-frequency peaks to grain boundaries, which are reduced in high temperature deposited samples. Hyper β-phase deposition temperatures show a sudden rise in resistance and lower capacitance due to increased roughness of samples.

  14. Formation and Morphology of Anodic Oxide Films of Ti

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The morphology and structure of the oxide films of Ti in H3PO4 were investigated by galvanostatic anodization, SEM and XRD. The oxide film grew from some pores in the grooves to layered microdomains as increasing anodizing voltage. The crystallinity of the oxide films decreased with the increase of the concentration of the electrolyte. The model has been proposed for the growth of the oxide films by two steps, i.e. by uniform thickening and by local deposition.

  15. Morphological Study Of Palladium Thin Films Deposited By Sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Salcedo, K L; Rodriguez, C A [Grupo Plasma Laser y Aplicaciones, Ingenieria Fisica, Universidad Tecnologica de Pereira (Colombia); Perez, F A [WNANO, West Virginia University (United States); Riascos, H [Grupo Plasma Laser y Aplicaciones, Departamento de Fisica, Universidad Tecnologica de Pereira (Colombia)

    2011-01-01

    This paper presents a morphological analysis of thin films of palladium (Pd) deposited on a substrate of sapphire (Al{sub 2}O{sub 3}) at a constant pressure of 3.5 mbar at different substrate temperatures (473 K, 523 K and 573 K). The films were morphologically characterized by means of an Atomic Force Microscopy (AFM); finding a relation between the roughness and the temperature. A morphological analysis of the samples through AFM was carried out and the roughness was measured by simulating the X-ray reflectivity curve using GenX software. A direct relation between the experimental and simulation data of the Palladium thin films was found.

  16. Understanding and controlling morphology formation in Langmuir-Blodgett block copolymer films using PS-P4VP and PS-P4VP/PDP.

    Science.gov (United States)

    Perepichka, Iryna I; Lu, Qing; Badia, Antonella; Bazuin, C Geraldine

    2013-04-09

    This contribution offers a comprehensive understanding of the factors that govern the morphologies of Langmuir-Blodgett (LB) monolayers of amphiphilic diblock copolymers (BCs). This is achieved by a detailed investigation of a wide range of polystyrene-poly(4-vinyl pyridine) (PS-P4VP) block copolymers, in contrast to much more limited ranges in previous studies. Parameters that are varied include the block ratios (mainly for similar total molecular weights, occasionally other total molecular weights), the presence or not of 3-n-pentadecylphenol (PDP, usually equimolar with VP, with which it hydrogen bonds), the spreading solution concentration ("low" and "high"), and the LB technique (standard vs "solvent-assisted"). Our observations are compared with previously published results on other amphiphilic diblock copolymers, which had given rise to contradictory interpretations of morphology formation. Based on the accumulated results, we re-establish early literature conclusions that three main categories of LB block copolymer morphologies are obtained depending on the block ratio, termed planar, strand, and dot regimes. The block composition boundaries in terms of mol % block content are shown to be similar for all BCs having alkyl chain substituents on the hydrophilic block (such as PS-P4VP/PDP) and are shifted to higher values for BCs with no alkyl chain substituents (such as PS-P4VP). This is attributed to the higher surface area per repeat unit of the hydrophilic block monolayer on the water surface for the former, as supported by the onset and limiting areas of the Langmuir isotherms for the BCs in the dot regime. 2D phase diagrams are discussed in terms of relative effective surface areas of the two blocks. We identify and discuss how kinetic effects on morphology formation, which have been highlighted in more recent literature, are superposed on the compositional effects. The kinetic effects are shown to depend on the morphology regime, most strongly

  17. Morphological Control Agent in Ternary Blend Bulk Heterojunction Solar Cells

    Directory of Open Access Journals (Sweden)

    Hsueh-Chung Liao

    2014-11-01

    Full Text Available Bulk heterojunction (BHJ organic photovoltaic (OPV promise low cost solar energy and have caused an explosive increase in investigations during the last decade. Control over the 3D morphology of BHJ blend films in various length scales is one of the pillars accounting for the significant advance of OPV performance recently. In this contribution, we focus on the strategy of incorporating an additive into BHJ blend films as a morphological control agent, i.e., ternary blend system. This strategy has shown to be effective in tailoring the morphology of BHJ through different inter- and intra-molecular interactions. We systematically review the morphological observations and associated mechanisms with respect to various kinds of additives, i.e., polymers, small molecules and inorganic nanoparticles. We organize the effects of morphological control (compatibilization, stabilization, etc. and provide general guidelines for rational molecular design for additives toward high efficiency and high stability organic solar cells.

  18. 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.

  19. 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.

  20. Controlling Solid-Gas Reactions at Nanoscale for Enhanced Thin Film Morphologies and Device Performances in Solution-Processed Cu2ZnSn(S,Se)4 Solar Cells.

    Science.gov (United States)

    Jiang, Chengyang; Hsieh, Yao-Tsung; Zhao, Hongxiang; Zhou, Huanping; Yang, Yang

    2015-09-02

    Using Cu2ZnSn(S,Se)4 (CZTSSe) as a model system, we demonstrate the kinetic control of solid-gas reactions at nanoscale by manipulating the surface chemistry of both sol-gel nanoparticles (NPs) and colloidal nanocrystals (NCs). Specifically, we first identify that thiourea (commonly used as sulfur source in sol-gel processes for metal sulfides) can transform into melamine upon film formation, which serves as surface ligands for as-formed Cu2ZnSnS4 (CZTS) NPs. We further reveal that the presence of these surface ligands can significantly affect the outcome of the solid-gas reactions, which enables us to effectively control the selenization process during the fabrication of CZTSSe solar cells and achieve optimal film morphologies (continuous large grains) by fine-tuning the amount of surface ligands used. Such enhancement leads to better light absorption and allows us to achieve 6.5% efficiency from CZTSSe solar cells processed via a sol-gel process using nontoxic, low boiling point mixed solvents. We believe our discovery that the ligand of particulate precursors can significantly affect solid-gas reactions is universal to solid-state chemistry and will boost further research in both understanding the fundamentals of solid-state reactions at nanoscale and taking advantage of these reactions to fabricate crystalline thin film semiconductors with better morphologies and performances.

  1. Film morphology and ultrafast photoexcitation dynamics in polyfluorene

    Science.gov (United States)

    Korovyanko, O. J.; Vardeny, Z. V.

    2002-04-01

    We study the effect of sample morphology on ultrafast dynamics of photoexcited species in poly(9,9-dioctyl)fluorene (PFO). We show that within 200 fs both excitons and geminate polaron pairs with distinctly different absorption bands in the visible-near infrared spectral range are photogenerated in PFO solutions, pristine films, thermal and vapor treated films. However the branching ratio between the excitons and polaron pairs, as well as the polaron pair recombination kinetics depends on film morphology; polaron pair generation is enhanced and their recombination kinetics is faster in a solid phase, called the β phase, where the polymer chains are more planar.

  2. Thickness-dependent spontaneous dewetting morphology of ultrathin Ag films.

    Science.gov (United States)

    Krishna, H; Sachan, R; Strader, J; Favazza, C; Khenner, M; Kalyanaraman, R

    2010-04-16

    We show here that the morphological pathway of spontaneous dewetting of ultrathin Ag films on SiO2 under nanosecond laser melting is dependent on film thickness. For films with thickness h of 2 nm intermolecular forces, we have estimated the morphological transition thickness for the intermolecular forces for Ag on SiO2. The theory predictions agree well with observations for Ag. These results show that it is possible to form a variety of complex Ag nanomorphologies in a consistent manner, which could be useful in optical applications of Ag surfaces, such as in surface enhanced Raman sensing.

  3. Structure and morphology of laser-ablated WO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, O.M.; Swapnasmitha, A.S. [Sri Venkateswara University, Department of Physics, Tirupati (India); John, J.; Pinto, R. [Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai (India)

    2005-11-01

    The structure and surface morphology of WO{sub 3} thin films deposited by a laser-ablation technique have been found to be strongly dependent on the deposition conditions and the nature of the substrate. By precisely controlling the substrate temperature and the oxygen partial pressure, amorphous, polycrystalline, nano-crystalline and iso-epitaxial WO{sub 3} thin films were successfully grown. The structure and surface morphological features of the films from X-ray diffraction and atomic force microscopy data are described in relation to the deposition conditions. (orig.)

  4. Morphology Analysis of Cu Film Fractures in Sandwiched Methylmethacrylate Plates

    Directory of Open Access Journals (Sweden)

    Cristiano Fidani

    2015-06-01

    Full Text Available Thin films of Cu were evaporated on solid plates of polymethylmethacrylate (PMMA. A polymerization process was made to realize sandwiched structure to protect the Cu films. Fracturing of the metal film surface was observed with several morphologies showing two different fracture systems. Surface film morphology was analysed in terms of the distribution area of the islands and contour fractal dimension. The island areas showed a maximum corresponding to 42 nm of the Cu thickness, it was also the threshold to observe the second fracture system. The fractures pattern resulted to be scale invariant with fractal dimensions between 1.55 and 1.7. The minimum fractal dimension also occurred at the film thickness corresponding to the maximum island area. The reported effects can be understood on the basis of different thermal expansion coefficients of the two materials and their thermally induced adhesion.DOI: http://dx.doi.org/10.5755/j01.ms.21.2.6518

  5. MORPHOLOGICAL STUDIES ON THERMOTROPIC LIQUID CRYSTALLINE POLYESTER——MORPHOLOGY OF SHEAR ORIENTED FILMS

    Institute of Scientific and Technical Information of China (English)

    WANG Xiayu; DONG Yanming; LI Xianxing; XIONG Qianzhen

    1989-01-01

    The morphology of shear-oriented films of a thermotropic liquid crystalline polyester containing a triad ester mesogenic unit and a flexible spacer has been investigated in details. The formation conditions and process, the fine structures and the relaxation process of mat structure in the oriented films have been observed and discussed.

  6. Temperature-assisted morphological transition in CuPc thin films

    Science.gov (United States)

    Bae, Yu Jeong; Pham, Thi Kim Hang; Kim, Tae Hee

    2016-05-01

    Ex-situ and in-situ morphological analyses were performed for Cu-phthalocyanine (CuPc) organic semiconductor films by using atomic force microscopy (AFM) and reflection high-energy electron diffraction (RHEED). The focus was the effects of post-annealing on the structural characteristics of CuPc films grown on MgO(001) layers by using an ultra-high-vacuum thermal evaporator. Sphere-to-nanofibril and 2-D to 3-D morphological transitions were observed with increasing CuPc thickness beyond 3 nm. The surface morphology and the crystallinity were drastically improved after an additional cooling of the post-annealed CuPc films thinner than 3 nm. Our results highlight that molecular orientation and structural ordering can be effectively controlled by using different temperature treatments and a proper combination of material, film thickness, and substrate.

  7. Morphology in electrochemically grown conducting polymer films

    Science.gov (United States)

    Rubinstein, Israel; Gottesfeld, Shimshon; Sabatani, Eyal

    1992-01-01

    A conducting polymer film with an improved space filling is formed on a metal electrode surface. A self-assembling monolayer is formed directly on the metal surface where the monolayer has a first functional group that binds to the metal surface and a second chemical group that forms a chemical bonding site for molecules forming the conducting polymer. The conducting polymer is then conventioonally deposited by electrochemical deposition. In one example, a conducting film of polyaniline is formed on a gold electrode surface with an intermediate monolayer of p-aminothiophenol.

  8. Structural morphology of amorphous conducting carbon film

    Indian Academy of Sciences (India)

    P N Vishwakarma; V Prasad; S V Subramanyam; V Ganesan

    2005-10-01

    Amorphous conducting carbon films deposited over quartz substrates were analysed using X-ray diffraction and AFM technique. X-ray diffraction data reveal disorder and roughness in the plane of graphene sheet as compared to that of graphite. This roughness increases with decrease in preparation temperature. The AFM data shows surface roughness of carbon films depending on preparation temperatures. The surface roughness increases with decrease in preparation temperature. Also some nucleating islands were seen on the samples prepared at 900°C, which are not present on the films prepared at 700°C. Detailed analysis of these islands reveals distorted graphitic lattice arrangement. So we believe these islands to be nucleating graphitic. Power spectrum density (PSD) analysis of the carbon surface indicates a transition from the nonlinear growth mode to linear surface-diffusion dominated growth mode resulting in a relatively smoother surface as one moves from low preparation temperature to high preparation temperature. The amorphous carbon films deposited over a rough quartz substrate reveal nucleating diamond like structures. The density of these nucleating diamond like structures was found to be independent of substrate temperature (700–900°C).

  9. Surface morphology of ultrathin graphene oxide films obtained by the SAW atomization

    Science.gov (United States)

    Balachova, Olga V.; Balashov, Sergey M.; Costa, Carlos A. R.; Pavani Filho, A.

    2015-08-01

    Lately, graphene oxide (GO) thin films have attracted much attention: they can be used as humidity-sensitive coatings in the surface acoustic wave (SAW) sensors; being functionalized, they can be used in optoelectronic or biodevices, etc. In this research we study surface morphology of small-area thin GO films obtained on Si and quartz substrates by deposition of very small amounts of H2O-GO aerosols produced by the SAW atomizer. An important feature of this method is the ability to work with submicrovolumes of liquids during deposition that provides relatively good control over the film thickness and quality, in particular, minimization of the coffee ring effect. The obtained films were examined using AFM and electron microscopy. Image analysis showed that the films consist of GO sheets of different geometry and sizes and may form discrete or continuous coatings at the surface of the substrates with the minimum thickness of 1.0-1.8 nm which corresponds to one or two monolayers of GO. The thickness and quality of the deposited films depend on the parameters of the SAW atomization (number of atomized droplets, a volume of the initial droplet, etc.) and on sample surface preparation (activation in oxygen plasma). We discuss the structure of the obtained films, uniformity and the surface coverage as a function of parameters of the film deposition process and sample preparation. Qualitative analysis of adhesion of GO films is made by rinsing the samples in DI water and subsequent evaluation of morphology of the remained films.

  10. Surface Morphology of Annealed Lead Phthalocyanine Thin Films

    Directory of Open Access Journals (Sweden)

    P.Kalugasalam,

    2010-06-01

    Full Text Available The thin films of Lead Phthalocyanine (PbPc on glass substrates were prepared by Vacuum deposition. The thickness of the films was 450 nm. The sample annealed in high vacuum at 373 K temperature. The sample has been analysed by X-ray diffraction, scanning electron microscopy and atomic force microscopy in order to get structural and surface morphology of the PbPc thin film. The formation of XRD patterns of PbPc shows a triclinic grains (T seen along with monoclinic (M forms of PbPc. The sample is annealed at 373 K temperatures; the film shows peaks that assigned to the triclinic phase. SEM and AFM are the best tools to investigate the surface smoothness and to find the grain size of the particles. The grain size is calculated for all films of different thicknesses. The annealed AFM micrograph shows that the surface of the films consists of large holes. The annealed AFM image indicates a smooth surface. It is very clear that the grain size decreases with increase in the annealing temperature. The roughness also decreases with the increase in film annealing temperature. Annealed film leads to the oxidation of the hthalocyanine with oxygen absorbed or diffused. Therefore, the heat is responsible for the increase in film thickness. Since the films expand, it is believed that the porosity is increased.

  11. Structure and Morphology Effects on the Optical Properties of Bimetallic Nanoparticle Films Laser Deposited on a Glass Substrate

    Directory of Open Access Journals (Sweden)

    A. O. Kucherik

    2017-01-01

    Full Text Available Moving nanosecond laser system is used for laser-assisted thermodiffusion deposition of metallic nanoparticles from water-based colloidal solutions. The results obtained for both gold and silver nanoparticles show that film morphology strongly depends on laser scanning speed and the number of passages. We show, furthermore, the possibility of producing bimetallic Au:Ag thin films by laser irradiation of the mixed solutions. As a result of several laser scans, granular nanometric films are found to grow with a well-controlled composition, thickness, and morphology. By changing laser scanning parameters, film morphology can be varied from island structures to quasi-periodic arrays. The optical properties of the deposited structures are found to depend on the film composition, thickness, and mean separation between the particles. The transparency spectra of the deposited films are shown to be defined by their morphology.

  12. Dry Etching of Copper Phthalocyanine Thin Films: Effects on Morphology and Surface Stoichiometry

    OpenAIRE

    Brett, Michael J.; Dijken, Jaron G. Van

    2012-01-01

    We investigate the evolution of copper phthalocyanine thin films as they are etched with argon plasma. Significant morphological changes occur as a result of the ion bombardment; a planar surface quickly becomes an array of nanopillars which are less than 20 nm in diameter. The changes in morphology are independent of plasma power, which controls the etch rate only. Analysis by X-ray photoelectron spectroscopy shows that surface concentrations of copper and oxygen increase with etch time, whi...

  13. Surface Morphology of Undoped and Doped ZnSe Films

    Science.gov (United States)

    George, T.; Hayes, M.; Chen, H.; Chattopadhyay, K.; Thomas E.; Morgan, S.; Burger, A.

    1998-01-01

    Rare-earth doped ions in polar II-VI semiconductors have recently played an important role in the optical properties of materials and devices. In this study, undoped ZnSe and erbium doped ZnSe films were grown by radio frequency (RF) magnetron sputtering method. Atomic Force Microscopy (AFM) was used together with optical microscopy and UV-Vis spectroscopy to characterize the films. Doped samples were found to have higher surface roughness and quite different surface morphology compared to that of undoped samples. The grown films generally show a relatively smooth and uniform surface indicating that they are of overall good quality. The impact of plasma etching on ZnSe:Er film examined under AFM is also discussed.

  14. Effect of external electric field on morphology of copper phthalocyanine-fullerene blended films during annealing

    Science.gov (United States)

    Parhi, Anukul Prasad; Iyer, S. Sundar Kumar

    2016-03-01

    The thin-film morphology and segregated phases of constituents in blends of organic semiconductors play an important role in determining the performance of devices fabricated with these constituents. In this study, we explored the effect of an external electric field applied during annealing on the morphology and phase of blended films of two popular organic semiconductors, copper pthalocyanine (CuPc) and buckminsterfullerene (C60). Films of different blend ratios annealed at various temperatures in both the presence and absence of an electric field were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and ultraviolet-visible (UV-vis) spectroscopy. The characteristics of annealed pristine CuPc films were also included for comparison. The observed changes in the properties of the blended films following the annealing, including the abrupt phase segregation of the blended constituents in the films, are discussed. The polarizability of the molecules was calculated using density functional theory (DFT) to explain the interaction, stacking, and segregation of the molecules in the blend. The results showed that application of an electric field during annealing of the blended films is an additional control parameter that can help tune the properties of the blended film. [Figure not available: see fulltext.

  15. Electrochemical and morphological characterisation of polyphenazine films on copper

    Energy Technology Data Exchange (ETDEWEB)

    Gouveia-Caridade, Carla; Romeiro, Andreia; Brett, Christopher M.A., E-mail: cbrett@ci.uc.pt

    2013-11-15

    The morphology of films of the phenazine polymers poly(neutral red) (PNR), poly(brilliant cresyl blue) (PBCB), poly(Nile blue A) (PNB) and poly(safranine T) (PST), formed by potential cycling electropolymerisation on copper electrodes, in order to reduce the corrosion rate of copper, has been examined by scanning electron microscopy (SEM). The copper surface was initially partially passivated in sodium oxalate, hydrogen carbonate or salicylate solution, in order to inhibit copper dissolution at potentials where phenazine monomer oxidation occurs, and to induce better polymer film adhesion. SEM images were also taken of partially passivated copper in order to throw light on the different morphology and anti-corrosive behaviour of the polyphenazine films. Analysis of the morphology of the polymer-coated copper with best anti-corrosive behaviour after 72 h immersion in 0.1 M KCl, Cu/hydrogen carbonate/PNB, showed that the surface is completely covered by closely packed crystals. By contrast, images of PST films on copper partially passivated in oxalate solution, that had the least protective behaviour, showed large amounts of insoluble corrosion products after only 4 h immersion in 0.1 M KCl.

  16. Surface morphology and composition studies in InGaN/GaN film grown by MOCVD

    Institute of Scientific and Technical Information of China (English)

    Tao Tao; Han Ping; Shi Yi; Zheng Youdou; Zhang Zhao; Liu Lian; Su Hui; Xie Zili; Zhang Rong; Liu Bin; Xiu Xiangqian; Li Yi

    2011-01-01

    InGaN filmsweredepositedon(0001)sapphiresubstrates with GaN buffer layers under different growth temperatures by metalorganic chemical vapor deposition.The In-composition of InGaN film was approximately controlled by changing the growth temperature.The connection between the growth temperature,In content,surface morphology and defect formation was obtained by X-ray diffraction,scanning electron microscopy (SEM) and atomic force microscopy (AFM).Meanwhile,by comparing the SEM and AFM surface morphology images,we proposed several models of three different defects and discussed the mechanism of formation.The prominent effect of higher growth temperature on the quality of the InGaN films and defect control were found by studying InGaN films at various growth temperatures.

  17. Structure and Morphology of Phthalocyanine Films Grown in Electrical Fields by Vapor Deposition

    Science.gov (United States)

    Zhu, Shen; Banks, C. E.; Frazier, D. O.; Penn, B.; Abdeldayem, H.; Hicks, R.; Burns, H. D.; Thompson, G. W.

    1999-01-01

    Phthalocyanine (Pc) films have been synthesized by vapor deposition on quartz substrates, some of which were coated with a very thin gold film before depositing Pc films. Electrical fields up to 6200 V/cm between a mech electrode and the substrate are introduced during film growth. These films have been characterized by x-ray diffraction and scanning electron microscopy. The molecular orientations and surface morphology of Pc films were changed under the electrical fields. The surface of these films grown without electrical field shows whisk-like morphology. When films are deposited under an electrical field, a dense film with flat surface is obtained.

  18. Engineering the Crystalline Morphology of Polymer Thin Films via Physical Vapor Deposition

    Science.gov (United States)

    Jeong, Hyuncheol; Arnold, Craig; Priestley, Rodney

    Thin-film growth via physical vapor deposition (PVD) has been successfully exploited for the delicate control of film structure for molecular and atomic systems. The application of such a high-energetic process to polymeric film growth has been challenged by chemical degradation. However, recent development of Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique opened up a way to deposit a variety of macromolecules in a PVD manner. Here, employing MAPLE technique to the growth of semicrystalline polymer thin films, we show the engineering of crystalline film morphology can be achieved via manipulation of substrate temperature. This is accomplished by exploiting temperature effect on crystallization kinetics of polymers. During the slow film growth crystallization can either be permitted or suppressed, and crystal thickness can be tuned via temperature modulation. In addition, we report that the crystallinity of polymer thin films may be significantly altered with deposition temperature in MAPLE processing. We expect that this ability to manipulate crystallization kinetics during polymeric film growth will open the possibility to engineer structure in thin film polymeric-based devices in ways that are difficult by other means.

  19. Role of organoclay in controlling the morphology and crystal-growth behavior of biodegradable polymer-blend thin films studied using atomic force microscopy

    CSIR Research Space (South Africa)

    Malwela, T

    2014-09-01

    Full Text Available clays, their organic modifications and their initial d(sub001)-spacing on the morphology and crystal growth behavior of the PLA/PBSA blend were studied. An atomic force microscopy equipped with a hot-stage scanner was used to examine the crystalline...

  20. Effect of film morphology on oxygen and water interaction with copper phthalocyanine

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Nicholas [California State University, Long Beach (CSULB); Gredig, Thomas [California State University, Long Beach (CSULB); Ivanov, Ilia N [ORNL

    2016-01-01

    Copper phthalocyanine (CuPc) films of thickness 25 nm and 100 nm were grown by thermal sublimation at 25 C, 150 C, and 250 C in order to vary morphology. Using a source-measure unit and a quartz crystal microbalance (QCM), we measured changes in electrical resistance and film mass in situ during exposure to controlled pulses of O2 and H2O vapor. Mass loading by O2 was enhanced by a factor of 5 in films deposited at 250 C, possibly due to the ~200 C CuPc transition which allows higher O2 mobility between stacked molecules. While gas/vapor sorption occurred over timescales of < 10 minutes, resistance change occurred over timescales > 1 hour, suggesting that mass change occurs by rapid adsorption at active surface sites, whereas resistive response is dominated by slow diffusion of adsorbates into the film bulk. Resistive response generally increases with film deposition temperature due to increased porosity associated with larger crystalline domains. The 25 nm thick films exhibit higher resistive response than 100 nm thick films after an hour of O2/H2O exposure due to the smaller analyte diffusion length required for reaching the film/electrode interface. We found evidence of decoupling of CuPc from the gold-coated QCM crystal due to preferential adsorption of O2/H2O molecules on gold, which is consistent with findings of other studies.

  1. RF Magnetron Sputtering Grown Cu2O Film Structural, Morphological, and Electrical Property Dependencies on Substrate Type.

    Science.gov (United States)

    Ahn, Heejin; Um, Youngho

    2015-03-01

    We investigated the structural, morphological, and electrical properties of cuprous oxide (Cu2O) film dependency on substrate type. Thin films grown using RF magnetron sputtering were characterized by scanning electron microscopy, X-ray diffraction (XRD), and Hall effect measurements. Cu2O thin films were deposited onto sapphire (0001), Si (100), and MgO (110) substrates, and showed Cu2O single phase only, which was confirmed by XRD measurement. Relatively larger compressive strain existed in Cu2O film grown on sapphire and Si, while a smaller tensile strain appeared in Cu2O film grown on MgO. Cu2O thin film crystallite sizes showed a linear dependence on strain. Moreover, film carrier concentration and mobility increased with increasing strain, while resistivity decreased with decreasing strain. Cu2O film strain due to induced strain opens the possibility of controlling structural and electrical properties in device applications.

  2. Predictive modeling of nanoscale domain morphology in solution-processed organic thin films

    Science.gov (United States)

    Schaaf, Cyrus; Jenkins, Michael; Morehouse, Robell; Stanfield, Dane; McDowall, Stephen; Johnson, Brad L.; Patrick, David L.

    2017-09-01

    The electronic and optoelectronic properties of molecular semiconductor thin films are directly linked to their extrinsic nanoscale structural characteristics such as domain size and spatial distributions. In films prepared by common solution-phase deposition techniques such as spin casting and solvent-based printing, morphology is governed by a complex interrelated set of thermodynamic and kinetic factors that classical models fail to adequately capture, leaving them unable to provide much insight, let alone predictive design guidance for tailoring films with specific nanostructural characteristics. Here we introduce a comprehensive treatment of solution-based film formation enabling quantitative prediction of domain formation rates, coverage, and spacing statistics based on a small number of experimentally measureable parameters. The model combines a mean-field rate equation treatment of monomer aggregation kinetics with classical nucleation theory and a supersaturation-dependent critical nucleus size to solve for the quasi-two-dimensional temporally and spatially varying monomer concentration, nucleation rate, and other properties. Excellent agreement is observed with measured nucleation densities and interdomain radial distribution functions in polycrystalline tetracene films. Numerical solutions lead to a set of general design rules enabling predictive morphological control in solution-processed molecular crystalline films.

  3. Relationships between Lead Halide Perovskite Thin-Film Fabrication, Morphology, and Performance in Solar Cells.

    Science.gov (United States)

    Sharenko, Alexander; Toney, Michael F

    2016-01-20

    Solution-processed lead halide perovskite thin-film solar cells have achieved power conversion efficiencies comparable to those obtained with several commercial photovoltaic technologies in a remarkably short period of time. This rapid rise in device efficiency is largely the result of the development of fabrication protocols capable of producing continuous, smooth perovskite films with micrometer-sized grains. Further developments in film fabrication and morphological control are necessary, however, in order for perovskite solar cells to reliably and reproducibly approach their thermodynamic efficiency limit. This Perspective discusses the fabrication of lead halide perovskite thin films, while highlighting the processing-property-performance relationships that have emerged from the literature, and from this knowledge, suggests future research directions.

  4. Morphological Evolution of Gyroid-Forming Block Copolymer Thin Films with Varying Solvent Evaporation Rate.

    Science.gov (United States)

    Wu, Yi-Hsiu; Lo, Ting-Ya; She, Ming-Shiuan; Ho, Rong-Ming

    2015-08-05

    In this study, we aim to examine the morphological evolution of block copolymer (BCP) nanostructured thin films through solvent evaporation at different rates for solvent swollen polystyrene-block-poly(l-lactide) (PS-PLLA). Interesting phase transitions from disorder to perpendicular cylinder and then gyroid can be found while using a partially selective solvent for PS to swell PS-PLLA thin film followed by solvent evaporation. During the transitions, gyroid-forming BCP thin film with characteristic crystallographic planes of (111)G, (110)G, and (211)G parallel to air surface can be observed, and will gradually transform into coexisting (110)G and (211)G planes, and finally transforms to (211)G plane due to the preferential segregation of constituted block to the surface (i.e., the thermodynamic origin for self-assembly) that affects the relative amount of each component at the air surface. With the decrease on the evaporation rate, the disorder phase will transform to parallel cylinder and then directly to (211)G without transition to perpendicular cylinder phase. Most importantly, the morphological evolution of PS-PLLA thin films is strongly dependent upon the solvent removal rate only in the initial stage of the evaporation process due to the anisotropy of cylinder structure. Once the morphology is transformed back to the isotropic gyroid structure after long evaporation, the morphological evolution will only relate to the variation of the surface composition. Similar phase transitions at the substrate can also be obtained by controlling the ratio of PLLA-OH to PS-OH homopolymers to functionalize the substrate. As a result, the fabrication of well-defined nanostructured thin films with controlled orientation can be achieved by simple swelling and deswelling with controlled evaporation rate.

  5. 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.

  6. Controlled release of tocopherols from polymer blend films

    Science.gov (United States)

    Obinata, Noe

    Controlled release packaging has great potential to increase storage stability of foods by releasing active compounds into foods continuously over time. However, a major limitation in development of this technology is the inability to control the release and provide rates useful for long term storage of foods. Better understanding of the factors affecting active compound release is needed to overcome this limitation. The objective of this research was to investigate the relationship between polymer composition, polymer processing method, polymer morphology, and release properties of active compounds, and to provide proof of principle that compound release is controlled by film morphology. A natural antioxidant, tocopherol was used as a model active compound because it is natural, effective, heat stable, and soluble in most packaging polymers. Polymer blend films were produced from combination of linear low density polyethylene (LLDPE) and high density polyethylene (HDPE), polypropylene (PP), or polystyrene (PS) with 3000 ppm mixed tocopherols using conventional blending method and innovative blending method, smart blending with a novel mixer using chaotic advection. Film morphologies were visualized with scanning electron microscopy (SEM). Release of tocopherols into 95% ethanol as a food simulant was measured by UV/Visible spectrophotometry or HPLC, and diffusivity of tocopherols in the polymers was estimated from this data. Polymer composition (blend proportions) and processing methods have major effects on film morphology. Four different types of morphologies, dispersed, co-continuous, fiber, and multilayer structures were developed by either conventional extrusion or smart blending. With smart blending of fixed polymer compositions, different morphologies were progressively developed with fixed polymer composition as the number of rod rotations increased, providing a way to separate effects of polymer composition and morphology. The different morphologies

  7. Electrically tunable pore morphology in nanoporous gold thin films

    Institute of Scientific and Technical Information of China (English)

    Tatiana S. Dorofeeva; Erkin Seker

    2015-01-01

    Nanoporous gold (np-Au) is an emerging nanostructured material that exhibits many desirable properties, including high electrical and thermal conductivity, high surface area-to-volume ratio, tunable pore morphology well-established surface-binding chemistry, and compatibility with microfabrication. These features make np-Au a popular material for use in fuel cells, optical and electrical biosensors, drug delivery vehicles, neural electrode coatings, and as a model system for nanoscale mechanics. In each of its many applications, np-Au morphology plays an essential role in the overall device operation. Therefore, precise morphological control is necessary to attain optimal device performance. Traditionally thermal treatment by furnaces and hot plates is used to obtain np-Au with self-similar but coarser morphologies. However, this approach lacks the ability to create different morphologies on a single substrate and requires high temperatures (〉 250 ℃) incompatible with most plastic substrates. Herein, we report electro-annealing as a novel method that permits control of the extent and location of pore coarsening on a single substrate in one fast treatment step. The electro-annealing entails much lower temperatures (〈 150 ℃) than traditional thermal treatment, putatively due to electrically assisted phenomena contributing to the thermally activated surface diffusion of gold atoms, responsible for coarsening. Overall, this approach is easily scaled to display multiple pore morphologies on a single chip, therefore enabling high-throughput screening of optimal nanostructures for specific applications.

  8. Electron confinement in thin metal films. Structure, morphology and interactions

    Energy Technology Data Exchange (ETDEWEB)

    Dil, J.H.

    2006-05-15

    This thesis investigates the interplay between reduced dimensionality, electronic structure, and interface effects in ultrathin metal layers (Pb, In, Al) on a variety of substrates (Si, Cu, graphite). These layers can be grown with such a perfection that electron confinement in the direction normal to the film leads to the occurrence of quantum well states in their valence bands. These quantum well states are studied in detail, and their behaviour with film thickness, on different substrates, and other parameters of growth are used here to characterise a variety of physical properties of such nanoscale systems. The sections of the thesis deal with a determination of quantum well state energies for a large data set on different systems, the interplay between film morphology and electronic structure, and the influence of substrate electronic structure on their band shape; finally, new ground is broken by demonstrating electron localization and correlation effects, and the possibility to measure the influence of electron-phonon coupling in bulk bands. (orig.)

  9. Dry Etching of Copper Phthalocyanine Thin Films: Effects on Morphology and Surface Stoichiometry

    Directory of Open Access Journals (Sweden)

    Michael J. Brett

    2012-08-01

    Full Text Available We investigate the evolution of copper phthalocyanine thin films as they are etched with argon plasma. Significant morphological changes occur as a result of the ion bombardment; a planar surface quickly becomes an array of nanopillars which are less than 20 nm in diameter. The changes in morphology are independent of plasma power, which controls the etch rate only. Analysis by X-ray photoelectron spectroscopy shows that surface concentrations of copper and oxygen increase with etch time, while carbon and nitrogen are depleted. Despite these changes in surface stoichiometry, we observe no effect on the work function. The absorbance and X-ray diffraction spectra show no changes other than the peaks diminishing with etch time. These findings have important implications for organic photovoltaic devices which seek nanopillar thin films of metal phthalocyanine materials as an optimal structure.

  10. Dry etching of copper phthalocyanine thin films: effects on morphology and surface stoichiometry.

    Science.gov (United States)

    Van Dijken, Jaron G; Brett, Michael J

    2012-08-24

    We investigate the evolution of copper phthalocyanine thin films as they are etched with argon plasma. Significant morphological changes occur as a result of the ion bombardment; a planar surface quickly becomes an array of nanopillars which are less than 20 nm in diameter. The changes in morphology are independent of plasma power, which controls the etch rate only. Analysis by X-ray photoelectron spectroscopy shows that surface concentrations of copper and oxygen increase with etch time, while carbon and nitrogen are depleted. Despite these changes in surface stoichiometry, we observe no effect on the work function. The absorbance and X-ray diffraction spectra show no changes other than the peaks diminishing with etch time. These findings have important implications for organic photovoltaic devices which seek nanopillar thin films of metal phthalocyanine materials as an optimal structure.

  11. Morphology and crystal structure control of alpha-Fe2O3 films by hydrothermal-electrochemical deposition in the presence of Ce3+ and/or acetate, F- ions

    OpenAIRE

    Yılmaz, Özgür; Ünal, Uğur

    2016-01-01

    Hydrothermal-electrochemical growth of Hematite (alpha-Fe2O3) thin films in the presence of Ce3+ and/or CH3COO- and F- ions is reported. Primary attention is paid to understanding the synergistic effect of temperature and additive ions on the growth of Hematite particles. The literature describes the shape-controlled electrodeposition of iron oxide films, but these reports involve low-temperature depositions (

  12. Texture control and growth mechanism of WSe2 film prepared by rapid selenization of W film

    Science.gov (United States)

    Li, Hongchao; Gao, Di; Li, Kun; Pang, Mengde; Xie, Senlin; Liu, Rutie; Zou, Jianpeng

    2017-02-01

    The tungsten diselenide (WSe2) films with different orientation present unique properties suitable for specific applications, such as WSe2 with a C-axis⊥substrate for optoelectronics and WSe2 with a C-axis // substrate for electrocatalysts. Orientation control of WSe2 is essential for realizing the practical applications. In this letter, a WSe2 film has been prepared via rapid selenization of a magnetron-sputtered tungsten (W) film. The influence of the magnetron-sputtered W film on WSe2 film growth was studied systematically. Scanning electron microscopy, X-ray diffractometry and high-resolution transmission electron microscopy were used to evaluate the morphology, microstructure and phase composition of the W and WSe2 films. The substrate temperature has a significant effect on the W film phase composition, but little effect on the WSe2 film orientation. The WSe2 orientation can be controlled by changing the W film microstructure. A dense W film that is deposited at low pressure is conducive to the formation of WSe2 with a C-axis⊥substrate, whereas a porous W film deposited at high pressure favors the formation of WSe2 with a C-axis // substrate. A growth model for the WSe2 film with different texture has been proposed based on the experimental results. The direction of selenium (Se) vapor diffusion differs at the top and side surfaces. This is a key factor for the preparation of anisotropic WSe2 films. Highly oriented WSe2 films with a C-axis⊥substrate grow from the dense W film deposited at low pressure because Se vapor can only diffuse into the W film from the top surface where it is converted into selenide. Highly oriented WSe2 with a C-axis // substrate can be achieved for the porous W film that is deposited at high pressure because the nanopores provide a fast transmission tunnel for Se vapor diffusion. These findings will contribute to the controlled fabrication of WSe2 film and provide a theoretical basis for its application.

  13. Swift heavy ion irradiation induced modification of structure and surface morphology of BiFeO3 thin film

    Indian Academy of Sciences (India)

    B N Dash; P Mallick; P Dash; R Biswal; Jai Prakash; A Tripathi; D Kanjilal; N C Mishra

    2013-10-01

    BiFeO3 (BFO) thin films of thickness about 800 nm deposited on Si (100) substrates by sol–gel spin coating method were irradiated by 200 MeV Ag ions. Modification of structure and surface morphology of the films under irradiation was studied using glancing incidence X-ray diffraction (GIXRD) and atomic force microscope (AFM). Fluence dependence of GIXRD peak intensity indicated formation of 10 nm diameter cylindrical amorphous columns in crystalline BFO due to 200 MeV Ag ion irradiation. AFM analysis indicated that the pristine film consists of agglomerated grains with diffuse grain boundary. Irradiation led to reduced agglomeration of the grains with the formation of sharper grain boundaries. The rms roughness (rms) estimated from AFM analysis increased from 6.2 in pristine film to 12.7 nm when the film irradiated at a fluence of 1 × 1011 ions cm-2. Further irradiation led to decrease of rms which finally saturated at a value of 7–8 nm at high ion fluences. The power spectral density analysis indicated that the evolution of surface morphology of the pristine film is governed by the combined effect of evaporation condensation and volume diffusion processes. Swift heavy ion irradiation seems to increase the dominance of volume diffusion in controlling surface morphology of the film at high ion fluences.

  14. Morphologies in Solvent-Annealed Clotrimazole Thin Films Explained by Hansen-Solubility Parameters.

    Science.gov (United States)

    Ehmann, Heike M A; Zimmer, Andreas; Roblegg, Eva; Werzer, Oliver

    2014-03-05

    The induction of different crystal morphologies is of crucial importance for many applications. In this work, the preparation of various crystal morphologies within clotrimazole films on glass substrates is demonstrated. Amorphous clotrimazole thin films were transformed via vapor annealing into crystalline structures; highly monodisperse/multidisperse crystallites, spherulite, or dendritic structures were obtained as the solvent was exchanged. X-ray diffraction experiments reveal that the same polymorph is present for all samples but with varying texture. The achieved morphologies are explained in terms of Hansen-solubility parameters and vapor pressures; thus, the different morphologies and crystal orientations can be explained by solvent-solid interaction strengths within the thin film samples.

  15. Composition, XRD and morphology study of laser prepared LiNbO3 films

    Science.gov (United States)

    Jelínek, M.; Havránek, V.; Remsa, J.; Kocourek, T.; Vincze, A.; Bruncko, J.; Studnička, V.; Rubešová, K.

    2013-03-01

    LiNbO3 films were deposited by PLD from LiNbO3 crystalline or from three different stoichiometric or Li-enriched LiNbO3 targets. Polycrystalline films were prepared on SiO2/Si or sapphire substrates at temperatures T S ˜650-750 °C. Main attention was paid to the influence of targets preparation and the deposition conditions on films composition, morphology and crystallinity. The thin-film morphology was determined by SEM microscopy. The composition was measured by SIMS, RBS, PIXE and PIGE methods. Highly oriented, smooth and stoichiometric LiNbO3 films were synthesized.

  16. Acetate Salts as Nonhalogen Additives To Improve Perovskite Film Morphology for High-Efficiency Solar Cells.

    Science.gov (United States)

    Wu, Qiliang; Zhou, Pengcheng; Zhou, Weiran; Wei, Xiangfeng; Chen, Tao; Yang, Shangfeng

    2016-06-22

    A two-step method has been popularly adopted to fabricate a perovskite film of planar heterojunction organo-lead halide perovskite solar cells (PSCs). However, this method often generates uncontrollable film morphology with poor coverage. Herein, we report a facile method to improve perovskite film morphology by incorporating a small amount of acetate (CH3COO(-), Ac(-)) salts (NH4Ac, NaAc) as nonhalogen additives in CH3NH3I solution used for immersing PbI2 film, resulting in improved CH3NH3PbI3 film morphology. Under the optimized NH4Ac additive concentration of 10 wt %, the best power conversion efficiency (PCE) reaches 17.02%, which is enhanced by ∼23.2% relative to that of the pristine device without additive, whereas the NaAc additive does not lead to an efficiency enhancement despite the improvement of the CH3NH3PbI3 film morphology. SEM study reveals that NH4Ac and NaAc additives can both effectively improve perovskite film morphology by increasing the surface coverage via diminishing pinholes. The improvement on CH3NH3PbI3 film morphology is beneficial for increasing the optical absorption of perovskite film and improving the interfacial contact at the perovskite/spiro-OMeTAD interface, leading to the increase of short-circuit current and consequently efficiency enhancement of the PSC device for NH4Ac additive only.

  17. Systematic study on the effect of solvent removal rate on the morphology of solvent vapor annealed ABA triblock copolymer thin films.

    Science.gov (United States)

    Albert, Julie N L; Young, Wen-Shiue; Lewis, Ronald L; Bogart, Timothy D; Smith, Jasmine R; Epps, Thomas H

    2012-01-24

    Nanoscale self-assembly of block copolymer thin films has garnered significant research interest for nanotemplate design and membrane applications. To fulfill these roles, control of thin film morphology and orientation is critical. Solvent vapor annealing (SVA) treatments can be used to kinetically trap morphologies in thin films not achievable by traditional thermal treatments, but many variables affect the outcome of SVA, including solvent choice, total solvent concentration/swollen film thickness, and solvent removal rate. In this work, we systematically examined the effect of solvent removal rate on the final thin film morphology of a cylinder-forming ABA triblock copolymer. By kinetically trapping the film morphologies at key points during the solvent removal process and then using successive ultraviolet ozone (UVO) etching steps followed by atomic force microscopy (AFM) imaging to examine the through-film morphologies of the films, we determined that the mechanism for cylinder reorientation from substrate-parallel to substrate-perpendicular involved the propagation of changes at the free surface through the film toward the substrate as a front. The degree of reorientation increased with successively slower solvent removal rates. Furthermore, the AFM/UVO etching scheme permitted facile real-space analysis of the thin film internal structure in comparison to cross-sectional transmission electron microscopy.

  18. Synthesis and morphological modification of semiconducting Mg(Zn)Al(Ga)–LDH/ITO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Valente, Jaime S., E-mail: jsanchez@imp.mx [Instituto Mexicano del Petróleo, Eje Central # 152, 07730 México D.F. (Mexico); López-Salinas, Esteban [Instituto Mexicano del Petróleo, Eje Central # 152, 07730 México D.F. (Mexico); Prince, Julia [Universidad Anáhuac México Norte, Av. Universidad Anáhuac # 46, Huixquilucan, Edo. de México 52786 (Mexico); González, Ignacio; Acevedo-Peña, Prospero [Universidad Autónoma Metropolitana-Iztapalapa, Departamento de Química, Apdo. Postal 55-534, 09340 México D.F. (Mexico); Ángel, Paz del [Instituto Mexicano del Petróleo, Eje Central # 152, 07730 México D.F. (Mexico)

    2014-09-15

    Layered double hydroxide (LDH) thin films with different chemical compositions (MgZnAl, MgZnGa, MgGaAl) and varying thicknesses were easily prepared by sol–gel method followed by dip-coating. Films were chemically uniform, transparent and well adhered to a conductive indium tin oxide (ITO) substrate. Structure, chemical composition and morphology of the thin films were characterized by XRD-GADDS, SEM-EDS and AFM. Additionally, the semiconducting properties of all the prepared films were studied through the Mott–Schottky relationship; such properties were closely related to the chemical compositions of the film. The films were characterized after electrochemical treatment and important modifications regarding surface morphology, particle and crystal sizes were observed. An in-depth study was conducted in order to investigate the effect of several different electrochemical treatments on the morphology, particle size distribution and crystal size of LDH thin films. Upon electrochemical treatment, the films' surface became smooth and the particles forming the films were transformed from flaky open LDH platelets to uniformly distributed close-packed LDH nanoparticles. - Highlights: • Semiconducting Mg(Zn)Al(Ga)–LDH/ITO thin films prepared by sol–gel. • LDH thin films show a turbostratic morphology made up of porous flakes. • Electrochemical treatments change the flaky structure into a nanoparticle array.

  19. Organic Based Solar Cells with Morphology Control

    OpenAIRE

    Andersen, Thomas Rieks; Bundgaard, Eva; Jørgensen, Mikkel

    2013-01-01

    The field of organic solar cells has in the last years gone through an impressive development with efficiencies reported up to 12 %. For organic solar cells to take the leap from primarily being a laboratory scale technology to being utilized as renewable energy source, several issues need to be addressed. Among these are a more direct transfer of new materials tested on a laboratory scale to large scale production than offered by spincoating, a method offering direct control of the morpholog...

  20. Morphologies and Superhydrophobicity of Hybrid Film Surfaces Based on Silica and Fluoropolymer

    Institute of Scientific and Technical Information of China (English)

    Ailan QU; Xiufang WEN; Pihui PI; Jiang CHENG; Zhuoru YANG

    2008-01-01

    Fluoropolymer and different kinds of silica particles were used for controlling surface chemistry and morphology,respectively. A superhydrophobic surface originated from strawberry-like or quincunx-shaped composite silica particles was obtained. The dual size particles are obtained by utilizing the graft of different modified silica particles with epoxy functional group and amine functional group. This makes the surface of film form a composite interface to have irregular binary structure which plays an essential role in trapping air between the substrate surface and the liquid droplets to be necessary for high contact angle and low contact anglehysteresis. The maximum contact angle for water on the hybrid film is about 174±2° and the contact angle hysteresis is less than 2°. The surface morphologies, roughness and the wettability on the surface of films containing different structural silica particles were compared. It was shown that the hierarchical irregularly structure with a low roughness factor and high air-trapped ratio is indispensable for superhydrophobic surface.Although this structural surfaces based on composite silica particles play a vital role in governing the surface wettability, it is necessary to combine with a low surface energy to make the surface superhydrophobic.

  1. Surface morphology of titanium nitride thin films synthesized by DC reactive magnetron sputtering

    Directory of Open Access Journals (Sweden)

    Ţǎlu Ştefan

    2015-03-01

    Full Text Available In this paper the influence of temperature on the 3-D surface morphology of titanium nitride (TiN thin films synthesized by DC reactive magnetron sputtering has been analyzed. The 3-D morphology variation of TiN thin films grown on p-type Si (100 wafers was investigated at four different deposition temperatures (473 K, 573 K, 673 K, 773 K in order to evaluate the relation among the 3-D micro-textured surfaces. The 3-D surface morphology of TiN thin films was characterized by means of atomic force microscopy (AFM and fractal analysis applied to the AFM data. The 3-D surface morphology revealed the fractal geometry of TiN thin films at nanometer scale. The global scale properties of 3-D surface geometry were quantitatively estimated using the fractal dimensions D, determined by the morphological envelopes method. The fractal dimension D increased with the substrate temperature variation from 2.36 (at 473 K to 2.66 (at 673 K and then decreased to 2.33 (at 773 K. The fractal analysis in correlation with the averaged power spectral density (surface yielded better quantitative results of morphological changes in the TiN thin films caused by substrate temperature variations, which were more precise, detailed, coherent and reproducible. It can be inferred that fractal analysis can be easily applied for the investigation of morphology evolution of different film/substrate interface phases obtained using different thin-film technologies.

  2. Morphologies-controlled Fabrication of Microstructured ZnO Films and Their Photocatalytic Performances%不同形貌的微米 ZnO 薄膜的制备及其光催化性能研究

    Institute of Scientific and Technical Information of China (English)

    李秀艳; 李鑫; 魏兵

    2016-01-01

    Microstructured ZnO films with different morphologies (fragmental block,mushroom,long-rod and short-rod) were successfully synthesized by a solvothermal route in different solvents using Zn foil as both the substrate and Zn source.The structures and morphologies of products were characterized with X-ray diffraction (XRD), scanning electron microscopy ( SEM) and transmission electron microscopy ( TEM).In addition, the optical properties ( UV-visible diffuse reflectance and photoluminescence ) and photocatalytic activities of products were compared.The effects of morphology on the photocatalytic activity was also discussed in this paper .%以锌片为锌源及基片,采用溶剂热法合成出不同形貌的ZnO微米薄膜(碎石状、蘑菇状、长棒和短棒状)。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)等测试手段对样品的结构和形貌进行了表征。另外,对产品的光学(紫外可见漫反射和光致发光)性能及光催化活性进行了表征和对比,同时还讨论了形貌对光催化活性的影响。

  3. Organic Based Solar Cells with Morphology Control

    DEFF Research Database (Denmark)

    Andersen, Thomas Rieks

    The field of organic solar cells has in the last years gone through an impressive development with efficiencies reported up to 12 %. For organic solar cells to take the leap from primarily being a laboratory scale technology to being utilized as renewable energy source, several issues need...... to be addressed. Among these are a more direct transfer of new materials tested on a laboratory scale to large scale production than offered by spincoating, a method offering direct control of the morphology in the active layer, and a more environmental friendly processing, where the vast use of organic solvents...... offers a great challenge. In this thesis the development of inks with a pre-arranged morphology was attempted by two methods. First by grafting of silicon nanoparticles with an organic phenylene vinylene oligomer, the resulting particles were analyzed by 1H-NMR, absorption spectroscopy, Atomic Force...

  4. Effect of substrate temperature on structural, morphological, optical and electrical properties of IGZO thin films

    Science.gov (United States)

    Jayaraman, Vinoth Kumar; Álvarez, Arturo Maldonado; Olvera Amador, María de la luz

    2017-02-01

    Indium and gallium co-doped zinc oxide (IGZO) thin films were deposited on glass substrates by ultrasonic spray pyrolysis. Physical properties such as structural, morphological, optical and electrical properties were examined on IGZO thin films with respect to the changes in the substrate temperature (425, 450 and 475 °C). Structural results showed that IGZO films were crystalline and presented hexagonal wurtzite structure. Morphological studies proved that the substrate temperature changed the sizes of hexagonal nanostructures of IGZO. Optical transmittance in the UV-vis region and electrical measurements confirmed that IGZO films were transparent (>70%) with a minimum electrical resistivity 10.5×10-3 Ω cm.

  5. Effect of interface on surface morphology and proton conduction of polymer electrolyte thin films.

    Science.gov (United States)

    Ohira, Akihiro; Kuroda, Seiichi; Mohamed, Hamdy F M; Tavernier, Bruno

    2013-07-21

    To understand the relationship between surface morphology and proton conduction of polymer electrolyte thin films, perfluorinated ionomer Nafion® thin films were prepared on different substrates such as glassy carbon (GC), hydrophilic-GC (H-GC), and platinum (Pt) as models for the ionomer film within a catalyst layer. Atomic force microscopy coupled with an electrochemical (e-AFM) technique revealed that proton conduction decreased with film thickness; an abrupt decrease in proton conductance was observed when the film thickness was less than ca. 10 nm on GC substrates in addition to a significant change in surface morphology. Furthermore, thin films prepared on H-GC substrates with UV-ozone treatment exhibited higher proton conduction than those on untreated GC substrates. However, Pt substrates exhibited proton conduction comparable to that of GCs for films thicker than 20 nm; a decrease in proton conduction was observed at ∼5 nm thick film but was still much higher than for carbon substrates. These results indicate that the number of active proton-conductive pathways and/or the connectivity of the proton path network changed with film thickness. The surface morphology of thinner films was significantly affected by the film/substrate interface and was fundamentally different from that of the bulk thick membrane.

  6. Investigation of solvent annealing time dependence on morphology formation in polystyrene-block-polylactide thin films

    Science.gov (United States)

    Gnabasik, Ryan; Nelson, Gunnar; Baruth, Andrew

    2015-03-01

    Solvent vapor annealing exposes a block polymer film to the vapors of one or more solvents, swelling the film. This process increases polymer mobility and can direct a self-assembly process by tuning the surface energy. Despite its efficacy to produce well-ordered, periodic nanostructures, no standardized production scheme exists. This is primarily due to a lack of understanding the intricate role multiple, incommensurate parameters play. By analogy to thermal annealing of elemental solids, the time a thin film spends in an equilibrium solvent concentration is one factor that will dictate the degree of ordering. To elucidate, optimized annealing conditions for perpendicular cylinder forming polystyrene-block-polylactide exist at solvent concentrations just below the order-disorder transition, where the kinetic and thermal processes required for recrystallization and crystal growth are optimally fast (similar to thermal annealing). By use of a purpose-built, climate-controlled solvent annealing chamber, we map out the annealing time dependence for non-optimized solvent concentrations. Namely, at lower solvent concentrations, where mobility is limited, longer times are required for large lateral correlation lengths. In situ spectral reflectance monitors solvent concentration, regulated viaa mass-flow controlled solvent inlet, offering precision control over annealing. Atomic force microscopy, in conjunction with O2 plasma etching, provides 3-dimensional imaging of the nanoscale morphology. This work was funded by NASA Nebraska Space Grant.

  7. Method of making controlled morphology metal-oxides

    Science.gov (United States)

    Ozcan, Soydan; Lu, Yuan

    2016-05-17

    A method of making metal oxides having a preselected morphology includes preparing a suspension that includes a solvent, polymeric nanostructures having multiplicities of hydroxyl surface groups and/or carboxyl surface groups, and a metal oxide precursor. The suspension has a preselected ratio of the polymeric nanostructures to the metal oxide precursor of at least 1:3, the preselected ratio corresponding to a preselected morphology. Subsequent steps include depositing the suspension onto a substrate, removing the solvent to form a film, removing the film from the substrate, and annealing the film to volatilize the polymeric nanostructures and convert the metal oxide precursor to metal oxide nanoparticles having the preselected morphology or to a metal oxide nanosheet including conjoined nanoparticles having the preselected morphology.

  8. The optical behavior of VC{sub 2} film modulated by the morphology and preferred growing axis

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Seong Cheol; Lee, Myeong Soon; Kim, Don [Dept. of Chemistry, Pukyong National University, Busan (Korea, Republic of)

    2017-01-15

    We have prepared a smart VO{sub 2} film on a sapphire (0001) substrate by a direct thermal treat of a mixture of polyvinylpyrrolidone and VOCl{sub 2} solution at 803 K under an inert condition. The optical characteristics of the film near the phase transition temperature could be controlled by the surface morphology (mainly particle size) and preferred growing crystal axis of the film. The surface morphology and the preferred axis were related to the thickness of the VO{sub 2} film. The optical properties of the films could be grouped by three types: S-, M- and L-type. The S-type film, a brown colored thin film (⁓0.3 μm in thickness), which consists of small VO2 particles (< (⁓0.3 μm in diameter) and highly oriented to the preferred growing orientation (020), cut off infrared (IR) radiation at the high-temperature (high-T: above the transition temperature) phase and passes IR at the low-temperature (low-T: below transition temperature) phase. The transmission gap at 1550 nm between the low-T and high-T phases of the S-type film was (⁓25%. The transition phenomena also observed in dc electrical resistance measurement at the same transition temperatures; T{sub H} = (⁓340 K, observed in the heating process, and T{sub C} = (⁓334 K, observed in the cooling process. However, M- and L-type films, thicker and more isotropic than S-type, have different optical behavior. Other physicochemical properties of the films were investigated to unveil the phase transition.

  9. Study of Low Temperature Fuel Cells Thin Films Morphology by GISAXS

    Science.gov (United States)

    Irita, Tomomi; Russell, Thomas

    2007-03-01

    Grazing incidence small angle x-ray scattering experiments were performed on thin films of Nafion solutions as a function of time as the solvent, methanol/water, evaporated. The development and orientation of the structure and morphology in the thin films, at the free surface and in the bulk of the film, was characterized by the scattering below and above the critical angle. The scattering profiles indicated that Nafion thin morphology was strongly influenced by the conformations of Nafion molecules in the solutions. In addition, the morphology in thin films of sulfonated block copolymers of polystyrene-b-poly(ethylene-o-butylene)-b-polystyrene, an alternative material for fuel cell applications, was characterized by GISAXS and scanning force microscopy using different solvents and under an applied electric field. Both the solvents used and the applied field was found to markedly influence the orientation of the ion conducting domains in the films.

  10. The influence of nanoscale morphology on the resistivity of cluster-assembled nanostructured metallic thin films

    Energy Technology Data Exchange (ETDEWEB)

    Barborini, E; Bertolini, G; Repetto, P; Leccardi, M; Vinati, S [Tethis srl, via Franco Russoli 3, 20143 Milano (Italy); Corbelli, G; Milani, P, E-mail: emanuele.barborini@tethis-lab.co, E-mail: pmilani@mi.infn.i [CIMAINA and Dipartimento di Fisica, Universita di Milano, via Celoria 16, 20133 Milano (Italy)

    2010-07-15

    We have studied in situ the evolution of the electrical resistivity of Fe, Pd, Nb, W and Mo cluster-assembled films during their growth by supersonic cluster beam deposition. We observed resistivity of cluster-assembled films several orders of magnitude larger than the bulk, as well as an increase in resistivity by increasing the film thickness in contrast to what was observed for atom-assembled metallic films. This suggests that the nanoscale morphological features typical of ballistic films growth, such as the minimal cluster-cluster interconnection and the evolution of surface roughness with thickness, are responsible for the observed behaviour.

  11. Tuning morphology and magnetism in epitaxial L10 -FePt films

    Science.gov (United States)

    Lupo, P.; Orna, J.; Casoli, F.; Nasi, L.; Ranzieri, P.; Calestani, D.; Algarabel, P.; Morellón, L.; Albertini, F.

    2013-01-01

    In this work, well-ordered epitaxial FePt thin films have been grown by RF sputtering on two different substrates (MgO (100) and SrTiO3 (100)) and the effect of different lattice parameters between the substrate and FePt film on morphology and magnetic behavior has been considered. Growth conditions have been optimized to obtain different morphologies and magnetic behaviors.

  12. Morphologies in Solvent-Annealed Clotrimazole Thin Films Explained by Hansen-Solubility Parameters

    OpenAIRE

    Ehmann, Heike M. A.; Zimmer, Andreas; Roblegg, Eva; Werzer, Oliver

    2014-01-01

    The induction of different crystal morphologies is of crucial importance for many applications. In this work, the preparation of various crystal morphologies within clotrimazole films on glass substrates is demonstrated. Amorphous clotrimazole thin films were transformed via vapor annealing into crystalline structures; highly monodisperse/multidisperse crystallites, spherulite, or dendritic structures were obtained as the solvent was exchanged. X-ray diffraction experiments reveal that the sa...

  13. Impact of film thickness on the morphology of mesoporous carbon films using organic-organic self-assembly.

    Science.gov (United States)

    Vogt, Bryan D; Chavez, Vicki L; Dai, Mingzhi; Arreola, M Regina Croda; Song, Lingyan; Feng, Dan; Zhao, Dongyuan; Perera, Ginusha M; Stein, Gila E

    2011-05-03

    Mesoporous polymer and carbon thin films are prepared by the organic-organic self-assembly of an oligomeric phenolic resin with an amphiphilic triblock copolymer template, Pluronic F127. The ratio of resin to template is selected such that a body-centered cubic (Im3m) mesostructure is formed in the bulk. However, well-ordered mesoporous films are not always obtained for thin films (body-centered cubic symmetry with a preferential orientation of the closest-packed (110) plane parallel to the substrate. Film thickness and initial composition of the carbonizable precursors in the template are critical factors in determining the morphology of mesoporous carbon films. These results provide insight into why difficulties have been reported in producing ultrathin ordered mesoporous carbon films using cooperative organic-organic self-assembly.

  14. Controlling the Morphology of Carbon Gels

    Directory of Open Access Journals (Sweden)

    S. R. Mukai

    2012-12-01

    Full Text Available Carbon gels are unique porous carbons, which aretypically obtained through the carbonization ofresorcinol-formaldehyde gels. This material ispractically an aggregate of nanometer-sized carbonparticles. Nanopores, mostly in the size range ofmesopores, exist between the particles. Smallerpores, micropores being the majority, also exist withinthe particles. Therefore, this material has ahierarchical pore system in which short microporesare directly connected to mesopores.The precursor of carbon gels can be obtained throughsol-gel transition. Therefore there is a high possibilitythat the morphology of the resulting carbon can beeasily controlled using various molding methods.We have actually challenged the controlling of themorphology of carbon gels, and have succeeded inobtaining them in the form of disks, microspheresand microhoneycombs. Details of such carbon gelswill be reported.

  15. Surface morphology and photoluminescence properties of ZnO thin films obtained by PLD

    Institute of Scientific and Technical Information of China (English)

    FAN Xi-mei; LIAN Jian-she; GUO Zuo-xing; JIANG Qing

    2005-01-01

    ZnO thin films on Si(111) substrate were deposited by laser ablation of Zn target in oxygen reactive atmosphere, Nd-YAG laser with wavelength of 1 064 nm was used as laser source. XRD and FESEM microscopy were applied to characterize the structure and surface morphology of the deposited ZnO films. The optical properties of the ZnO thin films were characterized by photoluminescence. The UV and deep level (yellow-green) light were observed from the films. The UV light is the intrinsic property and deep level light is attributed to the existence of antisite defects (OZn). The intensity of UV and deep level light depends strongly on the surface morphology and is explained by the surface roughness of ZnO film. A strongly UV emission can be obtained from ZnO film with surface roughness in nanometer range.

  16. Morphological phase diagrams of C60 and C70 films on graphite

    Science.gov (United States)

    Sato, Kazuma; Tanaka, Tomoyasu; Akaike, Kouki; Kanai, Kaname

    2017-10-01

    The morphologies of C60 and C70 fullerene films vacuum-deposited onto graphite at various deposition rates and grown at several temperatures were investigated using atomic force microscopy. These fullerene films on graphite are model systems of physisorption of organic molecules that likely exhibit little chemical interaction with the graphite's surface. The morphologies of C60 and C70 films grown on graphite can be understood well from growth models previously reported. Comparison of the morphological phase diagrams obtained for C60 and C70 indicate that the diffusion properties of the adsorbed molecule are key in determining the morphology of the obtained film. The low diffusion rate of C70 resulted in various film morphologies for all deposition conditions tested. Also, the obtained phase diagrams can be understood by the results of fractal dimension analysis on the C60 and C70 islands. The fundamental understanding of film growth obtained using these ideal physisorption systems will aid in understanding film growth by other molecular adsorption systems.

  17. Quantitative characterization of morphological evolution in Q=2 Potts model aluminum thin films

    NARCIS (Netherlands)

    Alsem, DH; Stach, EA; de Hosson, JTM; Aziz, MJ; Bartelt, NC; Berbezier,; Hannon, JB; Hearne, SJ

    2003-01-01

    In this research, we have focused on the morphological evolution of a model metal film / silicon substrate system. When aluminum (Al) is physical vapor deposited on (100) oriented single crystal silicon (Si) at 280degreesC it grows heteroepitaxially. Crystallographically, the resulting films are a P

  18. Solvothermal growth and morphology study of Cu 2Se films

    Science.gov (United States)

    Lin, Fei; Bian, Guo-Qing; Lei, Zhi-Xin; Lu, Zhe-Jun; Dai, Jie

    2009-05-01

    Solvothermal growth of cuprous selenide films on copper substrate has been succeeded by treating copper foil in the mixture of selenium powder and amines or hydrazine. The films were characterized by methods of XRD, SEM, TEM and optical spectra (Cu 2Se, JCPDS 47-1448). Films with hexagonal microcrystals can be obtained in hydrazine/water reaction system. When CTAB (CTAB = cetyltrimethylammonium bromide) is added to the system, the film is composed of thin leaf-like microcrystals. When ethylenediamine (en) is used as solvent, the leaf-like microcrystals are crimped.

  19. Morphological Control for High Performance, Solution-Processed Planar Heterojunction Perovskite Solar Cells

    KAUST Repository

    Eperon, Giles E.

    2013-09-09

    Organometal trihalide perovskite based solar cells have exhibited the highest efficiencies to-date when incorporated into mesostructured composites. However, thin solid films of a perovskite absorber should be capable of operating at the highest efficiency in a simple planar heterojunction configuration. Here, it is shown that film morphology is a critical issue in planar heterojunction CH3NH3PbI3-xCl x solar cells. The morphology is carefully controlled by varying processing conditions, and it is demonstrated that the highest photocurrents are attainable only with the highest perovskite surface coverages. With optimized solution based film formation, power conversion efficiencies of up to 11.4% are achieved, the first report of efficiencies above 10% in fully thin-film solution processed perovskite solar cells with no mesoporous layer. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Morphological characteristics and barrier properties of thermoplastic starch/chitosan blown film.

    Science.gov (United States)

    Dang, Khanh Minh; Yoksan, Rangrong

    2016-10-01

    Fabrication of starch-based edible film using blown film extrusion is challenging and interesting because this process provides continuous operation with shorter production time and lower energy consumption, is less labor intensive, and results in higher productivity than the conventional solution casting technique. Previously, we reported on the preparation and some properties of thermoplastic starch/chitosan (TPS/CTS) blown films; however, their morphological characteristics and barrier properties had not yet been elucidated. The present work thus aims to investigate the effect of chitosan (0.37-1.45%) on morphological characteristics, water vapor and oxygen barrier properties as well as hydrophilicity of the TPS and TPS/CTS films. The relationship between morphological characteristics and properties of the films was also discussed. Scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM) and X-ray photoelectron spectroscopy (XPS) confirmed the distribution and deposition of chitosan on the film surface. The existence of chitosan on the surface imparted the improved water vapor and oxygen barrier properties and the reduced surface hydrophilicity to the film. The results suggest that this biodegradable bio-based TPS/CTS film could potentially be used as an edible film for food and pharmaceutical applications.

  1. Unusual Morphologies of Poly(vinyl alcohol) Thin Films Adsorbed on Poly(dimethylsiloxane) Substrates.

    Science.gov (United States)

    Karki, Akchheta; Nguyen, Lien; Sharma, Bhanushee; Yan, Yan; Chen, Wei

    2016-04-05

    Adsorption of poly(vinyl alcohol) (PVOH), 99% and 88% hydrolyzed poly(vinyl acetate), to poly(dimethylsiloxane) (PDMS) substrates was studied. The substrates were prepared by covalently attaching linear PDMS polymers of 2, 9, 17, 49, and 116 kDa onto silicon wafers. As the PDMS molecular weight/thickness increases, the adsorbed PVOH thin films progressively transition from continuous to discontinuous morphologies, including honeycomb and fractal/droplet. The structures are the result of thin film dewetting that occurs upon exposure to air. The PVOH film thickness does not vary significantly on these PDMS substrates, implicating the PDMS thickness as the cause for the morphology differences. The adsorbed PVOH thin films are less stable and have a stronger tendency to dewet on thicker, more liquid-like PDMS layers. When PVOH(99%) and PVOH(88%) thin films are compared, fractal and droplet morphologies are observed on high molecular weight PDMS substrates, respectively. The formation of the unique fractal features in the PVOH(99%) thin films as well as other crystalline and semicrystalline thin films is most likely driven by crystallization during the dehydration process in a diffusion-limited aggregation fashion. The only significant enhancement in hydrophilicity via PVOH adsorption was obtained on PDMS(2k), which is completely covered with a PVOH thin film. To mimic the lower receding contact angle and less liquid-like character of the PDMS(2k) substrate, light plasma treatment of the higher molecular weight PDMS substrates was carried out. On the treated PDMS substrates, the adsorbed PVOH thin films are in the more continuous honeycomb morphology, giving rise to significantly enhanced wettability. Furthermore, hydrophobic recovery of the hydrophilized PDMS substrates was not observed during a 1 week period. Thus, light plasma oxidation and subsequent PVOH adsorption can be utilized as a means to effectively hydrophilize conventional PDMS substrates. This study

  2. Effect of Substrate Temperature on Structural and Morphological Parameters Of ZnTe Thin Films

    Directory of Open Access Journals (Sweden)

    K.D. Patel

    2011-01-01

    Full Text Available Vacuum evaporated thin films of Zinc Telluride (ZnTe of 5000 Å thickness have been deposited on glass substrates at different substrate temperatures (303 K, 373 K, 448 K. Structural parameters were obtained using XRD analysis. Atomic Force Microscope (AFM in non-contact mode has been used to study the surface morphological properties of the deposited thin films. The results obtained from structural and surface morphological studies have been correlated and it is found that the films deposited at higher substrate temperatures possess increasingly good crystallinity and smoother surfaces.

  3. Environmentally induced chemical and morphological heterogeneity of zinc oxide thin films

    Science.gov (United States)

    Jiang, Hua; Chou, Kang Wei; Petrash, Stanislas; Williams, Garth; Thieme, Juergen; Nykypanchuk, Dmytro; Li, Li; Muto, Atsushi; Chen-Wiegart, Yu-chen Karen

    2016-08-01

    Zinc oxide (ZnO) thin films have been reported to suffer from degradation in electrical properties, when exposed to elevated heat and humidity, often leading to failures of electronic devices containing ZnO films. This degradation appears to be linked to water and oxygen penetration into the ZnO film. However, a direct observation in the ZnO film morphological evolution detailing structural and chemical changes has been lacking. Here, we systematically investigated the chemical and morphological heterogeneities of ZnO thin films caused by elevated heat and humidity, simulating an environmental aging. X-ray fluorescence microscopy, X-ray absorption spectroscopy, grazing incidence small angle and wide angle X-ray scattering, scanning electron microscopy (SEM), ultra-high-resolution SEM, and optical microscopy were carried out to examine ZnO and Al-doped ZnO thin films on two different substrates—silicon wafers and flexible polyethylene terephthalate (PET) films. In the un-doped ZnO thin film, the simulated environmental aging is resulting in pin-holes. In the Al-doped ZnO thin films, significant morphological changes occurred after the treatment, with an appearance of platelet-shaped structures that are 100-200 nm wide by 1 μm long. Synchrotron x-ray characterization further confirmed the heterogeneity in the aged Al-doped ZnO, showing the formation of anisotropic structures and disordering. X-ray diffraction and X-ray absorption spectroscopy indicated the formation of a zinc hydroxide in the aged Al-doped films. Utilizing advanced characterization methods, our studies provided information with an unprecedented level of details and revealed the chemical and morphologically heterogeneous nature of the degradation in ZnO thin films.

  4. Environmentally induced chemical and morphological heterogeneity of zinc oxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Hua [Department of Materials Science and Engineering, Stony Brook University, Stony Brook, New York 11790 (United States); Chou, Kang Wei [Henkel Ibérica S. A. Edificio Eureka, 08193, Campus UAB, Barcelona (Spain); Petrash, Stanislas [Henkel Corporation, 10 Finderne Avenue, Bridgewater, New Jersey 08807 (United States); Williams, Garth; Thieme, Juergen; Li, Li; Chen-Wiegart, Yu-chen Karen, E-mail: ycchen@bnl.gov [National Synchrotron Light Source II, Brookhaven National Laboratory, 743 Brookhaven Avenue, Upton, New York 11973-5000 (United States); Nykypanchuk, Dmytro [Center for Functional Nanomaterials, Brookhaven National Laboratory, 735 Brookhaven Avenue, Upton, New York 11973-5000 (United States); Muto, Atsushi [Hitachi High Technologies America, 22610 Gateway Center Drive, Clarksburg, Maryland 20871 (United States)

    2016-08-29

    Zinc oxide (ZnO) thin films have been reported to suffer from degradation in electrical properties, when exposed to elevated heat and humidity, often leading to failures of electronic devices containing ZnO films. This degradation appears to be linked to water and oxygen penetration into the ZnO film. However, a direct observation in the ZnO film morphological evolution detailing structural and chemical changes has been lacking. Here, we systematically investigated the chemical and morphological heterogeneities of ZnO thin films caused by elevated heat and humidity, simulating an environmental aging. X-ray fluorescence microscopy, X-ray absorption spectroscopy, grazing incidence small angle and wide angle X-ray scattering, scanning electron microscopy (SEM), ultra-high-resolution SEM, and optical microscopy were carried out to examine ZnO and Al-doped ZnO thin films on two different substrates—silicon wafers and flexible polyethylene terephthalate (PET) films. In the un-doped ZnO thin film, the simulated environmental aging is resulting in pin-holes. In the Al-doped ZnO thin films, significant morphological changes occurred after the treatment, with an appearance of platelet-shaped structures that are 100–200 nm wide by 1 μm long. Synchrotron x-ray characterization further confirmed the heterogeneity in the aged Al-doped ZnO, showing the formation of anisotropic structures and disordering. X-ray diffraction and X-ray absorption spectroscopy indicated the formation of a zinc hydroxide in the aged Al-doped films. Utilizing advanced characterization methods, our studies provided information with an unprecedented level of details and revealed the chemical and morphologically heterogeneous nature of the degradation in ZnO thin films.

  5. In vitro degradation and release characteristics of spin coated thin films of PLGA with a "breath figure" morphology.

    Science.gov (United States)

    Ponnusamy, Thiruselvam; Lawson, Louise B; Freytag, Lucy C; Blake, Diane A; Ayyala, Ramesh S; John, Vijay T

    2012-01-01

    Poly (lactic-co-glycolic acid) (PLGA) coatings on implant materials are widely used in controlled drug delivery applications. Typically, such coatings are made with non-porous films. Here, we have synthesized a thin PLGA film coating with a highly ordered microporous structure using a simple and inexpensive water templating "breath figure" technique. A single stage process combining spin coating and breath figure process was used to obtain drug incorporated porous thin films. The films were characterized by scanning electron microscope (SEM) to observe the surface and bulk features of porosity and also, degradation pattern of the films. Moreover, the effect of addition of small amount of poly (ethylene glycol) (PEG) into PLGA was characterized. SEM analysis revealed an ordered array of ~2 µm sized pores on the surface with the average film thickness measured to be 20 µm. The incorporation of hydrophilic poly (ethylene glycol) (PEG) enhances pore structure uniformity and facilitates ingress of water into the structure. A five week in vitro degradation study showed a gradual deterioration of the breath figure pores. During the course of degradation, the surface pore structure deteriorates to initially flatten the surface. This is followed by the formation of new pinprick pores that eventually grow into a macroporous film prior to film breakup. Salicylic acid (highly water soluble) and Ibuprofen (sparingly water soluble) were chosen as model drug compounds to characterize release rates, which are higher in films of the breath figure morphology rather than in non-porous films. The results are of significance in the design of biodegradable films used as coatings to modulate delivery.

  6. Effect of Substrate Morphology on Growth and Field Emission Properties of Carbon Nanotube Films

    Directory of Open Access Journals (Sweden)

    Kumar Vikram

    2008-01-01

    Full Text Available AbstractCarbon nanotube (CNT films were grown by microwave plasma-enhanced chemical vapor deposition process on four types of Si substrates: (i mirror polished, (ii catalyst patterned, (iii mechanically polished having pits of varying size and shape, and (iv electrochemically etched. Iron thin film was used as catalytic material and acetylene and ammonia as the precursors. Morphological and structural characteristics of the films were investigated by scanning and transmission electron microscopes, respectively. CNT films of different morphology such as vertically aligned, randomly oriented flowers, or honey-comb like, depending on the morphology of the Si substrates, were obtained. CNTs had sharp tip and bamboo-like internal structure irrespective of growth morphology of the films. Comparative field emission measurements showed that patterned CNT films and that with randomly oriented morphology had superior emission characteristics with threshold field as low as ~2.0 V/μm. The defective (bamboo-structure structures of CNTs have been suggested for the enhanced emission performance of randomly oriented nanotube samples.

  7. Influence of Sputtering Gas on Morphological and Optical Properties of Magnesium Films

    Institute of Scientific and Technical Information of China (English)

    Yogendra K. Gautam; Amit K. Chawla; Vipin Chawla; R.D. Agrawal; Ramesh Chandra

    2011-01-01

    The influence of sputtering gas (He & Ar) on the structural properties of Mg thin films has been investigated. The optical property (reflectance) that results from the growth of films at varying substrate temperatures (Tsub) was also studied. The deposited films were characterized by using X-ray diffraction (XRD), field emission scaning electron microscopy (FE-SEM), atomic force microscopy (AFM) and UV-Vis-NIR spectrophotometer. The smaller crystallite size and lower deposition rate were observed in the presence of Helium atmosphere compared to Argon. Morphology of the films shows 2D hexagonal geometry of grains in the deposition temperature range (Tsub≈50-150℃) in both the sputtering gases. The surface roughness of the polycrystalline films were found to increase with increase in the deposition temperature of both ambient gases. Optical reflectance of Mg films was measured in near infrared region and larger reflectance was observed from Mg films sputtered in He atmosphere compared to that in argon.

  8. Morphological, Mechanical and Thermal Study of ZnO Nanoparticle Reinforced Chitosan Based Transparent Biocomposite Films

    Science.gov (United States)

    Das, Kunal; Maiti, Sonakshi; Liu, Dagang

    2014-04-01

    Chitosan based biocomposite transparent films reinforced with zinc oxide (ZnO) nanoparticles at different loading i.e. 2, 4 and 6 wt% were successfully prepared by solution casting method. Shape, size and geometry of the zinc oxide nanoparticles were characterized by scanning electron microscopy (SEM). The biocomposite films were subjected to mechanical characterization, thermal analysis, morphology study and moisture uptake behaviour. The characterization tools used here include wide angle X-ray diffraction study, scanning electron microscopic analysis, differential scanning calorimetric analysis and also UV-visible transmittance behavior. SEM micrographs revealed uniformly dispersed ZnO nanoparticles in biocomposite films. Improvement of the tensile strength about 133 % was observed significantly in case of 4 wt% loaded chitosan/ZnO films with respect to the neat chitosan film. 43 % higher transparency was observed in case of 2 wt% ZnO loaded biocomposites films, thus indicating the best combination of properties of 2 wt% ZnO loaded biocomposite films.

  9. An AFM study of the morphology and local mechanical properties of superconducting YBCO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Soifer, Ya.M.; Verdyan, A.; Azoulay, J.; Kazakevich, M.; Rabkin, E

    2004-02-01

    The morphology of thin superconducting YBCO films deposited on sapphire and on SrTiO{sub 3} was studied with the help of atomic force and scanning electron microscopies. The intrinsic mechanical properties in the flat, particles-free and chemically homogeneous regions of the films were determined with the aid of nanoindenting atomic force microscope. Also the microscopy studies revealed the difference in topography of the films, the nanohardness and Young's modulus of two films were very close to each other. For the indents shallower than 0.2 of the film thickness the Young's modulus and hardness of the films on two different substrates converged to the values of 210 and 8.5 GPa, respectively. The possible deformation mechanisms determining the localized deformation of intrinsically brittle ceramic films are discussed.

  10. An AFM study of the morphology and local mechanical properties of superconducting YBCO thin films

    Science.gov (United States)

    Soifer, Ya. M.; Verdyan, A.; Azoulay, J.; Kazakevich, M.; Rabkin, E.

    2004-02-01

    The morphology of thin superconducting YBCO films deposited on sapphire and on SrTiO 3 was studied with the help of atomic force and scanning electron microscopies. The intrinsic mechanical properties in the flat, particles-free and chemically homogeneous regions of the films were determined with the aid of nanoindenting atomic force microscope. Also the microscopy studies revealed the difference in topography of the films, the nanohardness and Young’s modulus of two films were very close to each other. For the indents shallower than 0.2 of the film thickness the Young’s modulus and hardness of the films on two different substrates converged to the values of 210 and 8.5 GPa, respectively. The possible deformation mechanisms determining the localized deformation of intrinsically brittle ceramic films are discussed.

  11. Surface morphology and magnetic property of wrinkled FeGa thin films fabricated on elastic polydimethylsiloxane

    Science.gov (United States)

    Zhang, Shuanglan; Zhan, Qingfeng; Yu, Ying; Liu, Luping; Li, Huihui; Yang, Huali; Xie, Yali; Wang, Baomin; Xie, Shuhong; Li, Run-Wei

    2016-03-01

    We investigated the surface morphology and the magnetic property of wrinkled Fe81Ga19 (FeGa) thin films fabricated in two different processes onto elastic polydimethylsiloxane (PDMS) substrates. The films obtained by directly depositing Ta and FeGa layers on a pre-strained PDMS substrate display a sinusoidally wrinkled surface and a weak magnetic anisotropy. The wavelength and amplitude of the sinusoidal morphology linearly increase with the metallic layer thickness, while the magnetic anisotropy decreases with increasing FeGa thickness. The other films grown by depositing FeGa layer on a wrinkled Ta/PDMS surface show a remarkable uniaxial magnetic anisotropy. The strength of magnetic anisotropy increases with increasing FeGa thickness. The magnetic anisotropy can be ascribed to the surface anisotropy, the magnetostrictive anisotropy, and the shape anisotropy caused, respectively, by the magnetic charges on wavy morphology, the residual mechanical stress, and the inhomogeneous thickness of FeGa films.

  12. Characterization of crystalline structure and morphology of NiO thin films.

    Science.gov (United States)

    Shin, Hyemin; Choi, Soo-Bin; Yu, Chung-Jong; Kim, Jae-Yong

    2011-05-01

    We investigated the relation of sputtering powers with structural and morphological properties of nickel oxide (NiO) thin films. NiO thin films were fabricated by using an rf-reactive sputtering method on Si(100) substrates with a Ni target in a partial pressure of oxygen and argon. The films were deposited by various rf-sputtering powers from 100 to 200 W at room temperature. The phases and crystalline structures of the deposited films were investigated by using grazing incident X-ray diffraction (XRD). The thickness and surface morphology of the films were investigated by using a field emission-scanning electron microscopy (FE-SEM). The different sputtering conditions drastically affected the crystallinity and the surface morphology of NiO thin films. A combined analysis of the data obtained from X-ray diffraction and SEM images demonstrates that the preferred orientation of NiO films tends to grow from (111) to (200) direction as increasing the sputtering power, which can be explained by in terms of the surface energy along the indexing plane in an fcc structure. As increasing the rf power, lattice constants decreased from 4.26 to 4.20 angstroms and samples became high-quality crystals. Under our experimental condition, NiO films prepared at 150 W with 20% partial pressure of oxygen and 7 cm distance from the sample to the target show the best quality of the crystal.

  13. Band Bending in Conjugated Polymer Films: Role of Morphology and Implications for Bulk Charge Transport Characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Green, Peter [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Wenderott, J. K. [University of Michigan; Dong, Ban Xuan [University of Michigan

    2017-08-14

    The performance of power conversion devices is impacted by the energy level alignment at the interface between the conjugated polymer and conductive substrate. While band bending has been known to vary between conjugated polymers, we show that the degree of band bending within the same polymer can be just as significant with morphology change. Specifically, a significant band bending effect, studied via Kelvin probe force microscopy (KPFM), was exhibited by poly(3-hexylthiophene) (P3HT) films fabricated using matrix assisted pulsed laser evaporation (MAPLE) in contrast to the conventional spin-cast P3HT films. This finding is associated with a broadening of the density of states (DOS) in the MAPLE-deposited P3HT films, originating from the more disordered structure of the film. These findings, to the best of our knowledge, illustrate for the first time a strong connection between morphology, energy level alignment, and bulk transport in conjugated polymer films.

  14. Composition, XRD and morphology study of laser prepared LiNbO{sub 3} films

    Energy Technology Data Exchange (ETDEWEB)

    Jelinek, M.; Remsa, J.; Kocourek, T. [Institute of Physics ASCR v.v.i., Prague 8 (Czech Republic); Czech Technical University in Prague, Faculty of Biomedical Engineering, Sitna, Kladno (Czech Republic); Havranek, V. [Nuclear Physics Institute ASCR, Rez near Prague (Czech Republic); Vincze, A.; Bruncko, J. [International Laser Centre, Bratislava 4 (Slovakia); Studnicka, V. [Institute of Physics ASCR v.v.i., Prague 8 (Czech Republic); Rubesova, K. [Institute of Chemical Technology, Prague 6 (Czech Republic)

    2013-03-15

    LiNbO{sub 3} films were deposited by PLD from LiNbO{sub 3} crystalline or from three different stoichiometric or Li-enriched LiNbO{sub 3} targets. Polycrystalline films were prepared on SiO{sub 2}/Si or sapphire substrates at temperatures T{sub S} {proportional_to}650-750 C. Main attention was paid to the influence of targets preparation and the deposition conditions on films composition, morphology and crystallinity. The thin-film morphology was determined by SEM microscopy. The composition was measured by SIMS, RBS, PIXE and PIGE methods. Highly oriented, smooth and stoichiometric LiNbO{sub 3} films were synthesized. (orig.)

  15. Molecular Strategies for Morphology Control in Semiconducting Polymers for Optoelectronics.

    Science.gov (United States)

    Rahmanudin, Aiman; Sivula, Kevin

    2017-06-28

    Solution-processable semiconducting polymers have been explored over the last decades for their potential applications in inexpensively fabricated transistors, diodes and photovoltaic cells. However, a remaining challenge in the field is to control the solid-state self-assembly of polymer chains in thin films devices, as the aspects of (semi)crystallinity, grain boundaries, and chain entanglement can drastically affect intra-and inter-molecular charge transport/transfer and thus device performance. In this short review we examine how the aspects of molecular weight and chain rigidity affect solid-state self-assembly and highlight molecular engineering strategies to tune thin film morphology. Side chain engineering, flexibly linking conjugation segments, and block co-polymer strategies are specifically discussed with respect to their effect on field effect charge carrier mobility in transistors and power conversion efficiency in solar cells. Example systems are taken from recent literature including work from our laboratories to illustrate the potential of molecular engineering semiconducting polymers.

  16. Multi-scale characterization of surface blistering morphology of helium irradiated W thin films

    Energy Technology Data Exchange (ETDEWEB)

    Yang, J.J., E-mail: jjyang@scu.edu.cn [Key Laboratory of Radiation Physics and Technology of Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu, Sichuan 610064 (China); Zhu, H.L. [Key Laboratory of Radiation Physics and Technology of Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu, Sichuan 610064 (China); Wan, Q. [Institute of Structural Mechanics, China Academy of Engineering Physics, Mianyang, Sichuan 621900 (China); Peng, M.J. [Key Laboratory of Radiation Physics and Technology of Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu, Sichuan 610064 (China); Ran, G., E-mail: gran@xmu.edu.cn [School of Energy Research, Xiamen University, Xiamen, Fujian 361005 (China); Tang, J.; Yang, Y.Y.; Liao, J.L.; Liu, N. [Key Laboratory of Radiation Physics and Technology of Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu, Sichuan 610064 (China)

    2015-09-01

    Highlights: • Multi-scale blistering morphology of He irradiated W film was studied. • This complex morphology was first characterized by wavelet transform approach. - Abstract: Surface blistering morphologies of W thin films irradiated by 30 keV He ion beam were studied quantitatively. It was found that the blistering morphology strongly depends on He fluence. For lower He fluence, the accumulation and growth of He bubbles induce the intrinsic surface blisters with mono-modal size distribution feature. When the He fluence is higher, the film surface morphology exhibits a multi-scale property, including two kinds of surface blisters with different characteristic sizes. In addition to the intrinsic He blisters, film/substrate interface delamination also induces large-sized surface blisters. A strategy based on wavelet transform approach was proposed to distinguish and extract the multi-scale surface blistering morphologies. Then the density, the lateral size and the height of these different blisters were estimated quantitatively, and the effect of He fluence on these geometrical parameters was investigated. Our method could provide a potential tool to describe the irradiation induced surface damage morphology with a multi-scale property.

  17. Atomic Force Microscopy Studies on The Surface Morphologies of Chemical Bath Deposited Cus Thin Films

    Directory of Open Access Journals (Sweden)

    Ho Soonmin

    2016-06-01

    Full Text Available In this work, copper sulphide thin films were deposited onto microscope glass slide by chemical bath deposition technique. The tartaric acid was served as complexing agent to chelate with Cu2+ to obtain complex solution. The influence of pH value on the surface morphologies of the films has been particularly investigated using the atomic force microscopy technique. The atomic force microscopy results indicate that the CuS films deposited at pH 1 were uniform, compact and pinhole free. However, the incomplete surface coverage observed for the films prepared at high pH (pH 2 and 2.5 values.

  18. Thermal stability, optical property, and morphology of flexible organoclay films.

    Science.gov (United States)

    Shin, Jieun; Chang, Jin-Hae

    2011-07-01

    Novel organo-saponite (organo-SPT) films with excellent thermal stability and optical property were synthesized by solution casting. Na ion-exchanged saponite (pristine SPT), hexadecylammonium ion-exchanged SPT (C16-SPT), hexadecyltriphenyl phosphonium ion-exchanged SPT (C16PPh3-SPT), and tetraphenyl phosphonium ion-exchanged SPT (PPh4-SPT) were used to prepare clay films. We examined the relationship between the structures and properties of the various SPT films. SPT films were examined by means of wide-angle X-ray diffraction (XRD), electronic microscopy (FE-SEM), thermogravimetric analysis (TGA), ultraviolet-visible (UV-vis.) spectrometer. On the basis of these analyses, we sought to improve both the thermal stability and the optical properties. Clay films composed of C16PPh3-SPT and PPh4-SPT were found to be more thermally stable than those composed of pristine SPT or C16-SPT. On the other hand, the transmittance was not significantly affected by variations in the organo-SPT material.

  19. New insights in the structural and morphological properties of sol-gel deposited ZnO multilayer films

    Science.gov (United States)

    Demes, T.; Ternon, C.; Riassetto, D.; Roussel, H.; Rapenne, L.; Gélard, I.; Jimenez, C.; Stambouli, V.; Langlet, M.

    2016-08-01

    This study shows how the structural and morphological properties of sol-gel deposited ZnO films can be precisely tuned and selectively controlled. For that purpose, ZnO films have been deposited through a multilayer sol-gel route using solutions of zinc acetate dihydrate (ZAD) diluted in 1-butanol. The opto-geometrical, morphological, and structural properties of these films have been thoroughly studied in relation to the ZAD concentration in butanol, number of deposited single-layers, and heat-treatment conditions. On this basis, different physical processes occurring over the multilayer deposition procedure have been discussed to explain how the experimental parameters influence the film properties and enable to tune the grain size, texture coefficient, and surface coverage rate in a wide range of values. This work is a first step toward the optimized growth of ZnO nanowires on sol-gel films and their subsequent integration in 2D or 3D nanowire-based biosensors.

  20. Thickness effect on the microstructure, morphology and optoelectronic properties of ZnS films

    Science.gov (United States)

    Prathap, P.; Revathi, N.; Venkata Subbaiah, Y. P.; Ramakrishna Reddy, K. T.

    2008-01-01

    Thin films of ZnS with thicknesses ranging from 100 to 600 nm have been deposited on glass substrates by close spaced thermal evaporation. All the films were grown at the same deposition conditions except the deposition time. The effect of thickness on the physical properties of ZnS films has been studied. The experimental results indicated that the thickness affects the structure, lattice strain, surface morphology and optoelectronic properties of ZnS films significantly. The films deposited at a thickness of 100 nm showed hexagonal structure whereas films of thickness 300 nm or more showed cubic structure. However, coexistence of both cubic and hexagonal structures was observed in the films of 200 nm thickness. The surface roughness of the films showed an increasing trend at higher thicknesses of the films. A blue-shift in the energy band gap along with an intense UV emission band was observed with the decrease of film thickness, which are ascribed to the quantum confinement effect. The behaviour of optical constants such as refractive index and extinction coefficient were analysed. The variation of refractive index and extinction coefficient with thickness was explained on the basis of the contribution from the packing density of the layers. The electrical resistivity as well as the activation energy were evaluated and found to decrease with the increase of film thickness. The thickness had a significant influence on the optical band gap as well as the luminescence intensity.

  1. Controlled antiseptic release by alginate polymer films and beads.

    Science.gov (United States)

    Liakos, Ioannis; Rizzello, Loris; Bayer, Ilker S; Pompa, Pier Paolo; Cingolani, Roberto; Athanassiou, Athanassia

    2013-01-30

    Biodegradable polymeric materials based on blending aqueous dispersions of natural polymer sodium alginate (NaAlg) and povidone iodine (PVPI) complex, which allow controlled antiseptic release, are presented. The developed materials are either free standing NaAlg films or Ca(2+)-cross-linked alginate beads, which properly combined with PVPI demonstrate antibacterial and antifungal activity, suitable for therapeutic applications, such as wound dressing. Glycerol was used as the plasticizing agent. Film morphology was studied by optical and atomic force microscopy. It was found that PVPI complex forms well dispersed circular micro-domains within the NaAlg matrix. The beads were fabricated by drop-wise immersion of NaAlg/PVPI/glycerol solutions into aqueous calcium chloride solutions to form calcium alginate beads encapsulating PVPI solution (CaAlg/PVPI). Controlled release of PVPI was possible when the composite films and beads were brought into direct contact with water or with moist media. Bactericidal and fungicidal properties of the materials were tested against Escherichia coli bacteria and Candida albicans fungi. The results indicated very efficient antibacterial and antifungal activity within 48 h. Controlled release of PVPI into open wounds is highly desired in clinical applications to avoid toxic doses of iodine absorption by the wound. A wide variety of applications are envisioned such as external and internal wound dressings with controlled antiseptic release, hygienic and protective packaging films for medical devices, and polymer beads as water disinfectants.

  2. Synthesis and photoluminescence enhancement of nano-PAA-ZnCl2 with controllable dimension and morphology

    Science.gov (United States)

    Wu, Jianguo; Wang, Kaige; Zhou, Yukun; Wang, Shuang; Zhang, Chen; Wang, Guiren; Bai, Jintao

    2016-12-01

    One kind of ZnCl2 nano-films with controllable dimension and morphology is successfully synthesized on the top surface of nano-porous anodic alumina membrane (nano-PAAM) by self-organized method. The nano-PAA-ZnCl2 composite films are characterized by field emission scanning electron microscopy, energy dispersive spectrometer, and laser confocal Raman spectroscopy. The results indicate that the concentration of initial ZnCl2 solution, the depth of nano-PAAM substrate and the growth time of ZnCl2 crystals have important influences on the properties of nano-composite films. Furthermore, the characteristics of nano-composites such as the photoluminescence (PL) spectra are investigated. Compared with the nano-PAAM substrate, at room temperature, all of the nano-PAA-ZnCl2 composite films have both the same excitation center (335 nm) and emission center (430 nm), no matter what the nano-composite morphologies being; and the PL intensity of nano-PAA-ZnCl2 composite films are all enhanced and the maximum enhancement is two times; after annealing at 500 °C, the emission spectra of the nano-composite films stabilized at the 385 nm, 402 nm and 430 nm. The research provides a new, simple, economical and practical technology to fabricate nano-PAA composite films with higher luminousintensity.

  3. Structural, morphological and Raman studies of pulse electrosynthesised indium antimonide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Joginder, E-mail: joginderchauhan82@gmail.com; Chandel, Tarun; Rajaram, P. [School of Studies in Physics, Jiwaji University, Gwalior (MP), India-474011 (India)

    2015-08-28

    InSb films deposited on fluorine doped tin oxide (FTO) substrates by a pulse elctrodeposition technique. The deposition was carried out at an applied potential −1.3V versus Ag/AgCl electrode. Structural, morphological and optical studies were performed on the electrodeposited InSb. X-ray diffraction (XRD) studies show that the deposited InSb films are polycrystalline in nature having the zinc blend structure. The crystallite size (D), dislocation density (δ) and strain (ε) were calculated using XRD results. The EDAX analysis shows that chemical composition of In{sup 3+} and Sb{sup 3+} ions is close to the required stoichiometry. The surface morphology of the deposited films was examined using scanning electron microscopy (SEM). SEM studies reveal that the surface of the films is uniformly covered with submicron sized spherical particles. However, the crystallite size determined by the Scherrer method shows a size close to 30 nm. Surface morphology studies of the InSb films were also performed using atomic force microscopy (AFM). The average surface roughness as measured by AFM is around 40 nm. Hot probe studies show that all the electrodeposited thin films have n type conductivity and the thickness of the films is calculated using electrochemical formula.

  4. Effect of Applied Current Density on Morphological and Structural Properties of Electrodeposited Fe-Cu Films

    Institute of Scientific and Technical Information of China (English)

    Umut Sarac; M. Celalettin Baykul

    2012-01-01

    A detailed study has been carried out to investigate the effect of applied current density on the composition, crystallographic structure, grain size, and surface morphology of Fe-Cu films. X-ray diffraction (XRD) results show that the films consist of a mixture of face-centered cubic (fcc) Cu and body centered cubic (bcc) ~-Fe phases. The average crystalline size of both Fe and Cu particles decreases as the applied current density becomes more negative. Compositional analysis of Fe-Cu films indicates that the Fe content within the films increases with decreasing current density towards more negative values. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) have been used to investigate the surface morphology of Fe-Cu films. It is observed that the surface morphology of the films changes from dendritic structure to a cauliflower structure as the applied current density becomes more negative. The surface roughness and grain size of the Fe-Cu films decrease with decreasing applied current density towards more negative values.

  5. Morphological instability in epitaxially strained dislocation-free solid films - Linear stability theory

    Science.gov (United States)

    Spencer, B. J.; Voorhees, P. W.; Davis, S. H.

    1993-01-01

    The morphological instability of a growing epitaxially strained dislocation-free solid film is analyzed. An evolution equation for the film surface is derived in the dilute limit of vacancies based on surface diffusion driven by a stress-dependent chemical potential. From the time-dependent linear stability problem the conditions for which a growing film is unstable are determined. It is found that the instability is driven by the lattice mismatch between the film and the substrate; however, low temperatures as well as elastically stiff substrates are stabilizing influences. The results also reveal that the critical film thickness for instability depends on the growth rate of the film itself. Detailed comparison with experimental observations indicates that the instability described exhibits many of the observed features of the onset of the 'island instability'.

  6. Achieving 3-D Nanoparticle Assembly in Nanocomposite Thin Films via Kinetic Control

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Jingyu; Xiao, Yihan; Xu, Ting [UCB

    2017-02-20

    Nanocomposite thin films containing well-ordered nanoparticle (NP) assemblies are ideal candidates for the fabrication of metamaterials. Achieving 3-D assembly of NPs in nanocomposite thin films is thermodynamically challenging as the particle size gets similar to that of a single polymer chain. The entropic penalties of polymeric matrix upon NP incorporation leads to NP aggregation on the film surface or within the defects in the film. Controlling the kinetic pathways of assembly process provides an alternative path forward by arresting the system in nonequilibrium states. Here, we report the thin film 3-D hierarchical assembly of 20 nm NPs in supramolecules with a 30 nm periodicity. By mediating the NP diffusion kinetics in the supramolecular matrix, surface aggregation of NPs was suppressed and NPs coassemble with supramolecules to form new 3-D morphologies in thin films. The present studies opened a viable route to achieve designer functional composite thin films via kinetic control.

  7. Upper spine morphology in hypophosphatemic rickets and healthy controls

    DEFF Research Database (Denmark)

    Gjørup, Hans; Sonnesen, Liselotte; Beck-Nielsen, Signe S

    2014-01-01

    BACKGROUND/OBJECTIVES: The aim of this study was to describe upper spine morphology in adult patients with hypophosphatemic rickets (HR) compared with controls to assess differences in spine morphology in terms of severity of skeletal impact and to study associations between spine morphology and ...

  8. Surface morphology of PS-PDMS diblock copolymer films

    DEFF Research Database (Denmark)

    Andersen, T.H.; Tougaard, S.; Larsen, N.B.

    2001-01-01

    Spin coated thin films (∼400 Å) of poly(styrene)–poly(dimethylsiloxane) (PS–PDMS) diblock copolymers have been investigated using X-ray Photoelectron Spectroscopy and Atomic Force Microscopy. Surface segregation of the poly(dimethylsiloxane) blocks was studied for five diblock copolymers which...

  9. Morphology reliance of cobalt sulfide thin films: A chemo-thermo-mechanical perception

    Energy Technology Data Exchange (ETDEWEB)

    Kamble, S.S. [Thin Film & Solar Studies Research Laboratory, Solapur University, Solapur 413 255, M.S. (India); Sikora, A. [Electrotechnical Institute, Division of Electrotechnology & Materials Science, ul. M Skłodowskiej-Curie 55/61, 50-369 Wroclaw (Poland); Pawar, S.T. [Thin Film & Solar Studies Research Laboratory, Solapur University, Solapur 413 255, M.S. (India); Kambale, R.C. [Department of Physics, University of Pune, Ganeshkhind, Pune 411 007, M.S. (India); Maldar, N.N. [School of Chemical Sciences, Solapur University, Solapur 413 255, M.S. (India); Deshmukh, L.P., E-mail: laldeshmukh@gmail.com [Thin Film & Solar Studies Research Laboratory, Solapur University, Solapur 413 255, M.S. (India)

    2015-05-15

    Highlights: • Optimized heterogeneous growth process for the deposition of CoS thin films. • As-obtained CoS thin films exhibit hexagonal crystal structure. • Optimized CoS thin films were Co{sup 2+} rich in nature. • Magnetic force microscopy revealed randomly scattered magnetic constellations. - Abstract: We report onto the morphology dependency of CoS thin films by studying the role of mechanical agitation, thermal assistance and deposition duration in an aqueous alkaline bath (pH = 9 ± 0.1). The deposition of CoS thin films was carried out at different mechanical stirring rates, deposition temperatures and times. As-optimized CoS thin film were of polycrystalline nature and exhibited hexagonal crystal structure. Co{sup 2+} rich nature (≈85%) of optimistically grown thin film was detected. Complex multifaceted webbed network of as-grown elongated and threaded into each other CoS crystals was observed through a scanning electron microscope. Surface morphology was further studied by means of an atomic force microscopy. Existence of magnetic domains was marked in the magnetic force microscopy. As-grown CoS thin films were having transmission index of 0.5 with a band gap of ≈1.59 eV.

  10. Relationship between crystal morphology and photoluminescence in polynanocrystalline lead sulfide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Kaci, S., E-mail: k_samira05@yahoo.f [Silicon Technology Development Unit 2, Bd Frantz FANON, BP 140 Alger 7 Merveilles, Algiers (Algeria); Keffous, A. [Silicon Technology Development Unit 2, Bd Frantz FANON, BP 140 Alger 7 Merveilles, Algiers (Algeria); Trari, M. [Houari Boumediene Science and Technology University (USTHB), Chemical Faculty, Algiers (Algeria); Fellahi, O.; Menari, H.; Manseri, A. [Silicon Technology Development Unit 2, Bd Frantz FANON, BP 140 Alger 7 Merveilles, Algiers (Algeria); Guerbous, L. [Algiers Nuclear Research Center, Algiers (Algeria)

    2010-10-15

    Thin films of lead sulfide (PbS) nanoparticles were grown on corning glass and Si(1 0 0) substrates by polyethylene glycol-assisted chemical bath deposition (CBD) method. This paper compares the morphology and the luminescence properties (PL) of the deposited thin films in the presence (or absence) of PEG300 and investigates the effect of deposition temperatures. Surface morphology and photoluminescence properties of samples were analyzed. The PL data show a blue-shift from the normal emission at {approx}2900 nm in PbS bulk to {approx}360 nm in nanoparticles of PbS thin films. Furthermore, the PL emission of the films obtained without the addition of PEG300 (type 1) was slightly shifted from that of the films obtained in presence of PEG300 (type 2) from {approx}360 to {approx}470 nm. The blue-shifting of the emission wavelengths from 2900 to {approx}360 or 470 nm is attributed to quantum confinement of charge carriers in the restricted volume of nanoparticles, while the shift between the two types of PbS nanoparticles thin films is speculated to be due to an increase in the defect concentration. The blue-shift increased with increase of the deposition temperature, which suggests that there has been a relative depletion in particle sizes during the CBD of the films at higher temperatures. The PbS nanocrystalline thin films obtained in the presence of PEG300 at 60 {sup o}C exhibit a high blue luminescence.

  11. Fabrication processing effects on the microstructure and morphology of erbium film

    Institute of Scientific and Technical Information of China (English)

    Shen Hua-Hai; Peng Shu-Ming; Long Xing-Gui; Zhou Xiao-Song; Yang Li; Liu Jin-Hua; Sun Qing-Qiang; Zu Xiao-Tao

    2012-01-01

    The effect of substrate temperature on the microstructure and the morphology of erbium film are systematically investigated using X-ray diffraction (XRD) and scanning electron microscopy (SEM).All the erbium films are grown by electron-beam vapor deposition (EBVD).A novel preparation method for observing the cross-section morphology of the erbium film is developed.The films deposited at 200 ℃ have (002) preferred orientation,and the films deposited at 450 ℃ have a mixed (100) and (101) texture,due to the different growth mechanisms of surface energy minimization and recrystallization,respectively.The peak positions and the full widths at half maximum (FWHMs) of erbium diffraction lines (100),(002),and (101) shift towards higher angles and decrease with the increasing substrate temperature in a largely uniform manner,respectively.Also,the lattice constants decrease with increasing temperature.The transition in the film stresses can be used to interpret the changes in peak positions,FWHMs,and lattice constants.The stress is compressive for the as-growth films,and is counteracted by the tensile strees formed during the process of temperature cooling to room temperature.The tensile stress mainly originates from the difference in the coefficients of thermal expansion of the substrate-film couple.

  12. Effect of oxygen on the surface morphology of CuGaS{sub 2} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Smaili, F., E-mail: fethi.smaili@voila.fr [Laboratoire de Photovoltaique et Materiaux Semi-conducteurs -ENIT BP 37, Le belvedere 1002-Tunis (Tunisia); Kanzari, M. [Laboratoire de Photovoltaique et Materiaux Semi-conducteurs -ENIT BP 37, Le belvedere 1002-Tunis (Tunisia)

    2009-08-01

    Since the effect of oxygen is very significant during the heat treatment of the thin films, we study the effect of this during the annealing of CuGaS{sub 2} thin films by two different types. In this study, CuGaS{sub 2} thin films were deposited by vacuum thermal evaporation of CuGaS{sub 2} powder on heated glass substrates at 200 deg. C submitted to a thermal gradient. The films are annealed in air and under nitrogen atmosphere at 400 deg. C for 2 h. In order to improve our understanding of the influence of oxygen during two annealing types on device performance, we have investigated our CuGaS{sub 2} material by X-ray diffraction, scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive X-ray analysis (EDX) and spectrophotometry. A correlation was established between the surface roughness, growth morphology and optical properties, of the annealed CuGaS{sub 2} thin films. It was found that annealing of CuGaS{sub 2} film in nitrogen atmosphere leads to a decrease of the mean grain size and to an evolution of a (112) preferred film orientation. Annealing in air results in the growth of oxide phases such as CuO and modifies the films structure and their surface morphology.

  13. Morphological and optical investigation of Sol-Gel ZnO films

    Science.gov (United States)

    Ivanova, T.; Harizanova, A.; Petrova, A.

    2016-03-01

    This paper presents morphological and optical studies of the properties of spin-coated ZnO films depending on the annealing temperatures. The films microstructure was explored using a scanning nano-hardness measuring device of the NanoScan family, based on the principles of atomic force microscopy, in a constant frequency mode. The surface study revealed that the root-mean-square (RMS) surface roughness of 985.64×985.64 nm ZnO films becomes greater with the increase of the annealing temperature, but the film surface remains uniform and smooth. The results were confirmed by XRD analysis, which demonstrated that the crystallite size grew from 25 to 36 nm with the thermal treatments. The ZnO films possessed high transmittance in the visible spectral range and the optical band gaps in ZnO films varied from 3.25 eV to 3.52 eV. The optical and morphological properties of the ZnO films formed on Si and quartz substrates are very good. The sol-gel approach proposed for deposition of nanostructured ZnO films is promising for applications in optoelectronic devices or solar cells.

  14. Morphology of superconducting FeSe thin films grown by MBE and RF-sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Kronenberg, Alexander; Venzmer, Eike; Haaf, Sebastian ten; Jourdan, Martin [Institut fuer Physik, Johannes Gutenberg Universitaet Mainz (Germany); Maletz, Janek [Institut fuer Physik, Johannes Gutenberg Universitaet Mainz (Germany); Leibniz-Institut fuer Festkoerper- und Werkstoffforschung, Dresden (Germany)

    2013-07-01

    Tunneling spectroscopy on planar junctions is the most direct approach for the investigation of superconducting coupling mechanisms. However, it requires smooth interfaces at the tunneling barrier. The morphology of superconducting thin films of FeSe grown by MBE and co-sputtering (RF) from an iron and a selenium target are compared. MBE deposited films show an extreme sensitivity to stoichiometry, deposition temperature and choice of substrate. These films exhibit macroscopic crevices and a pronounced roughness, rendering the preparation of tunneling junctions impossible. However, sputter deposited epitaxial FeSe thin films clearly show a more favorable morphology. Optical microscopy, AFM and SEM demonstrate a smooth surface with segregations which are eliminated by proper choice of the deposition parameters.

  15. Correlation between composition, morphology and optical properties of PVK: n-ZnO:CTAB thin films

    Science.gov (United States)

    Azizi, Samir; Belhaj, Marwa; Zargouni, Sarra; Dridi, Cherif

    2017-07-01

    In this study, we report on the effect of zinc oxide nanoparticles ( n-ZnO) content and surfactant addition on the performance of poly ( N-vinylcarbazole) (PVK): n-ZnO nanocomposite thin films. Morphological and optical properties of ZnO, PVK and PVK: n-ZnO:cetyltrimethyl ammonium bromide (CTAB) hybrid films were investigated by atomic force microscopy (AFM), UV-Visible spectrophotometry and photoluminescence (PL) spectroscopy. We noticed that surface morphology was very dependent on surfactant addition into inorganic and organic components and on the ZnO content in the mixture. The optical absorption spectra of PVK: n-ZnO thin films showed a red shift of the optical band gap energy. Besides, PL measurements demonstrated an interfacial charge transfer between PVK matrix and ZnO nanoparticles through the reduced PL intensity of nanocomposites compared to PVK thin films.

  16. Structural and morphological characterization of CdSe:Mn thin films

    Indian Academy of Sciences (India)

    SARIKA SINGH; A K SHRIVASTAVA

    2017-07-01

    CdSe:Mn thin films were grown by chemical bath deposition. The pH of the solution was maintained at 11. Dry films so obtained were annealed in vacuum ($10^{−1}$ Torr) for about 2 h at 400$^{\\circ}$C. The annealed samples were subjected to morphological and structural characterization using scanning electron microscope and XRD. XRD was used for structural characterization whereas scanning electron microscope shows the surface morphology of the films. XRD spectra reveal that the grown CdSe films are polycrystalline in nature and have cubic structure. The average particle size decreases on doping CdSe with Mn ions. The FE-SEM images show spherical particles having uniform distribution. Optical characterization was done using PL studies and UV–Visible spectrophotometer. PL spectra show an increase in PL intensity on doping. Optical band gap also decreases on doping.

  17. Frictional and morphological properties of Au-MoS2 films sputtered from a compact target

    Science.gov (United States)

    Spalvins, T.

    1984-01-01

    AuMoS2 films 0.02 to 1.2 microns thick were sputtered from target compacted from 5 wt % Au + 95 wt % MoS2, to investigate the frictional and morphological film growth characteristics. The gold dispersion effects in MoS2 films are of interest to increase the densitification and strengthening of the film structure. Three microstructural growth stages were identified on the nano-micro-macrostructural level. During sliding both sputtered Au-MoS2 and MoS2 films have a tendency to break within the columner region. The remaining or effective film, about 0.2 microns thick, performs the lubrication. The Au-MoS2 films displayed a lower friction coefficient with a high degree of frictional stability and less wear debris generation as compared to pure MoS2 films. The more favorable frictional characteristics of the Au-MoS2 films are attributed to the effective film thickness and the high density packed columner zone which has a reduced effect on the fragmentation of the tapered crystallites during fracture.

  18. Sputtered Ag thin films with modified morphologies: Influence on wetting property

    Energy Technology Data Exchange (ETDEWEB)

    Dutheil, P., E-mail: perrine.dutheil@univ-orleans.fr [GREMI, UMR 7344- Université D’Orléans, 14 rue d’Issoudun, BP 6744, Orléans 45067 (France); Thomann, A.L.; Lecas, T.; Brault, P. [GREMI, UMR 7344- Université D’Orléans, 14 rue d’Issoudun, BP 6744, Orléans 45067 (France); Vayer, M. [ICMN, UMR 7374- Université D’Orléans, 1b rue de la Férollerie, Orléans 45071 (France)

    2015-08-30

    Graphical abstract: - Highlights: • Ag thin films are deposited by DC magnetron sputtering on Si and W/Si layers. • The influence of the W underlayer morphology on Ag film growth is evidenced. • Variation of the Ag growth mode and roughness is investigated by SEM and AFM. • Wetting property is correlated to the roughness of Ag deposits on Si and W layers. - Abstract: Silver thin films with thickness ranging from 3 nm to 33 nm were sputter deposited onto silicon wafers and tungsten layers. Those W layers were previously synthesized in the same DC magnetron sputter deposition system with various experimental conditions (argon pressure, target to substrate distance) in order to stabilize different surface morphologies. SEM observations and AFM images showed that the growth mode of Ag films is similar on Si substrates and on the smoothest W layers, whereas it is modified for rough W layers made of sharp grains. The effect of the W layer morphology on Ag film growth was clearly evidenced when the deposition took place at high temperature. It is seen that performing the deposition onto substrates of various morphologies allows tailoring the wetting property of the Ag deposit.

  19. Surface scanning inspection system particle detection dependence on aluminum film morphology

    Science.gov (United States)

    Prater, Walter; Tran, Natalie; McGarvey, Steve

    2012-03-01

    Physical vapor deposition (PVD) aluminum films present unique challenges when detecting particulate defects with a Surface Scanning Inspection System (SSIS). Aluminum (Al) films 4500Å thick were deposited on 300mm particle grade bare Si wafers at two temperatures using a Novellus Systems INOVA® NExT,.. Film surface roughness and morphology measurements were performed using a Veeco Vx310® atomic force microscope (AFM). AFM characterization found the high deposition temperature (TD) Al roughness (Root Mean Square 16.5 nm) to be five-times rougher than the low-TD Al roughness (rms 3.7 nm). High-TD Al had grooves at the grain boundaries that were measured to be 20 to 80 nm deep. Scanning electron microscopy (SEM) examination, with a Hitachi RS6000 defect review SEM, confirmed the presence of pronounced grain grooves. SEM images established that the low-TD filmed wafers have fine grains (0.1 to 0.3 um diameter) and the high-TD film wafers have fifty-times larger equiaxed plateletshape grains (5 to 15 um diameter). Calibrated Poly-Styrene Latex (PSL) spheres ranging in size from 90 nm to 1 μm were deposited in circular patterns on the wafers using an aerosol deposition chamber. PSL sphere depositions at each spot were controlled to yield 2000 to 5000 counts. A Hitachi LS9100® dark field full wafer SSIS was used to experimentally determine the relationship of the PSL sphere scattered light intensity with S-polarized light, a measure of scattering cross-section, with respect to the calibrated PSL sphere diameter. Comparison of the SSIS scattered light versus PSL spot size calibration curves shows two distinct differences. Scattering cross-section (intensity) of the PSL spheres increased on the low-TD Al film with smooth surface roughness and the low-TD Al film defect detection sensitivity was 126 nm compared to 200 nm for the rougher high- TD Al film. This can be explained by the higher signal to noise attributed to the smooth low-TD Al. Dark field defect detection on

  20. Polymer Brush Grafted Nanoparticles and Their Impact on the Morphology Evolution of Polymer Blend Films

    Science.gov (United States)

    Chung, Hyun-Joong; Ohno, Kohji; Composto, Russell

    2013-03-01

    We present an novel pathway to control the location of nanoparticles (NPs) in phase-separating polymer blend films containing poly(methyl methacrylate) (PMMA) and poly(styrene-ran-acrylonitrile) (SAN). Because hydrophobic polymer phases have a small interfacial energy, ~1 mJ/m2, subtle changes in the NP surface functionality can be used to guide NPs to either the interface between immiscible polymers or into one of the phases. Based on this idea, we designed a class of NPs grafted with PMMA brushes. These PMMA brushes were grown from the NP surface by atom transfer radical polymerization (ATRP), which results in chains terminated with chlorine atoms. The chain end can be substituted with protons (H) by dehalogenation. As a result, the NPs are strongly segregated at the interface when grafted PMMA chains are short (Mn =1.8K) and the end group is Cl, whereas NPs partition into PMMA-rich phase when chains are long (Mn =160K) and/or when chains are terminated with hydrogen. The Cl end groups and shorter chain length cause an increase in surface energy for the NPs. The increase in surface energy of short-chained NPs can be attributed to (i) an extended brush conformation (entropic) and/or (ii) a high density of ``unfavorable'' end groups (enthalpic). Finally, the impact of NPs on the morphological evolution of the polymer blend films will be discussed. Ref: H.-J.Chung et al., ACS Macro Lett. 1(1), 252-256 (2012).

  1. Organic semiconductor growth and morphology considerations for organic thin-film transistors.

    Science.gov (United States)

    Virkar, Ajay A; Mannsfeld, Stefan; Bao, Zhenan; Stingelin, Natalie

    2010-09-08

    Analogous to conventional inorganic semiconductors, the performance of organic semiconductors is directly related to their molecular packing, crystallinity, growth mode, and purity. In order to achieve the best possible performance, it is critical to understand how organic semiconductors nucleate and grow. Clever use of surface and dielectric modification chemistry can allow one to control the growth and morphology, which greatly influence the electrical properties of the organic transistor. In this Review, the nucleation and growth of organic semiconductors on dielectric surfaces is addressed. The first part of the Review concentrates on small-molecule organic semiconductors. The role of deposition conditions on film formation is described. The modification of the dielectric interface using polymers or self-assembled mono-layers and their effect on organic-semiconductor growth and performance is also discussed. The goal of this Review is primarily to discuss the thin-film formation of organic semiconducting species. The patterning of single crystals is discussed, while their nucleation and growth has been described elsewhere (see the Review by Liu et. al).([¹]) The second part of the Review focuses on polymeric semiconductors. The dependence of physico-chemical properties, such as chain length (i.e., molecular weight) of the constituting macromolecule, and the influence of small molecular species on, e.g., melting temperature, as well as routes to induce order in such macromolecules, are described.

  2. GISAXS View of Induced Morphological Changes in Nanostructured CeVO4 Thin Films

    Directory of Open Access Journals (Sweden)

    Magdy Lučić Lavčević

    2011-01-01

    Full Text Available Nanostructured CeVO4 films, designed for applications in electrochemical cells and electrochromic devices, were obtained on glass substrates by the sol-gel process. An analysis of morphological modifications in these films, induced by ultrasonication, annealing, and introduction of lithium ions, was performed, using the grazing-incidence small-angle X-ray scattering technique (GISAXS. The GISAXS results are discussed and related with complementary examinations of the same films in real space, performed by scanning electron microscopy on a different length scale.

  3. Composite Films of Arabinoxylan and Fibrous Sepiolite: Morphological, Mechanical, and Barrier Properties

    DEFF Research Database (Denmark)

    Sárossy, Zsuzsa; Blomfeldt, J.O.; Hedenqvist, Mikael S.

    2012-01-01

    in the arabinoxylan films and sepiolite fiber aggregation was not found. FT-IR spectroscopy provided some evidence for hydrogen bonding between sepiolite and arabinoxylan. Consistent with these findings, mechanical testing showed increases in film stiffness and strength with sepiolite addition and the effect of poly(ethylene...... glycol) methyl ether (mPEG) plasticizer addition. Incorporation of sepiolite did not significantly influence the thermal degradation or the gas barrier properties of arabinoxylan films, which is likely a consequence of sepiolite fiber morphology. In summary, sepiolite was shown to have potential...

  4. Effects of heat treatment on morphological, optical and electrical properties of ITO films by sol-gel technique

    Institute of Scientific and Technical Information of China (English)

    LI Zhi-hua; KE Yu-peng; REN Dong-yan

    2008-01-01

    Indium-tin-oxide(ITO) films were prepared on the quarts glass by sol-gel technique. Effects of different heat treatment temperatures and cooling methods on the morphological, optical and electrical properties of ITO films were measured by TG/DTA, IR, XRD, SEM, UV-VIS spectrometer and four-probe apparatus. It is found that the crystallized ITO films exhibit a polycrystalline cubic bixbyite structure. The heat treatment process has significant effects on the morphological, optical and electrical properties of ITO films. Elevating the heat treatment temperature can perfect the crystallization process of ITO films, therefore the optical and electrical properties of ITO films are improved. But the further increasing of heat treatment temperature results in the increment of ITO films' resistivity. Compared with ITO films elaborated by furnace cooling, those prepared through air cooling have following characteristics as obviously decreased crystalline size, deeply declined porosity, more compact micro-morphology, improved electrical property and slightly decreased optical transmission.

  5. Morphology Development in Solution-Processed Functional Organic Blend Films: An In Situ Viewpoint

    KAUST Repository

    Richter, Lee J.

    2017-04-17

    Solution-processed organic films are a facile route to high-speed, low cost, large-area deposition of electrically functional components (transistors, solar cells, emitters, etc.) that can enable a diversity of emerging technologies, from Industry 4.0, to the Internet of things, to point-of-use heath care and elder care. The extreme sensitivity of the functional performance of organic films to structure and the general nonequilibrium nature of solution drying result in extreme processing-performance correlations. In this Review, we highlight insights into the fundamentals of solution-based film deposition afforded by recent state-of-the-art in situ measurements of functional film drying. Emphasis is placed on multimodal studies that combine surface-sensitive X-ray scattering (GIWAXS or GISAXS) with optical characterization to clearly define the evolution of solute structure (aggregation, crystallinity, and morphology) with film thickness.

  6. Effects of annealing time on the structure, morphology, and stress of gold-chromium bilayer film

    Science.gov (United States)

    Zhang, Hong; Jin, Yun-Xia; Wang, Hu; Kong, Fang-Yu; Huang, Hao-Peng; Cui, Yun

    2016-10-01

    In this work, a 200-nm-thick gold film with a 10-nm-thick chromium layer used as an adhesive layer is fabricated on fused silica by the electron beam evaporation method. The effects of annealing time at 300 °C on the structure, morphology and stress of the film are studied. We find that chromium could diffuse to the surface of the film by formatting a solid solution with gold during annealing. Meanwhile, chromium is oxidized on the surface and diffused downward along the grain grooves in the gold film. The various operant mechanisms that change the residual stresses of gold films for different annealing times are discussed. Project supported by the National Natural Science Foundation of China (Grant No. 61405225).

  7. Structural and morphological properties of metallic thin films grown by pulsed laser deposition for photocathode application

    Science.gov (United States)

    Lorusso, A.; Gontad, F.; Caricato, A. P.; Chiadroni, E.; Broitman, E.; Perrone, A.

    2016-03-01

    In this work yttrium and lead thin films have been deposited by pulsed laser deposition technique and characterized by ex situ different diagnostic methods. All the films were adherent to the substrates and revealed a polycrystalline structure. Y films were uniform with a very low roughness and droplet density, while Pb thin films were characterized by a grain morphology with a relatively high roughness and droplet density. Such metallic materials are studied because they are proposed as a good alternative to copper and niobium photocathodes which are generally used in radiofrequency and superconducting radiofrequency guns, respectively. The photoemission performances of the photocathodes based on Y and Pb thin films have been also studied and discussed.

  8. Effect of morphology on the electrical transport properties of polyaniline films for electronic applications

    Energy Technology Data Exchange (ETDEWEB)

    Hardaker, S.S.; Eaiprasertsak, K.; Yon, J.; Gregory, R.V.; Tessema, G.X.

    1998-07-01

    Although it is well known that the oxidation state of polyaniline is an important characteristic, there are few reports of its influence on the development of morphology and electrical properties in fibers and films. In this work, differential scanning calorimetry is used in conjunction with measurements of temperature dependence of conductivity and thermoelectric power to elucidate the intimate relationship between structure and properties. By increasing the amount of chemical reduction of polyaniline solutions, films are repaired which exhibit a thermal transition between 300 and 385 C, indicative of melting. Increasing the chemical reduction also increases the conductivity of iodine doped films. The most reduced film exhibited a semiconductor transport mechanism, while the other films could be modeled with a quasi-one dimensional variable range hopping mechanism. The temperature dependence of conductivity also showed increasing order for increasing reduction, consistent with the DSC results.

  9. Physiochemical Characterization of Iodine (V Oxide Part II: Morphology and Crystal Structure of Particulate Films

    Directory of Open Access Journals (Sweden)

    Brian K. Little

    2015-11-01

    Full Text Available In this study, the production of particulate films of iodine (V oxides is investigated. The influence that sonication and solvation of suspended particles in various alcohol/ketone/ester solvents have on the physical structure of spin or drop cast films is examined in detail with electron microscopy, powder x-ray diffraction, and UV-visible absorption spectroscopy. Results indicate that sonicating iodine oxides in alcohol mixtures containing trace amounts of water decreases deposited particle sizes and produces a more uniform film morphology. UV-visible spectra of the pre-cast suspensions reveal that for some solvents, the iodine oxide oxidizes the solvent, producing I2 and lowering the pH of the suspension. Characterizing the crystals within the cast films reveal their composition to be primarily HI3O8, their orientations to exhibit a preferential orientation, and their growth to be primarily along the ac-plane of the crystal, enhanced at higher spin rates. Spin-coating at lower spin rates produces laminate-like particulate films versus higher density, one-piece films of stacked particles produced by drop casting. The particle morphology in these films consists of a combination of rods, plates, cubes, and rhombohedra structure.

  10. On the Morphology of the SDS Film on the Surface of Borosilicate Glass

    Directory of Open Access Journals (Sweden)

    Zih-Yao Shen

    2017-05-01

    Full Text Available Surfactant films on solid surfaces have attracted much attention because of their scientific interest and applications, such as surface treatment agent, or for micro- or nano-scale templates for microfluidic devices. In this study, anionic surfactant sodium dodecyl sulfate (SDS solutions with various charged inorganic salts was spread on a glass substrate and dried to form an SDS thin film. Atomic force microscopy (AFM was employed to observe the micro-structure of the SDS thin film. The effects of inorganic salts on the morphology of the SDS film were observed and discussed. The results of experiments demonstrated that pure SDS film formed patterns of long, parallel, highly-ordered stripes. The existence of the inorganic salt disturbed the structure of the SDS film due to the interaction between the cationic ion and the anionic head groups of SDS. The divalent ion has greater electrostatic interaction with anionic head groups than that of the monovalent ion, and causes a gross change in the morphology of the SDS film. The height of the SDS bilayer measured was consistent with the theoretical value, and the addition of the large-sized monovalent ion would lead to lowering the height of the adsorbed structures.

  11. Physicochemical and morphological properties of plasticized poly(vinyl alcohol)-agar biodegradable films.

    Science.gov (United States)

    Madera-Santana, T J; Freile-Pelegrín, Y; Azamar-Barrios, J A

    2014-08-01

    The effects of the addition of glycerol (GLY) on the physicochemical and morphological properties of poly(vinyl alcohol) (PVA)-agar films were reported. PVA-agar films were prepared by solution cast method, and the addition of GLY in PVA-agar films altered the optical properties, resulting in a decrease in opacity values and in the color difference (ΔE) of the films. Structural characterization using Fourier transformation infrared (FTIR) spectroscopy and X-ray diffraction (XRD) indicated that the presence of GLY altered the intensity of the bands (from 1200 to 800cm(-1)) and crystallinity. The characterization of the thermal properties indicated that an increase in the agar content produces a decrease in the melting temperature and augments the heat of fusion. Similar tendencies were observed in plasticized films, but at different magnification. The formulation that demonstrated the lowest mechanical properties contained 25wt.% agar, whereas the formulation that contained 75wt.% agar demonstrated a significant improvement. The water vapor transmission rate (WVTR) and surface morphology analysis demonstrated that the structure of PVA-agar films is reorganized upon GLY addition. The physicochemical properties of PVA-agar films using GLY as a plasticizer provide information for the application of this formulation as packaging material for specific food applications.

  12. Controllable wettability and morphology of electrodeposited surfaces on zinc substrates

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Binyan; Lu, Shixiang, E-mail: shixianglu@bit.edu.cn; Xu, Wenguo, E-mail: wenguoxu60@bit.edu.cn; Cheng, Yuanyuan

    2016-01-01

    Graphical abstract: Superhydrophobic surfaces combining hierarchical micro/nanostructures were fabricated on zinc substrates by etching, electrodeposition of ZnO coatings and annealing. Such superhydrophobic surfaces offer possibilities for chemical, biological, electronic and microfluidic applications. - Highlights: • Superhydrophobic surface was fabricated via electrodeposition of ZnO and annealing. • The ZnO hierarchical micro/nanostructures contribute to the surface superhydrophobicity. • Surface wettability and morphology can be controlled by varying process conditions. • The anti-icing properties and reversible wetting behaviors of the ZnO coatings were studied. - Abstract: Superhydrophobic surfaces combining hierarchical micro/nanostructures were fabricated on zinc substrates by etching in hydrochloric acid solution, electrodeposition of ZnO coatings and subsequent thermal annealing. The optimal coatings were electrodeposited at −1.25 V for 900 s on the etched zinc substrates and then annealed at 200 °C for 60 min, which could achieve a maximum water contact angle of 170 ± 2° and an ultra-low sliding angle of approximately 0°. By conducting SEM and water CA analysis, we found that the morphology and wettability of prepared samples were controllable by the fabrication process. Interestingly, even without any additional modification, the samples prepared under different electrodeposition conditions (including Zn(CH{sub 3}COO){sub 2} concentration from 5 mM to 40 mM and deposition time from 300 s to 1500 s) exhibited superhydrophobic character. The influences of the Zn(CH{sub 3}COO){sub 2} concentration, deposition time, annealing temperature and annealing time on the wetting behaviors were also discussed in detail. Such superhydrophobic surfaces possess long-term stability, and good corrosion resistance as well as self-cleaning ability. In addition, the anti-icing properties of the ZnO films were investigated. These surfaces could be rapidly and

  13. Effects of Sn-doping on morphology and optical properties of CdTe polycrystalline films

    Institute of Scientific and Technical Information of China (English)

    Li Jin; Yang Linyu; Jian Jikang; Zou Hua; Sun Yanfei

    2009-01-01

    Sn-doped CdTe polycrystalline films were successfully deposited on ITO glass substrates by close space sublimation. The effects of Sn-doping on the microstructure, surface morphology, and optical properties of polycrystalline films were studied using X-ray diffraction, scanning electron microscopy, and ultraviolet-visible spectrophotometry, respectively. The results show that the lower molar ratio of Sn and CdTe conduces to a strongly preferential orientation of (111) in films and a larger grain size, which indicates that the crystallinity of films can be improved by appropriate Sn-doping. As the molar ratio of Sn and CdTe increases, the preferential orientation of (111) in films becomes weaker, the grain size becomes smaller, and the crystal boundary becomes indistinct, which indicates that the crystallization growth of films is incomplete. However, as the Sn content increases, optical absorption becomes stronger in the visible region. In summary, a strongly preferential orientation of (111) in films and a larger grain size can be obtained by appropriate Sn-doping (molar ratio of Sn : CdTe = 0.06 : 1), while the film retains a relatively high optical absorption in the visible region. However, Sn-doping has no obvious influence on the energy gap of CdTe films.

  14. Tailor-Made Additives for Morphology Control in Molecular Bulk-Heterojunction Photovoltaics

    KAUST Repository

    Graham, Kenneth R.

    2013-01-09

    Tailor-made additives, which are molecules that share the same molecular structure as a parent molecule with only slight structural variations, have previously been demonstrated as a useful means to control crystallization dynamics in solution. For example, tailor-made additives can be added to solutions of a crystallizing parent molecule to alter the crystal growth rate, size, and shape. We apply this strategy as a means to predictably control morphology in molecular bulk-heterojunction (BHJ) photovoltaic cells. Through the use of an asymmetric oligomer substituted with a bulky triisobutylsilyl end group, the morphology of BHJ blends can be controlled resulting in a near doubling (from 1.3 to 2.2%) in power conversion efficiency. The use of tailor-made additives provides promising opportunities for controlling crystallization dynamics, and thereby film morphologies, for many organic electronic devices such as photovoltaics and field-effect transistors. © 2012 American Chemical Society.

  15. Tailor-made additives for morphology control in molecular bulk-heterojunction photovoltaics.

    Science.gov (United States)

    Graham, Kenneth R; Stalder, Romain; Wieruszewski, Patrick M; Patel, Dinesh G Dan; Salazar, Danielle H; Reynolds, John R

    2013-01-01

    Tailor-made additives, which are molecules that share the same molecular structure as a parent molecule with only slight structural variations, have previously been demonstrated as a useful means to control crystallization dynamics in solution. For example, tailor-made additives can be added to solutions of a crystallizing parent molecule to alter the crystal growth rate, size, and shape. We apply this strategy as a means to predictably control morphology in molecular bulk-heterojunction (BHJ) photovoltaic cells. Through the use of an asymmetric oligomer substituted with a bulky triisobutylsilyl end group, the morphology of BHJ blends can be controlled resulting in a near doubling (from 1.3 to 2.2%) in power conversion efficiency. The use of tailor-made additives provides promising opportunities for controlling crystallization dynamics, and thereby film morphologies, for many organic electronic devices such as photovoltaics and field-effect transistors.

  16. Annealing assisted structural and surface morphological changes in Langmuir–Blodgett films of nickel octabutoxy phthalocyanine

    Energy Technology Data Exchange (ETDEWEB)

    Shilpa Harish, T.; Viswanath, P., E-mail: viswanath@cnsms.res.in

    2016-01-01

    We report our studies on thin films of metallo-phthalocyanine (MPc), Nickel(II)1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine (NiPc(OBu){sub 8}) transferred in a well defined thermodynamic state over a self assembled monolayer (octadecyl trichlorosilane)/SiO{sub 2}/Si substrate using the Langmuir–Blodgett (LB) method. The films are characterized using differential scanning calorimetry (DSC), grazing incidence X-ray diffraction (GIXD) and atomic force microscopy (AFM) techniques. DSC studies on powdered samples in the bulk indicate enantiotropic solid–solid phase transition. GIXD studies on the as-deposited LB film show a Bragg peak indicating crystallinity of the thin film. Annealing (373 K) results in reduction of lattice spacing (1.21 Å) signifying changes in molecular packing within the unit cell. At this stage, an additional Bragg peak is observed which grows at the expense of the former one and they coexist between 373 K and 423 K. A discontinuity in lattice spacing from 20.73 to 15.12 Å with annealing indicates clearly a structural change of the underlying crystalline lattice. Correspondingly, the surface morphology images obtained using AFM show, with annealing, a transformation from spherical granular morphology to elongated, flat crystallites suggesting asymmetric growth process. Statistical parameters of the grain extracted from the AFM images show that the size, fractal dimension and circularity are affected by annealing. Based on these studies, we infer the structural and surface morphological changes of the meta-stable phase (Form I) to the stable phase (Form II) in annealed LB films of phthalocyanine. - Highlights: • Langmuir–Blodgett (LB) films of phthalocyanine subjected to thermal annealing. • Structural transformation and coexistence of polymorphs in LB films • Surface morphology changes from nanoscale grains to elongated crystallites. • Reduction of fractal dimension and circularity index reveals asymmetric growth.

  17. Improved Morphology of Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate) Thin Films for All-Electrospray-Coated Organic Photovoltaic Cells

    OpenAIRE

    Yingjie Liao; Takeshi Fukuda; Norihiko Kamata

    2016-01-01

    Spray coating technique has been established as a promising substitute for the traditional coating methods in the fabrication of organic devices in many reports recently. Control of film morphology at the microscopic scale is critical if spray-coated devices are to achieve high performance. Here we investigate electrospray deposition protocols for the fabrication of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) thin films with a single additive system under ambient condi...

  18. The role of seeding in the morphology and wettability of ZnO nanorods films on different substrates

    Energy Technology Data Exchange (ETDEWEB)

    Rodríguez, Juan [Facultad de Ciencias, Universidad Nacional de Ingeniería, P.O. Box 31-139, Lima 31, Perú (Peru); Onna, Diego [DQIAQF-INQUIMAE, FCEyN-Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, 1428 Buenos Aires (Argentina); Sánchez, Luis [Facultad de Ciencias, Universidad Nacional de Ingeniería, P.O. Box 31-139, Lima 31, Perú (Peru); Marchi, M. Claudia [DQIAQF-INQUIMAE, FCEyN-Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, 1428 Buenos Aires (Argentina); Centro de Microscopias Avanzadas, FCEyN-Universidad ed Buenos Aires, Ciudad Universitaria, Pab. I, 1428 Buenos Aires (Argentina); Candal, Roberto, E-mail: rjcandal@gmail.com [DQIAQF-INQUIMAE, FCEyN-Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, 1428 Buenos Aires (Argentina); ECyT, 3iA, Universidad Nacional de San Martín, Martín de Irigoyen No 3100 (1650), San Martín, Pcia de Buenos Aires (Argentina); Ponce, Silvia [Universidad de Lima, Av. Javier Prado Este s/n, Monterrico, Lima 33, Perú (Peru); Bilmes, Sara A. [DQIAQF-INQUIMAE, FCEyN-Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, 1428 Buenos Aires (Argentina)

    2013-08-15

    Spray pyrolysis (SP) and spray-gel (SG) techniques were used to deposit ZnO seeds on Fluor doped tin oxide glasses (FTO), heated at 350 °C or 130 °C, and PET heated at 90 °C. The effect of seeding on the morphology and wettability of ZnO nanorods (NRs) films grown by wet chemical methods was analyzed. The morphology and wettability of ZnO NRs films depend on the seeding process. SP seeds formed from zinc acetate dissolved in water ethanol mixtures yield vertically aligned ZnO NRs, whose diameters and dispersion size are determined by the ethanol/water ratio in the precursor solution. SG seeds formed from a methanol ZnO sol produce a ring patterned distribution on the FTO substrate. The drying of ZnO sol drops impinging on the substrate produces high density of seeds along a ring yielding textured films with NRs vertically oriented on the rings and multi-oriented outside them. This effect was not observed when ZnO NRs grown onto the ZnO/PET substrate, however rod diameter is related with the density of seeds. This way to control the density and diameter of NRs deposited onto a substrate modify the wettability and opens new possibilities for the design of tailored nanomaterials for photochemical applications. Both type of NRs films showed a strong luminescence emission in the UV and in the blue, associated with surface and intrinsic defects.

  19. The role of seeding in the morphology and wettability of ZnO nanorods films on different substrates

    Science.gov (United States)

    Rodríguez, Juan; Onna, Diego; Sánchez, Luis; Marchi, M. Claudia; Candal, Roberto; Ponce, Silvia; Bilmes, Sara A.

    2013-08-01

    Spray pyrolysis (SP) and spray-gel (SG) techniques were used to deposit ZnO seeds on Fluor doped tin oxide glasses (FTO), heated at 350 °C or 130 °C, and PET heated at 90 °C. The effect of seeding on the morphology and wettability of ZnO nanorods (NRs) films grown by wet chemical methods was analyzed. The morphology and wettability of ZnO NRs films depend on the seeding process. SP seeds formed from zinc acetate dissolved in water ethanol mixtures yield vertically aligned ZnO NRs, whose diameters and dispersion size are determined by the ethanol/water ratio in the precursor solution. SG seeds formed from a methanol ZnO sol produce a ring patterned distribution on the FTO substrate. The drying of ZnO sol drops impinging on the substrate produces high density of seeds along a ring yielding textured films with NRs vertically oriented on the rings and multi-oriented outside them. This effect was not observed when ZnO NRs grown onto the ZnO/PET substrate, however rod diameter is related with the density of seeds. This way to control the density and diameter of NRs deposited onto a substrate modify the wettability and opens new possibilities for the design of tailored nanomaterials for photochemical applications. Both type of NRs films showed a strong luminescence emission in the UV and in the blue, associated with surface and intrinsic defects.

  20. Growth, morphology, and conductivity in semimetallic/metallic films on Si(001)

    Energy Technology Data Exchange (ETDEWEB)

    Jnawali, Giriraj

    2009-06-09

    This dissertation deals with the study of epitaxial growth of semimetallic (Bi) and metallic (Ag) films on Si(001) as well as in situ electrical transport study of those films via surface manipulation. The focus of the transport measurements is to study the influence of the surface morphology or structure on the resistance of the film. In spite of the large lattice mismatch and different lattice geometry, it is possible to grow epitaxial Bi(111) films on Si(001) substrates, which are surprisingly smooth, relaxed and almost free of defects. Due to the two-fold symmetry of the substrates, the Bi(111) film is composed of crystallites rotated by 90 with respect to each other. Annealing of 6 nm film from 150 K to 450 K enables the formation of a periodic interfacial misfit dislocations, which accommodates a remaining lattice mismatch of 2.3 %. The surface/interface roughness and the bulk defect density of the film found to be extremely low, indicating the high crystalline quality of the film with atomically smooth surface and abrupt interface. Similar to the Bi films, Ag grows in a (111) orientation on Si(001) with two 90 rotated domains. The remaining strain of 2.2 % (tensile) is accommodated by the formation of an ordered network of dislocations. The Ag film exhibits atomically smooth surface. Those Bi films and Ag films were used as model systems to study the influence of the surface morphology on the electrical resistance. Surprisingly, all the Bi films (3-170 nm thicknesses) have shown an anomalous behavior of conductance with temperature and thickness. As in the case of doped semiconductor, the conductance increases exponentially from 150 K to 300 K and saturates at 350 K before finally decreasing with temperature. In situ measurements of the resistance during additional Bi deposition on the smooth Bi(111) films exhibit a square root dependent with coverage after a linear increase at very low coverage (1 % of a BL). During additional deposition of Bi, carriers are

  1. SnO{sub 2} thin-films prepared by a spray-gel pyrolysis: Influence of sol properties on film morphologies

    Energy Technology Data Exchange (ETDEWEB)

    Luyo, Clemente [Facultad de Ciencias, Universidad Nacional de Ingenieria, Casilla 31-139, Lima (Peru); Fabregas, Ismael [INQUIMAE-DQIAQF, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria Pabellon 2, C1428EHA Buenos Aires (Argentina); Reyes, L. [Facultad de Ciencias, Universidad Nacional de Ingenieria, Casilla 31-139, Lima (Peru); Solis, Jose L.; Rodriguez, Juan; Estrada, Walter [Facultad de Ciencias, Universidad Nacional de Ingenieria, Casilla 31-139, Lima (Peru); Instituto Peruano de Energia Nuclear, Av. Canada 1470, San Borja, Lima 41 (Peru); Candal, Roberto J. [INQUIMAE-DQIAQF, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria Pabellon 2, C1428EHA Buenos Aires (Argentina)], E-mail: candal@qi.fcen.uba.ar

    2007-11-01

    Nanostructured tin oxide films were prepared by depositing different sols using the so-called spray-gel pyrolysis process. SnO{sub 2} suspensions (sols) were obtained from tin (IV) tert-amyloxide (Sn(t-OAm){sub 4}) or tin (IV) chloride pentahydrate (SnCl{sub 4}.5H{sub 2}O) precursors, and stabilized with ammonia or tetraethylammonium hydroxide (TEA-OH). Xerogels from the different sols were obtained by solvent evaporation under controlled humidity. The Relative Gelling Volumes (RGV) of these sols strongly depended on the type of precursor. Xerogels obtained from inorganic salts gelled faster, while, as determined by thermal gravimetric analysis, occluding a significant amount of volatile compounds. Infrared spectroscopic analysis was performed on raw and annealed xerogels (300, 500 deg. C, 1 h). Annealing removed water and ammonium or alkyl ammonium chloride, increasing the number of Sn-O-Sn bonds. SnO{sub 2} films were prepared by spraying the sols for 60 min onto glass and alumina substrates at 130 deg. C. The films obtained from all the sols were amorphous or displayed a very small grain size, and crystallized after annealing at 400 deg. C or 500 deg. C in air for 2 h. X-ray diffraction analysis showed the presence of the cassiterite structure and line broadening indicated a polycrystalline material with a grain size in the nanometer range. Results obtained from Scanning Electron Microscopy analysis demonstrated a strong dependence of the film morphology on the RGV of the sols. Films obtained from Sn(t-OAm){sub 4} showed a highly textured morphology based on fiber-shape bridges, whereas the films obtained from SnCl{sub 4}.5H{sub 2}O had a smoother surface formed by 'O-ring' shaped domains. Lastly, the performance of these films as gas sensor devices was tested. The conductance (sensor) response for ethanol as a target analyte was of the same order of magnitude for the three kinds of films. However, the response of the highly textured films was more

  2. Polymers for opto-electronic applications: structure and morphology of thin films and their interfaces

    NARCIS (Netherlands)

    van Hutten, P F; Krasnikov, V.V.; Hadziioannou, G

    2001-01-01

    Organic-organic and metal-organic interfaces are explored. The influence of the morphology of thin films of MEH-phenylene-vinylene oligomer (OPV5):C60 blends on their photovoltaic characteristics is demonstrated. An interdigitating structure is considered to be favorable for efficient operation. The

  3. Controlled release properties of zein-fatty acid blend films for multiple bioactive compounds.

    Science.gov (United States)

    Arcan, Iskender; Yemenicioğlu, Ahmet

    2014-08-13

    To develop edible films having controlled release properties for multiple bioactive compounds, hydrophobicity and morphology of zein films were modified by blending zein with oleic (C18:1)Δ⁹, linoleic (C18:2)Δ(9,12), or lauric (C₁₂) acids in the presence of lecithin. The blend zein films showed 2-8.5- and 1.6-2.9-fold lower initial release rates for the model active compounds, lysozyme (LYS) and (+)-catechin (CAT), than the zein control films, respectively. The change of fatty acid chain length affected both CAT and LYS release rates while the change of fatty acid double bond number affected only the CAT release rate. The film morphologies suggested that the blend films owe their controlled release properties mainly to the microspheres formed within their matrix and encapsulation of active compounds. The blend films showed antilisterial activity and antioxidant activity up to 81 μmol Trolox/cm². The controlled release of multiple bioactive compounds from a single film showed the possibility of combining application of active and bioactive packaging technologies and improving not only safety and quality but also health benefits of packed food.

  4. Study of Hydrogen flame annealed Au thin-film surface morphology, integrity and film quality on various substrate surfaces

    Science.gov (United States)

    Schell, Michael; Senevirathne, Indrajith

    2013-03-01

    Au thin-films have many applications in both industry and proof of concept investigations in device engineering. Typical Au depositions on substrate give rise to Stanski-Krastanov (SK) like growth while Frank-van der Merwe (FM) mode like growth is desired in many molecular self assembly and other engineering applications. Au films are magnetron sputter deposited at 100mtorr at low deposition rates (~ 1ML/min) on cleaved/fresh mica, glass microscopy slides and Si surfaces. Samples are hydrogen flame annealed to facilitate surface diffusion with minimal film contamination. Resulting Au surfaces were investigated and compared against purchased Au(111) on mica (standard) surface. Regular and custom built hydrophilic and hydrophobic AFM (Atomic Force Microcopy) probes were used in contact, and non contact AFM with topography and phase imaging to access the contamination and surface defects. Surface integrity, roughness, corrugation and morphology on Au surfaces were estimated. LHU Nanotechnology Program, PASSHE FPDC (LOU # 2010-LHU-03).

  5. Surface morphology stabilization by chemical sputtering in carbon nitride film growth

    Energy Technology Data Exchange (ETDEWEB)

    Buijnsters, J G [Institute for Molecules and Materials (IMM), Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen (Netherlands); Vazquez, L [Instituto de Ciencia de Materiales de Madrid (CSIC), C/Sor Juana Ines de la Cruz 3, 28049 Madrid (Spain)

    2008-01-07

    We have studied the influence of chemical sputtering effects on the morphology of carbon nitride films grown on silicon substrates by electron cyclotron resonance chemical vapour deposition. This study has been performed by comparing the evolution of their morphology with that of hydrogenated amorphous carbon films grown under similar conditions, where these effects are not present. When chemical sputtering effects operate we observe a film surface stabilization for length scales in the 60-750 nm range after a threshold roughness of about 3-4 nm has been developed. This stabilization is explained on the basis of the re-emission of nitrogen etching species, which is confirmed by growth experiments on microstructured substrates. (fast track communication)

  6. Gelatin/potato starch edible biocomposite films: Correlation between morphology and physical properties.

    Science.gov (United States)

    Podshivalov, Aleksandr; Zakharova, Mariia; Glazacheva, Ekaterina; Uspenskaya, Mayya

    2017-02-10

    The paper presents the results of studies of the microstructure morphology and the operational properties of the gelatin/potato starch/glycerol edible biocomposite films varying in the starch content from 0 to 50wt% prepared by casting film-forming solution and dying at 36°C for 15h. The biocomposite films were shown phase separated heterogeneous morphology with the gelatin matrix as a continuous phase and microgranules of starch as a minor phase. It is found that when the starch content ≤ 30wt% the phase separation mechanism is nucleation and grow, whereas the starch content > 30wt% then the spinodal decomposition is the dominant mechanism. The work focuses on findings the influence of the phase separation mechanisms on the size of starch granules during the drying process, as well as the impact of these mechanisms on optical, frictional, mechanical, thermal and water-barrier properties.

  7. Optical properties and surface morphology of ZnTe thin films prepared by multiple potential steps

    Energy Technology Data Exchange (ETDEWEB)

    Gromboni, Murilo F.; Lucas, Francisco W. S.; Mascaro, Lucia H., E-mail: lmascaro@ufscar.br [Universidade de Federal de Sao Carlos (LIEC/UFSCar), SP (Brazil). Departamento de Quimica. Lab. de Eletroquimica e Ceramica

    2014-03-15

    In this work, the ZnTe thin films were electrodeposited using potentiostatic steps, on Pt substrate. The effect of steps number, the deposition time for each element (Zn or Te) and layer order (Zn/Te or Te/Zn) in the morphology, composition, band gap energy and photocurrent was evaluated. Microanalysis data showed that the ratio Zn/Te ranged from 0.12 and 0.30 and the film was not stoichiometric. However, the band-gap value obtained from in all experimental conditions used in this work was 2.28 eV, indicating film growth of ZnTe. The samples with higher Zn showed higher photocurrent, which was of the order of 2.64 μA cm{sup -2} and dendritic morphology (author)

  8. INFLUENCE OF PH ON THE STRUCTURAL AND MORPHOLOGICAL PROPERTIES OF ZnS THIN FILMS

    Directory of Open Access Journals (Sweden)

    A KASSIM

    2010-06-01

    Full Text Available The ZnS thin films have been obtained from aqueous solution by means of cyclic voltammetry method. The electrochemical bath consisted of zinc sulphate, sodium thiosulfate and triethanolamine. The effect of electrolyte pH on the properties of ZnS thin films was investigated within the range from 3 to 9. The cyclic voltammetry was used to analyse the electrochemical bath. The structural and morphological of thin films were investigated by X-ray diffraction and atomic force microscopy, respectively. The thin films obtained have cubic structure and single phase as analysed by XRD. As the pH was reduced from 9 to 3, the intensities of the peaks corresponding to ZnS increased. AFM image shows the thin films prepared at pH 3 are homogeneous and well covered on the substrate. These thin films consist of small grains which lead to deposition of smoother films. However, as the pH increases up to 7, the number of grains decreases and larger grain size could be obtained. Therefore, the pH plays a major role in synthesis of ZnS thin film and the pH 3 is the best pH under current conditions.

  9. Morphology effects on spin-dependent transport and recombination in polyfluorene thin films

    Science.gov (United States)

    Miller, Richards; van Schooten, K. J.; Malissa, H.; Joshi, G.; Jamali, S.; Lupton, J. M.; Boehme, C.

    2016-12-01

    We have studied the role of spin-dependent processes on conductivity in polyfluorene (PFO) thin films by preforming continuous wave (cw) electrically detected magnetic resonance (EDMR) spectroscopy at temperatures between 10 K and room temperature using microwave frequencies between about 1 GHz and 20 GHz, as well as pulsed EDMR at the X band (10 GHz). Variable frequency EDMR allows us to establish the role of spin-orbit coupling in spin-dependent processes whereas pulsed EDMR allows for the observation of coherent spin motion effects. We used PFO for this study in order to allow for the investigation of the effects of microscopic morphological ordering since this material can adopt two distinct intrachain morphologies: an amorphous (glassy) phase, in which monomer units are twisted with respect to each other, and an ordered (β) phase, where all monomers lie within one plane. In thin films of organic light-emitting diodes, the appearance of a particular phase can be controlled by deposition parameters and solvent vapor annealing, and is verified by electroluminescence spectroscopy. Under bipolar charge-carrier injection conditions, we conducted multifrequency cw EDMR, electrically detected Rabi spin-beat experiments, and Hahn echo and inversion-recovery measurements. Coherent echo spectroscopy reveals electrically detected electron-spin-echo envelope modulation due to the coupling of the carrier spins to nearby nuclear spins. Our results demonstrate that, while conformational disorder can influence the observed EDMR signals, including the sign of the current changes on resonance as well as the magnitudes of local hyperfine fields and charge-carrier spin-orbit interactions, it does not qualitatively affect the nature of spin-dependent transitions in this material. In both morphologies, we observe the presence of at least two different spin-dependent recombination processes. At room temperature and 10 K, polaron-pair recombination through weakly spin-spin coupled

  10. Effect of electrolytes on electrochromic properties and morphology of poly(2,5-dimethoxy aniline) films

    Indian Academy of Sciences (India)

    Bureerat Suephatthima; Nophawan Paradee; Anuvat Sirivat; Datchanee Pattavarakorn

    2014-08-01

    Poly(2,5-dimethoxyaniline) (PDMA) was electrochemically synthesized in oxalic (H2C2O4) nitric (HNO3) and hydrochloric (HCl) acids and deposited onto flexible indium tin oxide at various synthesis times and deposition potentials as electrochromic materials. The PDMA films were characterized by FT–IRspectrometry, scanning electron microscopy, UV–Vis spectrophotometry and cyclic voltammetry. All PDMA films show reversible colour changes from yellow to green corresponding to the transition from the fully reduced state to the fully oxidized state under potential switching. The surface morphology and thickness of PDMA films depend critically on the type of acids used in the electrochemical polymerization process. The morphology of PDMA are highly porous microfibres (H2C2O4 and HNO3), tiny granular aggregate (HCl) and particle agglomerate depending on the polymerization time. The fastest response time observed via colour changing of 3.7 s is obtained from the HCl–PDMA film at 3.5 volt and at the synthesis time of 6 min, as primarily due to the thickness of the film. The flexible PDMA film is demonstrated here as a potential candidate to be used in electrochromic devices.

  11. Studies on the Optical Properties and Surface Morphology of Cobalt Phthalocyanine Thin Films

    Directory of Open Access Journals (Sweden)

    Benny Joseph

    2008-01-01

    Full Text Available Thin films of Cobalt Phthalocyanine (CoPc are fabricated at a base pressure of 10-5 m.bar using Hind-Hivac thermal evaporation plant. The films are deposited on to glass substrates at various temperatures 318, 363, 408 and 458K. The optical absorption spectra of these thin films are measured. The present studies reveal that the optical band gap energies of CoPc thin films are almost same on substrate temperature variation. The structure and surface morphology of the films deposited on glass substrates of temperatures 303, 363 and 458K are studied using X-ray diffractograms and Scanning Electron Micrographs (SEM, which show that there is a change in the crystallinity and surface morphology due to change in the substrate temperatures. Full width at half maximum (FWHM intensity of the diffraction peaks is also found reduced with increasing substrate temperatures. Scanning electron micrographs show that these crystals are needle like, which are interconnected at high substrate temperatures. The optical band gap energy is almost same on substrate temperature variation. Trap energy levels are also observed for these films.

  12. Studies on the Optical Properties and Surface Morphology of Nickel Phthalocyanine Thin Films

    Directory of Open Access Journals (Sweden)

    Benny Joseph

    2007-01-01

    Full Text Available Thin films of Nickel Phthalocyanine (NiPc are fabricated at a base pressure of 10-5 m.bar using Hind-Hivac thermal evaporation plant. The films are deposited on to glass substrates at various temperatures 318, 363, 408 and 458K. The optical absorption spectra of these thin films are measured. Present studies reveal that the optical band gap energies of NiPc thin films are highly dependent on the substrate temperatures. The structure and surface morphology of the films deposited on glass substrates of temperatures 303, 363 and 458K are studied using X-ray diffractograms and Scanning Electron Micrographs (SEM, show that there is a change in the crystallinity and surface morphology due to change in the substrate temperatures. Full width at half maximum (FWHM intensity of the diffraction peaks is also found reduced with increasing substrate temperatures. Scanning electron micrographs show that these crystals are fiber like at high substrate temperatures. The optical band gap increases with increase in substrate temperature and is then reduced with fiber-like grains at 408K. The band gap increases again at 458K with full of fiber like grains. Trap energy levels are also observed for these films.

  13. Effect of zinc oxide film morphologies on the formation of Shewanella putrefaciens biofilm.

    Science.gov (United States)

    Dai, Yue; Sun, Tong; Zhang, Zhibing; Zhang, Zhenyu J; Li, Jian-Rong

    2017-02-09

    Zinc oxide (ZnO) films were prepared on aluminum substrate by a hydrothermal method to investigate the effect of their surface characteristics, including morphology and hydrophobicity, on the corresponding antibiofilm performance. The surface characteristics of the prepared ZnO films were examined by a comprehensive range of methodologies, suggesting that films of distinctive surface morphologies were successfully formed. Subsequently, their antibiofilm activities, using Shewanella putrefaciens as a model bacterium, were assessed. Surface measurements confirmed that the ZnO films equipped with a nanoscopic needlelike surface feature are more hydrophobic than those possessing densely packed microflakes. The reduced number of live cells and presence of biofilm, confirmed by optical and electron microscopy results, suggest that the former films possess an excellent antibiofilm performance. It is believed that the engineered nanoscopic needle feature might penetrate the cell membrane when they are in contact, allowing the effective substance of ZnO antibacterial ingredients to diffuse into the embedded bacteria. Furthermore, such surface characteristics might perturb the integrity of the cell membrane causing the intracellular substance is leaked from the cells. As such, the combinatorial effects of nanoscopic feature resulted in an inhibited growth of S. putrefaciens biofilm on ZnO film.

  14. Nanostructured films from phthalocyanine and carbon nanotubes: surface morphology and electrical characterization.

    Science.gov (United States)

    Brito, Jackeline B; Gomes, Douglas J C; Justina, Vanessa D; Lima, Aline M F; Olivati, Clarissa A; Silva, Josmary R; de Souza, Nara C

    2012-02-01

    We report on the investigation of the surface morphology and DC conductivity of nanostructured layer-by-layer (LbL) films from nickel tetrasulfonated phthalocyanine (NiTsPc) alternated with either multi-walled carbon nanotubes (MWNTs/NiTsPc) or multi-walled carbon nanotubes dispersed in chitosan (MWNTs+Ch/NiTsPc). We have explored the surface morphology of the films by using fractal concepts and dynamic scale laws. The MWNTs/NiTsPc LbL films were found to have a fractal dimension of ca. 2, indicating a quasi Euclidean surface. MWNTs+Ch/NiTsPc LbL films are described by the Lai-Das Sarma-Villain (LDV) model, which predicts the deposition of particles and their subsequent relaxation. An increase in the wetting contact angle of MWNTs+Ch/NiTsPc LbL films was observed, as compared with MWNTs/NiTsPc LbL films, which presented an increase in the fractal dimension of the first system. Room temperature conductivities were found be ca. 0.45 S/cm for MWNTs/NiTsPc and 1.35 S/cm for MWNTs+Ch/NiTsPc.

  15. Effects of surface morphology on the anchoring and electrooptical dynamics of confined nanoscale liquid crystalline films.

    Science.gov (United States)

    Noble, Alison R; Kwon, Hye J; Nuzzo, Ralph G

    2002-12-18

    The orientation and dynamics of two 40-nm thick films of 4-n-pentyl-4'-cyanobiphenyl (5CB), a nematic liquid crystal, have been studied using step-scan Fourier transform infrared spectroscopy (FTIR). The films are confined in nanocavities bounded by an interdigitated electrode array (IDA) patterned on a zinc selenide (ZnSe) substrate. The effects of the ZnSe surface morphology (specifically, two variations of nanometer-scale corrugations obtained by mechanical polishing) on the initial ordering and reorientation dynamics of the electric-field-induced Freedericksz transition are presented here. The interaction of the 5CB with ZnSe surfaces bearing a spicular corrugation induces a homeotropic (surface normal) alignment of the film confined in the cavity. Alternately, when ZnSe is polished to generate fine grooves along the surface, a planar alignment is promoted in the liquid crystalline film. Time-resolved FTIR studies that enable the direct measurement of the rate constants for the electric-field-induced orientation and thermal relaxation reveal that the dynamic transitions of the two film structures are significantly different. These measurements quantitatively demonstrate the strong effects of surface morphology on the anchoring, order, and dynamics of liquid crystalline thin films.

  16. Mushroom-shaped Morphology Formed in Thin Films of Cylinder-forming Block Copolymer

    Institute of Scientific and Technical Information of China (English)

    GONG Yu-mei; SONG Jing-chuan; ZHANG Gui-xia

    2011-01-01

    The morphology of the film of polystyrene-block-poly(methyl methacrylate)(PS-b-PMMA) block copolymer having polystyrene(PS) cylinder forming composition spin-coated on a neutral brush modified silicon substrate has been investigated in this report. A mushroom-shaped morphology formed in the film with one period to two periods(L0-2L0) in thickness, which was spin-coated under a low humidity condition(RH ca.13%) and then thermally annealed at an extreme high temperature(230 ℃). The results suggest that the spin-coating condition together with the confinement conditions plays a crucial role in the interesting morphology formation.

  17. Polythiophene: Synthesis in aqueous medium and controllable morphology

    Institute of Scientific and Technical Information of China (English)

    LIU RuoChen; LIU ZhengPing

    2009-01-01

    Various morphologies of polythiophene have been designed and successfully prepared by chemical oxidative polymerization in the presence of phase transfer catalyst (PTC) cetyltrimethylammonium bromide (CTAB) in aqueous medium. The morphologies of polythiophene could be controlled in ribbons, fibers and spherical particles by changing the concentrations of reductant, oxidant and phase transfer catalyst. The structure, thermal stability and the conductivity have been characterized, and a mechanism for the transformation of the morphology of polythiophene has been proposed.

  18. Morphology-Controlled Growth of AIN One-Dimensional Nanostructures

    Institute of Scientific and Technical Information of China (English)

    Ting XIE; Min YE; Xiaosheng FANG; Zhi JIANG; Li CHEN; Mingguang KONG; Yucheng WU; Lide ZHANG

    2008-01-01

    Aluminum nitride (AIN) nanowires, serrated nanoribbons, and nanoribbons were selectively obtained through a simple chloride assisted chemical vapor deposition process. The morphologies of the products could be controlled by adjusting the deposition position and the flux of the reactant gas. The morphologies and structures of the AIN products were investigated in detail. The formation mechanism of the as-prepared different morphologies of AIN one-dimensional (1D) nanostructures was discussed on the basis of the experimental results.

  19. Control of surface ripple amplitude in ion beam sputtered polycrystalline cobalt films

    Energy Technology Data Exchange (ETDEWEB)

    Colino, Jose M., E-mail: josemiguel.colino@uclm.es [Institute of Nanoscience, Nanotechnology and Molecular Materials, University of Castilla-La Mancha, Campus de la Fabrica de Armas, Toledo 45071 (Spain); Arranz, Miguel A. [Facultad de Ciencias Quimicas, University of Castilla-La Mancha, Ciudad Real 13071 (Spain)

    2011-02-15

    We have grown both polycrystalline and partially textured cobalt films by magnetron sputter deposition in the range of thickness (50-200 nm). Kinetic roughening of the growing film leads to a controlled rms surface roughness values (1-6 nm) increasing with the as-grown film thickness. Ion erosion of a low energy 1 keV Ar+ beam at glancing incidence (80{sup o}) on the cobalt film changes the surface morphology to a ripple pattern of nanometric wavelength. The wavelength evolution at relatively low fluency is strongly dependent on the initial surface topography (a wavelength selection mechanism hereby confirmed in polycrystalline rough surfaces and based on the shadowing instability). At sufficiently large fluency, the ripple wavelength steadily increases on a coarsening regime and does not recall the virgin surface morphology. Remarkably, the use of a rough virgin surface makes the ripple amplitude in the final pattern can be controllably increased without affecting the ripple wavelength.

  20. Role of substrate morphology in ion induced dewetting of thin solid films

    Energy Technology Data Exchange (ETDEWEB)

    Repetto, Luca, E-mail: luca.repetto@unige.it [Physics Department and Nanomed Labs, Università di Genova, Via Dodecaneso 33, 16146 Genova (Italy); Lo Savio, Roberto [Physics Department and Nanomed Labs, Università di Genova, Via Dodecaneso 33, 16146 Genova (Italy); Šetina Batič, Barbara [Inštitut Za Kovinske Materiale in Tehnologije, Lepi pot 11, 1000 Ljubljana (Slovenia); Firpo, Giuseppe; Valbusa, Ugo [Physics Department and Nanomed Labs, Università di Genova, Via Dodecaneso 33, 16146 Genova (Italy)

    2014-10-01

    Highlights: • We have created by ion bombardment silicon substrates with different topographies. • The substrates have been characterized by ellipsometry, AFM, SEM and EDX. • The substrates have been used for experiments of ion induced Cr films. • We show that different substrate topographies can induce different dewetted patterns. • Substrate topography can favor spinodal dewetting against heterogeneous nucleations. - Abstract: We investigate the role of the substrate morphology in the dewetting of ultrathin chromium films irradiated with 30 keV Ga ions. Silicon surfaces with different roughness were used as substrates for the films. The results of the irradiation experiments and of related simulations indicate that the chromium films can undergo a dewetting-like process through the two standard channels that show up for liquids, namely the spinodal channel, and the dewetting by heterogeneous nucleation. The two processes are competitive, and the prevailing one can be predicted and selected according to the characteristics of the substrate.

  1. Photoinduced charge generation rates in soluble P3HT : PCBM nano-aggregates predict the solvent-dependent film morphology

    Science.gov (United States)

    Roy, Palas; Jha, Ajay; Dasgupta, Jyotishman

    2016-01-01

    The device efficiency of bulk heterojunction (BHJ) solar cells is critically dependent on the nano-morphology of the solution-processed polymer : fullerene blend. Active control on blend morphology can only emanate from a detailed understanding of solution structures during the film casting process. Here we use photoinduced charge transfer (CT) rates to probe the effective length scale of the pre-formed solution structures and their energy disorder arising from a mixture of poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) in three different organic solvents. The observed solvent-dependent ultrafast biphasic rise of the transient polaron state in solution along with changes detected in the C&z.dbd;C stretching frequency of bound PCBM provides direct evidence for film-like P3HT : PCBM interfaces in solution. Using the diffusive component of the charge transfer rate, we deduce ~3-times larger functional nano-domain size in toluene than in chlorobenzene thereby correctly predicting the relative polymer nanofiber widths observed in annealed films. We thus provide first experimental evidence for the postulated polymer : fullerene : solvent ternary phase that seeds the eventual morphology in spin-cast films. Our work motivates the design of new chemical additives to tune the grain size of the evolving polymer : fullerene domains within the solution phase.The device efficiency of bulk heterojunction (BHJ) solar cells is critically dependent on the nano-morphology of the solution-processed polymer : fullerene blend. Active control on blend morphology can only emanate from a detailed understanding of solution structures during the film casting process. Here we use photoinduced charge transfer (CT) rates to probe the effective length scale of the pre-formed solution structures and their energy disorder arising from a mixture of poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) in three

  2. Trends in Controllable Oil Film Bearings

    DEFF Research Database (Denmark)

    Santos, Ilmar

    2011-01-01

    This work gives an overview about the theoretical and experimental achievements of mechatronics applied to oil film bearings, with the aim of: controlling the lateral vibration of flexible rotating shafts; modifying bearing dynamic characteristics, as stiffness and damping properties; increasing...... the rotational speed ranges by improving damping and eliminating instability problems, for example, by compensating cross-coupling destabilizing effects; reducing startup torque and energy dissipation in bearings; compensating thermal effects. It is shown that such controllable bearings can act as "smart......" components and be applied to rotating machines with the goal of avoiding unexpected stops of plants, performing rotordynamic tests and identifying model parameters "on site". Emphasis is given to the controllable lubrication (active lubrication) applied to different types of oil film bearings, i...

  3. Nanoscale Morphology Control in Functional Polymer Systems

    Institute of Scientific and Technical Information of China (English)

    Joachim; Loos; Svetlana; Chevtchenko

    2007-01-01

    1 Results In high-performance organic solar cells,the photoactive layer consists of a blend of an electron donor and an electron acceptor constituent,a so-called bulk heterojunction.The requirements to morphology of the efficient photoactive layer are nanoscale phase separation,which provides large interface area for exciton dissociation,and at the same time continuous pathways for transport of free charge carriers to the appropriate electrodes.In this context,the research is now focused on a better und...

  4. Effect of RF power and gas flow ratio on the growth and morphology of the PECVD SiC thin films for MEMS applications

    Indian Academy of Sciences (India)

    Bhavana Peri; Bikash Borah; Raj Kishora Dash

    2015-08-01

    Low-temperature plasma enhanced chemical vapour deposition (PECVD) deposited silicon carbide (SiC) thin films are promising materials for the development of high-temperature working microelectromechanical system (MEMS) owing to their excellent mechanical properties, non-corrosive nature and ability to withstand high temperature. However, the surface roughness of such thin films is the main obstacle to achieve thicker thin films for MEMS applications as the surface becomes more rougher with the increase in the thickness of PECVD SiC thin films. Therefore, in this present study, thicker SiC thin films were deposited by PECVD process by using CH4 and SiH4 as the precursor gases in the presence of Ar as the carrier gas and two process parameters, i.e., radio frequency (RF) power with mixed frequency condition and flow ratio of silane to methane were varied by keeping the temperature and pressure constant to investigate the influence of these parameters on the growth rate, surface roughness and morphology of SiC thin films. It was observed that both the RF power (with the mixed frequency condition) and flow ratio of SiH4/CH4 can control the growth rate, surface roughness and morphology of the PECVD SiC thin films. Higher the carbon content in the thin films the surface became more smoother, whereas the surface became for rougher by increasing the RF power.

  5. Morphology and swelling of Os(II) polyvinyl-bypyridile films

    Energy Technology Data Exchange (ETDEWEB)

    Ybarra, G. [Centro de Investigacion sobre Electrodeposicion y Procesos Superficiales, Instituto Nacional de Tecnologia Industrial, CC 157 (1650) San Martin (Argentina); Moina, C. [Centro de Investigacion sobre Electrodeposicion y Procesos Superficiales, Instituto Nacional de Tecnologia Industrial, CC 157 (1650) San Martin (Argentina); Molina, F.V. [INQUIMAE, Departamento de Quimica Inorganica, Analitica y Quimica Fisica, Facultad de Ciencias Exactas y Naturales, UBA, Ciudad Universitaria, Pabellon II, 1428 Buenos Aires (Argentina); Florit, M.I. [INIFTA, Facultad de Ciencias Exactas, UNLP, Sucursal 4, Casilla de Correo 16, 1900 La Plata (Argentina); Posadas, D. [INIFTA, Facultad de Ciencias Exactas, UNLP, Sucursal 4, Casilla de Correo 16, 1900 La Plata (Argentina)]. E-mail: dposadas@inifta.unlp.edu.ar

    2005-02-15

    In this work, we studied the changes in volume of an electroactive polymer as [Os(bipy){sub 2} (PVP){sub 10}Cl]{sup 2+}. The dependence of the polymer volume on the solution pH and applied potential was measured. The morphology of [Os(bipy){sub 2} (PVP){sub 10}Cl]{sup 2+}, deposited onto monocrystalline Si substrates, both by drop coating and by spin coating was studied by AFM. Drop-coated films show a globular structure on top of a thin and homogeneous film while spin-coated films are even and homogeneous. The volume changes with the pH of the external solution were measured following the changes in the globules size of drop-coated films. Also, the thickness dependence of spin-coated films on pH was measured by AFM. Both the size of the globules and the thickness of the films increase as the pH of the external solution decreases. The possible reasons for this increase are discussed. The volume change following the oxidation of a drop-coated polymer was estimated from the projected area obtained by optical microscopy with image capture. The images show an increase in the projected area as the film is progressively oxidized. The possible reasons for this increase in volume are discussed.

  6. Morphology and mechanisms of picosecond ablation of metal films on fused silica substrates

    Science.gov (United States)

    Bass, Isaac L.; Negres, Raluca A.; Stanion, Ken; Guss, Gabe; Keller, Wesley J.; Matthews, Manyalibo J.; Rubenchik, Alexander M.; Yoo, Jae Hyuck; Bude, Jeffrey D.

    2016-12-01

    The ablation of magnetron sputtered metal films on fused silica substrates by a 1053 nm, picosecond class laser was studied as part of a demonstration of its use for in-situ characterization of the laser spot under conditions commonly used at the sample plane for laser machining and damage studies. Film thicknesses were 60 and 120 nm. Depth profiles and SEM images of the ablation sites revealed several striking and unexpected features distinct from those typically observed for ablation of bulk metals. Very sharp thresholds were observed for both partial and complete ablation of the films. Partial film ablation was largely independent of laser fluence with a surface smoothness comparable to that of the unablated surface. Clear evidence of material displacement was seen at the boundary for complete film ablation. These features were common to a number of different metal films including Inconel on commercial neutral density filters, stainless steel, and aluminum. We will present data showing the morphology of the ablation sites on these films as well as a model of the possible physical mechanisms producing the unique features observed.

  7. New approach towards an optimized light trapping morphology of Al-doped ZnO films

    Energy Technology Data Exchange (ETDEWEB)

    Sittinger, V.; Dewald, W.; Szyszka, B. [Fraunhofer Institute for Surface Engineering and Thin Films IST, Braunschweig (Germany); Saeuberlich, F. [Schmid Technology Center, Dunningen (Germany); Stannowski, B. [Competence Centre Thin-Film- and Nanotechnology for Photovoltaics Berlin (Germany)

    2011-04-15

    Throughout the last years strong efforts have been make to use Al-doped ZnO films on glass as substrates for amorphous or amorphous/microcrystalline silicon solar cells. The material promises better performance at low cost especially because ZnO:Al can be roughened in order to enhance the light scattering into the cell. Best optical and electrical properties are usually achieved by RF sputtering of ceramic targets. Aluminium doped ZnO films were deposited dynamically by DC magnetron sputtering from a ceramic ZnO:Al{sub 2}O{sub 3} target (1 wt.%) onto an additional seed layer. The process parameters, namely oxygen partial pressure, total pressure and temperature were kept constant, only the seed layer thickness was varied. ZnO:Al{sub 2}O{sub 3} films are investigated in respect of optical, electrical properties and etch enhanced morphology for a-Si:H/{mu}c-Si:H solar cells. Additionally the etch morphology was examined by SEM. The seed layer allows getting an optimized light trapping morphology after the hydrochloric etching which shows nearly the same as a pure RF sputtered film. (orig.)

  8. Role of chloride in the morphological evolution of organo-lead halide perovskite thin films.

    Science.gov (United States)

    Williams, Spencer T; Zuo, Fan; Chueh, Chu-Chen; Liao, Chien-Yi; Liang, Po-Wei; Jen, Alex K-Y

    2014-10-28

    A comprehensive morphological study was used to elucidate chloride's role in CH(3)NH(3)PbI(3-x)Cl(x) film evolution on a conducting polymer, PEDOT:PSS. Complex ion equilibria and aggregation in solution, as well as the role they play in nucleation, are found to ultimately be responsible for the unique morphological diversity observed in perovskite films grown in the presence of the chloride ion. An intermediate phase that is generated upon deposition and initial annealing templates continued self-assembly in the case of CH(3)NH(3)PbI(3-x)Cl(x). In the absence of chloride, the film growth of CH(3)NH(3)PbI(3) is directed by substrate interfacial energy. By employing the through-plane TEM analysis, we gain detailed insight into the unique crystallographic textures, grain structures, and elemental distributions across the breadth of films grown from precursor solutions with different chemistries. The lattice coherence seen in morphologies generated under the influence of chloride provides a physical rational for the enhancement in carrier diffusion length and lifetime.

  9. Structural, Morphological, and LPG Sensing Properties of Al-Doped ZnO Thin Film Prepared by SILAR

    OpenAIRE

    Shampa Mondal; Shatabda Bhattacharya; Mitra, P.

    2013-01-01

    Undoped and aluminum doped zinc oxide (AZO) thin films were deposited on glass substrates by successive ion layer adsorption and reaction (SILAR) technique from ammonium zincate complex. The thin films are characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) for their structural and morphological studies. Both undoped and Al-doped film show strong preferred c-axis orientation. The texture coefficient (TC) of the film along (002) direction increases due to Al incorpo...

  10. Rootlike Morphology of ZnO:Al Thin Film Deposited on Amorphous Glass Substrate by Sol-Gel Method

    OpenAIRE

    Heri Sutanto; Sufwan Durri; Singgih Wibowo; Hady Hadiyanto; Eko Hidayanto

    2016-01-01

    Zinc oxide (ZnO) and aluminum doped zinc oxide (ZnO:Al) thin films have been deposited onto a glass substrate by sol-gel spray coating method at atmospheric pressure. X-ray diffractometer (XRD), scanning electron microscopy (SEM), and UV-Vis spectrophotometer have been used to characterize the films. XRD spectra indicated that all prepared thin films presented the wurtzite hexagonal structure. SEM images exhibited rootlike morphology on the surface of thin films and the shortest root diameter...

  11. Electronic and Morphological Inhomogeneities in Pristine and Deteriorated Perovskite Photovoltaic Films

    Energy Technology Data Exchange (ETDEWEB)

    Berweger, Samuel; MacDonald, Gordon A.; Yang, Mengjin; Coakley, Kevin J.; Berry, Joseph J.; Zhu, Kai; DelRio, Frank W.; Wallis, Thomas M.; Kabos, Pavel

    2017-02-07

    We perform scanning microwave microscopy (SMM) to study the spatially varying electronic properties and related morphology of pristine and degraded methylammonium lead-halide (MAPI) perovskite films fabricated under different ambient humidity. We find that higher processing humidity leads to the emergence of increased conductivity at the grain boundaries but also correlates with the appearance of resistive grains that contain PbI2. Deteriorated films show larger and increasingly insulating grain boundaries as well as spatially localized regions of reduced conductivity within grains. These results suggest that while humidity during film fabrication primarily benefits device properties due to the passivation of traps at the grain boundaries and self-doping, it also results in the emergence of PbI2-containing grains. We further establish that MAPI film deterioration under ambient conditions proceeds via the spatially localized breakdown of film conductivity, both at grain boundaries and within grains, due to local variations in susceptibility to deterioration. These results confirm that PbI2 has both beneficial and adverse effects on device performance and provide new means for device optimization by revealing spatial variations in sample conductivity as well as morphological differences in resistance to sample deterioration.

  12. Structure and morphology of thin films of linear aliphatic polyesters prepared by spin-coating.

    Science.gov (United States)

    Hernández, J J; Rueda, D R; García-Gutiérrez, M C; Nogales, A; Ezquerra, T A; Soccio, M; Lotti, N; Munari, A

    2010-07-06

    Thin films, with thicknesses from 10 to 400 nm of linear aliphatic polyesters (X, Y), based on propylenediol (X = 3) and on dicarboxylic acid of different chain length (Y = 2, 3, and 4 CH(2) units) were prepared by spin coating of CHCl(3) polymer solutions with different polymer concentrations. Morphology and structure of the spin coated thin films were investigated by atomic force microscopy (AFM) and by grazing incidence X-ray scattering techniques at small, (GISAXS) and wide angles (GIWAXS). AFM revealed a strong dewetting for all three polymers for coatings thinner than 100 nm. The polymer films are clearly semicrystalline for thicknesses higher than 50 nm. GIWAXS of the thicker films revealed their oriented crystalline nature. An edge-on-lamellae morphology is clearly shown by the AFM-phase images even for relatively thin films. SAXS with the beam parallel to the sample plane also support the presence of lamellae perpendicular to the substrate. The use of a mu-beam helped to interpret the GIWAXS patterns and allowed to obtain oriented WAXS patterns from melt solidified filaments. Thus, a crystal chain packing is proposed for the three polymers and consequently the indexing of the observed reflections. Accordingly, the polymer chains lie parallel to the substrate being the bc plane of the monoclinic crystal unit cell parallel to the substrate.

  13. Influence of Ruthenium doping on Structural and Morphological Properties of MoO3 Thin Films

    Directory of Open Access Journals (Sweden)

    S. D. Gothe

    2016-09-01

    Full Text Available The present work examines the effect of Ru doping on MoO3 thin films on steel substrate deposited by Sol-gel spin coat method. The annealing temperature was 6000C for pure MoO3 and 8000C for Ru doped thin films. The doping concentration of Ru was varied from 10 to 50wt%. The influence of Ru doping on structural and morphological properties of MoO3 thin films were studied. The XRD revealed that all films are highly crystalline in nature with monoclinic phase for molybdenum peaks. In the doped XRD pattern some new peaks were observed and are matched with ruthenium orthorhombic phase indicating an incorporation of dopant in pure molybdenum oxide. The same is confirmed with the compositional analysis by EDAX. The SEM images of the MoO3 resemble a rod like surface with porous morphology. Incorporation of Ru ions in molybdenum oxide decreases the length of the rods and vanishes after 40wt%. Tetragonal grain size increases from 20wt% of Ru and becomes maximum at 50wt% of Ru doped thin films

  14. Effects of Saponification Rate on Electrooptical Properties and Morphology of Poly(vinyl alcohol)/Liquid Crystal Composite Films

    Science.gov (United States)

    Ono, Hiroshi; Kawatsuki, Nobuhiro

    1995-03-01

    The relationship between the saponification rate of poly(vinyl alcohol) (PVA), and the electrooptical properties and morphology of the PVA/liquid crystal (LC) composite films was investigated. Light transmission clazing and the LC droplet size were varied by changing the saponification rate or the blend ratio of two kinds of PVA with different saponification rates because the refractive index and surface tension could be controlled by the saponification rate of PVA. The threshold voltage decreased with increasing saponification rate though the extrapolation length was decreased. It was suggested that the electrooptical properties were strongly dependent on the droplet size.

  15. Effect of the cathodic polarization on structural and morphological proprieties of FTO and ITO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Cid, C.C. Plá [LabSiN, Departamento de Física, Universidade Federal de Santa Catarina, Caixa Postal 476, 88040-900 Florianópolis, SC (Brazil); Spada, E.R., E-mail: edspada@gmail.com [LabSiN, Departamento de Física, Universidade Federal de Santa Catarina, Caixa Postal 476, 88040-900 Florianópolis, SC (Brazil); Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, 13560-970 São Carlos, SP (Brazil); Sartorelli, M.L. [LabSiN, Departamento de Física, Universidade Federal de Santa Catarina, Caixa Postal 476, 88040-900 Florianópolis, SC (Brazil)

    2013-05-15

    This paper deals on the influence of the potentiodynamic stress on structural and morphological proprieties of fluorine-doped tin oxide (FTO, SnO{sub 2}:F) and indium tin oxide (ITO, In{sub 2}O{sub 3}:Sn) commercial substrates. The potential range is between 0.0 and −2.0 (V/SCE) using an electrolyte with neutral pH. The electrochemical behavior was investigated from cyclic voltammetry technique and chronopotentiometric curves. These electrochemical results were associated to the X-ray diffraction (XRD) spectra and morphology images acquired by scanning electron microscopy (SEM). The main results show that structural and morphological properties of FTO substrates after cathodic polarization remain near constant when compared with ITO films. The ITO substrates show morphological changes after treatment and the XRD patterns indicate the formation of a crystalline structure with In metallic characteristic, at neutral pH.

  16. Synthesis and controllable wettability of micro- and nanostructured titanium phosphate thin films formed on titanium plates.

    Science.gov (United States)

    Yada, Mitsunori; Inoue, Yuko; Sakamoto, Ayako; Torikai, Toshio; Watari, Takanori

    2014-05-28

    The hydrothermal treatment of a titanium plate in a mixed aqueous solution of hydrogen peroxide and aqueous phosphoric acid under different conditions results in the formation of various titanium phosphate thin films. The films have various crystal structures such as Ti2O3(H2PO4)2·2H2O, α-titanium phosphate (Ti(HPO4)2·H2O), π-titanium phosphate (Ti2O(PO4)2·H2O), or low-crystallinity titanium phosphate and different morphologies that have not been previously reported such as nanobelts, microflowers, nanosheets, nanorods, or nanoplates. The present study also suggests the mechanisms behind the formation of these thin films. The crystal structure and morphology of the titanium phosphate thin films depend strongly on the concentration of the aqueous hydrogen peroxide solution, the amount of phosphoric acid, and the reaction temperature. In particular, hydrogen peroxide plays an important role in the formation of the titanium phosphate thin films. Moreover, controllable wettability of the titanium phosphate thin films, including superhydrophilicity and superhydrophobicity, is reported. Superhydrophobic surfaces with controllable adhesion to water droplets are obtained on π-titanium phosphate nanorod thin films modified with alkylamine molecules. The adhesion force between a water droplet and the thin film depends on the alkyl chain length of the alkylamine and the duration of ultraviolet irradiation utilized for photocatalytic degradation.

  17. Structural, morphology and electrical properties of layered copper selenide thin film

    Science.gov (United States)

    Ying Chyi Liew, J.; Talib, Zainal; Mahmood, W.; Yunus, M.; Zainal, Zulkarnain; Halim, Shaari; Moksin, Mohd; Yusoff, Wan; Pah Lim, K.

    2009-06-01

    Thin films of copper selenide (CuSe) were physically deposited layer-by-layer up to 5 layers using thermal evaporation technique onto a glass substrate. Various film properties, including the thickness, structure, morphology, surface roughness, average grain size and electrical conductivity are studied and discussed. These properties are characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), ellipsometer and 4 point probe at room temperature. The dependence of electrical conductivity, surface roughness, and average grain size on number of layers deposited is discussed.

  18. Controlling the morphology of carbon nanotube arrays: from spinnable forests to undulating foams

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yingying [Los Alamos National Laboratory; Zou, Guifu [Los Alamos National Laboratory; Stan, Liliana [Los Alamos National Laboratory; Hawley, Marilyn E [Los Alamos National Laboratory; Sheehan, Chris J [Los Alamos National Laboratory; Zhu, Yuntain [Los Alamos National Laboratory; Jia, Quanxi [Los Alamos National Laboratory; Doorn, Stephen K [NCSU; Htoon, Han [NCSU

    2009-01-01

    By controlling catalyst pretreatment conditions, we demonstrate that the degree of spinnability of carbon nanotubes (CNTs) is closely related to the morphology of CNT arrays. Shortest catalyst pretreatment time led to CNT arrays with the best spinnability, while prolonged pretreatment resulted in coarsening of catalyst particles and non-spinnable CNTs. We further demonstrate the growth of undulating CNT arrays with uniform and tunable waviness by controlling the coalescence of catalyst particles. The CNT arrays can be tuned from well-aligned, spinnable forests to uniformly wavy, foam-like films by controlling catalyst pretreatment conditions.

  19. Morphological and compositional engineering of Ni/carbon nanotube composite film via a novel cyclic voltammetric route

    Indian Academy of Sciences (India)

    Yu Jun Yang

    2012-08-01

    Ni/multi-walled carbon nanotubes (MWCNTs) composite films were deposited on the glassy carbon electrode (GCE) by a Ni plating bath containing homogeneously dispersed MWCNTs using polyvinylpyrrolidone (PVP) as dispersion additive. Incorporation of MWCNTs into Ni matrix was greatly enhanced by the application of cyclic voltammetric (CV) deposition technique. The structure and nature of the Ni/MWCNT were characterized by field emission scanning electron microscope (FE-SEM) and X-ray diffraction (XRD). The results show that the content of MWCNT and the morphology of the deposited Ni/MWCNT composite film can be controlled by selecting the appropriate electroplating conditions. Further study indicates that the obtained Ni/MWCNT showed excellent electro-catalytic activity for the oxidation of ethanol in alkaline solution.

  20. Morphological Evolution of Multilayer Ni/NiO Thin Film Electrodes during Lithiation.

    Science.gov (United States)

    Evmenenko, Guennadi; Fister, Timothy T; Buchholz, D Bruce; Li, Qianqian; Chen, Kan-Sheng; Wu, Jinsong; Dravid, Vinayak P; Hersam, Mark C; Fenter, Paul; Bedzyk, Michael J

    2016-08-10

    Oxide conversion reactions in lithium ion batteries are challenged by substantial irreversibility associated with significant volume change during the phase separation of an oxide into lithia and metal species (e.g., NiO + 2Li(+) + 2e(-) → Ni + Li2O). We demonstrate that the confinement of nanometer-scale NiO layers within a Ni/NiO multilayer electrode can direct lithium transport and reactivity, leading to coherent expansion of the multilayer. The morphological changes accompanying lithiation were tracked in real-time by in-operando X-ray reflectivity (XRR) and ex-situ cross-sectional transmission electron microscopy on well-defined periodic Ni/NiO multilayers grown by pulsed-laser deposition. Comparison of pristine and lithiated structures reveals that the nm-thick nickel layers help initiate the conversion process at the interface and then provide an architecture that confines the lithiation to the individual oxide layers. XRR data reveal that the lithiation process starts at the top and progressed through the electrode stack, layer by layer resulting in a purely vertical expansion. Longer term cycling showed significant reversible capacity (∼800 mA h g(-1) after ∼100 cycles), which we attribute to a combination of the intrinsic bulk lithiation capacity of the NiO and additional interfacial lithiation capacity. These observations provide new insight into the role of metal/metal oxide interfaces in controlling lithium ion conversion reactions by defining the relationships between morphological changes and film architecture during reaction.

  1. Morphological Evolution of Multilayer Ni/NiO Thin Film Electrodes during Lithiation

    Energy Technology Data Exchange (ETDEWEB)

    Evmenenko, Guennadi; Fister, Timothy T.; Buchholz, D. Bruce; Li, Qianqian; Chen, Kan-Sheng; Wu, Jinsong; Dravid, Vinayak P.; Hersam, Mark C.; Fenter, Paul; Bedzyk, Michael J.

    2016-08-10

    Oxide conversion reactions in lithium ion batteries are challenged by substantial irreversibility associated with significant volume change during the phase separation of an oxide into lithia and metal species (e.g., NiO + 2Li(+) + 2e(-) -> Ni + Li2O). We demonstrate that the confinement of nanometer-scale NiO layers within a Ni/NiO multilayer electrode can direct lithium transport and reactivity, leading to coherent expansion of the multilayer. The morphological changes accompanying lithiation were tracked in real-time by in-operando X-ray reflectivity (XRR) and ex situ cross-sectional transmission electron microscopy on well-defined periodic Ni/NiO multilayers grown by pulsed-laser deposition. Comparison of pristine and lithiated structures reveals that the nm-thick nickel layers help initiate the conversion process at the interface and then provide an architecture that confines the lithiation to the individual oxide layers. XRR data reveal that the lithiation process starts at the top and progressed through the electrode stack, layer by layer resulting in a purely vertical expansion. Longer term cycling showed significant reversible capacity (similar to 800 mA h g(-1) after similar to 100 cycles), which we attribute to a combination of the intrinsic bulk lithiation capacity of the NiO and additional interfacial lithiation capacity. These observations provide new insight into the role of metal/metal oxide interfaces in controlling lithium ion conversion reactions by defining the relationships between morphological changes and film architecture during reaction.

  2. In situ morphology studies of the mechanism for solution additive effects on the formation of bulk heterojunction films

    KAUST Repository

    Richter, Lee J.

    2014-09-29

    The most successful active film morphology in organic photovoltaics is the bulk heterojunction (BHJ). The performance of a BHJ arises from a complex interplay of the spatial organization of the segregated donor and acceptor phases and the local order/quality of the respective phases. These critical morphological features develop dynamically during film formation, and it has become common practice to control them by the introduction of processing additives. Here, in situ grazing incidence X-ray diffraction (GIXD) and grazing incidence small angle X-ray scattering (GISAXS) studies of the development of order in BHJ films formed from the donor polymer poly(3-hexylthiophene) and acceptor phenyl-C61-butyric acid methyl ester under the influence of two common additives, 1,8-octanedithiol and 1-chloronaphthalene, are reported. By comparing optical aggregation to crystallization and using GISAXS to determine the number and nature of phases present during drying, two common mechanisms by which the additives increase P3HT crystallinity are identified. Additives accelerate the appearance of pre-crystalline nuclei by controlling solvent quality and allow for extended crystal growth by delaying the onset of PCBM-induced vitrification. The glass transition effects vary system-to-system and may be correlated to the number and composition of phases present during drying. Synchrotron X-ray scattering measurements of nanoscale structure evolution during the drying of polymer-fullerene photovoltaic films are described. Changes in the number and nature of phases, as well as the order within them, reveals the mechanisms by which formulation additives promote structural characteristics leading to higher power conversion efficiencies.

  3. Controlled Morphology of Porous Polyvinyl Butyral Nanofibers

    Directory of Open Access Journals (Sweden)

    Daniela Lubasova

    2011-01-01

    Full Text Available A simple and effective method for the fabrication of porous nanofibers based on the solvent evaporation methods in one-step electrospinning process from the commercial polyvinyl butyral (PVB is presented. The obtained nanofibers are prevalently amorphous with diameters ranging from 150 to 4350 nm and specific surface area of approximately 2–20 m2/g. Pore size with irregular shape of the porous PVB fibers ranged approximately from 50 to 200 nm. The effects of polymer solution concentration, composition of the solvents mixture, and applied voltage on fiber diameter and morphology were investigated. The theoretical approach for the choice of poor and good solvents for PVB was explained by the application Hansen solubility parameter (HSP and two-dimensional graph. Three basic conditions for the production of porous PVB nanofibers were defined: (i application of good/poor solvent mixture for spinning solution, (ii differences of the evaporation rate between good/poor solvent, and (iii correct ratios of good/poor solvent (v/v. The diameter of prepared porous PVB fibers decreased as the polymer concentration was lowered and with higher applied voltage. These nanofiber sheets with porous PVB fibers could be a good candidate for high-efficiency filter materials in comparison to smooth fibers without pores.

  4. Surface Morphology and Growth of Anodic Titania Nanotubes Films: Photoelectrochemical Water Splitting Studies

    Directory of Open Access Journals (Sweden)

    Chin Wei Lai

    2015-01-01

    become the most studied material as they exhibit promising functional properties. In the present study, anodic TiO2 films with different surface morphologies can be synthesized in an organic electrolyte of ethylene glycol (EG by controlling an optimum content of ammonium fluoride (NH4F using electrochemical anodization technique. Based on the results obtained, well-aligned and bundle-free TiO2 nanotube arrays with diameter of 100 nm and length of 8 µm were successfully synthesized in EG electrolyte containing ≈5 wt% of NH4F for 1 h at 60 V. However, formation of nanoporous structure and compact oxide layer would be favored if the content of NH4F was less than 5 wt%. In the photoelectrochemical (PEC water splitting studies, well-aligned TiO2 nanotubular structure exhibited higher photocurrent density of ≈1 mA/cm2 with photoconversion efficiency of ≈2% as compared to the nanoporous and compact oxide layer due to the higher active surface area for the photon absorption to generate more photo-induced electrons during photoexcitation stage.

  5. Improvement of the multilayer morphology (alumina/Cu/YIG/Cu) to characterize YIG thin film

    Energy Technology Data Exchange (ETDEWEB)

    Khalil, Ismail; Siblini, Ali; Chatelon, Jean Pierre; Blanc-Mignon, Marie Francoise; Rousseau, Jean Jacques [Universite de Saint Etienne, Jean Monnet, 42023 Saint Etienne (France); Universite de Lyon (France)

    2011-07-15

    The aim of our study is to characterize yttrium iron garnet (YIG) thin film for its applications in the microwaves and magneto-optical domains. For this purpose, we have manufactured a microinductor by deposition of YIG film between two copper layers on an alumina substrate. Multilayers have been deposited by radio-frequency magnetron sputtering technique. Thin films of YIG are amorphous after deposition; a post-thermal annealing at 740 C for 2 h is necessary to obtain satisfactory magnetic properties. In this work, we have studied the effects of different parameters concerning the substrate surface state, deposition and post-thermal treatment of YIG and copper thin films on their structure and morphological properties. We have come against several mechanical and electrical problems: crack formation, detachment of YIG or Cu films from the substrate, deterioration of Cu films, open or short circuits. The roughness of alumina substrate and the annealing mode play an important role on the quality of the microinductor prototype. After several tests by varying different parameters, we have established a protocol permitting to manufacture a prototype of good quality. This prototype is characterized using: profilometry, scanning electron microscopy, X-ray diffraction, vibrating sample magnetometry, and a precision LCR meter. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Structure and morphology of magnetron sputter deposited ultrathin ZnO films on confined polymeric template

    Science.gov (United States)

    Singh, Ajaib; Schipmann, Susanne; Mathur, Aakash; Pal, Dipayan; Sengupta, Amartya; Klemradt, Uwe; Chattopadhyay, Sudeshna

    2017-08-01

    The structure and morphology of ultra-thin zinc oxide (ZnO) films with different film thicknesses on confined polymer template were studied through X-ray reflectivity (XRR) and grazing incidence small angle X-ray scattering (GISAXS). Using magnetron sputter deposition technique ZnO thin films with different film thicknesses (molecular weight of polystyrene). The detailed internal structure, along the surface/interfaces and the growth direction of the system were explored in this study, which provides insight into the growth procedure of ZnO on confined polymer and reveals that a thin layer of ZnO, with very low surface and interface roughness, can be grown by DC magnetron sputtering technique, with approximately full coverage (with bulk like electron density) even in nm order of thickness, in 2-7 nm range on confined polymer template, without disturbing the structure of the underneath template. The resulting ZnO-polystyrene hybrid systems show strong ZnO near band edge (NBE) and deep-level (DLE) emissions in their room temperature photoluminescence spectra, where the contribution of DLE gets relatively stronger with decreasing ZnO film thickness, indicating a significant enhancement of surface defects because of the greater surface to volume ratio in thinner films.

  7. Enhanced Photocatalytic Performance Depending on Morphology of Bismuth Vanadate Thin Film Synthesized by Pulsed Laser Deposition.

    Science.gov (United States)

    Jeong, Sang Yun; Choi, Kyoung Soon; Shin, Hye-Min; Kim, Taemin Ludvic; Song, Jaesun; Yoon, Sejun; Jang, Ho Won; Yoon, Myung-Han; Jeon, Cheolho; Lee, Jouhahn; Lee, Sanghan

    2017-01-11

    We have fabricated high quality bismuth vanadate (BiVO4) polycrystalline thin films as photoanodes by pulsed laser deposition (PLD) without a postannealing process. The structure of the grown films is the photocatalytically active phase of scheelite-monoclinic BiVO4 which was obtained by X-ray diffraction (XRD) analysis. The change of surface morphology for the BIVO4 thin films depending on growth temperature during synthesis has been observed by scanning electron microscopy (SEM), and its influence on water splitting performance was investigated. The current density of the BiVO4 film grown on a glass substrate covered with fluorine-doped tin oxide (FTO) at 230 °C was as high as 3.0 mA/cm(2) at 1.23 V versus the potential of the reversible hydrogen electrode (VRHE) under AM 1.5G illumination, which is the highest value so far in previously reported BiVO4 films grown by physical vapor deposition (PVD) methods. We expect that doping of transition metal or decoration of oxygen evolution catalyst (OEC) in our BiVO4 film might further enhance the performance.

  8. ZnO based transparent conductive oxide films with controlled type of conduction

    Energy Technology Data Exchange (ETDEWEB)

    Zaharescu, M., E-mail: mzaharescu@icf.ro [Institute of Physical Chemistry “Ilie Murgulescu”, Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania); Mihaiu, S., E-mail: smihaiu@icf.ro [Institute of Physical Chemistry “Ilie Murgulescu”, Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania); Toader, A. [Institute of Physical Chemistry “Ilie Murgulescu”, Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania); Atkinson, I., E-mail: irinaatkinson@yahoo.com [Institute of Physical Chemistry “Ilie Murgulescu”, Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania); Calderon-Moreno, J.; Anastasescu, M.; Nicolescu, M.; Duta, M.; Gartner, M. [Institute of Physical Chemistry “Ilie Murgulescu”, Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania); Vojisavljevic, K.; Malic, B. [Institute Jožef Stefan, Ljubljana (Slovenia); Ivanov, V.A.; Zaretskaya, E.P. [State Scientific and Production Association “Scientific-Practical Materials Research Center of the National Academy of Science Belarus, P. Brovska str.19, 220072, Minsk (Belarus)

    2014-11-28

    The transparent conductive oxide films with controlled type of conduction are of great importance and their preparation is intensively studied. In our work, the preparation of such films based on doped ZnO was realized in order to achieve controlled type of conduction and high concentration of the charge carriers. Sol–gel method was used for films preparation and several dopants were tested (Sn, Li, Ni). Multilayer deposition was performed on several substrates: SiO{sub 2}/Si wafers, silica-soda-lime and/or silica glasses. The structural and morphological characterization of the obtained films were done by scanning electron microscopy, X-ray diffraction, X-ray fluorescence, X-ray photoelectron spectroscopy and atomic force microscopy respectively, while spectroscopic ellipsometry and transmittance measurements were done for determination of optical properties. The selected samples with the best structural, morphological and optical properties were subjected to electrical measurement (Hall and Seebeck effect). In all studied cases, samples with good adherence and homogeneous morphology as well as monophasic wurtzite type structure were obtained. The optical constants (refractive index and extinction coefficient) were calculated from spectroscopic ellipsometry data using Cauchy model. Films with n- or p-type conduction were obtained depending on the composition, number of deposition and thermal treatment temperature. - Highlights: • Transparent conductive ZnO based thin films were prepared by the sol–gel method. • Controlled type of conduction is obtained in (Sn, Li) doped and Li-Ni co-doped ZnO films. • Hall and Seebeck measurements proved the p-type conductivity for Li-Ni co-doped ZnO films. • The p-type conductivity was maintained even after 4-months of storage. • Influence of dopant- and substrate-type on the ZnO films properties was established.

  9. Structural, compositional and morphological studies of thermally evaporated MoO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Senthilkumar, R., E-mail: raviganesa@rediffmail.com, E-mail: gravicrc@gmail.com; Ravi, G., E-mail: raviganesa@rediffmail.com, E-mail: gravicrc@gmail.com [Department of Physics, Alagappa University, Karaikudi - 630003 (India)

    2014-04-24

    Molybdenum oxide (MoO{sub 3}) nanostructures were grown on different substrates such as glass, indium tin oxide coated glass and fluorine doped glass by thermal evaporation of MoO{sub 3} powder at elevated temperature (750°C) using tube furnace without any catalyst and then by subsequent O{sub 2}/Ar flow rate. The morphology, composition and crystal structure were examined by using SEM, EDAX, Laser Raman and XRD. The films are polycrystalline with well-defined diffraction peaks and it consist of MoO{sub 3} with α-orthorhombic structure. The synthesized MoO{sub 3} belongs to different morphologies, generally nanobelt and nanohunk structures. The EDAX spectra confirm the films are composed only of Mo and O atoms. The O/Mo ratio is nearly equal to 3 that shows the stoichiometry of MoO{sub 3}.

  10. Sandwich heterostructures of antimony trioxide and bismuth trioxide films: Structural, morphological and optical analysis

    Science.gov (United States)

    Condurache-Bota, Simona; Praisler, Mirela; Gavrila, Raluca; Tigau, Nicolae

    2017-01-01

    Thin film heterostructures can be advantageous since they either exhibit novel or a combination of the properties of their components. Here we propose sandwich-type of heterostructures made of antimony trioxide and bismuth trioxide thin films, which were deposited on glass substrates by thermal vacuum deposition at three substrate temperatures, 50° Celsius apart. Their morphology and optical properties are studied as compared to the corresponding monolayers. It was found that even small substrate temperature changes strongly influence their morphology, increasing their roughness, while the optical transmittance shows a slight decrease as compared with the individual layers. The corresponding absorption coefficient exhibits intermediate values as compared to the component oxides, while the energy bandgaps for the indirect allowed transitions move towards the Infrared when overlapping the antimony and bismuth trioxides.

  11. Morphology and ion-conductivity of gelatin-LiClO4 films: fractional diffusion analysis.

    Science.gov (United States)

    Basu, Tania; Goswami, Minakshi Maitra; Middya, T R; Tarafdar, Sujata

    2012-09-13

    Biopolymers are expected to replace synthetic polymers in the quest for cost-effective, environment friendly, and pollution free technology. We report here a study on gelatin films with different concentrations of lithium perchlorate, which may be a candidate for electrolyte material in solid polymer batteries. Morphology studies and impedance spectroscopy both are done on the same set of samples. We study the microstructure of the film by SEM and try to see if a correlation between impedance spectroscopy results and features of gel morphology can be identified. A network structure is revealed in the SEM images where details of the network parameters appear to depend on the salt fraction. Analysis of the impedance measurements is done using a physically meaningful model based on material properties instead of the usual equivalent circuit formalism, where circuit elements are difficult to interpret. We find that anomalous diffusion of charge carriers plays an important role; this is incorporated through a fractional calculus approach.

  12. Improvement of Flame-made ZnO Nanoparticulate Thick Film Morphology for Ethanol Sensing

    Directory of Open Access Journals (Sweden)

    Sukon Phanichphant

    2007-05-01

    Full Text Available ZnO nanoparticles were produced by flame spray pyrolysis using zinc naphthenate as a precursor dissolved in toluene/acetonitrile (80/20 vol%. The particles properties were analyzed by XRD, BET. The ZnO particle size and morphology was observed by SEM and HR-TEM revealing spheroidal, hexagonal, and rod-like morphologies. The crystallite sizes of ZnO spheroidal and hexagonal particles ranged from 10-20 nm. ZnO nanorods were ranged from 10-20 nm in width and 20-50 nm in length. Sensing films were produced by mixing the nanoparticles into an organic paste composed of terpineol and ethyl cellulose as a vehicle binder. The paste was doctor-bladed onto Al2O3 substrates interdigitated with Au electrodes. The morphology of the sensing films was analyzed by optical microscopy and SEM analysis. Cracking of the sensing films during annealing process was improved by varying the heating conditions. The gas sensing of ethanol (25-250 ppm was studied at 400 °C in dry air containing SiC as the fluidized particles. The oxidation of ethanol on the surface of the semiconductor was confirmed by mass spectroscopy (MS. The effect of micro-cracks was quantitatively accounted for as a provider of extra exposed edges. The sensitivity decreased notably with increasing crack of sensing films. It can be observed that crack widths were reduced with decreasing heating rates. Crack-free of thick (5 μm ZnO films evidently showed higher sensor signal and faster response times (within seconds than cracked sensor. The sensor signal increased and the response time decreased with increasing ethanol concentration.

  13. Morphology and oxygen incorporation effect on antimicrobial activity of silver thin films

    OpenAIRE

    2016-01-01

    Ag and AgxO thin films were deposited by non-reactive and reactive pulsed DC magnetron sputtering, respectively, with the final propose of functionalizing the SS316L substrate with antibacterial properties. The coatings were characterized chemically, physically and structurally. The coatings nanostructure was assessed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), while the coatings morphology was determined by scanning electron microscopy (SEM). The XRD and XPS analys...

  14. Morphology, conductivity, and wetting characteristics of PEDOT:PSS thin films deposited by spin and spray coating

    Science.gov (United States)

    Zabihi, F.; Xie, Y.; Gao, S.; Eslamian, M.

    2015-05-01

    The goal of this paper is to study the characteristics of PEDOT:PSS thin films and the effects of varying the processing parameters on the structure, functionality, and surface wetting of spun-on and spray-on PEDOT:PSS thin films. PEDOT:PSS is a polymer mixture, which is electrically conductive and transparent and, therefore, is an attractive material for some optoelectronic applications, such as organic and perovskite solar cells. In this work, the films are fabricated using spin coating (a lab-scale method) and spray coating (an up-scalable method). The effects of spinning speed, drying time, and post-annealing temperature on spun-on samples and the effects of the substrate temperature and number of spray passes (deposition layers) on spray-on samples, as well as the effect of precursor solution concentration on both cases are investigated. Various characterization tools, such as AFM, SEM, XRD, confocal laser scanning microscopy (CLSM), and electrical conductivity measurements are used to determine the film roughness, thickness, structure, and morphology. The solution precursor physical data, such as contact angle on glass substrates, viscosity, and interfacial tension, are also obtained within a practical range of temperatures and concentrations. It is found that in both spin and spray coating routes, only well-controlled operating conditions result in the formation of conductive and defect-free PEDOT:PSS films. The formation of PEDOT:PSS thin films with small grains composed of PEDOT forming the core of the grains and PSS forming a shell or coating, which are evenly distributed in a PSS-rich matrix, is favored. Conditions leading to the above-mentioned electrically conductive scenario are identified. Other topics, such as the formation of defects and dewetting, are also elucidated.

  15. Controlled nanostructuration of polycrystalline tungsten thin films

    Energy Technology Data Exchange (ETDEWEB)

    Girault, B. [Institut P' (UPR 3346 CNRS), Universite de Poitiers, ENSMA, Bd Pierre et Marie Curie, 86962 Futuroscope Cedex (France); Institut de Recherche en Genie Civil et Mecanique (UMR CNRS 6183), LUNAM Universite, Universite de Nantes, Centrale Nantes, CRTT, 37 Bd de l' Universite, BP 406, 44602 Saint-Nazaire Cedex (France); Eyidi, D.; Goudeau, P.; Guerin, P.; Bourhis, E. Le; Renault, P.-O. [Institut P' (UPR 3346 CNRS), Universite de Poitiers, ENSMA, Bd Pierre et Marie Curie, 86962 Futuroscope Cedex (France); Sauvage, T. [CEMHTI/CNRS (UPR 3079 CNRS), Universite d' Orleans, 3A rue de la Ferollerie, 45071 Orleans Cedex 2 (France)

    2013-05-07

    Nanostructured tungsten thin films have been obtained by ion beam sputtering technique stopping periodically the growing. The total thickness was maintained constant while nanostructure control was obtained using different stopping periods in order to induce film stratification. The effect of tungsten sublayers' thicknesses on film composition, residual stresses, and crystalline texture evolution has been established. Our study reveals that tungsten crystallizes in both stable {alpha}- and metastable {beta}-phases and that volume proportions evolve with deposited sublayers' thicknesses. {alpha}-W phase shows original fiber texture development with two major preferential crystallographic orientations, namely, {alpha}-W<110> and unexpectedly {alpha}-W<111> texture components. The partial pressure of oxygen and presence of carbon have been identified as critical parameters for the growth of metastable {beta}-W phase. Moreover, the texture development of {alpha}-W phase with two texture components is shown to be the result of a competition between crystallographic planes energy minimization and crystallographic orientation channeling effect maximization. Controlled grain size can be achieved for the {alpha}-W phase structure over 3 nm stratification step. Below, the {beta}-W phase structure becomes predominant.

  16. 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.

  17. Optical and morphological properties of sol gel derived titanium dioxide films

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, A. B. [Department of Physics, Nabira Mahavidyalaya, Katol-441302 (India); Sharma, S. K. [Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore-560012 (India); M, Vishwas [Department of Physics, Govt. Science College, Bangalore-560067 (India); Rao, K. Narasimha [Department of Instrumentation, Indian Institute of Science, Bangalore-560012 (India)

    2015-08-28

    Titanium oxide (Titania) thin films were synthesized on different substrates via the sol-gel dip-coating method using alkoxide solution. Some selected samples were also prepared with different percentage of Lead (Pb). The influence of Pb addition in precursor sol on the optical properties of titanium dioxide thin films was studied. The optical transmittance in the visible region has increased with increase in weight percentage of lead. The refractive index was slightly decreased with Pb addition. Crystallization of these coatings was achieved through thermal annealing at temperatures above 400 °C. The structural properties and surface morphology of the crystallized coatings were studied by Scanning Electron Microscopy. Increase in average grain size from 250 nm to 350 nm with increase in Pb concentration is observed. Films were appeared to more coarse with increase in Pb addition. An increase in Pb addition resulted increase in average roughness from 12 nm to 25 nm.

  18. Morphology, surface topography and optical studies on electron beam evaporated MgO thin films

    Indian Academy of Sciences (India)

    A Chowdhury; J Kumar

    2006-10-01

    Electron beam evaporated thin films of MgO powder synthesized by burning of magnesium ribbon in air and sol–gel technique are studied for their microstructure (SEM), surface topography (AFM), and optical transmission behaviour (UV-visible spectroscopy). MgO thin films are shown to be either continuous or have mesh like morphology. The bar regions are believed to be of magnesium hydroxide formed due to absorption of moisture. Their AFM images exhibit columnar/pyramidal/truncated cone structure, providing support to the 3D Stranski–Krastanov model for film growth. Further, they are shown to have high transmittance (∼90%) in the wavelength range 400–600 nm, but absorb radiation below 350 nm substantially giving signature of a band transition.

  19. Ascorbic acid and BSA protein in solution and films: interaction and surface morphological structure.

    Science.gov (United States)

    Maciel, Rafael R G; de Almeida, Adriele A; Godinho, Odin G C; Gorza, Filipe D S; Pedro, Graciela C; Trescher, Tarquin F; Silva, Josmary R; de Souza, Nara C

    2013-01-01

    This paper reports on the study of the interactions between ascorbic acid (AA) and bovine serum albumin (BSA) in aqueous solution as well as in films (BSA/AA films) prepared by the layer-by-layer technique. Regarding to solution studies, a hyperchromism (in the range of ultraviolet) was found as a function of AA concentration, which suggested the formation of aggregates from AA and BSA. Binding constant, K, determined for aggregates from BSA and AA was found to be about 10(2) M(-1), which indicated low affinity of AA with BSA. For the BSA/AA films, it was also noted that the AA adsorption process and surface morphological structures depended on AA concentration. By changing the contact time between the AA and BSA, a hypochromism was revealed, which was associated to decrease of accessibility of solvent to tryptophan due to formation of aggregates. Furthermore, different morphological structures of aggregates were observed, which were attributed to the diffusion-limited aggregation. Since most of studies of interactions of drugs and proteins are performed in solution, the analysis of these processes by using films can be very valuable because this kind of system is able to employ several techniques of investigation in solid state.

  20. Structure, morphology and electrical characterizations of direct current sputtered ZnO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Yang, L., E-mail: liu.yang@univ-littoral.fr [Univ Lille Nord de France, ULCO, UDSMM, 62228 Calais (France); Duponchel, B. [Univ Lille Nord de France, ULCO, UDSMM, 59140 Dunkerque (France); Cousin, R.; Gennequin, C. [Univ Lille Nord de France, ULCO, UCEIV, 59140 Dunkerque (France); Leroy, G.; Gest, J.; Carru, J.-C. [Univ Lille Nord de France, ULCO, UDSMM, 62228 Calais (France)

    2012-05-01

    ZnO thin films were deposited on glass substrates by direct current (DC) sputtering technique at room temperature (RT) to 400 Degree-Sign C with a 99.999% pure ZnO target. Then the samples deposited at RT were annealed in air from the RT to 400 Degree-Sign C. The effects of substrate temperature (T{sub s}) and annealing treatment (T{sub a}) on the crystallization behavior and the morphology have been studied by X-ray diffraction and atomic force microscopy. We also compared the structural properties of samples deposited at 400 Degree-Sign C on glass to those deposited on Pt/silicon substrate. The resistivity, surface roughness and size of the grains have also been studied and correlated to the thickness of ZnO films deposited on Pt/Si substrates. The experimental results reveal that the substrate has a major influence on the structural and morphological properties. For the films deposited on glass, below 400 Degree-Sign C, T{sub s} and T{sub a} have a similar influence on the structure of the films. Moreover, the ZnO samples deposited at RT and annealed in air have poor electrical properties.

  1. Morphological, structural and optical properties of ZnO thin films deposited by dip coating method

    Energy Technology Data Exchange (ETDEWEB)

    Marouf, Sara; Beniaiche, Abdelkrim; Guessas, Hocine, E-mail: aziziamor@yahoo.fr [Laboratoire des Systemes Photoniques et Optiques Non Lineaires, Institut d' Optique et Mecanique de Precision, Universite Ferhat Abbas-Setif 1, Setif (Algeria); Azizi, Amor [Laboratoire de Chimie, Ingenierie Moleculaire et Nanostructures, Universite Ferhat Abbas-Setif 1, Setif (Algeria)

    2017-01-15

    Zinc oxide (ZnO) thin films were deposited on glass substrate by dip coating technique. The effects of sol aging time on the deposition of ZnO films was studied by using the field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and optical transmission techniques. The morphology of the films strongly depends on preparation route and deposition technique. It is noteworthy that films deposited from the freshly prepared solution feature indistinct characteristics; had relatively poor crystalline quality and low optical transmittance in the visible region. The increase in sol aging time resulted in a gradual improvement in crystallinity (in terms of peak sharpness and peak intensity) of the hexagonal phase for all diffraction peaks. Effect of sol aging on optical transparency is quite obvious through increased transmission with prolonged sol aging time. Interestingly, 72-168 h sol aging time was found to be optimal to achieve smooth surface morphology, good crystallinity and high optical transmittance which were attributed to an ideal stability of solution. These findings present a better-defined and more versatile procedure for production of clean ZnO sols of readily adjustable nanocrystalline size. (author)

  2. Thickness dependent electronic structure and morphology of rubrene thin films on metal, semiconductor, and dielectric substrates

    Science.gov (United States)

    Sinha, Sumona; Mukherjee, M.

    2013-08-01

    The evolution of the electronic structure and morphology of rubrene thin films on noble-metal, semiconductor and dielectric substrates have been investigated as a function of thickness of deposited films by using photoelectron spectroscopy and atomic force microscopy. The clean polycrystalline Au and Ag were used as noble-metals, whereas, H passivated and SiO2 coated Si (100) were used as semiconductors and dielectric substrates. Discussion and comparison on interface dipole, energy level alignment, and surface morphology for the four cases are presented. The formation of dipole at metallic interfaces is found to occur due to push back effect. S parameter obtained from the variation of barrier height with the change of work function of the contacting metal indicates moderately weak interaction between rubrene and the metal substrates. The thickness dependent energy level alignment of the physisorbed rubrene films on different substrates is explained by a dielectric model in terms of electrostatic screening of photo-holes or photoemission final state relaxation energy. Films on all the substrates are found to grow following Stranski-Krastnov type growth mode and are more ordered at higher coverage.

  3. Stretching-induced nanostructures on shape memory polyurethane films and their regulation to osteoblasts morphology.

    Science.gov (United States)

    Xing, Juan; Ma, Yufei; Lin, Manping; Wang, Yuanliang; Pan, Haobo; Ruan, Changshun; Luo, Yanfeng

    2016-10-01

    Programming such as stretching, compression and bending is indispensible to endow polyurethanes with shape memory effects. Despite extensive investigations on the contributions of programming processes to the shape memory effects of polyurethane, less attention has been paid to the nanostructures of shape memory polyurethanes surface during the programming process. Here we found that stretching could induce the reassembly of hard domains and thereby change the nanostructures on the film surfaces with dependence on the stretching ratios (0%, 50%, 100%, and 200%). In as-cast polyurethane films, hard segments sequentially assembled into nano-scale hard domains, round or fibrillar islands, and fibrillar apophyses. Upon stretching, the islands packed along the stretching axis to form reoriented fibrillar apophyses along the stretching direction. Stretching only changed the chemical patterns on polyurethane films without significantly altering surface roughness, with the primary composition of fibrillar apophyses being hydrophilic hard domains. Further analysis of osteoblasts morphology revealed that the focal adhesion formation and osteoblasts orientation were in accordance with the chemical patterns of the underlying stretched films, which corroborates the vital roles of stretching-induced nanostructures in regulating osteoblasts morphology. These novel findings suggest that programming might hold great potential for patterning polyurethane surfaces so as to direct cellular behavior. In addition, this work lays groundwork for guiding the programming of shape memory polyurethanes to produce appropriate nanostructures for predetermined medical applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. A liquid-like model for the morphology evolution of ion bombarded thin films

    Energy Technology Data Exchange (ETDEWEB)

    Repetto, L., E-mail: luca.repetto@unige.it [Department of Physics and Nanomed Labs, Università di Genova, Via Dodecaneso 33, 16146 Genova (Italy); Lo Savio, R. [Department of Physics and Nanomed Labs, Università di Genova, Via Dodecaneso 33, 16146 Genova (Italy); Šetina Batič, B. [Inštitut Za Kovinske Materiale in Tehnologije, Lepi pot 11, 1000 Ljubljana (Slovenia); Firpo, G.; Angeli, E.; Valbusa, U. [Department of Physics and Nanomed Labs, Università di Genova, Via Dodecaneso 33, 16146 Genova (Italy)

    2015-07-01

    Thin solid films exposed to ion irradiation exhibit a peculiar evolution that can differ substantially from what is observed for bulk samples. The phenomenology of the patterns that self-organize on the substrate is very rich, with morphologies that display several degrees of order upon the modification of initial film characteristics and irradiation parameters. This richness paves the way for the fabrication of novel functional surfaces, but it is also an indication of the complexity of the underlying driving mechanisms. A remarkable simplification for the comprehension of these phenomena can come from the noteworthy similarity of the obtained patterns with those showing up when liquids dewet from their substrates. Here, we analyze the possibility to apply a liquid-like model to explain the morphology evolution of ion bombarded thin films for the whole phenomenology showing up in experiments. In establishing this connection between liquids and ion bombarded thin films, we propose to use also for liquids the insight gained for our system with recent experiments that stress the importance of the substrate topography for the selection of the dewetting mechanism. If confirmed, this result would lead to a reconsideration of the importance of capillary waves in spinodal dewetting, and will help to understand the low reproducibility of the related experimental results.

  5. Surface morphology influence on deuterium retention in beryllium films prepared by thermionic vacuum arc method

    Science.gov (United States)

    Anghel, A.; Porosnicu, C.; Badulescu, M.; Mustata, I.; Lungu, C. P.; Sugiyama, K.; Lindig, S.; Krieger, K.; Roth, J.; Nastuta, A.; Rusu, G.; Popa, G.

    2009-01-01

    In a plasma-confinement device, material eroded from plasma facing components will be transported and re-deposited at other locations inside the reaction chamber. Since beryllium from the first wall of the ITER fusion reactor will be eroded, ionized in the scrape-off layer plasma and finally re-deposited on divertor surfaces flowing along the magnetic field, it is important to study the properties of divertor armour materials (C, W) coated with beryllium. By applying different bias voltages (-200 V to +700 V) to the substrates during deposition, the morphology of the obtained films was modified. The films' morphology was characterized by means of AFM and SEM, and it was found that the coatings prepared using negative bias voltage at the substrate during deposition are more compact and have a smoother surface compared to the samples prepared with positive bias voltage. The thickness and composition of each film were measured using Rutherford backscattering spectrometry (RBS). A study of deuterium implantation and retention into the prepared films was performed at IPP Garching in the high current ion source.

  6. Controlling Growth Orientation of Phthalocyanine Films by Electrical Fields

    Science.gov (United States)

    Zhu, S.; Banks, C. E.; Frazier, D. O.; Ila, D.; Muntele, I.; Penn, B. G.; Sharma, A.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    Organic Phthalocyanine films have many applications ranging from data storage to various non-linear optical devices whose quality is affected by the growth orientation of Phthalocyanine films. Due to the structural and electrical properties of Phthalocyanine molecules, the film growth orientation depends strongly on the substrate surface states. In this presentation, an electrical field up to 4000 V/cm is introduced during film growth. The Phthalocyanine films are synthesized on quartz substrates using thermal evaporation. An intermediate layer is deposited on some substrates for introducing the electrical field. Scanning electron microscopy, x-ray diffraction, and Fourier transform infrared spectroscopy are used for measuring surface morphology, film structure, and optical properties, respectively. The comparison of Phthalocyanine films grown with and without the electrical field reveals different morphology, film density, and growth orientation, which eventually change optical properties of these films. These results suggest that the growth method in the electrical field can be used to synthesized Phthalocyanine films with a preferred crystal orientation as well as propose an interaction mechanism between the substrate surface and the depositing molecules. The details of growth conditions and of the growth model of how the Phthalocyanine molecules grow in the electrical field will be discussed.

  7. Performances of screen-printing silver thick films: Rheology, morphology, mechanical and electronic properties

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Jung-Shiun; Liang, Jau-En; Yi, Han-Liou [Department of Chemical Engineering, National Chung Cheng University, Chia Yi 621, Taiwan, ROC (China); Chen, Shu-Hua [China Steel Corporation, Kaohsiung City 806, Taiwan, ROC (China); Hua, Chi-Chung, E-mail: chmcch@ccu.edu.tw [Department of Chemical Engineering, National Chung Cheng University, Chia Yi 621, Taiwan, ROC (China)

    2016-06-15

    Numerous recent applications with inorganic solar cells and energy storage electrodes make use of silver pastes through processes like screen-printing to fabricate fine conductive lines for electron conducting purpose. To date, however, there have been few studies that systematically revealed the properties of the silver paste in relation to the mechanical and electronic performances of screen-printing thick films. In this work, the rheological properties of a series of model silver pastes made of silver powders of varying size (0.9, 1.3, and 1.5 μm) and shape (irregular and spherical) were explored, and the results were systematically correlated with the morphological feature (scanning electron microscopy, SEM) and mechanical (peeling test) and electronic (transmission line method, TLM) performances of screen-printing dried or sintered thick films. We provided evidence of generally intimate correlations between the powder dispersion state in silver pastes—which is shown to be well captured by the rheological protocols employed herein—and the performances of screen-printing thick films. Overall, this study suggests the powder dispersion state and the associated phase behavior of a paste sample can significantly impact not only the morphological and electronic but also mechanical performances of screen-printing thick films, and, in future perspectives, a proper combination of silver powders of different sizes and even shapes could help reconcile quality and stability of an optimum silver paste. - Highlights: • Powder dispersion correlates well with screen-printing thick film performances. • Rheological fingerprints can be utilized to fathom the powder dispersion state. • Good polymer-powder interactions in the paste ensure good powder dispersion. • Time-dependent gel-like viscoelastic features are found with optimum silver pastes. • The size and shape of functional powder affect the dispersion and film performances.

  8. Morphology, conductivity, and wetting characteristics of PEDOT:PSS thin films deposited by spin and spray coating

    Energy Technology Data Exchange (ETDEWEB)

    Zabihi, F.; Xie, Y.; Gao, S.; Eslamian, M., E-mail: Morteza.Eslamian@sjtu.edu.cn

    2015-05-30

    Highlights: • Nanostructure of spun-on and spray-on PEDOT:PSS thin films is studied. • A correlation is established between the film nanostructure and electrical conductivity. • Effect of process parameters is studied on the film characteristics. • A high solution concentration, high process temperature and multiple deposition layers are recommended. - Abstract: The goal of this paper is to study the characteristics of PEDOT:PSS thin films and the effects of varying the processing parameters on the structure, functionality, and surface wetting of spun-on and spray-on PEDOT:PSS thin films. PEDOT:PSS is a polymer mixture, which is electrically conductive and transparent and, therefore, is an attractive material for some optoelectronic applications, such as organic and perovskite solar cells. In this work, the films are fabricated using spin coating (a lab-scale method) and spray coating (an up-scalable method). The effects of spinning speed, drying time, and post-annealing temperature on spun-on samples and the effects of the substrate temperature and number of spray passes (deposition layers) on spray-on samples, as well as the effect of precursor solution concentration on both cases are investigated. Various characterization tools, such as AFM, SEM, XRD, confocal laser scanning microscopy (CLSM), and electrical conductivity measurements are used to determine the film roughness, thickness, structure, and morphology. The solution precursor physical data, such as contact angle on glass substrates, viscosity, and interfacial tension, are also obtained within a practical range of temperatures and concentrations. It is found that in both spin and spray coating routes, only well-controlled operating conditions result in the formation of conductive and defect-free PEDOT:PSS films. The formation of PEDOT:PSS thin films with small grains composed of PEDOT forming the core of the grains and PSS forming a shell or coating, which are evenly distributed in a PSS

  9. Quantitative correlation between air induced changes of electronic parameters and morphological features of copper phthalocyanine thin film surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Grządziel, L., E-mail: Lucyna.Grzadziel@polsl.pl; Krzywiecki, M.

    2015-01-15

    In this work, utilizing fine-resolved photoemission yield spectroscopy (PYS) method, the set of electronic parameters of the space charge layer of 16 nm-copper phthalocyanine (CuPc) thin films deposited on n-type Si(111) substrate covered with modified SiO{sub 2} was determined after long term air exposure. The PYS investigation revealed that work function and surface band bending increased upon gas adsorption by 0.64 eV and 0.32 eV respectively for organic layer and surface dipole effect appeared as the shift in electron affinity of 0.32 eV. Obtained results were compared with photoemission data received for corresponding CuPc films on different types of silicon Si(111) substrate. Collected parameters were correlated with the morphological features of the CuPc's surfaces measured applying atomic force microscopy (AFM) ability. Results of compiled PYS and AFM studies indicated particular electronic tendency for oxidation processes for certain shapes of phthalocyanine crystallites. It may suggest that by manipulation of the initial films' morphology it would be possible to control the air stability of the CuPc-based electronic devices and their vulnerability to degradation processes. - Highlights: • PYS study of 16 nm-CuPc/RCA-SiO{sub 2}/n-Si(111) electronic properties after air exposure. • eV{sub s}, χ{sub s}, φ changes due to oxidation process compared to the other CuPc results. • Electronic parameters shift correlated with morphological features obtained by AFM.

  10. Structural and morphological characterizations of ZnO films grown on GaAs substrates by MOCVD

    Energy Technology Data Exchange (ETDEWEB)

    Agouram, S.; Zuniga Perez, J.; Munoz-Sanjose, V. [Universitat de Valencia, Departamento de Fisica Aplicada y Electromagnetismo, Burjassot (Spain)

    2007-07-15

    ZnO films were grown on GaAs(100), GaAs(111)A and GaAs(111)B substrates by metal organic chemical vapour deposition (MOCVD). Diethylzinc (DEZn) and tertiarybutanol (t-butanol) were used as Zn and O precursors, respectively. The influence of the growth temperature and GaAs substrate orientation on the crystalline orientation and morphology of the ZnO grown films has been analysed. Crystallinity of grown films was studied by X-ray diffraction (XRD); thickness and morphology of ZnO films were investigated by scanning electron microscopy (SEM). SEM results reveal significant differences between morphologies depending on growth temperature but not significant differences were detected on the texture of grown films. (orig.)

  11. Morphology and Crystallization of Thin Films of Asymmetric Organic-Organometallic Diblock Copolymers of Isoprene and Ferrocenyldimethylsilane

    NARCIS (Netherlands)

    Lammertink, Rob G.H.; Hempenius, Mark A.; Vancso, G. Julius

    2000-01-01

    The morphology of thin films of asymmetric block copolymers of poly(isoprene-block-ferrocenyldimethylsilane) was studied using atomic force microscopy, transmission electron microscopy, and optical microscopy. Block copolymers with the organometallic (ferrocenylsilane) phase between 20 and 28 vol %

  12. Kinetic Monte Carlo simulation of film morphologies at the initial stages

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The morphologies at the initial stages of thin film growth were studied by using Kinetic Monte Carlo techniques.A more efficient model was used to calculate the activity energy.The model involves incident atom attachment,diffusion,detachment from the surface,detached atom returning,and dimer diffusion.We edited a set of software of the model and simulated the surface morphologies by the principle of computer graphics.It is shown that the nucleuses formed at the initial stages and the surface morphologies at high temperatures are very different from those at low temperatures.The later surface growth depends on the nucleuses at the initial stages.The mechanism results from the atom thermal movement,the temperature determines the diffusion ability,and the deposition rate determines the diffusion time.

  13. Kinetic Monte Carlo simulation of film morphologies at the initial stages

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The morphologies at the initial stages of thin film growth were studied by using Kinetic Monte Carlo techniques. A more efficient model was used to calculate the activity energy. The model involves incident atom attachment, diffusion, detachment from the surface, detached atom returning, and dimer diffusion. We edited a set of software of the model and simulated the surface morphologies by the principle of computer graphics. It is shown that the nucleuses formed at the initial stages and the surface morphologies at high temperatures are very different from those at low temperatures. The later surface growth depends on the nucleuses at the initial stages. The mechanism results from the atom thermal movement, the temperature determines the diffusion ability, and the deposition rate determines the diffusion time.

  14. Effect of Nitridation on Morphology, Structural Properties and Stress of A1N Films

    Institute of Scientific and Technical Information of China (English)

    HU Wei-Guo; JIAO Chun-Mei; WEI Hong-Yuan; ZHANG Pan-Feng; KANG Wing-Ting; ZHANG Ri-Qing; LIU Xiang-Lin

    2008-01-01

    @@ We investigate effects of nitridation on A1N morphology, structural properties and stress.It is found that 3 min nitridation can prominently improve A1N crystal structure, and slightly smooth the surface morphology.However, 10min nitridation degrades out-of-plane crystal structure and surface morphology instead.Additionally, 3-min nitridation introduces more tensile stress (1.5 GPa) in A1N films, which can be attributed to the weaker islands 2D coalescent.Nitridation for 10 rain can introduce more defects, or even forms polycrystallinity interlayer, which relaxes the stress.Thus, the stress in A1N with 10 min nitridation decreases to -0.2 GPa compressive stress.

  15. Use of modified chemical route for ZnSe nanocrystalline thin films growth: Study on surface morphology and physical properties

    Science.gov (United States)

    Kale, R. B.; Lokhande, C. D.; Mane, R. S.; Han, Sung-Hwan

    2006-06-01

    The zinc selenide thin films have been deposited using modified chemical bath deposition (M-CBD) method. Zinc acetate and sodium selenosulphate were used as Zn 2+ and Se 2- ion sources, respectively. The preparative parameters such as concentration, pH, number of deposition cycles have been optimized in order to deposit ZnSe thin films. The as-deposited ZnSe thin films are specularly reflective and faint yellowish in color. The as-deposited ZnSe films are annealed in an air atmosphere at 473 K for 2 h. The films are characterized using structural, morphological, compositional, optical and electrical properties.

  16. The anodizing behavior of aluminum in malonic acid solution and morphology of the anodic films

    Science.gov (United States)

    Ren, Jianjun; Zuo, Yu

    2012-11-01

    The anodizing behavior of aluminum in malonic acid solution and morphology of the anodic films were studied. The voltage-time response for galvanostatic anodization of aluminum in malonic acid solution exhibits a conventional three-stage feature but the formation voltage is much higher. With the increase of electrolyte concentration, the electrolyte viscosity increases simultaneously and the high viscosity decreases the film growth rate. With the concentration increase of the malonic acid electrolyte, the critical current density that initiates local "burning" on the sample surface decreases. For malonic acid anodization, the field-assisted dissolution on the oxide surface is relatively weak and the nucleation of pores is more difficult, which results in greater barrier layer thickness and larger cell dimension. The embryo of the porous structure of anodic film has been created within the linear region of the first transient stage, and the definite porous structure has been established before the end of the first transient stage. The self-ordering behavior of the porous film is influenced by the electrolyte concentration, film thickness and the applied current density. Great current density not only improves the cell arrangement order but also brings about larger cell dimension.

  17. Effect of electrodeposition potential on composition and morphology of CIGS absorber thin film

    Indian Academy of Sciences (India)

    N D Sang; P H Quang; L T Tu; D T B Hop

    2013-08-01

    CuInGaSe (CIGS) thin films were deposited on Mo/soda-lime glass substrates by electrodeposition at different potentials ranging from −0.3 to −1.1 V vs Ag/AgCl. Cyclic voltammetry (CV) studies of unitary Cu, Ga, In and Se systems, binary Cu–Se, Ga–Se and In–Se systems and quaternary Cu–In–Ga–Se were carried out to understand the mechanism of deposition of each constituent. Concentration of the films was determined by energy dispersive spectroscopy. Structure and morphology of the films were characterized by X-ray diffraction and scanning electron microscope. The underpotential deposition mechanism of Cu–Se and In–Se phases was observed in voltammograms of binary and quaternary systems. Variation in composition with applied potentials was explained by cyclic voltammetry (CV) data. A suitable potential range from −0.8 to −1.0 V was found for obtaining films with desired and stable stoichiometry. In the post-annealing films, chalcopyrite structure starts forming in the samples deposited at −0.5 V and grows on varying the applied potential towards negative direction. By adjusting the composition of electrolyte, we obtained the desired stoichiometry of Cu(In0.7Ga0.3)Se2.

  18. Physicochemical and morphological properties of spin-coated poly(3-alkylthiophene) thin films

    Energy Technology Data Exchange (ETDEWEB)

    Nicho, M.E.; Medrano, G.; Gueizado, M. [Centro de Investigacion en Ingenieria y Ciencias Aplicadas, Universidad Autonoma del Estado de Morelos (UAEM), Av. Universidad 1001, Colonia Chamilpa, C.P. 62210, Cuernavaca, Morelos (Mexico); Hernandez, F. [Centro de Investigacion en Ingenieria y Ciencias Aplicadas, Universidad Autonoma del Estado de Morelos (UAEM), Av. Universidad 1001, Colonia Chamilpa, C.P. 62210, Cuernavaca, Morelos (Mexico); Facultad de Ciencias Quimicas e Ingenieria, UAEM (Mexico); Hu, H. [Departamento de Materiales Solares, Centro de Investigacion en Energia, UNAM, Temixco, Morelos, 62580 (Mexico); Guerrero, J.A. [Centro de Investigaciones Quimicas, UAEM (Mexico)

    2009-01-15

    Poly(3-hexylthiophene) (P3HT) and poly(3-octylthiophene) (P3OT) were synthesized by direct oxidation of the respective monomers with FeCl{sub 3} as oxidant/catalyst. It was observed that the type of monomer affected the molecular weight and polydispersity as well as degree of regioregularity of the polymer, measured by size exclusion chromatography and by {sup 1}H nuclear magnetic resonance, respectively. Homogeneous P3HT and P3OT films were prepared by spin-coating technique with different polymer concentration in solutions. Morphology study with atomic force microscopy indicates the cluster size difference between P3HT and P3OT films. Optical absorption properties of the polymeric films were analyzed in pristine and doped state. The electrochemical characterization of the poly(3-alquilthiophenes) (P3Ats) films showed two oxidation peaks, one at 0.35 V vs. Ag/AgCl, and the second one at 0.8 V vs. Ag/AgCl. The colors of the film at these two potentials were black and blue, respectively. (author)

  19. Temperature Dependent Thermal Conductivity and Thermal Interface Resistance of Pentacene Thin Films with Varying Morphology.

    Science.gov (United States)

    Epstein, Jillian; Ong, Wee-Liat; Bettinger, Christopher J; Malen, Jonathan A

    2016-07-27

    Temperature dependent thermal conductivities and thermal interface resistances of pentacene (Pn) thin films deposited on silicon substrates and self-assembled monolayer-modified [octadecyltrichlorosilane (OTS) and (3-aminopropyl)triethoxysilane (APTES)] silicon substrates were measured using frequency domain thermoreflectance. Atomic force microscopy images were used to derive an effective film thickness for thermal transport that accounts for surface roughness. Data taken over a temperature range of 77-300 K for various morphologies and film thicknesses show that the thermal conductivity increases with increasing Pn grain size. The sum of the substrate-Pn and Pn-gold thermal interface resistances was isolated from the intrinsic thermal resistance of the Pn films and found to be independent of surface chemistry. Corresponding Kapitza lengths of approximately 150 nm are larger than the physical thicknesses of typical Pn thin films and indicate that the interfaces play a dominant role in the total thermal resistance. This study has implications for increasing the performance and effective thermal management of small molecule electronic and energy conversion devices.

  20. Nano-structured morphological features of pulsed direct current magnetron sputtered Mo films for photovoltaic applications

    Energy Technology Data Exchange (ETDEWEB)

    Karthikeyan, Sreejith, E-mail: s.karthikeyan@edu.salford.ac.uk; Hill, Arthur E.; Pilkington, Richard D.

    2011-10-31

    Historically, molybdenum thin films have been used as the back contact for Cu(In,Ga)Se{sub 2} based solar cells and as such the properties of these layers play an important role in the overall cell structure. This paper describes the production of molybdenum films using pulsed d.c. magnetron sputtering from compressed molybdenum powder targets. The films were deposited at different substrate temperatures under constant power and constant current modes, and analysed using X-ray diffraction, scanning electron microscopy, atomic force microscopy and four point resistance probe. Mechanical strain and resistivity were found to decrease with substrate temperature together with a shift in the (110) crystallographic plane towards higher diffraction angles. All films were well adhered to the glass substrates irrespective of their high tensile strain. Surface morphology analysis revealed the presence of nano-structured stress relief patterns which can enhance the nucleation sites for subsequent CuInSe{sub 2} deposition. A high-resolution cross sectional image showed the columnar growth of the films. Surface roughness analysis revealed that roughness increased with increase in substrate temperature.

  1. Structural and morphological study of ZnO thin films electrodeposited on n-type silicon

    Energy Technology Data Exchange (ETDEWEB)

    Ait Ahmed, N., E-mail: nadiaitahmed@yahoo.fr [Laboratoire de Technologie des materiaux et Genie des Procedes : Equipe d' electrochimie - Corrosion Universite Abderrahmane Mira, Bejaia, 06000 (Algeria); Unite de Developpement de la Technologie du Silicium, 02 Bd Frantz Fanon, B.P. 140, Alger 7 Merveilles (Algeria); Fortas, G. [Unite de Developpement de la Technologie du Silicium, 02 Bd Frantz Fanon, B.P. 140, Alger 7 Merveilles (Algeria); Hammache, H. [Laboratoire de Technologie des materiaux et Genie des Procedes : Equipe d' electrochimie - Corrosion Universite Abderrahmane Mira, Bejaia, 06000 (Algeria); Sam, S.; Keffous, A.; Manseri, A. [Unite de Developpement de la Technologie du Silicium, 02 Bd Frantz Fanon, B.P. 140, Alger 7 Merveilles (Algeria); Guerbous, L. [Centre de Recherche Nucleaire d' Alger (Algeria); Gabouze, N., E-mail: ngabouze@yahoo.fr [Unite de Developpement de la Technologie du Silicium, 02 Bd Frantz Fanon, B.P. 140, Alger 7 Merveilles (Algeria)

    2010-10-01

    In this work, we report on the electrodeposition of ZnO thin films on n-Si (1 0 0) and glass substrates. The influence of the deposition time on the morphology of ZnO thin films was investigated. The ZnO thin films were characterized by X-ray diffraction (XRD), energy dispersive X-ray (EDS) and scanning electron microscopy (SEM). The results show a variation of ZnO texture from main (0 0 2) at 10 min to totally (1 0 1) at 15 min deposition time. The photoluminescence (PL) studies show that both UV ({approx}382 nm) and blue ({approx}432 nm) luminescences are the main emissions for the electrodeposited ZnO films. In addition, the film grown at 15 min indicates an evident decrease of the yellow-green ({approx}520 nm) emission band comparing with that of 10 min. Finally, transmittance spectra show a high transmission value up to 85% in the visible wavelength range. Such results would be very interesting for solar cells applications.

  2. About the Interactions Controlling Nafion's Viscoelastic Properties and Morphology

    NARCIS (Netherlands)

    Melchior, Jan-Patrick; Bräuniger, Thomas; Wohlfarth, Andreas; Portale, Giuseppe; Kreuer, Klaus-Dieter

    2015-01-01

    Interactions controlling the viscoelastic properties of Nafion are identified by investigating morphological changes induced through stretching at a wide range of controlled temperature and relative humidity. H-2-goniometer NMR exploiting the pseudonematic effect in D2O-containing membranes provides

  3. Influence of Heat Treatment on the Morphologies of Copper Nanoparticles Based Films by a Spin Coating Method

    Directory of Open Access Journals (Sweden)

    Wei Liu

    2017-01-01

    Full Text Available We have investigated the influence of heat treatment on the morphologies of copper nanoparticles based films on glass slides by a spin coating method. The experiments show that heat treatment can modify the sizes and morphologies of copper nanoparticles based films on glass slides. We suggest that through changing the parameters of heat treatment process may be helpful to vary the scattering and absorbing intensity of copper nanoparticles when used in energy harvesting/conversion and optical devices.

  4. Studies on the Surface Morphology and Orientation of CeO2 Films Deposited by Pulsed Laser Ablation

    Science.gov (United States)

    Develos, Katherine; Kusunoki, Masanobu; Ohshima, Shigetoshi

    1998-11-01

    We studied the surface morphology and orientation of CeO2 films grown by pulsed laser ablation (PLA) on r-cut (1\\=102) Al2O3 substrates and evaluated the effects of predeposition annealing conditions of Al2O3 and film thickness of CeO2. The annealing of Al2O3 substrates improves the smoothness of the surface and performing this in high vacuum leads to better crystallinity and orientation of deposited CeO2 films compared to those annealed in oxygen. A critical value of the film thickness was found beyond which the surface roughness increases abruptly. Atomic force microscopy (AFM) study showed that the surface of CeO2 films is characterized by a mazelike pattern. Increasing the film thickness leads to the formation of larger islands which cause the increase in the surface roughness of the films. The areal density and height of these islands increased with film thickness.

  5. Composite films of poly(vinyl alcohol)-chitosan-bacterial cellulose for drug controlled release.

    Science.gov (United States)

    Pavaloiu, Ramona-Daniela; Stoica-Guzun, Anicuta; Stroescu, Marta; Jinga, Sorin Ion; Dobre, Tanase

    2014-07-01

    Mono and multilayer composite films of poly(vinyl alcohol)-chitosan-bacterial cellulose (PVA/chitosan/BC) have been prepared to achieve controlled release of ibuprofen sodium salt (IbuNa) as model drug. The composite films have been characterized by Fourier transformed infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Surface morphology was investigated by scanning electron microscopy (SEM). Equilibrium swelling was measured in water at two different pH values and in vitro release of IbuNa in pH 1.2 and pH 7.4 media was studied. The release experiments revealed that drug release is pH sensitive. The release kinetics of IbuNa could be described by the Fickian model of diffusion with a good agreement. The IbuNa release rate was decreasing for all the films as the BC concentration was increased in the films composition, the decrease being higher for the multilayer films.

  6. Electrical and Morphological Properties of Inkjet Printed Pedot/PSS Films

    Energy Technology Data Exchange (ETDEWEB)

    Garnett, E.; Ginley, D.

    2005-01-01

    Organic solar cells and LEDs are becoming more popular because their low cost materials, potential manufacturability, and recent gains in efficiency make them feasible for widespread commercialization in the near future. One significant manufacturing problem, especially for OLEDs, is the cost associated with creating patterned devices with spatially non-specific deposition methods such as spincoating. Inkjet printing can remove this problem. In recent years, inkjet printed polyethylene(3,4-dioxythiophene)/ polystyrene sulfonate (PEDOT/PSS) has been incorporated into many organic devices to help charge transfer, but there has not been much research regarding the effect of different printing parameters on the electrical and morphological film properties. In this work, an atomic force microscope, four point probe, and Kelvin probe were used to study the effects of printing parameters on roughness, conductivity and workfunction. Inkjet printed PEDOT films were also compared to spincoated films to determine how the polymer deposition method affects the above properties. Generally, inkjet printing created rougher but more conductive films with a smaller workfunction. Additionally, it was demonstrated that the workfunction of PEDOT films could be tuned over a range of about 0.5 V by changing the solvent mixture or substrate surface pretreatment. All additives to the as received PEDOT/PSS suspension caused the workfunction to decrease. It was discovered that workfunction decreases as printing voltage increases, but the trend reverses after annealing the films. This phenomenon suggests that when DMSO interacts with PEDOT, the workfunction changes. Finally, the results support previous publications suggesting that DMSO increases conductivity through a screening effect and also by changing the distribution of PEDOT and PSS in the film.

  7. Relevance of annealing on the stoichiometry and morphology of transparent thin films

    Energy Technology Data Exchange (ETDEWEB)

    Prepelita, P., E-mail: prepelitapetro@yahoo.co.uk [National Institute for Laser, Plasma and Radiation Physics, 409 Atomistilor Street, PO Box MG-36, 077125 Magurele, Ilfov (Romania); Craciun, V. [National Institute for Laser, Plasma and Radiation Physics, 409 Atomistilor Street, PO Box MG-36, 077125 Magurele, Ilfov (Romania); Sbarcea, G. [ICPE – CA, Splaiul Unirii 313, Sector 3, 74204 Bucharest (Romania); Garoi, F. [National Institute for Laser, Plasma and Radiation Physics, 409 Atomistilor Street, PO Box MG-36, 077125 Magurele, Ilfov (Romania)

    2014-07-01

    Transparent thin films of SnO{sub 2}, ZnO:Al, and ITO were deposited onto glass substrate by vacuum thermal evaporation technique, from 0.5 cm diameter grains (i.e. ITO, ZnO:Al (3%) and SnO{sub 2}) with 99.99% purity. To improve the quality (i.e. stoichiometry and morphology) of these thin films, they were annealed at 400 °C in air for 2 h. Following this annealing, the samples become suitable to be used as contact electrodes for solar cells. The investigations were performed on samples having a polycrystalline structure, as revealed by X-ray diffraction analysis after annealing process. Moreover, these thin films had a strong orientation with the following planes parallel to the substrate: (1 0 1) for SnO{sub 2}, (0 0 2) for ZnO:Al and (2 2 2) for ITO film respectively. Atomic force microscopy (AFM) investigations of the ZnO:Al (R{sub rms} = 2.8 nm) and ITO samples (R{sub rms} = 11 nm) show they are homogeneous and a slightly higher roughness (R{sub rms} = 51 nm) for the SnO{sub 2} thin film surface. The size and shape of the grains were also observed and investigated by scanning electron microscopy (SEM). All SnO{sub 2}, ZnO:Al and ITO transparent thin films are uniform and dense.The values obtained for electrical resistivity, transmission and energy bandgap as well as conductivity and transparency properties of these thin films, make them suitable to be used as transparent contact electrodes for solar cells.

  8. Infrared control coating of thin film devices

    Science.gov (United States)

    Berland, Brian Spencer; Stowell, Jr., Michael Wayne; Hollingsworth, Russell

    2017-02-28

    Systems and methods for creating an infrared-control coated thin film device with certain visible light transmittance and infrared reflectance properties are disclosed. The device may be made using various techniques including physical vapor deposition, chemical vapor deposition, thermal evaporation, pulsed laser deposition, sputter deposition, and sol-gel processes. In particular, a pulsed energy microwave plasma enhanced chemical vapor deposition process may be used. Production of the device may occur at speeds greater than 50 Angstroms/second and temperatures lower than 200.degree. C.

  9. Infrared control coating of thin film devices

    Energy Technology Data Exchange (ETDEWEB)

    Berland, Brian Spencer; Stowell, Jr., Michael Wayne; Hollingsworth, Russell

    2017-02-28

    Systems and methods for creating an infrared-control coated thin film device with certain visible light transmittance and infrared reflectance properties are disclosed. The device may be made using various techniques including physical vapor deposition, chemical vapor deposition, thermal evaporation, pulsed laser deposition, sputter deposition, and sol-gel processes. In particular, a pulsed energy microwave plasma enhanced chemical vapor deposition process may be used. Production of the device may occur at speeds greater than 50 Angstroms/second and temperatures lower than 200.degree. C.

  10. Nanoscale size effects on the mechanical properties of platinum thin films and cross-sectional grain morphology

    KAUST Repository

    Abbas, K

    2015-12-10

    © 2016 IOP Publishing Ltd. The mechanical behavior of polycrystalline Pt thin films is reported for thicknesses of 75 nm, 100 nm, 250 nm, and 400 nm. These thicknesses correspond to transitions between nanocrystalline grain morphology types as found in TEM studies. Thinner samples display a brittle behavior, but as thickness increases the grain morphology evolves, leading to a ductile behavior. During evolution of the morphology, dramatic differences in elastic moduli (105-160 GPa) and strengths (560-1700 MPa) are recorded and explained by the variable morphology. This work suggests that in addition to the in-plane grain size of thin films, the transitions in cross-sectional morphologies of the Pt films significantly affect their mechanical behavior.

  11. Structural and morphological properties of HfxZr 1-xO2 thin films prepared by Pechini route

    KAUST Repository

    García-Cerda, L. A.

    2010-03-01

    In this study, HfxZr1-xO2 (0 < x < 1) thin films were deposited on silicon wafers using a dip-coating technique and by using a precursor solution prepared by the Pechini route. The effects of annealing temperature on the structure and morphological properties of the proposed films were investigated. HfxZr1-xO2 thin films with 1, 3 and 5 layers were annealed in air for 2 h at 600 and 800 °C and the structural and morphological properties studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD results show that the films have monoclinic and tetragonal structure depending of the Hf and Zr concentration. SEM photographs show that all films consist of nanocrystalline grains with sizes in the range of 6 - 13 nm. The total film thickness is about 90 nm. © (2010) Trans Tech Publications.

  12. Surface morphology of polyethylene glycol films produced by matrix-assisted pulsed laser evaporation (MAPLE): Dependence on substrate temperature

    DEFF Research Database (Denmark)

    Rodrigo, K.; Czuba, P.; Toftmann, B.;

    2006-01-01

    The dependence of the surface morphology on the substrate temperature during film deposition was investigated for polyethylene glycol (PEG) films by matrix-assisted pulsed laser evaporation (MAPLE). The surface structure was studied with a combined technique of optical imaging and AFM measurements...

  13. Morphology and oxygen incorporation effect on antimicrobial activity of silver thin films

    Science.gov (United States)

    Rebelo, Rita; Manninen, N. K.; Fialho, Luísa; Henriques, Mariana; Carvalho, Sandra

    2016-05-01

    Ag and AgxO thin films were deposited by non-reactive and reactive pulsed DC magnetron sputtering, respectively, with the final propose of functionalizing the SS316L substrate with antibacterial properties. The coatings were characterized chemically, physically and structurally. The coatings nanostructure was assessed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), while the coatings morphology was determined by scanning electron microscopy (SEM). The XRD and XPS analyses suggested that Ag thin film is composed by metallic Ag, which crystallizes in fcc-Ag phase, while the AgxO thin film showed both metallic Ag and Agsbnd O bonds, which crystalize in fcc-Ag and silver oxide phases. The SEM results revealed that Ag thin film formed a continuous layer, while AgxO layer was composed of islands with hundreds of nanometers surrounded by small nanoparticles with tens of nanometers. The surface wettability and surface tension parameters were determined by contact angle measurements, being found that Ag and AgxO surfaces showed very similar behavior, with all the surfaces showing a hydrophobic character. In order to verify the antibacterial behavior of the coatings, halo inhibition zone tests were realized for Staphylococcus epidermidis and Staphylococcus aureus. Ag coatings did not show antibacterial behavior, contrarily to AgxO coating, which presented antibacterial properties against the studied bacteria. The presence of silver oxide phase along with the development of different morphology was pointed as the main factors in the origin of the antibacterial effect found in AgxO thin film. The present study demonstrated that AgxO coating presented antibacterial behavior and its application in cardiovascular stents is promising.

  14. The Applications of Morphology Controlled ZnO in Catalysis

    Directory of Open Access Journals (Sweden)

    Yuhai Sun

    2016-11-01

    Full Text Available Zinc oxide (ZnO, with the unique chemical and physical properties of high chemical stability, broad radiation absorption range, high electrochemical coupling coefficient, and high photo-stability, is an attractive multifunctional material which has promoted great interest in many fields. What is more, its properties can be tuned by controllable synthesized morphologies. Therefore, after the success of the abundant morphology controllable synthesis, both the morphology-dependent ZnO properties and their related applications have been extensively investigated. This review concentrates on the properties of morphology-dependent ZnO and their applications in catalysis, mainly involved reactions on green energy and environmental issues, such as CO2 hydrogenation to fuels, methanol steam reforming to generate H2, bio-diesel production, pollutant photo-degradation, etc. The impressive catalytic properties of ZnO are associated with morphology tuned specific microstructures, defects or abilities of electron transportation, etc. The main morphology-dependent promotion mechanisms are discussed and summarized.

  15. Morphological computation and morphological control: steps toward a formal theory and applications.

    Science.gov (United States)

    Füchslin, Rudolf M; Dzyakanchuk, Andrej; Flumini, Dandolo; Hauser, Helmut; Hunt, Kenneth J; Luchsinger, Rolf H; Reller, Benedikt; Scheidegger, Stephan; Walker, Richard

    2013-01-01

    Morphological computation can be loosely defined as the exploitation of the shape, material properties, and physical dynamics of a physical system to improve the efficiency of a computation. Morphological control is the application of morphological computing to a control task. In its theoretical part, this article sharpens and extends these definitions by suggesting new formalized definitions and identifying areas in which the definitions we propose are still inadequate. We go on to describe three ongoing studies, in which we are applying morphological control to problems in medicine and in chemistry. The first involves an inflatable support system for patients with impaired movement, and is based on macroscopic physics and concepts already tested in robotics. The two other case studies (self-assembly of chemical microreactors; models of induced cell repair in radio-oncology) describe processes and devices on the micrometer scale, in which the emergent dynamics of the underlying physical system (e.g., phase transitions) are dominated by stochastic processes such as diffusion.

  16. Growth morphology of nanoscale sputter-deposited Au films on amorphous soft polymeric substrates

    Energy Technology Data Exchange (ETDEWEB)

    Ruffino, F.; Grimaldi, M.G. [Universita di Catania, Dipartimento di Fisica e Astronomia, Catania (Italy); MATIS CNR-IMM, Catania (Italy); Torrisi, V.; Marletta, G. [University of Catania and CSGI, Laboratory for Molecular Surface and Nanotechnology (LAMSUN), Department of Chemical Sciences, Catania (Italy)

    2011-06-15

    The growth of a room-temperature sputter-deposited thin Au film on two soft polymeric substrates, polystyrene (PS) and poly(methyl methacrylate) (PMMA), from nucleation to formation of a continuous film is investigated by means of atomic force microscopy. In particular, we studied the surface morphology evolution of the film as a function of the deposition time observing an initial Au three-dimensional island-type growth. Then the Au film morphology evolves, with increasing deposition time, from hemispherical islands to partially coalesced worm-like island structures, to percolation, and finally to a continuous and rough film. The overall Au morphology evolution is discussed in the framework of the interrupted coalescence model, allowing us to evaluate the island critical radius for the partial coalescence R{sub c}=8.7{+-}0.9 nm for Au on PS and R{sub c}=7.6{+-}0.8 nm for Au on PMMA. Furthermore, the application of the kinetic freezing model allows us to evaluate the room-temperature surface diffusion coefficient D{sub s}{approx}1.8 x 10{sup -18} m{sup 2}/s for Au on PS and D{sub s}{approx}1.1 x 10{sup -18} m{sup 2}/s for Au on PMMA. The application of the Vincent model allows us, also, to evaluate the critical coverage (at which the percolation occurs) P{sub c}=61% for Au on PS and P{sub c}=56% for Au on PMMA. Finally, the dynamic scaling theory of a growing interface was applied to characterize the kinetic roughening of the Au film on both PMMA and PS. Such analyses allow us to evaluate the dynamic scaling, growth, and roughness exponents z=3.8{+-}0.4, {beta}=0.28{+-}0.03, {alpha}=1.06{+-}0.05 for the growth of Au on PS and z=4.3{+-}0.3, {beta}=0.23{+-}0.03, {alpha}=1.03{+-}0.05 for the growth of Au on PMMA, in agreement with a non-equilibrium but conservative and linear growth process in which the surface diffusion phenomenon plays a key role. (orig.)

  17. Template-controlled mineralization: Determining film granularity and structure by surface functionality patterns

    Directory of Open Access Journals (Sweden)

    Nina J. Blumenstein

    2015-08-01

    Full Text Available We present a promising first example towards controlling the properties of a self-assembling mineral film by means of the functionality and polarity of a substrate template. In the presented case, a zinc oxide film is deposited by chemical bath deposition on a nearly topography-free template structure composed of a pattern of two self-assembled monolayers with different chemical functionality. We demonstrate the template-modulated morphological properties of the growing film, as the surface functionality dictates the granularity of the growing film. This, in turn, is a key property influencing other film properties such as conductivity, piezoelectric activity and the mechanical properties. A very pronounced contrast is observed between areas with an underlying fluorinated, low energy template surface, showing a much more (almost two orders of magnitude coarse-grained film with a typical agglomerate size of around 75 nm. In contrast, amino-functionalized surface areas induce the growth of a very smooth, fine-grained surface with a roughness of around 1 nm. The observed influence of the template on the resulting clear contrast in morphology of the growing film could be explained by a contrast in surface adhesion energies and surface diffusion rates of the nanoparticles, which nucleate in solution and subsequently deposit on the functionalized substrate.

  18. Morphological, physical, antimicrobial and release properties of ZnO nanoparticles-loaded bacterial cellulose films.

    Science.gov (United States)

    Shahmohammadi Jebel, Fereshteh; Almasi, Hadi

    2016-09-20

    Bacterial cellulose (BC) monolayer and multilayer films, incorporating 5wt.% ZnO nanoparticles (NPs) have been obtained. Ultrasound (US) irradiation (40kHz) was applied during ZnO-BC nanocomposites preparation. X-ray diffraction (XRD) patterns showed that ZnO NPs were crystallized in their pure phase. SEM scanning electron microscopy (SEM) results indicated that US treatment causes to decrease ZnO particle size, forming a stable hybrid nanostructure and evenly distributed ZnO NPs coated BC nanofibers. ZnO NPs enhanced the mechanical properties and diminished water vapor permeability and moisture absorption of BC films. Antibacterial activity of ZnO-BC films against Staphylococcus aureus was more than Escherichia coli. The antibacterial activity was enhanced with the utilization of US irradiation. The ZnO release was influenced by films composition; the multilayer and US treated films being promising in order to achieve controlled release of ZnO. Results suggest that ZnO-BC films may be used as controlled release antimicrobial food active packaging.

  19. Thickness, morphology, and optoelectronic characteristics of pristine and surfactant-modified DNA thin films

    Science.gov (United States)

    Arasu, Velu; Reddy Dugasani, Sreekantha; Son, Junyoung; Gnapareddy, Bramaramba; Jeon, Sohee; Jeong, Jun-Ho; Park, Sung Ha

    2017-10-01

    Although the preparation of DNA thin films with well-defined thicknesses controlled by simple physical parameters is crucial for constructing efficient, stable, and reliable DNA-based optoelectronic devices and sensors, it has not been comprehensively studied yet. Here, we construct DNA and surfactant-modified DNA thin films by drop-casting and spin-coating techniques. The DNA thin films formed with different control parameters, such as drop-volume and spin-speed at given DNA concentrations, exhibit characteristic thickness, surface roughness, surface potential, and absorbance, which are measured by a field emission scanning electron microscope, a surface profilometer, an ellipsometer, an atomic force microscope, a Kelvin probe force microscope, and an UV–visible spectroscope. From the observations, we realized that thickness significantly affects the physical properties of DNA thin films. This comprehensive study of thickness-dependent characteristics of DNA and surfactant-modified DNA thin films provides insight into the choice of fabrication techniques in order for the DNA thin films to have desired physical characteristics in further applications, such as optoelectronic devices and sensors.

  20. Effect of acetylene flow rate on morphology and structure of carbon nanotube thick films grown by thermal chemical vapor deposition

    Institute of Scientific and Technical Information of China (English)

    CAO Zhangyi; SUN Zhuo; GUO Pingsheng; CHEN Yiwei

    2007-01-01

    Carbon nanotube (CNT) films were grown on nickel foil substrates by thermal chemical vapor deposition (CVD) with acetylene and hydrogen as the precursors. The morphology and structure of CNTs depending on the acetylene flow rate were characterized by a scanning electron microscope (SEM),a transmission electron microscope (TEM) and a Raman spectrometer,respectively.The effect of acetylene flow rate on the morphology and structure of CNT films was investigated.By increasing the acetylene flow rate from 10 to 90 sccm (standard cubic centimeter perminute),the yield and the diameter of CNTs increase.Also, the defects and amorphous phase in CNT films increase with increasing acetylene flow rate.

  1. Electronic excitation induced modifications of optical and morphological properties of PCBM thin films

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, T. [Department of Physics and Materials Research Centre, Malaviya National Institute of Technology, Jaipur 302017 (India); Singhal, R., E-mail: rsinghal.phy@mnit.ac.in [Department of Physics and Materials Research Centre, Malaviya National Institute of Technology, Jaipur 302017 (India); Vishnoi, R. [Department of Physics and Materials Research Centre, Malaviya National Institute of Technology, Jaipur 302017 (India); Department of Physics, Vardhman (P.G.) College, Bijnor 246701, U.P. (India); Sharma, P. [Department of Physics and Materials Research Centre, Malaviya National Institute of Technology, Jaipur 302017 (India); Patra, A.; Chand, S. [National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012 (India); Lakshmi, G.B.V.S. [Inter University Accelerator Centre, Post Box No. 10502, New Delhi 110067 (India); Biswas, S.K. [Department of Metallurgical and Materials Engineering, Malaviya National Institute of Technology, Jaipur 302017 (India)

    2016-07-15

    Highlights: • Spin casted PCBM thin films are irradiated by 90 MeV Ni{sup 7+} ion beam. • The decrease in band gap was found after irradiation. • There is a decomposition of molecular bond due to ion irradiation. • Roughness is also found to be dependent on incident ion fluence. - Abstract: Phenyl C{sub 61} butyric acid methyl ester (PCBM) is a fullerene derivative and most commonly used in organic photovoltaic devices both as electron acceptor and transporting material due to high electron mobility. PCBM is easy to spin caste on some substrate as it is soluble in chlorobenzene. In this study, the spin coated thin films of PCBM (on two different substrate, glass and double sided silicon) were irradiated using 90 MeV Ni{sup 7+} swift heavy ion beam at low fluences ranging from 1 × 10{sup 9} to 1 × 10{sup 11} ions/cm{sup 2} to study the effect of ion beam irradiation. The pristine and irradiated PCBM thin films were characterized by UV–visible absorption spectroscopy and fourier transform infrared spectroscopy (FTIR) to investigate the optical properties before and after irradiation. These thin films were further analyzed using atomic force microscopy (AFM) to investigate the morphological modifications which are induced by energetic ions. The variation in optical band gap after irradiation was measured using Tauc’s relation from UV–visible absorption spectra. A considerable change was observed with increasing fluence in optical band gap of irradiated thin films of PCBM with respect to the pristine film. The decrease in FTIR band intensity of C{sub 60} cage reveals the polymerization reaction due to high energy ion impact. The roughness is also found to be dependent on incident fluences. This study throws light for the application of PCBM in organic solar cells in form of ion irradiation induced nanowires of PCBM for efficient charge carrier transportation in active layer.

  2. Morphological characterization and AES depth profile analysis of CuInS{sub 2} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Calderon, C.; Oyola, J.S.; Gordillo, G. [Departamento de Fisica, Universidad Nacional de Colombia, Bogota (Colombia); Bartolo-Perez, P. [Departamento de Fisica Aplicada, CINVESTAV-IPN, Merida, Yucatan (Mexico); Clavijo, J. [Departamento de Quimica, Universidad Nacional de Colombia, Bogota (Colombia)

    2010-01-15

    This work presents results regarding the influence of preparation conditions on the morphological properties and on the chemical composition homogeneity of CuInS{sub 2} (CIS) thin films, grown by a chemical reaction of the precursor species evaporated sequentially on a soda-lime glass substrate, in a two- or three-stage process. The CIS samples were characterized using atomic force microscopy (AFM), scanning electron microscopy (SEM) and Auger electron spectroscopy (AES) depth profile measurements. The results showed that the deposition process and the ratio (evaporated Cu/evaporated In) affect the homogeneity of the chemical composition of the CIS film as well as the grain size. It was found that the samples grown in two stages are inhomogeneous in chemical composition and also Cu-rich near the film surface, probably due to the formation of a secondary Cu{sub 2}S phase in the surface region. The results also revealed that adding a third step in the deposition process improved the homogeneity in the chemical composition of CIS films and helped to remove the Cu{sub 2}S surface layer. The chemical composition of the samples deposited in a three-stage process is homogeneous in the whole volume, whereas the chemical composition in the bulk of samples deposited in a two-stage process is significantly different to that measured in the surface region. CIS films with characteristics found for the former case have demonstrated good properties for its use as absorber layers in thin film solar cells. (author)

  3. Electrochemical, morphological and microstructural characterization of carbon film resistor electrodes for application in electrochemical sensors

    Energy Technology Data Exchange (ETDEWEB)

    Gouveia-Caridade, Carla [Departamento de Quimica, Faculdade de Ciencias e Tecnologia, Universidade de Coimbra, 3004-535 Coimbra (Portugal); Soares, David M. [Instituto de Fisica Gleb Wataghin, Unicamp, Campinas, SP (Brazil); Liess, Hans-Dieter [Institut fuer Physik, Fakultaet fuer Elektrotechnik, Universitaet der Bundeswehr Muenchen, D-85577 Neubiberg (Germany); Brett, Christopher M.A. [Departamento de Quimica, Faculdade de Ciencias e Tecnologia, Universidade de Coimbra, 3004-535 Coimbra (Portugal)], E-mail: brett@ci.uc.pt

    2008-08-15

    The electrochemical and microstructural properties of carbon film electrodes made from carbon film electrical resistors of 1.5, 15, 140 {omega} and 2.0 k{omega} nominal resistance have been investigated before and after electrochemical pre-treatment at +0.9 V vs SCE, in order to assess the potential use of these carbon film electrodes as electrochemical sensors and as substrates for sensors and biosensors. The results obtained are compared with those at electrodes made from previously investigated 2 {omega} carbon film resistors. Cyclic voltammetry was performed in acetate buffer and phosphate buffer saline electrolytes and the kinetic parameters of the model redox system Fe(CN){sub 6}{sup 3-/4-} obtained. The 1.5 {omega} resistor electrodes show the best properties for sensor development with wide potential windows, similar electrochemical behaviour to those of 2 {omega} and close-to-reversible kinetic parameters after electrochemical pre-treatment. The 15 and 140 {omega} resistor electrodes show wide potential windows although with slower kinetics, whereas the 2.0 k{omega} resistor electrodes show poor cyclic voltammetric profiles even after pre-treatment. Electrochemical impedance spectroscopy related these findings to the interfacial properties of the electrodes. Microstructural and morphological studies were carried out using contact mode Atomic Force Microscopy (AFM), Confocal Raman spectroscopy and X-ray diffraction. AFM showed more homogeneity of the films with lower nominal resistances, related to better electrochemical characteristics. X-ray diffraction and Confocal Raman spectroscopy indicate the existence of a graphitic structure in the carbon films.

  4. Structural; morphological; optical and magnetic properties of Mn doped ferromagnetic ZnO thin film

    Science.gov (United States)

    Karmakar, R.; Neogi, S. K.; Banerjee, Aritra; Bandyopadhyay, S.

    2012-12-01

    The structural, optical and magnetic properties of the Zn1-xMnxO (0 disorder developed in the samples due to Mn doping. The films are of single phase in nature; no formation of any secondary phase has been detected from structural analysis. Absence of magnetic impurity phase in these films has been confirmed from morphological study also. Increasing tendency of lattice parameters and unit cell volume has been observed with increasing Mn doping concentration. The incorporation of Mn2+ ions introduces disorder in the system. That also leads to slight degradation in crystalline quality of the films with increasing doping. The grain size reduces with increase in Mn doping proportion. The band gaps shows red shift with doping and the width of localized states shows an increasing tendency with doping concentration. It is due to the formation of impurity band and trapping of Mn atoms, which leads to the generation of the defect states within the forbidden band. Photoluminescence (PL) spectra show gradual decrease of intensity of exitonic and defect related peaks with increasing Mn doping. Defect mediated intrinsic ferromagnetism has been observed even at room temperature for 5 at% Mn doped ZnO film. The strong presence of antiferromagnetic (AFM) interaction reduces the observed ferromagnetic moments.

  5. Tunability of morphological properties of Nd-doped TiO2 thin films

    Science.gov (United States)

    Saleem Bhatti, Arshad; Rehan, Imran; Sultana, Sabiha; Khan, Nauman; Qamar, Zahid; Rehan, Kamran

    2016-11-01

    In this work, an endeavor is made toward structural assessment and morphological variation of titanium dioxide (TiO2) thin films when doped with neodymium (Nd). The electron beam deposition technique was employed to fabricate Nd-based TiO2 thin films on n-Type Si substrates. Nd concentration was varied from 0.0 to 2.0 atomic percent (at.%) under identical growth environments. The films were deposited in an oxygen-deficient environment to cause the growth of rutile phases. Energy dispersive x-ray spectroscopy confirmed the presence and variation of Nd dopant in TiO2. X-ray diffraction analysis showed the transformation of amorphous structures of the as-grown samples to anatase polycrystalline after annealing at 500 °C, while atomic force microscopy exposed linearity in grain density in as-grown samples with doping until 1 at.%. Raman spectrums of as-grown and annealed samples revealed the growth of the anatase phase in the annealed samples. Based on these results it can be proposed that Nd doping has pronounced effects on the structural characteristics of TiO2 thin films.

  6. Morphology control of brushite prepared by aqueous solution synthesis

    Directory of Open Access Journals (Sweden)

    T. Toshima

    2014-03-01

    Full Text Available Dicalcium phosphate dihydrate (DCPD, CaHPO4·2H2O, also known as brushite, is one of the important bioceramics due to not only diseases factors such as kidney stone and plaque formation but also purpose as fluoride insolubilization material. It is used medicinally to supply calcium, and is of interest for its unique properties in biological and pathological mineralization. It is important to control the crystal morphology of brushite since its chemical reactivity depends strongly on its surface properties; thus, its morphology is a key issue for its applications as a functional material or precursor for other bioceramics. Here, we report the effects of the initial pH and the Ca and phosphate ion concentrations on the morphology of DCPD particles during aqueous solution synthesis. Crystal morphologies were analyzed by scanning electron microscopy and X-ray diffraction. The morphology phase diagram of DCPD crystallization revealed that increasing the initial pH and/or ion concentration transformed DCPD morphology from petal-like into plate-like structures.

  7. The morphology, microstructure, and luminescent properties of CdS/CdTe films

    Energy Technology Data Exchange (ETDEWEB)

    Al-Jassim, M.M.; Dhere, R.G.; Jones, K.M.; Hasoon, F.S.; Sheldon, P. [National Renewable Energy Lab., Golden, CO (United States)

    1998-09-01

    This paper is concerned with the characterization of CdS/CdTe polycrystalline thin films for solar cells. The morphology, microstructure, and luminescent properties are studied by a powerful array of characterization techniques. The presence of pinholes in 100-nm thick CdS is observed. The microstructure of CdS and CdTe films is shown to be heavily faulted polycrystalline. The effect of deposition temperature on the grain size and the microstructure is investigated. The interdiffusion of sulfur and tellurium at the CdS/CdTe interface is studied for the first time by a nanoprobe technique. Considerable amount of sulfur is detected in CdTe in the vicinity of the interface of samples deposited at 625 C. The recombination behavior of grain boundaries and intragrain defects is investigated in as-deposited and heat-treated samples.

  8. Dynamics of double-pulse laser produced titanium plasma inferred from thin film morphology and optical emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Krstulović, N., E-mail: niksak@ifs.hr [Institute of Physics, Bijenička 46, HR-10000 Zagreb (Croatia); Salamon, K., E-mail: ksalamon@ifs.hr [Institute of Physics, Bijenička 46, HR-10000 Zagreb (Croatia); Modic, M., E-mail: martina.modic@ijs.si [Jožef Stefan Institute, Jamova 39, 1001 Ljubljana (Slovenia); Bišćan, M., E-mail: mbiscan@ifs.hr [Institute of Physics, Bijenička 46, HR-10000 Zagreb (Croatia); Milat, O., E-mail: milat@ifs.hr [Institute of Physics, Bijenička 46, HR-10000 Zagreb (Croatia); Milošević, S., E-mail: slobodan@ifs.hr [Institute of Physics, Bijenička 46, HR-10000 Zagreb (Croatia)

    2015-05-01

    In this paper, dynamics of double-pulse laser produced titanium plasma was studied both directly using optical emission spectroscopy (OES) and indirectly from morphological properties of deposited thin films. Both approaches yield consistent results. Ablated material was deposited in a form of thin film on the Si substrate. During deposition, plasma dynamics was monitored using optical emission spectroscopy with spatial and temporal resolutions. The influence of ablation mode (single and double) and delay time τ (delay between first and second pulses in double-pulse mode) on plasma dynamics and consequently on morphology of deposited Ti-films was studied using X-ray reflectivity and atomic force microscopy. Delay time τ was varied from 170 ns to 4 μs. The results show strong dependence of both emission signal and Ti-film properties, such as thickness, density and roughness, on τ. In addition, correlation of average density and thickness of film is observed. These results are discussed in terms of dependency of angular distribution and kinetic energy of plasma plume particles on τ. Advantages of using double-pulse laser deposition for possible application in thin film production are shown. - Highlights: • Ti-thin films produced by single and double pulse laser ablation mode. • Ablation mode and delay time influenced plasma plume and film characteristics. • Films are most compact for optimized delay time (thinnest, smoothest and most dense). • Plasma dynamics can be inferred from film characteristics.

  9. Comparison of Microstructural and Morphological Properties of Electrodeposited Fe-Cu Thin Films with Low and High Fe : Cu Ratio

    Directory of Open Access Journals (Sweden)

    Umut Sarac

    2013-01-01

    Full Text Available Fe-Cu films with low and high Fe : Cu ratio have been produced from the electrolytes with different Fe ion concentrations at a constant deposition potential of −1400 mV versus saturated calomel electrode (SCE by electrodeposition technique onto indium tin oxide (ITO coated conducting glass substrates. It was observed that the variation of Fe ion concentration in the electrolyte had a very strong influence on the compositional, surface morphological, and microstructural properties of the Fe-Cu films. An increase in the Fe ion concentration within the plating bath increased the Fe content, consequently Fe : Cu ratio within the films. The crystallographic structure analysis showed that the Fe-Cu films had a mixture of face-centered cubic (fcc Cu and body centered cubic (bcc α-Fe phases. The average crystallite size decreased with the Fe ion concentration. The film electrodeposited from the electrolyte with low Fe ion concentration exhibited a morphology consisting of dendritic structures. However, the film morphology changed from dendritic structure to cauliflower-like structure at high Fe ion concentration. The surface roughness and grain size were found to decrease significantly with increasing Fe ion concentration in the electrolyte. The significant differences observed in the microstructural and morphological properties caused by the change of Fe ion concentration in the electrolyte were ascribed to the change of Fe : Cu ratio within the films.

  10. Effect of ion bombardment on the surface morphology of Zn-films sputtered in an unbalanced magnetron

    Energy Technology Data Exchange (ETDEWEB)

    Musil, J.; Matous, J.; Valvoda, V. [Academy of Sciences, Prague (Czech Republic). Inst. of Physics

    1995-02-01

    It is well known that magnetron sputtered films of low melting point T{sub m} materials have (due to their crystallisation at low substrate temperatures, T < 100{sup o}C) rough and diffusely reflecting surfaces, even when thin, for instance about 20 nm for In films. Only extremely thin films have a smooth and specular reflecting surface. This paper reports on the possibility of sputtering thick films of low T{sub m} materials with a smooth, optically specular reflecting surface using an unbalanced magnetron. To demonstrate this possibility, Zn films were studied and it was shown that a surface roughness of the film can be effectively controlled by ion bombardment of the film during growth. The smoothing of the Zn film does not depend on film thickness but on ion bombardment of the growing film. (author).

  11. Pin-Hole Free Perovskite Film for Solar Cells Application Prepared by Controlled Two-Step Spin-Coating Method

    Science.gov (United States)

    Bahtiar, A.; Rahmanita, S.; Inayatie, Y. D.

    2017-05-01

    Morphology of perovskite film is a key important for achieving high performance perovskite solar cells. Perovskite films are commonly prepared by two-step spin-coating method. However, pin-holes are frequently formed in perovskite films due to incomplete conversion of lead-iodide (PbI2) into perovskite CH3NH3PbI3. Pin-holes in perovskite film cause large hysteresis in current-voltage curve of solar cells due to large series resistance between perovskite layer-hole transport material. Moreover, crystal structure and grain size of perovskite crystal are also other important parameters for achieving high performance solar cells, which are significantly affected by preparation of perovskite film. We studied the effect of preparation of perovskite film using controlled spin-coating parameters on crystal structure and morphological properties of perovskite film. We used two-step spin-coating method for preparation of perovskite film with varied spinning speed, spinning time and temperature of spin-coating process to control growth of perovskite crystal aimed to produce high quality perovskite crystal with pin-hole free and large grain size. All experiment was performed in air with high humidity (larger than 80%). The best crystal structure, pin-hole free with large grain crystal size of perovskite film was obtained from film prepared at room temperature with spinning speed 1000 rpm for 20 seconds and annealed at 100°C for 300 seconds.

  12. Dopamine-induced silica-polydopamine hybrids with controllable morphology.

    Science.gov (United States)

    Ho, Chia-Che; Ding, Shinn-Jyh

    2014-04-01

    Novel silica-polydopamine hybrids, with controllable morphology, are facilely fabricated in an emulsion system consisting of tetraethyl orthosilicate, dopamine, water, and NaOH under weakly basic conditions (pH 8.5-10). An increase in initial pH favors the formation of nano-structured spherical silica-PDA hybrids from a flocculated structure.

  13. Synthesis of Au nanowires with controlled morphological and structural characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Gurvinder, E-mail: gurvinder.singh@ntnu.no [Ugelstad Laboratory, Department of Chemical Engineering, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim (Norway); Helvoort, Antonius T.J. van [Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway); Bandyopadhyay, Sulalit; Volden, Sondre; Andreassen, Jens-Petter [Ugelstad Laboratory, Department of Chemical Engineering, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim (Norway); Glomm, Wilhelm R., E-mail: Wilhelm.Glomm@sintef.no [Ugelstad Laboratory, Department of Chemical Engineering, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim (Norway); SINTEF Materials and Chemistry, Biotechnology and Nanomedicine Sector, NO-7491 Trondheim (Norway)

    2014-08-30

    Graphical abstract: - Highlights: • Synthesis of metal nanowires. • Control over structural and morphological characteristics via seed type nanoparticle. • Growth via surfactant or surface diffusion process. • Structural and surface characterization. - Abstract: A growth of one-dimensional noble metal nanostructure with controlled structural characteristic has been under intense investigation as the physical properties, for example, mechanical and electrical properties highly depend on the crystallinity of the nanostructure. Herein, we report a seed-mediated growth of gold nanowires with controlled structural and morphological characteristics, which can easily be varied by selecting appropriate seed nanoparticles, either spherical or rod type in aqueous solution at room temperature. The growth of nanowires was monitored by characterizing the samples at different time period during the reaction, and our observations suggest that growth occurs from seeds rapidly growing along one-dimension followed by surfactant induced fusion or welding and surface diffusion. The aspect ratio and morphology of these NWs can be tuned by CTAB concentration, pH and temperature of the growth solution. We show that the aspect ratio and morphology of these NWs can be tuned by the surfactant concentration, pH and temperature of the growth solution. Electron microscopy and X-ray Photoelectron spectroscopic techniques were employed for investigating structural and surface characteristics of nanowires. This approach can possibly help to synthesize nanowires of other metals with controlled crystalline behaviour which is highly essential for understanding their properties and practical applications in nanoelectronics, optical devices, catalysis, and sensors.

  14. Photo-irradiation effects on the surface morphology of poly(p-phenylene vinylene) films

    Energy Technology Data Exchange (ETDEWEB)

    Marletta, Alexandre, E-mail: marletta@ufu.br [Instituto de Fisica, Universidade Federal de Uberlandia, CP 593, 38400-902 Uberlandia, MG (Brazil); Vega, M.L. [Departamento de Fisica, Universidade Federal do Piaui, 64049-690 Teresina, PI (Brazil); Rodrigues, C.A. [Faculdade de Tecnologia e Ciencias, Rua Artemia Pires Freitas s/n, 44115-000 Feira de Santana, BA (Brazil); Gobato, Y. Galvao [Departamento de Fisica, Universidade Federal de Sao Carlos, CP 676, 13565-905 Sao Carlos, SP (Brazil); Costa, L.F.; Faria, R.M. [Instituto de Fisica de Sao Carlos, Universidade de Sao Paulo, CP 369, 13560-970 Sao Carlos, SP (Brazil)

    2010-03-01

    In this work, we have studied the surface morphology of photo-irradiated poly(p-phenylene vinylene) (PPV) thin films by using atomic force microscopy (AFM). We have analyzed the first-order statistical parameters, the height distribution and the distance between selected peaks. The second-order statistical analysis was introduced calculating the auto-covariance function to determine the correlation length between heights. We have observed that the photo-irradiation process produces a surface topology more homogeneous and isotropic such as a normal surface. In addition, the polymer surface irradiation can be used as a new methodology to obtain materials optically modified.

  15. Nickel-induced microwheel-like surface morphological evolution of ZnO thin films by spray pyrolysis

    Science.gov (United States)

    Tarwal, N. L.; Shinde, P. S.; Oh, Y. W.; Cerc Korošec, Romana; Patil, P. S.

    2012-11-01

    Nickel-zinc oxide (Ni-ZnO) thin films were deposited onto glass and tin-doped indium oxide-coated glass substrates by using a pneumatic spray pyrolysis technique at 450 °C from aqueous solutions of zinc acetate and nickel acetate precursors. The effect of nickel doping on structural, morphological and optical properties of the ZnO thin films has been studied. The X-ray diffraction patterns confirmed the polycrystalline nature of the films having hexagonal crystal structure. Ni-ZnO films with appropriate nickel doping revealed the occurrence of novel wheel-like surface morphology. The absorption edge of the Ni-ZnO films showed a red shift, meaning that the optical band gap energy decreases as the nickel doping concentration increases. A growth model is developed and proposed for the novel wheel-like morphology. All the thin films exhibited room-temperature photoluminescence. Pure ZnO and Ni-ZnO thin films were tested for their photoelectrochemical performance in 0.5 M Na2SO4 electrolyte solution. The values of fill factor and open circuit voltage were improved for the Ni-ZnO thin films.

  16. Nickel-induced microwheel-like surface morphological evolution of ZnO thin films by spray pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Tarwal, N.L.; Shinde, P.S.; Patil, P.S. [Shivaji University, Thin Film Materials Laboratory, Department of Physics, Kolhapur, Maharashtra (India); Oh, Y.W. [Kyungnam University, Department of Nano Engineering, Masan (Korea, Republic of); Cerc Korosec, Romana [University of Ljubljana, Faculty of Chemistry and Chemical Technology, Ljubljana (Slovenia)

    2012-11-15

    Nickel-zinc oxide (Ni-ZnO) thin films were deposited onto glass and tin-doped indium oxide-coated glass substrates by using a pneumatic spray pyrolysis technique at 450 C from aqueous solutions of zinc acetate and nickel acetate precursors. The effect of nickel doping on structural, morphological and optical properties of the ZnO thin films has been studied. The X-ray diffraction patterns confirmed the polycrystalline nature of the films having hexagonal crystal structure. Ni-ZnO films with appropriate nickel doping revealed the occurrence of novel wheel-like surface morphology. The absorption edge of the Ni-ZnO films showed a red shift, meaning that the optical band gap energy decreases as the nickel doping concentration increases. A growth model is developed and proposed for the novel wheel-like morphology. All the thin films exhibited room-temperature photoluminescence. Pure ZnO and Ni-ZnO thin films were tested for their photoelectrochemical performance in 0.5 M Na{sub 2}SO{sub 4} electrolyte solution. The values of fill factor and open circuit voltage were improved for the Ni-ZnO thin films. (orig.)

  17. Optical and Morphological Studies of Thermally Evaporated PTCDI-C8 Thin Films for Organic Solar Cell Applications

    Directory of Open Access Journals (Sweden)

    Ronak Rahimi

    2013-01-01

    Full Text Available PTCDI-C8 due to its relatively high photosensitivity and high electron mobility has attracted much attention in organic semiconductor devices. In this work, thin films of PTCDI-C8 with different thicknesses were deposited on silicon substrates with native silicon dioxide using a vacuum thermal evaporator. Several material characterization techniques have been utilized to evaluate the structure, morphology, and optical properties of these films. Their optical constants (refractive index and extinction coefficient have been extracted from the spectroscopic ellipsometry (SE. X-ray reflectivity (XRR and atomic force microscopy (AFM were employed to determine the morphology and structure as well as the thickness and roughness of the PTCDI-C8 thin films. These films revealed a high degree of structural ordering within the layers. All the experimental measurements were performed under ambient conditions. PTCDI-C8 films have shown to endure ambient condition which allows pots-deposition characterization.

  18. Composition and morphological characteristics of chemically sprayed fluorine-doped zinc oxide thin films deposited on Si(1 0 0)

    Energy Technology Data Exchange (ETDEWEB)

    Castaneda, L. [Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-186, 04510 D. F. (Mexico); Departamento de Fisica y Matematicas, Division de Ciencia, Arte y Tecnologia, Universidad Iberoamericana, Av. Prolongacion Paseo de la Reforma 880, Santa Fe 012100, D. F. (Mexico); Maldonado, A. [Depto. de Ing. Electrica, CINVESTAV IPN, SEES, Apartado Postal 14740, Mexico, D.F. 07000 (Mexico); Cheang-Wong, J.C. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Apartado Postal 20-364, Mexico, D.F. 01000 (Mexico); Terrones, M. [Advanced Materials Department, IPICYT, Camino a la Presa San Jose 2055, Col. Lomas, 4a. seccion, San Luis Potosi, 78216 (Mexico); Departamento de Fisica y Matematicas, Division de Ciencia, Arte y Tecnologia, Universidad Iberoamericana, Av. Prolongacion Paseo de la Reforma 880, Santa Fe 012100, D. F. (Mexico); Olvera, M. de la L [Depto. de Ing. Electrica, CINVESTAV IPN, SEES, Apartado Postal 14740, Mexico, D.F. 07000 (Mexico)]. E-mail: molvera@cinvestav.mx

    2007-03-01

    Fluorine-doped zinc oxide thin films (ZnO:F) were deposited on Si(1 0 0) substrates by the chemical spray technique (CST) from an aged-solution. The effect of the substrate temperature on the morphology and composition of the ZnO:F thin films was studied. The films were polycrystalline, with a preferential growth along the ZnO (0 0 2) plane, irrespective of the deposition temperature. The average crystal size within the films was ca. 35 nm and the morphology of the surface was found to be dependent on the substrate temperature. At low substrate temperatures irregular-shaped grains were observed, whereas at higher temperatures uniform flat grains were obtained. Elemental analysis showed that the composition of the films is close to stoichiometric ZnO and that samples contain quite a low fluorine concentration, which decreases as a function of the deposition temperature.

  19. Surface morphology engineering of metal-oxide films by chemical spray pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, J.; Solis, J.L.; Estrada, W. [Instituto Peruano de Energia Nuclear, Av. Canada 1470, San Borja, Lima (Peru); Facultad de Ciencias, Universidad Nacional de Ingenieria, P.O. Box 31-139, Lima (Peru); Gomez, M. [Facultad de Ciencias, Universidad Nacional de Ingenieria, P.O. Box 31-139, Lima (Peru)

    2007-07-01

    The Chemical Spray Pyrolysis technique and a combination of sol-gel and spray pyrolysis techniques have been used in order to monitor the morphology of metal-oxide-based thin films to be used as functional materials. We can obtain surfaces from specular to rough-porous according to the physico-chemical conditions of the precursor/spraying solution. We have produced coatings of ZnO-based and NiO{sub x}-based coatings from alcoholic and aqueous solutions. A single glass, ITO-precoated glass or alumina was used as the substrate. Porous materials of WO{sub 3}, WO{sub 3}-SnO{sub 2} and SnO{sub 2} have been produced by spraying either inorganic or metal alkoxide gels over a hot substrate. The morphologies of coatings were evaluated by either SEM or optical measurements. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  20. Structure and morphology studies of chromium film at elevated temperature in hypersonic environment

    Indian Academy of Sciences (India)

    G M Hegde; V Kulkarni; M Nagaboopathy; K P J Reddy

    2012-06-01

    This paper presents the after shock heated structural and morphological studies of chromium film coated on hypersonic test model as a passive drag reduction element. The structural changes and the composition of phases of chromium due to shock heating (2850 K) are characterized using X-ray diffraction studies. Surface morphology changes of chromium coating have been studied using scanning electron microscopy (SEM) before and after shock heating. Significant amount of chromium ablation and sublimation from the model surface is noticed from SEM micrographs. Traces of randomly oriented chromium oxides formed along the coated surface confirm surface reaction of chromium with oxygen present behind the shock. Large traces of amorphous chromium oxide phases are also observed.

  1. Deposition of matrix-free fullerene films with improved morphology by matrix-assisted pulsed laser evaporation (MAPLE)

    DEFF Research Database (Denmark)

    Canulescu, Stela; Schou, Jørgen; Fæster, Søren;

    2013-01-01

    Thin films of C60 were deposited by matrix-assisted pulsed laser evaporation (MAPLE) from a frozen target of anisole with 0.67 wt% C60. Above a fluence of 1.5 J/cm2 the C60 films are strongly non-uniform and are resulting from transfer of matrix-droplets containing fullerenes. At low fluence...... the fullerene molecules in the films are intact, the surface morphology is substantially improved and there are no measurable traces of the matrix molecules in the film. This may indicate a regime of dominant evaporation at low fluence which merges into the MAPLE regime of liquid ejection of the host matrix...

  2. Morphology and structural studies of WO3 films deposited on SrTiO3 by pulsed laser deposition

    Science.gov (United States)

    Kalhori, Hossein; Porter, Stephen B.; Esmaeily, Amir Sajjad; Coey, Michael; Ranjbar, Mehdi; Salamati, Hadi

    2016-12-01

    WO3 films have been grown by pulsed laser deposition on SrTiO3 (001) substrates. The effects of substrate temperature, oxygen partial pressure and energy fluence of the laser beam on the physical properties of the films were studied. Reflection high-energy electron diffraction (RHEED) patterns during and after growth were used to determine the surface structure and morphology. The chemical composition and crystalline phases were obtained by XPS and XRD respectively. AFM results showed that the roughness and skewness of the films depend on the substrate temperature during deposition. Optimal conditions were determined for the growth of the highly oriented films.

  3. A study of the morphology of photochromic and thermochromic MoO 3 amorphous films using an atomic force microscope

    Science.gov (United States)

    Chudnovskii, F. A.; Schaefer, D. M.; Gavrilyuk, A. I.; Reifenberger, R.

    The surface morphology of amorphous MoO 3 films enhanced by a coating of N.N-dimethylformamide was studied with an atomic force microscope. Images of the as-grown films revealed a surface structure consisting of ˜25 nm diameter clusters which had coalesced to form irregular-shaped grains with dimensions ranging between 100 and 190 nm. Similar structure was found in the films after a photochromic or thermochromic transition had occured. The relative surface areas of the films have been calculated and little change is observed after the photochromic transition while a ˜29 increase in surface area is observed after the thermochromic transition has taken place.

  4. On the structural, morphological, optical and electrical properties of sol-gel deposited ZnO:In films

    Energy Technology Data Exchange (ETDEWEB)

    Girtan, M., E-mail: mihaela.girtan@univ-angers.f [L PHI A, FRE CNRS 2988, 2, Bd. Lavoisier, University of Angers (France); Socol, M. [National Institute of Materials Physics, Bucharest (Romania); Pattier, B. [LPEC, UMR CNRS 6087 Universite du Maine, Le Mans (France); Sylla, M. [L PHI A, FRE CNRS 2988, 2, Bd. Lavoisier, University of Angers (France); Stanculescu, A. [National Institute of Materials Physics, Bucharest (Romania)

    2010-11-01

    Indium-doped zinc oxide thin films deposition was performed by the sol-gel technique using homogeneous and stable solutions of zinc acetate 2-hydrate and indium chloride in ethanol. Films were spin coated onto glass substrates. After drying and after a heat treatment at 450 {sup o}C, highly transparent (80%-90%) films were obtained. The effect on the structural, morphological, optical and electrical thin films properties of the dopant concentration was investigated. The temperature dependencies of the electrical conductivity under vacuum and in open atmosphere were analysed and discussed.

  5. Morphology and chain aggregation dependence of optical gain in thermally annealed films of the conjugated polymer poly[2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene

    Science.gov (United States)

    Lampert, Zach E.; Lappi, Simon E.; Papanikolas, John M.; Lewis Reynolds, C.; Osama Aboelfotoh, M.

    2013-06-01

    Aggregate formation in conjugated polymer films is one of the most important phenomena thought to influence the photophysical properties of optical devices based on these materials. In the current work, we report the results of a detailed investigation on the morphology and chain aggregation dependence of optical gain in spin-coated thin films of the conjugated polymer poly[2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene] (MEH-PPV). Extensive gain measurements are performed using the variable stripe length technique with picosecond pulse excitation. The polymer morphology and extent of aggregate formation in the films are controlled by thermal annealing, which is relevant to the fabrication and optimization of conjugated polymer-based optical devices. The aggregation state of the polymer chains increases with the annealing temperature, which results in a decrease in luminescence efficiency at low excitation density (≤1018 cm-3). However, the increase in aggregate formation with increasing annealing temperature does not significantly alter the optical gain; very large gain coefficients are still achieved in films containing a relatively large fraction of aggregates. Although the largest gain coefficients, 450 cm-1, are observed for as-cast (non-annealed) MEH-PPV films, very large gain coefficients of 315 and 365 cm-1 are also demonstrated for MEH-PPV films annealed at 60 and 80 °C, respectively, in spite of the enhanced packing morphology and conformational order of the polymer chains. These results are contrary to the commonly held view that aggregate formation has a detrimental effect on the amplified spontaneous emission behavior of polymer-based devices operating in the stimulated emission regime, as would be characteristic of lasers and optical amplifiers. Moreover, because aggregates promote favorable charge transport properties, our data have important implications for future development of electrically driven polymer lasers; improving carrier mobility

  6. Morphology and oxygen incorporation effect on antimicrobial activity of silver thin films

    Energy Technology Data Exchange (ETDEWEB)

    Rebelo, Rita, E-mail: ritarebelo@det.uminho.pt [2C2T, University of Minho, Campus de Azurém, 4800-058 Guimarães (Portugal); GRF-CFUM, University of Minho, Campus de Azurém, 4800-058 Guimarães (Portugal); CEB, Center for Biological Engineering, LIBRO—Laboratório de Biofilmes Rosário Oliveira, University of Minho, Campus de Gualtar, 4710-335 Braga (Portugal); Manninen, N.K. [GRF-CFUM, University of Minho, Campus de Azurém, 4800-058 Guimarães (Portugal); SEG-CEMUC, University of Coimbra, 3030-788 Coimbra (Portugal); Fialho, Luísa [GRF-CFUM, University of Minho, Campus de Azurém, 4800-058 Guimarães (Portugal); Henriques, Mariana [CEB, Center for Biological Engineering, LIBRO—Laboratório de Biofilmes Rosário Oliveira, University of Minho, Campus de Gualtar, 4710-335 Braga (Portugal); Carvalho, Sandra [GRF-CFUM, University of Minho, Campus de Azurém, 4800-058 Guimarães (Portugal); SEG-CEMUC, University of Coimbra, 3030-788 Coimbra (Portugal)

    2016-05-15

    Highlights: • Ag and Ag{sub x}O thin films were deposited by non-reactive and reactive pulsed DC magnetron sputtering. • Coatings were characterized chemically, physically and structurally. • In order to verify the antibacterial behavior of the coatings, halo inhibition zone tests were realized for Staphylococcus epidermidis and Staphylococcus aureus. • Ag{sub x}O coating presented antibacterial behavior. - Abstract: Ag and Ag{sub x}O thin films were deposited by non-reactive and reactive pulsed DC magnetron sputtering, respectively, with the final propose of functionalizing the SS316L substrate with antibacterial properties. The coatings were characterized chemically, physically and structurally. The coatings nanostructure was assessed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), while the coatings morphology was determined by scanning electron microscopy (SEM). The XRD and XPS analyses suggested that Ag thin film is composed by metallic Ag, which crystallizes in fcc-Ag phase, while the Ag{sub x}O thin film showed both metallic Ag and Ag−O bonds, which crystalize in fcc-Ag and silver oxide phases. The SEM results revealed that Ag thin film formed a continuous layer, while Ag{sub x}O layer was composed of islands with hundreds of nanometers surrounded by small nanoparticles with tens of nanometers. The surface wettability and surface tension parameters were determined by contact angle measurements, being found that Ag and Ag{sub x}O surfaces showed very similar behavior, with all the surfaces showing a hydrophobic character. In order to verify the antibacterial behavior of the coatings, halo inhibition zone tests were realized for Staphylococcus epidermidis and Staphylococcus aureus. Ag coatings did not show antibacterial behavior, contrarily to Ag{sub x}O coating, which presented antibacterial properties against the studied bacteria. The presence of silver oxide phase along with the development of different morphology was

  7. Supramolecular Approaches to Nanoscale Morphological Control in Organic Solar Cells.

    Science.gov (United States)

    Haruk, Alexander M; Mativetsky, Jeffrey M

    2015-06-11

    Having recently surpassed 10% efficiency, solar cells based on organic molecules are poised to become a viable low-cost clean energy source with the added advantages of mechanical flexibility and light weight. The best-performing organic solar cells rely on a nanostructured active layer morphology consisting of a complex organization of electron donating and electron accepting molecules. Although much progress has been made in designing new donor and acceptor molecules, rational control over active layer morphology remains a central challenge. Long-term device stability is another important consideration that needs to be addressed. This review highlights supramolecular strategies for generating highly stable nanostructured organic photovoltaic active materials by design.

  8. Thickness control in electrophoretic deposition of WO{sub 3} nanofiber thin films for solar water splitting

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Yuanxing; Lee, Wei Cheat; Canciani, Giacomo E.; Draper, Thomas C.; Al-Bawi, Zainab F. [Department of Chemistry, School of Life Sciences, University of Sussex, Brighton BN1 9QJ (United Kingdom); Bedi, Jasbir S. [School of Public Health & Zoonoses, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana 141004 Punjab (India); Perry, Christopher C. [Division of Biochemistry, School of Medicine, Loma Linda University, Loma Linda, CA 92350 (United States); Chen, Qiao, E-mail: qiao.chen@sussex.ac.uk [Department of Chemistry, School of Life Sciences, University of Sussex, Brighton BN1 9QJ (United Kingdom)

    2015-12-15

    Graphical abstract: - Highlights: • A novel method combining electrospinning and electrophoretic deposition was established for the creation of nanostructured semiconductor thin films. • The created thin films displayed a high chemical stability with a controllable thickness. • The PEC water splitting performance of the thin films was optimized by fine-tuning the thickness of the films. • A maximum photoconversion efficiency was achieved by 18 μm nanofibrous thin films. - Abstract: Electrophoretic deposition (EPD) of ground electrospun WO{sub 3} nanofibers was applied to create photoanodes with controlled morphology for the application of photoelectrochemical (PEC) water splitting. The correlations between deposition parameters and film thicknesses were investigated with theoretical models to precisely control the morphology of the nanostructured porous thin film. The photoconversion efficiency was further optimized as a function of film thickness. A maximum photoconversion efficiency of 0.924% from electrospun WO{sub 3} nanofibers that EPD deposited on a substrate was achieved at a film thickness of 18 μm.

  9. Dynamic control of crystallinity in polymer film casting process

    Directory of Open Access Journals (Sweden)

    Thananchai Leephakpreeda

    2005-05-01

    Full Text Available This paper presents an approach for dynamic control of crystallinity in polymer film casting process. As known, the transients of crystallization dictate the microstructures of semi-crystalline polymer during solidification. In turn, the properties of finished products can be determined by adjustable variables in polymer film casting process such as temperature of chill roll. In this work, an experimental model of the solidification in film casting process is derived by a system identification technique. This model is used to design a digital feedback controller including a state estimator. The simulation results show the effectiveness of the proposed control technique on an extruded film.

  10. Electronic excitation induced modifications of optical and morphological properties of PCBM thin films

    Science.gov (United States)

    Sharma, T.; Singhal, R.; Vishnoi, R.; Sharma, P.; Patra, A.; Chand, S.; Lakshmi, G. B. V. S.; Biswas, S. K.

    2016-07-01

    Phenyl C61 butyric acid methyl ester (PCBM) is a fullerene derivative and most commonly used in organic photovoltaic devices both as electron acceptor and transporting material due to high electron mobility. PCBM is easy to spin caste on some substrate as it is soluble in chlorobenzene. In this study, the spin coated thin films of PCBM (on two different substrate, glass and double sided silicon) were irradiated using 90 MeV Ni7+ swift heavy ion beam at low fluences ranging from 1 × 109 to 1 × 1011 ions/cm2 to study the effect of ion beam irradiation. The pristine and irradiated PCBM thin films were characterized by UV-visible absorption spectroscopy and fourier transform infrared spectroscopy (FTIR) to investigate the optical properties before and after irradiation. These thin films were further analyzed using atomic force microscopy (AFM) to investigate the morphological modifications which are induced by energetic ions. The variation in optical band gap after irradiation was measured using Tauc's relation from UV-visible absorption spectra. A considerable change was observed with increasing fluence in optical band gap of irradiated thin films of PCBM with respect to the pristine film. The decrease in FTIR band intensity of C60 cage reveals the polymerization reaction due to high energy ion impact. The roughness is also found to be dependent on incident fluences. This study throws light for the application of PCBM in organic solar cells in form of ion irradiation induced nanowires of PCBM for efficient charge carrier transportation in active layer.

  11. Property control of expanding thermal plasma deposited textured zinc oxide with focus on thin film solar cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Groenen, R. [Eindhoven University of Technology, Department of Applied Physics, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Loeffler, J. [Utrecht University, Debye Institute, SID-Physics of Devices, P.O. Box 80000, 3508 TA Utrecht (Netherlands); Linden, J.L. [TNO TPD, Division Models and Processes, P.O. Box 595, 5600 AN Eindhoven (Netherlands); Schropp, R.E.I. [Utrecht University, Debye Institute, SID-Physics of Devices, P.O. Box 80000, 3508 TA Utrecht (Netherlands); Sanden, M.C.M. van de [Eindhoven University of Technology, Department of Applied Physics, P.O. Box 513, 5600 MB Eindhoven (Netherlands)]. E-mail: m.c.m.v.d.sanden@tue.nl

    2005-12-01

    Property control of expanding thermal plasma deposited textured zinc oxide is demonstrated considering intrinsic, i.e. bulk, and extrinsic transparent conducting oxide quality relevant for application in thin film amorphous silicon pin solar cells. Particularly the interdependence of electrical conductivity, film composition and film morphology, i.e. structure, feature shape and roughness of the surface, is addressed. Control of film composition is mainly governed by plasma production and gas phase chemistry inherently inducing a significant contribution to film morphology, whereas control of film morphology solely is governed by near-substrate conditions. Especially the ratio of zinc to oxygen and the reactor chamber pressure appear to be determinative in obtaining zinc oxide exhibiting the appropriate intrinsic and extrinsic quality, i.e. a high electrical conductivity, a high transmittance, a textured rough surface morphology and a strong hydrogen plasma resistance. The solar cell performance of appropriate undoped and aluminium doped textured zinc oxide inherently obtained during deposition is comparable with respect to Asahi U-type fluorine-doped tin oxide.

  12. Stabilization of N,N′-bis(3-methylphenyl)-N,N′-bis(phenyl)benzidine thin film morphology with UV light

    Energy Technology Data Exchange (ETDEWEB)

    Tomović, A.Ž.; Markešević, N. [Institute of Physics, University of Belgrade, Pregrevica 118, 11000 Belgrade (Serbia); Scarpellini, M.; Bovio, S. [Interdisciplinary Centre for Nanostructured Materials and Interfaces (CIMAINA), Università di Milano, Via Celoria 16, 20133 Milan (Italy); Lucenti, E. [Interdisciplinary Centre for Nanostructured Materials and Interfaces (CIMAINA), Università di Milano, Via Celoria 16, 20133 Milan (Italy); Institute of Molecular Science and Technology of CNR, via Golgi 19, 20133 Milan (Italy); Milani, P. [Interdisciplinary Centre for Nanostructured Materials and Interfaces (CIMAINA), Università di Milano, Via Celoria 16, 20133 Milan (Italy); Zikic, R. [Institute of Physics, University of Belgrade, Pregrevica 118, 11000 Belgrade (Serbia); Jovanović, V.P., E-mail: vladimir.jovanovic@ipb.ac.rs [Institute of Physics, University of Belgrade, Pregrevica 118, 11000 Belgrade (Serbia); Srdanov, V.I. [Interdisciplinary Centre for Nanostructured Materials and Interfaces (CIMAINA), Università di Milano, Via Celoria 16, 20133 Milan (Italy)

    2014-07-01

    Owing to their low glass transition temperature, T{sub g}, amorphous thin films of N,N′-bis(3-methylphenyl)-N,N′-bis(phenyl)benzidine (TPD) undergo morphological changes even at room temperature. It has been noticed previously that exposure to UV light can increase apparent T{sub g} of TPD films and thus stabilize their morphology. However, the reason behind increase in structural stability was not examined at the time. Here we present evidence that TPD molecules undergo photo-oxidation in air when exposed to λ ≈ 350 nm radiation and that less than 5% of the photo-oxidized species are needed to prevent dewetting of thin TPD films. We propose that photo-oxidized TPD species bind strongly to both ordinary TPD molecules and to terminal hydroxyl groups at the substrate surface, which decreases mobility of TPD molecules and makes thin TPD film less prone to morphology changes. - Highlights: • We made variable thickness TPD films and exposed them to UV light under ambient conditions. • Mass spectroscopy and proton NMR measurements of irradiated and pristine TPD films • TPD molecules undergo oxidation process under UV light irradiation. • Dipole–dipole interactions may be responsible for stabilization of morphological changes.

  13. SEBS三嵌段共聚物膜的形态研究%Morphology of Films of SEBS Triblock Copolymers

    Institute of Scientific and Technical Information of China (English)

    韩霞; 刘洪来; 董亚明; 胡英

    2005-01-01

    Surface morphologies of the films of poly [styrene-b-(ethylene-co-butene)-b-styrene] (SEBS) have been studied by using tapping-mode atomic force microscopy (TM-AFM). The films of block copolymer were prepared both by spin-coating on mica and by solvent-casting on different solution surfaces. For spin-coating samples, the effect of solution concentration, solvent, and annealing temperature are investigated. It is shown that changing the concentration of the solution makes no difference on the morphology of the film of the block copolymer. The microstructures are quite stable during thermal annealing; only the size of the domains changes toward the equilibrium configuration. However, solvent annealing can notably change the microstructures. When different selective solvents are used for film spin-coating, different morphologies can be obtained and explained by the different solubility parameters of the solvents. As expected, significant different morphologies in the top and the bottom surfaces of the casting films were observed. The images of the top surfaces reveal cylinder microdomains, while those of the bottom surfaces were spherical morphologies.

  14. Stepwise morphological change of porous amorphous ice films observed through adsorption of methane

    Science.gov (United States)

    Horimoto, Noriko; Kato, Hiroyuki S.; Kawai, Maki

    2002-03-01

    Morphological change of amorphous ice films of D2O has been studied through adsorption of methane using thermal desorption spectroscopy (TDS) and infrared reflection absorption spectroscopy under ultrahigh vacuum. The investigated ice films were prepared under several different conditions; first, water (D2O) molecules are evaporated onto a Ru substrate at 25 K, and then subjected to an annealing process at various temperatures prior to methane deposition. On ice annealed at low temperatures, two desorption species of methane were observed in TDS: one was derived from methane adsorbed near the ice surface and the other was attributed to the desorption of methane encapsulated in ice during heating. Only the former species was observed when the annealing temperature exceeded 60 K. This indicates that reconstruction of ice occurs below 60 K, which inhibits the encapsulation of methane molecules from the amorphous ice. On the other hand, infrared spectra of ice covered with methane show that the micropores in ice start to collapse at ˜80 K, and ice becomes pore free at 120 K. We have found that the morphological change of amorphous ice induced by thermal relaxation takes place in a stepwise manner.

  15. Influence of Doping Concentration on Dielectric, Optical, and Morphological Properties of PMMA Thin Films

    Directory of Open Access Journals (Sweden)

    Lyly Nyl Ismail

    2012-01-01

    Full Text Available PMMA thin films were deposited by sol gel spin coating method on ITO substrates. Toluene was used as the solvent to dissolve the PMMA powder. The PMMA concentration was varied from 30 ~ 120 mg. The dielectric properties were measured at frequency of 0 ~ 100 kHz. The dielectric permittivity was in the range of 7.3 to 7.5 which decreased as the PMMA concentration increased. The dielectric loss is in the range of 0.01 ~ –0.01. All samples show dielectric characteristics which have dielectric loss is less than 0.05. The optical properties for thin films were measured at room temperature across 200 ~ 1000 nm wavelength region. All samples are highly transparent. The energy band gaps are in the range of 3.6 eV to 3.9 eV when the PMMA concentration increased. The morphologies of the samples show that all samples are uniform and the surface roughness increased as the concentration increased. From this study, it is known that, the dielectric, optical, and morphology properties were influenced by the amount of PMMA concentration in the solution.

  16. Production of Ti films with controlled texture

    Energy Technology Data Exchange (ETDEWEB)

    Musil, J. [Inst. of Physics, Academy of Sciences of the Czech Republic, Prague (Czech Republic); Vlcek, J. [West Bohemia Univ., Plzen (Czech Republic). Dept. of Phys.; Jezek, V. [West Bohemia Univ., Plzen (Czech Republic). Dept. of Phys.; Benda, M. [West Bohemia Univ., Plzen (Czech Republic). Dept. of Phys.; Kolega, M. [West Bohemia Univ., Plzen (Czech Republic). Dept. of Phys.; Boomsma, R. [Hauzer Techno Coating Europe BV, Venlo (Netherlands)

    1995-11-01

    This paper investigates the effects of (i) the substrate bias; (ii) the mixing of one or several additional elements with Ti; (iii) plasma nitriding of the presputtered film; and (iv) the film deposition rate on the structural properties of pure Ti and Ti-based films. The Ti-based films investigated were: Ti-SS (stainless steel), Ti-6Al-4V, Ti-Cu and Ti-Cr. The films were sputtered onto steel and glass substrates using a d.c. magnetron. The negative substrate bias U{sub s} used in the magnetron sputter ion plating process varied over a very wide range from 0 to -1500 V. The structural properties of the films were characterized by means of X-ray diffraction. Dramatic differences in the development of the crystal orientation with increasing negative bias for pure Ti and Ti-based films were found. While the pure Ti films were polycrystalline for all values of U{sub s}, the Ti-based films were formed not only as polycrystalline but also as amorphous or nanocrystalline substances, characterized by very broad (FWHM up to 10 ) reflection lines with very low intensities. The formation of nanocrystalline films is strongly dependent on the type and quantity of additional elements with Ti. Additionally, it was found that at a certain threshold value of the deposition rate the preferred orientation of pure Ti film switches from (002) to (010). This abrupt change in the film texture shows that there is a physical constraint on the maximum deposition rate if the resultant films are to have the same structural properties. (orig.)

  17. Electrochromic behaviour of Nb{sub 2}O{sub 5} thin films with different morphologies obtained by spray pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Romero, R.; Martin, F.; Leinen, D.; Ramos-Barrado, J.R. [Laboratorio de Materiales y Superficie (Unidad asociada al CSIC), Dptos Fisica Aplicada I and Ingeniera Quimica, Facultad de Ciencias, Universidad de Malaga (Spain); Dalchiele, E.A. [Instituto de Fisica, Facultad de Ingenieria, Universidad de la Republica, Montevideo (Uruguay)

    2009-02-15

    Two different procedures to stabilize the precursor NbCl{sub 5} have been applied to obtain Nb{sub 2}O{sub 5} thin films by spray pyrolysis. Depending on the procedure used, determined by the way in which the precursor solution was injected into the air stream of the spray nozzle, niobium oxide thin films with different surface morphologies can be obtained. The structural properties of the Nb{sub 2}O{sub 5} thin films depend on the post-annealing temperature because as-deposited films are amorphous, independently of the synthesis procedure used. The electrochromic behaviour has been estimated for all films, where monochromatic colouration efficiency (at 660 nm) of 25.5 cm{sup 2}/C and a cathodic charge density close to 24 mC/cm{sup 2} were found to give the best results to date for niobium oxide thin films obtained by spray pyrolysis. (author)

  18. Fabrication and morphology of (Hg,Re)-1212 thin films on LaAlO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Su, J.H.; Sastry, P.V.P.S.S.; Schwartz, J

    2003-04-15

    Superconducting (Hg,Re)Ba{sub 2}CaCu{sub 2}O{sub y} ((Hg,Re)-1212) thin films have been prepared on single crystal substrates of LaAlO{sub 3} by reacting laser deposited ReBaCaCuO precursor films with CaHgO{sub 2} in sealed quartz tubes. The effects of the deposition parameters such as laser fluence and substrate temperature, on surface morphology and microstructure were examined by atomic force microscopy (AFM) and scanning electron microscopy (SEM). AFM observations revealed that a granular structure was seen in the precursor films deposited at lower energy (less than 200 mJ) and disappeared at higher energy (250 mJ). SEM investigation on final reacted films showed that the precursor films deposited at 250 deg. C resulted in a well-connected and uniformly dense microstructure, whereas the films deposited at lower or higher temperatures were porous and non-uniform.

  19. Comparison of Morphological, Electrical and Optical Properties of as-deposited and annealed InSe Thin Films

    Directory of Open Access Journals (Sweden)

    M. Ariful Islam

    2015-04-01

    Full Text Available Indium selenide (InSe thin films have been deposited on to glass substrate by e-beam evaporation technique. Scanning Electron Microscopy (SEM has been used to study the surface morphology of the films. It is observed that the as-deposited InSe films have no sign of grains and the surfaces are almost smooth and uniform. While a number of grain boundaries are observed in the annealed films. Three different slopes in the conductivity vs temperature curves exhibits in as-deposited InSe films. If it is associated with three types of conduction mechanisms, then it might be interesting. The conductivity of annealed InSe films increases continuously with increasing temperature showing normal semiconducting behaviour. The direct optical band is found to decrease from 1.79 eV to 1.57 eV after annealing.

  20. Effect of Sheet Resistance and Morphology of ITO Thin Films on Polymer Solar Cell Characteristics

    Directory of Open Access Journals (Sweden)

    Ram Narayan Chauhan

    2012-01-01

    Full Text Available Solar cell fabrication on flexible thin plastic sheets needs deposition of transparent conducting anode layers at low temperatures. ITO thin films are deposited on glass by RF sputtering at substrate temperature of 70∘C and compare their phase, morphology, optical, and electrical properties with commercial ITO. The films contain smaller nanocrystallites in (222 preferred orientation and exhibit comparable optical transmittance (~95% in the wavelength range of 550–650 nm, but high sheet resistance of ~103 Ω/□ (the value being ~36 Ω/□ for commercial ITO.The polymer solar cells with PEDOT: PSS and P3HT: PCBM layers realized on RF sputtered vis-a-vis commercial ITO thin films are shown to display a marginal difference in power conversion efficiency, low fill factor, and low open-circuit voltage but increased short-circuit current density. The decrease in fill factor, open-circuit voltage is compensated by increased short-circuit current. Detailed study is made of increased short-circuit current density.

  1. Identification of nanoscale structure and morphology reconstruction in oxidized a-SiC:H thin films

    Energy Technology Data Exchange (ETDEWEB)

    Vasin, A.V.; Rusavsky, A.V.; Nazarov, A.N.; Lysenko, V.S.; Lytvyn, P.M.; Strelchuk, V.V. [Lashkaryov Institute of Semiconductor Physics, 41 Nauki Pr., Kiev 03028 (Ukraine); Kholostov, K.I.; Bondarenko, V.P. [Belarusian State University of Informatics and Radioelectronics, 6P. Brovki Str., Minsk 220013 (Belarus); Starik, S.P. [Bakul Institute of Superhard Materials, 2 Avtzavodskaya Str., Kiev 04074 (Ukraine)

    2012-11-01

    Highlights: Black-Right-Pointing-Pointer Increase of magnetron discharge power results in densification of a-SiC:H thin films. Black-Right-Pointing-Pointer The denser a-SiC:H material the better resistance to oxidation by oxygen. Black-Right-Pointing-Pointer Oxidation of soft a-SiC:H films can result in increase of electric conductivity. Black-Right-Pointing-Pointer Formation of graphitic clusters was found in a-SiC:H after annealing in oxygen. - Abstract: Oxidation behavior of a-SiC:H layers deposited by radio-frequency magnetron sputtering technique was examined by Kelvin probe force microscopy (KPFM) in combination with scanning electron microscopy, Fourier-transform infra-red spectroscopy and submicron selected area Raman scattering spectroscopy. Partially oxidized a-SiC:H samples (oxidation at 600 Degree-Sign C in oxygen) were examined to clarify mechanism of the oxidation process. Nanoscale and microscale morphological defects (pits) with dimension of about 50 nm and several microns respectively have appeared after thermal treatment. KPFM measurements exhibited the surface potential of the material in micro pits is significantly smaller in comparison with surrounding material. Submicron RS measurements indicates formation of graphite-like nano-inclusions in the pit defects. We conclude that initial stage of oxidation process in a-SiC:H films takes place not homogeneously throughout the layer but it is initiated in local nanoscale regions followed by spreading over all layer.

  2. Triggering the atomic layers control of hexagonal boron nitride films

    Energy Technology Data Exchange (ETDEWEB)

    Song, Yangxi [State Key Laboratory of Advanced Ceramic Fibers and Composites, College of Aerospace Science and Engineering, National University of Defense Technology, Changsha 410073 (China); Zhang, Changrui, E-mail: crzhang12@gmail.com [State Key Laboratory of Advanced Ceramic Fibers and Composites, College of Aerospace Science and Engineering, National University of Defense Technology, Changsha 410073 (China); Li, Bin [State Key Laboratory of Advanced Ceramic Fibers and Composites, College of Aerospace Science and Engineering, National University of Defense Technology, Changsha 410073 (China); Jiang, Da; Ding, Guqiao; Wang, Haomin [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050 (China); Xie, Xiaoming, E-mail: xmxie@mail.sim.ac.cn [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050 (China)

    2014-09-15

    Highlights: • Thickness of h-BN films can be controlled from double atomic layers to over ten atomic layers by adjusting the CVD parameters, quite different from the reported thickness control of up to tens of nanometers. (The interlayer distance of h-BN is 0.333 nm.) • Growth mechanisms of h-BN are discussed, especially for bilayer h-BN films. • Both epitaxial growth and diffusion-segregation process are involved in the synthesis of bilayer h-BN films. - Abstract: In this work, we report the successful synthesis of large scale hexagonal boron nitride films with controllable atomic layers. The films are grown on thin nickel foils via ambient pressure chemical vapor deposition with borazine as the precursor. The atomic layers of h-BN films can be controlled in a narrow range by adjusting growth time and the cooling rates. Transmission electron microscope results shows the h-BN films exhibit high uniformity and good crystalline. X-ray photoelectron spectroscopy shows the B/N elemental ratio is about 1.01. The h-BN films exhibit a pronounced deep ultraviolet absorption at 203.0 nm with a large optical band gap of 6.02 ± 0.03 eV. The results suggest potential applications of h-BN films in deep ultraviolet and dielectric materials. Growth mechanisms of h-BN films with thickness control are discussed, especially when the synthesized h-BN films after a higher cooling rate show an in-plane rotation angle between bilayers. Both epitaxial growth and diffusion-segregation process are involved in the synthesis of bilayer h-BN films.

  3. Controlled chemical and morphological surface modifications via pulsed plasma polymerizations: Synthesis of ultrahydrophobic surfaces

    Science.gov (United States)

    Qiu, Haibo

    The RF plasma polymerization of saturated linear and cyclic perfluoroalkane monomers and vinyl acetic acid were studied in this dissertation. Film chemical compositions, deposition rates, surface wettabilities and morphologies were characterized as functions of various plasma processing conditions. Large progressive changes in chemical compositions with sequential variations in plasma duty cycle were demonstrated in polymerization of both perfluoroalkane and vinyl acetic acid monomers. As anticipated, polymer films obtained from the perfluorocarbon monomers exhibited a general trend towards more linear structures with decreasing plasma duty cycles. However, completely unexpectedly, ultrahydrophobic films were obtained from some of these monomers under restricted duty cycle and power input conditions. SEM and XPS characterizations revealed that a rough, fibrous-like surface morphology is responsible for this ultrahydrophobicity, as opposed to unusual chemical compositions. The growth of the fibrous surface is believed to arise from nucleation and hillock-like growth patterns on selectively activated sites of the growing polymer film. Surface mobility of plasma generated reactive species apparently plays an important role in the growth of the fibrous ultrahydrophobic surfaces, as shown by substrate temperature studies. Additionally, the present study revealed a number of interesting new observations of significant differences in the chemical compositions and deposition rates of polymer films obtained from the diverse range of perfluorocarbon monomers employed in this work. The ultrahydrophobic fluorocarbon films discovered in this investigation were evaluated for use in several biomaterial applications. The results obtained show excellent marine antifouling properties for these surfaces, as documented in ocean testing experiments. These surfaces have also been shown to be useful in controlling protein and peptide surface adsorptions, as well as in the inflammatory

  4. Morphological Control: A Design Principal for Applications in Space Science

    Science.gov (United States)

    Füchslin, R. M.; Dumont, E.; Flumini, D.; Fuchs, H. U.; Hauser, H.; Jaeger, C.; Scheidegger, S.; Schönenberger-Deuel, J.; Lichtensteiger, L.; Luchsinger, R.; Weyland, M.

    Designing robots for applications in space flight requires a different prioritization of design criteria than for systems operating on Earth. In this article, we argue that the field of soft robotics offers novel approaches meeting the specific requirements of space flight. We present one especially promising construction principle, so called Tensairity, in some detail. Tensairity, as the name suggests, takes ideas from Tensegrity, but uses inflatable structures instead of cables and struts. Soft robots pose substantial challenges with respect to control. One way to meet these challenges is given by the concept of morphological computation and control. Morphological computation can be loosely defined as the exploitation of the shape, material properties, and dynamics of a physical system to improve the efficiency of computation and to deal with systems for which it is difficult to construct a virtual representation using a kinematic model. We discuss fundamental aspects of morphological control and their relevance for space flight. Besides low weight, small consumption of space in the inactive state and advantageous properties with respect to intrinsic safety and energy consumption, we discuss how the blurring of the discrimination of hard- and software leads to control strategies that require only very little and very simple electronic circuitry (which is beneficial in an environment with high irradiation). Finally, we present a research strategy that bundles activities in space flight with research and development in medicine, especially for support systems for an aging population, that are faced with similar morphological computing challenges to astronauts. Such a combination meets the demands for research that is not only effective, but also efficient with respect to economic resources.

  5. Morphology control of brushite prepared by aqueous solution synthesis

    OpenAIRE

    2014-01-01

    Dicalcium phosphate dihydrate (DCPD, CaHPO4·2H2O), also known as brushite, is one of the important bioceramics due to not only diseases factors such as kidney stone and plaque formation but also purpose as fluoride insolubilization material. It is used medicinally to supply calcium, and is of interest for its unique properties in biological and pathological mineralization. It is important to control the crystal morphology of brushite since its chemical reactivity depends strongly on its surfa...

  6. Morphology Control in co-evaporated bulk heterojunction solar cells

    OpenAIRE

    Kovacik, P; Assender, HE; Watt, AAR

    2013-01-01

    Bulk heterojunction solar cells made by vacuum co-evaporation of polythiophene (PTh) and fullerene (C60) are reported and the blend morphology control through donor-acceptor composition and post-situ annealing demonstrated. Co-deposited heterojunctions are shown to generate about 60% higher photocurrents than their thickness-optimized PTh/C60 planar heterojunction counterparts. Furthermore, by annealing the devices post-situ the power conversion efficiency is improved by as much as 80%. UV-vi...

  7. Surface morphology and impurity distribution of electron beam recrystallized silicon films on low cost substrates for solar cell absorber

    Institute of Scientific and Technical Information of China (English)

    FU Li; GROMBALL F; MüLLER J

    2006-01-01

    A line shaped electron beam recrystallised polycrystalline silicon film on the low cost substrate was investigated for the use of the solar cell absorber. The applied EB energy density strongly influences the surface morphology of the film system. Lower EB energy density results in droplet morphology and the rougher SiO2 capping layer due to the low fluidity. With the energy increasing, thecapping layer becomes smooth and continuous and less and small pinholes form in the silicon film. Tungstendisilicide (WSi2) is formed at the interface tungsten/silicon but also at the grain boundaries of the silicon. Because of the fast melting and cooling of the silicon film, the eutectic of silicon and tungstendisilicide mainly forms at the grain boundary of the primary silicon dendrites. The SEM-EDX analysis shows that there are no chlorine and hydrogen in the area surrounding a pinhole after recrystallization because of outgassing during the solidification.

  8. Enhanced the photocatalytic activity of Ni-doped ZnO thin films: Morphological, optical and XPS analysis

    Science.gov (United States)

    Abdel-wahab, M. Sh.; Jilani, Asim; Yahia, I. S.; Al-Ghamdi, Attieh A.

    2016-06-01

    Pure and Ni-doped ZnO thin films with different concentration of Ni (3.5 wt%, 5 wt%, 7 wt%) were prepared by DC/RF magnetron sputtering technique. The X-rays diffraction pattern showed the polycrystalline nature of pure and Ni-doped ZnO thin films. The surface morphology of pure and Ni doped ZnO thin films were investigated through atomic force microscope, which indicated the increase in the grain dimension and surface roughness with increasing the Ni doping. The UV-Visible transmission spectra showed the decrease in the transmittance of doped ZnO thin films with the incorporation of Ni dopants. The surface and chemical state analysis of pure and Ni doped ZnO thin films were investigated by X-rays photoelectron spectroscopy (XPS). The photocatalytic activities were evaluated by an aqueous solution of methyl green dye. The tungsten lamp of 500 W was used as a source of visible light for photocatalytic study. The degradation results showed that the Ni-doped ZnO thin films exhibit highly enhanced photocatalytic activity as compared to the pure ZnO thin films. The enhanced photocatalytic activities of Ni-doped ZnO thin films were attributed to the enhanced surface area (surface defects), surface roughness and decreasing the band gap of Ni-doped ZnO thin films. Our work supports the applications of thin film metal oxides in waste water treatment.

  9. Structural, morphological, electrical, and optical properties of silver thin films of varying thickness deposited on cupric oxide

    Science.gov (United States)

    Hajakbari, Fatemeh; Shafieinejad, Farzaneh

    2016-03-01

    In this investigation, silver (Ag) films of varying thickness (25-100 nm) were grown on cupric oxide (CuO) on silicon and quartz. The CuO preparation was carried out by the thermal oxidation annealing of copper (Cu) thin films deposited by DC magnetron sputtering. The physical properties of the prepared films were studied by different techniques. Rutherford backscattering spectroscopy (RBS) analysis indicated that the Ag film thickness was about 25-100 nm. X-ray diffraction (XRD) results showed that by increasing Ag thickness, the film crystallinity was improved. Also, atomic force microscopy (AFM) and scanning electron microscopy (SEM) results demonstrated that the surface morphology and the grain size were affected by the Ag film thickness. Furthermore, the electrical resistivity of films determined by four-point probe measurements versus the Ag film thickness was discussed. A reduction in the optical band gap energy of CuO is observed from 1.51 to 1.42 eV with an increase in Ag film thickness to 40 nm in Ag/CuO films.

  10. Synthesis of Silver Nanoparticle and Its Morphological Control

    Institute of Scientific and Technical Information of China (English)

    WANG Xiang-rong; ZHENG Min; XU Jian; WANG Chang-ping

    2009-01-01

    Silver nanoparticles with different morphologies were prepared in AgNO3 aqueous solution using nanocarbon as template medium and polymer surfactant as protecting agent in an ultrasonic field. The polymer surfactant polyvinylpyrrolidone ( PVP) was self-prepared and used directly in aqueous solution form. The molecular weight of PVP was measured by viscosimeter. The crystalline phase,component, size, and morphology of the as-synthesized silver naoparticles were characterized by XRD, TEM,FTIR, and Laser Granularity Instrument. The results indicated that ultrasonic was the key factor to deoxidize Ag+to be Ag°nanocarbon and polymer surfactants accelerated the deoxidization reaction course and controlled the agglomeration of freshly formed silver nanoparticles, the category of polymer surfactant had decisive effect on the morphology of as-synthesized nanoparticle. Well-defined dendrites silver nanoparticle could be attained when choosing PVP as surfactant in AgNO3 aqueous solution,while regular sphere silver nanoparticle could be synthesized in the presence of polyvinyl alcohol (PVA) surfactant.Moreover, the concentration of AgNO3 and ultrasonic action time also had obvious effect on the morphology of silver nanoparticle, low concentration of AgNO3 and long time of ultrasonic were not in favor of forming dendrite silver.

  11. Dynamic control of crystallinity in polymer film casting process

    OpenAIRE

    Thananchai Leephakpreeda

    2005-01-01

    This paper presents an approach for dynamic control of crystallinity in polymer film casting process. As known, the transients of crystallization dictate the microstructures of semi-crystalline polymer during solidification. In turn, the properties of finished products can be determined by adjustable variables in polymer film casting process such as temperature of chill roll. In this work, an experimental model of the solidification in film casting process is derived by a system identificatio...

  12. Physical properties and morphology of films prepared from microfibrillated cellulose and microfibrillated cellulose in combination with amylopectin

    DEFF Research Database (Denmark)

    Plackett, David; Anturi, Harvey; Hedenqvist, Mikael

    2010-01-01

    Two types of microfibrillated cellulose (MFC) were prepared using either a sulfite pulp containing a high amount of hemicellulose (MFC 1) or a carboxymethylated dissolving pulp (MFC 2). MFC gels were then combined with amylopectin solutions to produce solvent-cast MFC-reinforced amylopectin films...... to illustrate the morphology of MFC nanofibers in pure films and in an amylopectin matrix. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010...

  13. Improved Morphology of Poly(3,4-ethylenedioxythiophene:Poly(styrenesulfonate Thin Films for All-Electrospray-Coated Organic Photovoltaic Cells

    Directory of Open Access Journals (Sweden)

    Yingjie Liao

    2016-01-01

    Full Text Available Spray coating technique has been established as a promising substitute for the traditional coating methods in the fabrication of organic devices in many reports recently. Control of film morphology at the microscopic scale is critical if spray-coated devices are to achieve high performance. Here we investigate electrospray deposition protocols for the fabrication of poly(3,4-ethylenedioxythiophene:poly(styrenesulfonate (PEDOT:PSS thin films with a single additive system under ambient conditions at room temperature. Critical deposition parameters including solution composition, applied voltage, and relative humidity are discussed systematically. Optimized process for preparing homogenous PEDOT:PSS thin films is applied to all-electrospray-coated organic photovoltaic cells and contributes to a power conversion efficiency comparable to that of the corresponding all-spin-coated device.

  14. Optical and morphological characterization by atomic force microscopy of luminescent 2-styrylpyridine derivative compounds with Poly(N-vinylcarbazole) films

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Gutierrez, E., E-mail: cuper_enrique@msn.com [Centro de Quimica, Instituto de Ciencias, Universidad Autonoma de Puebla, Complejo de Ciencias, ICUAP, Edif. 103-F, 22 Sur y San Claudio, C.P. 72570 Puebla, Puebla (Mexico); Percino, M.J.; Chapela, V.M. [Centro de Quimica, Instituto de Ciencias, Universidad Autonoma de Puebla, Complejo de Ciencias, ICUAP, Edif. 103-F, 22 Sur y San Claudio, C.P. 72570 Puebla, Puebla (Mexico); Maldonado, J.L. [Centro de Investigaciones en Optica A.C. (CIO), Lomas del Bosque 115, Col. Lomas del Campestre, C.P. 37150, Leon Guanajuato (Mexico)

    2011-07-01

    The present work addresses the optical and morphological properties of organic films based on low molecular weight dyes styrylpyridine derivatives 2-styrylpyridine (A), 4-chlorophenyl-2-vinylpyridine (B) and 4-fluorophenyl-2-vinylpyridine (C), embedded in a polymeric matrix poly(N-vinylcarbazole) (PVK). The films were prepared by a spin-coating technique from solutions with dye:PVK ratios of 0.25:1, 0.5:1 and 1:1. Solvents were chloroform and toluene. The molar absorption coefficient ({epsilon}) spectra for a dye:PVK mixture in solution were a combination of the absorptions of both components separately, but for the deposited films, the shape of the spectrum showed that the poly(N-vinylcarbazole) absorption dominated. However, when the same films were dissolved again in CHCl{sub 3}, their spectra showed an absorption shape similar to that of the solution mixture before the deposition. Solution viscosity measurements were carried out with an Ubbelohde glass capillary viscometer to corroborate the results that showed a better mixture of the dye with the host in chloroform. The morphology of the prepared films was analyzed by atomic force microscopy and exhibited a solvent effect, with a pinhole-free, smooth surface when toluene was used and a wavy surface with chloroform. The ratio dye:matrix was the principal parameter for obtaining optical quality films; for 0.25:1 and 0.5:1 ratios, the films were of good quality, but for 1:1, the dye was expelled from the PVK and a crystallization was present over the surface of the films. Film thickness was also measured and films deposited from toluene solutions gave an average thickness of 54 nm while films from chloroform solutions had an average thickness greater than 160 nm that increased depending on chromophore concentration.

  15. Influence of current density on surface morphology and properties of pulse plated tin films from citrate electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Ashutosh; Bhattacharya, Sumit; Das, Siddhartha; Das, Karabi, E-mail: karabi@metal.iitkgp.ernet.in

    2014-01-30

    Bulk polycrystalline tin films have been processed by pulse electrodeposition technique from a simple solution containing triammonium citrate and stannous chloride. The cathodic investigations have been carried out by galvanostatic methods. As deposited samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). XRD analysis of the deposited films shows microcrystalline grains having β-Sn form. The surface morphology is very rough at lower current density, but becomes smooth at higher current density, and exhibits pyramid type morphology at all the current densities. The effect of current density on microhardness, melting behavior, and electrical resistivity are also reported here.

  16. License Plate Recognition for Parking Control System by Mathematical Morphology

    Institute of Scientific and Technical Information of China (English)

    Javier Ortiz; Alberto Gómez

    2014-01-01

    Nowadays, license plate recognition for parking systems is a critical task to provide automatic control of customers and payment. This paper introduces a new method for automatic recognition of license plates of vehicles by mathematical morphology. The proposed method can provide the license plate number of the plates in different light conditions, colors, sizes, and inclination (angles). The algorithm can recognize the license plates of European Union vehicles quickly and correctly. The pattern learning of mathematical skeletons has high efficiency in the process. The performance of the algorithm is demonstrated well by the test in a parking control system.

  17. Effect of Catalyst Film Thickness on Growth Morphology, Surface Wettability and Drag Reduction Property of Carbon Nanotubes

    Science.gov (United States)

    Ma, Weiwei; Zhou, Zhiping; Li, Gang; Li, Ping

    2016-10-01

    Nickel films were deposited on silicon substrates using magnetron sputtering method. The pretreatment process of nickel films under high temperature and ammonia atmosphere was investigated. The thickness of nickel film has a great influence on growth morphology of carbon nanotubes (CNTs). Too large or too small thickness would do harm to the orientated growth of CNTs. The inner structure, elements composition and growth mechanism have been confirmed by TEM and EDX characterization. The surface wettability and drag reduction property of CNTs were investigated. This paper can provide a new, effective method to further develop the practical application in micro/nano devices field.

  18. Controlling Particle Morphologies at Fluid Interfaces: Macro- and Micro- approaches

    Science.gov (United States)

    Beesabathuni, Shilpa Naidu

    The controlled generation of varying shaped particles is important for many applications: consumer goods, biomedical diagnostics, food processing, adsorbents and pharmaceuticals which can benefit from the availability of geometrically complex and chemically inhomogeneous particles. This thesis presents two approaches to spherical and non-spherical particle synthesis using macro and microfluidics. In the first approach, a droplet microfluidic technique is explored to fabricate spherical conducting polymer, polyaniline, particles with precise control over morphology and functionality. Microfluidics has recently emerged as an important alternate to the synthesis of complex particles. The conducting polymer, polyaniline, is widely used and known for its stability, high conductivity, and favorable redox properties. In this approach, monodisperse micron-sized polyaniline spherical particles were synthesized using two-phase droplet microfluidics from Aniline and Ammonium persulfate oxidative polymerization in an oil-based continuous phase. The morphology of the polymerized particles is porous in nature which can be used for encapsulation as well as controlled release applications. Encapsulation of an enzyme, glucose oxidase, was also performed using the technique to synthesize microspheres for glucose sensing. The polymer microspheres were characterized using SEM, UV-Vis and EDX to understand the relationship between their microstructure and stability. In the second approach, molten drop impact in a cooling aqueous medium to generate non-spherical particles was explored. Viscoelastic wax based materials are widely used in many applications and their performance and application depends on the particle morphology and size. The deformation of millimeter size molten wax drops as they impacted an immiscible liquid interface was investigated. Spherical molten wax drops impinged on a cooling water bath, then deformed and as a result of solidification were arrested into various

  19. Controllable precipitation of naproxen micro-particles with different morphologies

    Institute of Scientific and Technical Information of China (English)

    Peng Cheng; Kangkang Jin; Jing Cheng; Fang Yang; Zhigang Shen; Jianfeng Chen; Lixiong Wen

    2012-01-01

    A simple precipitation method was proposed to prepare naproxen micro-particles with different controllable morphologies,using capillary video microscopy to study the precipitation process.Different particle shapes were obtained including spherical,platelet-like,stick-like,needle-like,and butterfly-like,all in the micro-size range.It was found that the sizes and morphologies of the formed naproxen particles were sensitive to the nature and concentration of the added surfactant,and depended significantly on processing conditions such as temperature,stirring speed,and initial drug concentration.In addition,precipitation with different surfactant types and concentrations would not affect the crystal microstructure of the formed naproxen particles.

  20. Supramolecular Approaches to Nanoscale Morphological Control in Organic Solar Cells

    Science.gov (United States)

    Haruk, Alexander M.; Mativetsky, Jeffrey M.

    2015-01-01

    Having recently surpassed 10% efficiency, solar cells based on organic molecules are poised to become a viable low-cost clean energy source with the added advantages of mechanical flexibility and light weight. The best-performing organic solar cells rely on a nanostructured active layer morphology consisting of a complex organization of electron donating and electron accepting molecules. Although much progress has been made in designing new donor and acceptor molecules, rational control over active layer morphology remains a central challenge. Long-term device stability is another important consideration that needs to be addressed. This review highlights supramolecular strategies for generating highly stable nanostructured organic photovoltaic active materials by design. PMID:26110382

  1. Synthesis and optical properties of gold nanorods with controllable morphology

    Science.gov (United States)

    Ye, Tianyu; Dai, Zhigao; Mei, Fei; Zhang, Xingang; Zhou, Yuanming; Xu, Jinxia; Wu, Wei; Xiao, Xiangheng; Jiang, Changzhong

    2016-11-01

    Searching for architectural building blocks with tunable morphology and peculiarity is a prominent challenge for novel diagnostic and therapeutic applications. Here, the aqueous-based seed-mediated methods for preparing highly mono-dispersed Au nanorods with a different aspect ratio are systematically studied by controlling the amounts of Ag ions and seeds. We also explore the effect of pH on the synthesis of gold nanorods. The realization of the overlap of longitudinal plasmon band and excitation source with different degrees is made by changing the aspect ratio of nanorod in order to determine its effect on the overall surface enhancement. In addition, the gold octahedra are prepared by overgrowth on Au nanorods. The SERS effects of Au nanorods are researched and the FDTD simulations are performed to reveal the morphology induced plasmon modes.

  2. Supramolecular Approaches to Nanoscale Morphological Control in Organic Solar Cells

    Directory of Open Access Journals (Sweden)

    Alexander M. Haruk

    2015-06-01

    Full Text Available Having recently surpassed 10% efficiency, solar cells based on organic molecules are poised to become a viable low-cost clean energy source with the added advantages of mechanical flexibility and light weight. The best-performing organic solar cells rely on a nanostructured active layer morphology consisting of a complex organization of electron donating and electron accepting molecules. Although much progress has been made in designing new donor and acceptor molecules, rational control over active layer morphology remains a central challenge. Long-term device stability is another important consideration that needs to be addressed. This review highlights supramolecular strategies for generating highly stable nanostructured organic photovoltaic active materials by design.

  3. Linking rigid multibody systems via controllable thin fluid films

    DEFF Research Database (Denmark)

    Estupinan, Edgar Alberto; Santos, Ilmar

    2009-01-01

    , this paper gives a theoretical contribution to the combined fields of fluid–structure interaction and vibration control. The methodology is applied to a reciprocating linear compressor, where the dynamics of the mechanical components are described with help of multibody dynamics. The crank is linked...... of the journal orbits, maximum fluid film pressure and minimum fluid film thickness....

  4. In Search of Bibliographic Control for Instructional Motion Picture Films.

    Science.gov (United States)

    Coover, Robert W.

    This historical study report describes phases in the development of applicable standards for cataloging instructional motion picture films. Steps leading to the present state of the art are objectively presented, focusing on standards developed to establish bibliographic control of instructional motion picture films, contemporary reaction to such…

  5. Thermal Stability, Sorption Properties and Morphology of Films of Dipeptide and Tripeptide Based on L-Glycine

    Directory of Open Access Journals (Sweden)

    Marat A. Ziganshin

    2015-12-01

    Full Text Available The effect of the number of amino acid residues in L-glycyl-L-glycine and L-glycyl-L-glycyl-L-glycine on thermal stability of powders, the sorption properties and surface morphology of thin films has been found. Dipeptide forms the film coated with disk-shaped nano-objects on the hydrophilic substrate, while tripeptide self-organizes to the film coated with nano-crystals on the hydrophobic substrate. Replacement of substrates (hydrophilic↔hydrophobic leads to the formation of smooth films of studied oligopeptides. Powders of oligopeptides do not form stable clathrates with water and organic compounds at room temperature. But their thin films are capable to bind organic or water vapors with high thermodynamic activity. Surprising difference in sorption selectivity of dipeptide and tripeptide has been observed. L-G

  6. Ultra thin films of gadolinium deposited by evaporation in ultra high vacuum conditions: Composition, growth and morphology

    Energy Technology Data Exchange (ETDEWEB)

    Herrera-Sancho, O.A.; Castro-Gonzalez, D.; Araya-Pochet, J.A. [Centro de Investigacion en Ciencia e Ingenieria de Materiales, Universidad de Costa Rica, 2060 San Pedro, San Jose (Costa Rica); Escuela de Fisica, Universidad de Costa Rica, 2060 San Pedro, San Jose (Costa Rica); Vargas-Castro, W.E., E-mail: william.vargascastro@ucr.ac.cr [Centro de Investigacion en Ciencia e Ingenieria de Materiales, Universidad de Costa Rica, 2060 San Pedro, San Jose (Costa Rica); Escuela de Fisica, Universidad de Costa Rica, 2060 San Pedro, San Jose (Costa Rica)

    2011-02-01

    Ultra-thin gadolinium films with thicknesses between 8 and 101 A were deposited on AT-cut crystalline quartz substrates under ultra high vacuum conditions, and subsequently subjected to composition and morphologic characterization through X-ray photo-spectroscopy analysis and atomic force microscopy. Oxygen contamination is found on the samples, and its amount is estimated in terms of the thickness of an oxygen layer over the gadolinium films after subtracting the contribution to the XPS spectra of the underlying background. Atomic force microscope pictures provide evidence of having metal island films, with two growing regimes: the Volmer-Weber mode for the thinner films considered and the Stranski-Krastanov growing mode for the thicker ones. From evaluation of the sticking coefficient, the shape of the islands is approximated in terms of oblate spheroid caps and variation of the contact angle with film mass thickness is reported.

  7. Morphology and inner structure of ethanol sensitive thin films of tin oxide operating at near room temperature

    Science.gov (United States)

    Mahdi, O. S.; Malyar, I. V.; Galushka, V. V.; Smirnov, A. V.; Sinev, I. V.; Venig, S. B.

    2017-06-01

    Thin tin oxide films were fabricated by reactive RF magnetron sputtering. It was shown that the films possess gas sensitivity to ethanol vapor at 38°C. Measurements of the morphology and cleavage inner structure of the samples by atomic-force and scanning electron microscopy demonstrate that the films are composed of nanodimensional rod-like grains oriented normally to the substrate. The grains are separated by pores piercing the whole film. It was found that the grain diameter distribution is normal logarithmic one with several centers related as small integers, which indicates that the grains coalesce. The minimum grain size of 6 nm might correspond to the critical nucleus size under the used conditions of film deposition.

  8. Macromolecular Interactions Control Structural and Thermal Properties of Regenerated Tri-Component Blended Films

    Directory of Open Access Journals (Sweden)

    Ashley Lewis

    2016-11-01

    Full Text Available With a growing need for sustainable resources research has become highly interested in investigating the structure and physical properties of biomaterials composed of natural macromolecules. In this study, we assessed the structural, morphological, and thermal properties of blended, regenerated films comprised of cellulose, lignin, and hemicellulose (xylan using the ionic liquid 1-allyl-3-methylimidazolium chloride (AMIMCl. Attenuated total reflectance Fourier transform infrared (ATR-FTIR analysis, scanning electron microscopy (SEM, atomic force microscopy (AFM, X-ray scattering, and thermogravimetric analysis (TGA were used to qualitatively and quantitatively measure bonding interactions, morphology, and thermal stability of the regenerated films. The results demonstrated that the regenerated films’ structural, morphological, and thermal character changed as a function of lignin-xylan concentration. The decomposition temperature rose according to an increase in lignin content and the surface topography of the regenerated films changed from fibrous to spherical patterns. This suggests that lignin-xylan concentration alters the self-assembly of lignin and the cellulose microfibril development. X-ray scattering confirms the extent of the morphological and molecular changes. Our data reveals that the inter- and intra-molecular interactions with the cellulose crystalline domains, along with the amount of disorder in the system, control the microfibril dimensional characteristics, lignin self-assembly, and possibly the overall material′s structural and thermal properties.

  9. Surface morphology, growth rate and quality of diamond films synthesized in hot filament CVD system under various methane concentrations

    Science.gov (United States)

    Ali, M.; Ürgen, M.

    2011-08-01

    Hot filament chemical vapor deposition (CVD) technique has been used to deposit diamond films on silicon substrate. In the present study, diamond films were grown at various vol.% CH 4 in H 2 from 0.5% to 3.5%, at substrate temperature and pressure of 850 °C and 80 torr, respectively. Scanning electron microscopy, X-ray diffraction and Raman spectroscopy were employed to analyze the properties of deposited films. The formation of methyl radicals as a function of vol.% CH 4 not only changes film morphology but also increase film growth rate. At low, intermediate and high vol.% CH 4, cluster, faceted cubes and pyramidal features growth, were dominant. By increasing vol.% CH 4 from 0.5% to 3.5%, as the growth rate improved from ˜0.25 μm/h to ˜2.0 μm/h. Raman studies features revealed high purity diamond films at intermediate range of vol.% CH 4 and grain density increased by increasing CH 4 concentration. The present study represents experimentally surface morphology, growth rate and quality of diamond films grown in hot filament CVD system at various CH 4 concentrations.

  10. Statistical investigations of an ENIG Nickel film morphology by Atomic Force Microscopy

    Directory of Open Access Journals (Sweden)

    Germanicus Rosine Coq

    2016-01-01

    Full Text Available The morphology of a Nickel layer grown by an Electroless Nickel Immersion Gold (ENIG technique used for microelectronics interconnections is determined by Atomic Force Microscopy (AFM investigations. The root mean square (rms roughness, determined over a scanned area is a function of the AFM scanned area size. In this work, we propose to consider the dynamic scale theory and the power spectrum density (PSD analysis in order to perform a comprehensive determination of the surface properties of the ENIG nickel layer. Results highlight the existence of a first regime with a roughness exponent of 0.95 and a fractal dimension (DF of the nickel film about 2.05. This case study is presented in order to propose further investigations. In fact, same experimental procedure should be performed in a magnetic shielded zone where a very low noise level is available such as the Low-Noise Underground Laboratory (LSBB of Rustrel (France.

  11. CdS nanofilms: Effect of film thickness on morphology and optical band gap

    Science.gov (United States)

    Kumar, Suresh; Kumar, Santosh; Sharma, Pankaj; Sharma, Vineet; Katyal, S. C.

    2012-12-01

    CdS nanofilms of varying thickness (t) deposited by chemical bath deposition technique have been studied for structural changes using x-ray diffractometer (XRD) and transmission electron microscope (TEM). XRD analysis shows polycrystalline nature in deposited films with preferred orientation along (002) reflection plane also confirmed by selected area diffraction pattern of TEM. Uniform and smooth surface morphology observed using field emission scanning electron microscope. The surface topography has been studied using atomic force microscope. The optical constants have been calculated from the analysis of %T and %R spectra in the wavelength range 300 nm-900 nm. CdS nanofilms show a direct transition with red shift. The optical band gap decreases while the refractive index increases with increase in thickness of nanofilms.

  12. Effect of thickness on surface morphology, optical and humidity sensing properties of RF magnetron sputtered CCTO thin films

    Science.gov (United States)

    Ahmadipour, Mohsen; Ain, Mohd Fadzil; Ahmad, Zainal Arifin

    2016-11-01

    In this study, calcium copper titanate (CCTO) thin films were deposited on ITO substrates successfully by radio frequency (RF) magnetron sputtering method in argon atmosphere. The CCTO thin films present a polycrystalline, uniform and porous structure. The surface morphology, optical and humidity sensing properties of the synthesized CCTO thin films have been studied by X-ray diffraction (XRD), atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), UV-vis spectrophotometer and current-voltage (I-V) analysis. XRD and AFM confirmed that the intensity of peaks and pore size of CCTO thin films were enhanced by increasing the thin films. Tauc plot method was adopted to estimate the optical band gaps. The surface structure and energy band gaps of the deposited films were affected by film thickness. Energy band gap of the layers were 3.76 eV, 3.68 eV and 3.5 eV for 200 nm, 400 nm, and 600 nm CCTO thin films layer, respectively. The humidity sensing properties were measured by using direct current (DC) analysis method. The response times were 12 s, 22 s, and 35 s while the recovery times were 500 s, 600 s, and 650 s for 200 nm, 400 nm, and 600 nm CCTO thin films, respectively at humidity range of 30-90% relative humidity (RH).

  13. A novel method for controlled synthesis of nanosized hematite ({alpha}-Fe{sub 2}O{sub 3}) thin film on liquid-vapor interface

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Pawan [Jaypee University of Information Technology (India); Singh, Raj Kumar [CSIR-Indian Institute of Petroleum (India); Rawat, Nitin [Gwangju Institute of Science and Technology (Korea, Republic of); Barman, Partha Bir [Jaypee University of Information Technology (India); Katyal, Subhash Chander [Jaypee Institute of Information Technology (India); Jang, Hwanchol; Lee, Heung-No, E-mail: heungno@gist.ac.kr [Gwangju Institute of Science and Technology (Korea, Republic of); Kumar, Rajesh, E-mail: rajesh.kumar@juit.ac.in [Jaypee University of Information Technology (India)

    2013-04-15

    Hematite ({alpha}-Fe{sub 2}O{sub 3}) films with a high quality surface morphology have been formed at the liquid-vapor interface using a novel approach. The surface morphology/size of the nanoparticles constituting the film is tuned in a controlled manner. It is observed that the concentration of polyvinyl alcohol in the precursor Fe{sup 3+}/Fe{sup 2+} solution, the concentration of ammonia (NH{sub 3}) vapor, and the annealing temperature are factors influencing the surface morphology/size of nanoparticles. The diameter of the {alpha}-Fe{sub 2}O{sub 3} nanoparticles inside the film is controlled to be 2-15 nm by varying the synthesis conditions, and accordingly the films have roughness in the 1.34-6.8 nm range. The prepared {alpha}-Fe{sub 2}O{sub 3} films are crystalline in nature and exhibit superparamagnetic behavior at room temperature.

  14. Controlling the Pore Size of Mesoporous Carbon Thin Films through Thermal and Solvent Annealing.

    Science.gov (United States)

    Zhou, Zhengping; Liu, Guoliang

    2017-02-02

    Herein an approach to controlling the pore size of mesoporous carbon thin films from metal-free polyacrylonitrile-containing block copolymers is described. A high-molecular-weight poly(acrylonitrile-block-methyl methacrylate) (PAN-b-PMMA) is synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. The authors systematically investigate the self-assembly behavior of PAN-b-PMMA thin films during thermal and solvent annealing, as well as the pore size of mesoporous carbon thin films after pyrolysis. The as-spin-coated PAN-b-PMMA is microphase-separated into uniformly spaced globular nanostructures, and these globular nanostructures evolve into various morphologies after thermal or solvent annealing. Surprisingly, through thermal annealing and subsequent pyrolysis of PAN-b-PMMA into mesoporous carbon thin films, the pore size and center-to-center spacing increase significantly with thermal annealing temperature, different from most block copolymers. In addition, the choice of solvent in solvent annealing strongly influences the block copolymer nanostructure and the pore size of mesoporous carbon thin films. The discoveries herein provide a simple strategy to control the pore size of mesoporous carbon thin films by tuning thermal or solvent annealing conditions, instead of synthesizing a series of block copolymers of various molecular weights and compositions.

  15. The Impact of Morphology and Composition on the Resistivity and Oxidation Resistance of Metal Nanostructure Films

    Science.gov (United States)

    Stewart, Ian Edward

    Printed electronics, including transparent conductors, currently rely on expensive materials to generate high conductivity devices. Conductive inks for thick film applications utilizing inkjet, aerosol, and screen printing technologies are often comprised of expensive and rare silver particles. Thin film applications such as organic light emitting diodes (OLEDs) and organic photovoltaics (OPVs) predominantly employ indium tin oxide (ITO) as the transparent conductive layer which requires expensive and wasteful vapor deposition techniques. Thus an alternative to silver and ITO with similar performance in printed electronics warrants considerable attention. Copper nanomaterials, being orders of magnitude cheaper and more abundant than silver or indium, solution-coatable, and exhibiting a bulk conductivity only 6 % less than silver, have emerged as a promising candidate for incorporation in printed electronics. First, we examine the effect of nanomaterial shape on the conductivity of thick films. The inks used in such films often require annealing at elevated temperature in order to sinter the silver nanoparticles together and obtain low resistivities. We explore the change in morphology and resistivity that occurs upon heating thick films of silver nanowires (of two different lengths, Ag NWs), nanoparticles (Ag NPs), and microflakes (Ag MFs) deposited from water at temperatures between 70 and 400 °C. At the lowest temperatures, longer Ag NWs exhibited the lowest resistivity (1.8 x 10-5 O cm), suggesting that the resistivity of thick films of silver nanostructures is dominated by the contact resistance between particles. This result supported previous research showing that junction resistance between Ag NWs in thin film conductors also dominates optoelectronic performance. Since the goal is to replace silver with copper, we perform a similar analysis by using a pseudo-2D rod network modeling approach that has been modified to include lognormal distributions in length

  16. Investigations of the structural, morphological and electrical properties of multilayer ZnO/TiO2 thin films, deposited by sol-gel technique

    Science.gov (United States)

    Khan, M. I.; Bhatti, K. A.; Qindeel, Rabia; Bousiakou, Leda G.; Alonizan, Norah; Fazal-e-Aleem

    Investigations of the structural, morphological and electrical properties of multilayer ZnO/TiO2 thin films deposited by sol-gel technique on glass substrate. Sol-gel is a technique in which compound is dissolved in a liquid in order to bring it back as a solid in a controlled manner. TiO2 solution was obtained by dissolving 0.4 g of TiO2 nano powder in 5 ml ethanol and 5 ml diethylene glycol. ZnO solution was obtained by dissolving 0.88 g zinc acetate in 20 ml of 2-methoxyethanol. X-ray diffraction (XRD) (PW 3050/60 PANalytical X'Pert PRO diffractometer) results showed that the crystallinity is improved when the number of ZnO/TiO2 layers increased. Also it shows the three phases (rutile, anatase and brookite) of TiO2. Surface morphology measured by scanning electron microscopy (SEM) (Quanta 250 fei) revealed that Crakes are present on the surface of ZnO/TiO2 thin films which are decreased when the number of ZnO/TiO2 layers increased. Four point probe (KIETHLEY instrument) technique used to investigate the electrical properties of ZnO/TiO2 showed the average resistivity decreased by increasing the number of ZnO/TiO2 layers. These results indicated that the multilayer thin films improved the quality of film crystallinity and electrical properties as compared to single layer.

  17. Architectured morphologies of chemically prepared NiO/MWCNTs nanohybrid thin films for high performance supercapacitors.

    Science.gov (United States)

    Gund, Girish S; Dubal, Deepak P; Shinde, Sujata S; Lokhande, Chandrakant D

    2014-03-12

    The preparation of nanostructured metal oxide decorated on multiwalled carbon nanotubes (MWCNTs) nanohybrid films through simple, scalable, additive-free, binderless, and cost-effective route has fascinated significant attention not only in fundamental research areas but also its commercial applications, in order to reduce the growing environmental pollution and the cost of electrode fabrication. Here, we report the fabrication of highly flexible electrode with NiO/MWCNTs nanohybrid thin films directly on stainless steel substrate using successive ionic layer adsorption and reaction (SILAR) method. The impact of ratio of adsorption and reaction cycles on structural, surface areas and electrochemical properties of NiO/MWCNTs nanohybrids was investigated. X-ray diffraction measurements confirm the hybridization and face centered cubic (FCC) crystal structure of NiO in NiO/MWCNTs nanohybrids. In addition, these nanohybrids exhibit excellent surface properties such as uniform surface morphology, good surface area, pore volume, and uniform pore size distribution. The electrochemical tests demonstrate the highest specific capacitance of 1727 F g(-1) at 5 mA cm(-2) of current density with 91% capacitance retention after 2000 cycles. In addition, the Ragone plot confirms the better power and energy densities for all NiO/MWCNTs nanohybrids. The attractive electrochemical capacitive activity revealed by NiO/MWCNTs nanohybrid electrode proposes that it is an auspicious respondent for future energy storage application.

  18. Morphology, thermal, mechanical, and barrier properties of graphene oxide/poly(lactic acid) nanocomposite films

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seong Woo; Choi, Hyun Muk [Kyonggi University, Suwon (Korea, Republic of)

    2016-01-15

    To improve the physical and gas barrier properties of biodegradable poly(lactic acid) (PLA) film, two graphene nanosheets of highly functionalized graphene oxide (0.3 wt% to 0.7 wt%) and low-functionalized graphene oxide (0.5 wt%) were incorporated into PLA resin via solution blending method. Subsequently, we investigated the effects of material parameters such as loading level and degree of functionalization for the graphene nanosheets on the morphology and properties of the resultant nanocomposites. The highly functionalized graphene oxide (GO) caused more exfoliation and homogeneous dispersion in PLA matrix as well as more sustainable suspensions in THF, compared to low-functionalized graphene oxide (LFGO). When loaded with GO from 0.3 wt% to 0.7 wt%, the glass transition temperature, degree of crystallinity, tensile strength and modulus increased steadily. The GO gave rise to more pronounced effect in the thermal and mechanical reinforcement, relative to LFGO. In addition, the preparation of fairly transparent PLA-based nanocomposite film with noticeably improved barrier performance achieved only when incorporated with GO up to 0.7wt%. As a result, GO may be more compatible with hydrophilic PLA resin, compared to LFGO, resulting in more prominent enhancement of nanocomposites properties.

  19. Hydrodynamic effects on phase separation morphologies in evaporating thin films of polymer solutions

    Science.gov (United States)

    Zoumpouli, Garyfalia A.; Yiantsios, Stergios G.

    2016-08-01

    We examine effects of hydrodynamics on phase separation morphologies developed during drying of thin films containing a volatile solvent and two dissolved polymers. Cahn-Hilliard and Flory-Huggins theories are used to describe the free energy of the phase separating systems. The thin films, considered as Newtonian fluids, flow in response to Korteweg stresses arising due to concentration non-uniformities that develop during solvent evaporation. Numerical simulations are employed to investigate the effects of a Peclet number, defined in terms of system physical properties, as well as the effects of parameters characterizing the speed of evaporation and preferential wetting of the solutes at the gas interface. For systems exhibiting preferential wetting, diffusion alone is known to favor lamellar configurations for the separated phases in the dried film. However, a mechanism of hydrodynamic instability of a short length scale is revealed, which beyond a threshold Peclet number may deform and break the lamellae. The critical Peclet number tends to decrease as the evaporation rate increases and to increase with the tendency of the polymers to selectively wet the gas interface. As the Peclet number increases, the instability moves closer to the gas interface and induces the formation of a lateral segregation template that guides the subsequent evolution of the phase separation process. On the other hand, for systems with no preferential wetting or any other property asymmetries between the two polymers, diffusion alone favors the formation of laterally separated configurations. In this case, concentration perturbation modes that lead to enhanced Korteweg stresses may be favored for sufficiently large Peclet numbers. For such modes, a second mechanism is revealed, which is similar to the solutocapillary Marangoni instability observed in evaporating solutions when interfacial tension increases with the concentration of the non-volatile component. This mechanism may lead

  20. Crystallization-induced properties from morphology-controlled organic crystals.

    Science.gov (United States)

    Park, Chibeom; Park, Ji Eun; Choi, Hee Cheul

    2014-08-19

    During the past two decades, many materials chemists have focused on the development of organic molecules that can serve as the basis of cost-effective and flexible electronic, optical, and energy conversion devices. Among the potential candidate molecules, metal-free or metal-containing conjugated organic molecules offer high-order electronic conjugation levels that can directly support fast charge carrier transport, rapid optoelectric responses, and reliable exciton manipulation. Early studies of these molecules focused on the design and synthesis of organic unit molecules that exhibit active electrical and optical properties when produced in the form of thin film devices. Since then, researchers have worked to enhance the properties upon crystallization of the unit molecules as single crystals provide higher carrier mobilities and exciton recombination yields. Most recently, researchers have conducted in-depth studies to understand how crystallization induces property changes, especially those that depend on specific crystal surfaces. The different properties that depend on the crystal facets have been of particular interest. Most unit molecules have anisotropic structures, and therefore produce crystals with several unique crystal facets with dissimilar molecular arrangements. These structural differences would also lead to diverse electrical conductance, optical absorption/emission, and even chemical interaction properties depending on the crystal facet investigated. To study the effects of crystallization and crystal facet-dependent property changes, researchers must grow or synthesize crystals of highly conjugated molecules that have both a variety of morphologies and high crystallinity. Morphologically well-defined organic crystals, that form structures such as wires, rods, disks, and cubes, provide objects that researchers can use to evaluate these material properties. Such structures typically occur as single crystals with well-developed facets with

  1. Temperature-controlled transparent-film heater based on silver nanowire-PMMA composite film.

    Science.gov (United States)

    He, Xin; Liu, A'lei; Hu, Xuyang; Song, Mingxia; Duan, Feng; Lan, Qiuming; Xiao, Jundong; Liu, Junyan; Zhang, Mei; Chen, Yeqing; Zeng, Qingguang

    2016-11-25

    We fabricated a high-performance film heater based on a silver nanowire and polymethyl methacrylate (Ag NW-PMMA) composite film, which was synthesized with the assistance of mechanical lamination and an in situ transfer method. The films exhibit excellent conductivity, high figure of merit, and strong adhesion of percolation network to substrate. By controlling NW density, we prepared the films with a transmittance of 44.9-85.0% at 550 nm and a sheet resistance of 0.13-1.40 Ω sq(-1). A stable temperature ranging from 130 °C-40 °C was generated at 3.0 V within 10-30 s, indicating that the resulting film heaters show a rapid thermal response, low driving voltage and stable temperature recoverability. Furthermore, we demonstrated the applications of the film heater in defrosting and a physical therapeutic instrument. A fast defrosting on the composite film with a transmittance of 88% was observed by applying a 9 V driving voltage for 20 s. Meanwhile, we developed a physical therapeutic instrument with two modes of thermotherapy and electronic-pulse massage by using the composite films as two electrodes, greatly decreasing the weight and power consumption compared to a traditional instrument. Therefore, Ag NW-PMMA film can be a promising candidate for diversified heating applications.

  2. Temperature-controlled transparent-film heater based on silver nanowire-PMMA composite film

    Science.gov (United States)

    He, Xin; Liu, A.'lei; Hu, Xuyang; Song, Mingxia; Duan, Feng; Lan, Qiuming; Xiao, Jundong; Liu, Junyan; Zhang, Mei; Chen, Yeqing; Zeng, Qingguang

    2016-11-01

    We fabricated a high-performance film heater based on a silver nanowire and polymethyl methacrylate (Ag NW-PMMA) composite film, which was synthesized with the assistance of mechanical lamination and an in situ transfer method. The films exhibit excellent conductivity, high figure of merit, and strong adhesion of percolation network to substrate. By controlling NW density, we prepared the films with a transmittance of 44.9-85.0% at 550 nm and a sheet resistance of 0.13-1.40 Ω sq-1. A stable temperature ranging from 130 °C-40 °C was generated at 3.0 V within 10-30 s, indicating that the resulting film heaters show a rapid thermal response, low driving voltage and stable temperature recoverability. Furthermore, we demonstrated the applications of the film heater in defrosting and a physical therapeutic instrument. A fast defrosting on the composite film with a transmittance of 88% was observed by applying a 9 V driving voltage for 20 s. Meanwhile, we developed a physical therapeutic instrument with two modes of thermotherapy and electronic-pulse massage by using the composite films as two electrodes, greatly decreasing the weight and power consumption compared to a traditional instrument. Therefore, Ag NW-PMMA film can be a promising candidate for diversified heating applications.

  3. Controlling the microstructure of binary carbide films with elemental substitutions

    Science.gov (United States)

    Feller, K.; Haider, M.; Hodges, A.; Spreng, R.; Posbergh, E.; Woodward, H.; Lofland, S. E.; Hettinger, J. D.; Heon, M.; Gogotsi, Y.

    2011-03-01

    We report on experiments to control the microstructure of textured binary carbide thin films deposited by reactive magnetron sputter deposition. Controlling the microstructure in these materials is important as the microstructure of these films provides a template for the resulting carbide-derived carbon (CDC) film and impacts their performance. Specifically, a combinatorial approach is used to add chromium to TiC films creating a compositional gradient as a function of position. We present a measurement of surface roughness as a function of material composition. The resulting materials, (Ti 1-x Cr x) C films, are significantly smoother than their pure TiC counterparts and the resulting CDC's have correlated defects which will improve the performance of the CDC in supercapacitor applications. This work was supported by Rowan University and NSF under contract DMR-0503711.

  4. Microstructure, morphology, adhesion and tribological behavior of sputtered niobium carbide and bismuth films on tool steel

    Directory of Open Access Journals (Sweden)

    Laura Angélica Ardila Rodríguez

    2014-11-01

    Full Text Available Normal 0 21 false false false ES-CO X-NONE AR-SA Normal 0 21 false false false ES-CO X-NONE AR-SA NbC, Bi and Bi/NbC coatings were deposited on AISI M2 steel substrates using unbalanced magnetron sputtering at room temperature with zero bias voltage. Were studied the phase structure, the morphology, the adhesion and the tribological behavior of the three coatings. The niobium carbide film crystallized in the NbC cubic structure, and the bismuth layers had a rhombohedral phase with random orientation. The NbC coating had a smooth surface with low roughness, while the Bi layers on steel and on NbC coating had higher roughness and a morphology composed of large particles. By using a ductile Nb interlayer good adhesion between the NbC coating and the steel substrate was achieved. The Bi coating had better adhesion with the NbC layer than with the steel substrate. The tribological performance of the Bi coating on steel was not satisfactory, but according to the preliminary results, the produced NbC and Bi/NbC coatings have the potential to improve the tribological performance of the steel.

  5. Morphology and optical properties of poly(9,9' dioctyfluorene) films

    CERN Document Server

    Ariu, M

    2002-01-01

    This thesis concerns a study of the optical properties of the polymer poly(9,9'dioctylfluorene) (PFO). Polyfluorene polymers represent the current state-of-the-art materials for use in optoelectronic devices. Recently there has been a growing interest in investigating how changes in polymer morphology affect their optical properties and in turn how such information can be used to optimise device performance. The first part of this thesis deals with the characterization of PFO films prepared in four morphological phases, namely: as spin coated glass (SC PFO), nematic quenched glass (NQ PFO), crystalline (X PFO) and PFO having an extended chain conformation (beta-phase PFO). Infrared (FT-IR) and Raman spectroscopy have been used in order to correlate the polymer chain conformations in the four phases with the results reported from optical measurements. In order to do this, it has been necessary to analyse and assign the origin of the vibrational modes detected. This has been achieved via comparison with molecul...

  6. Breakthrough and future: nanoscale controls of compositions, morphologies, and mesochannel orientations toward advanced mesoporous materials.

    Science.gov (United States)

    Yamauchi, Yusuke; Suzuki, Norihiro; Radhakrishnan, Logudurai; Wang, Liang

    2009-01-01

    Currently, ordered mesoporous materials prepared through the self-assembly of surfactants have attracted growing interests owing to their special properties, including uniform mesopores and a high specific surface area. Here we focus on fine controls of compositions, morphologies, mesochannel orientations which are important factors for design of mesoporous materials with new functionalities. This Review describes our recent progress toward advanced mesoporous materials. Mesoporous materials now include a variety of inorganic-based materials, for example, transition-metal oxides, carbons, inorganic-organic hybrid materials, polymers, and even metals. Mesoporous metals with metallic frameworks can be produced by using surfactant-based synthesis with electrochemical methods. Owing to their metallic frameworks, mesoporous metals with high electroconductivity and high surface areas hold promise for a wide range of potential applications, such as electronic devices, magnetic recording media, and metal catalysts. Fabrication of mesoporous materials with controllable morphologies is also one of the main subjects in this rapidly developing research field. Mesoporous materials in the form of films, spheres, fibers, and tubes have been obtained by various synthetic processes such as evaporation-mediated direct templating (EDIT), spray-dried techniques, and collaboration with hard-templates such as porous anodic alumina and polymer membranes. Furthermore, we have developed several approaches for orientation controls of 1D mesochannels. The macroscopic-scale controls of mesochannels are important for innovative applications such as molecular-scale devices and electrodes with enhanced diffusions of guest species.

  7. The effect of grain orientation on the morphological stability of the organic–inorganic perovskite films under elevated temperature

    Science.gov (United States)

    Wang, Dong; Chang, Yue; Pang, Shuping; Cui, Guanglei

    2017-01-01

    The fast developing perovskite solar cells shows high efficiency and low cost. However, the stability problem restricts perovskite from commercial use. In this work, we have studied the effect of grain orientation on the morphological stability of perovskite thin films. By tuning the inorganic/organic ratio in the precursor solution, perovskite thin films with both high crystallinity and good morphological stability have been fabricated. The thermal stability of perovskite solar cells based on the optimized films has been tested. The device performance shows no degradation after annealing at 100 °C for 5 h in air. This finding provides general guidelines for the development of thermally stable perovskite solar cells. Project supported by the Youth Innovation Promotion Association of CAS (No. 2015167).

  8. Influence of substrate on structural, morphological and optical properties of ZnO films grown by SILAR method

    Indian Academy of Sciences (India)

    F N Jiménez-García; C L Londoño-Calderón; D G Espinosa-Arbeláez; A Del Real; M E Rodríguez-García

    2014-10-01

    ZnO films were obtained by successive ionic layer adsorption and reaction (SILAR) method from four different substrates: glass microslides, corning glass, quartz and silicon with and without oxide layer. For films deposition, a precursor solution of ZnSO4 was used, complexed with ammonium hydroxide. Prior to the film deposition, wettability of the substrates was analysed using a CCD camera. It was found that the Si without the oxide layer substrate shows hydrophobic behaviour, which makes the films less adherent and not uniform, while in the other substrates, the behaviour was optimal for the growing process. ZnO films grown on glass microslides, corning glass, quartz and Si with oxide layer were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV–Vis techniques. According to the XRD patterns, the films were polycrystalline, with hexagonal wurtzite structure and the patterns mentioned showed significant differences in crystallite sizes, microstrain and texture coefficient with respect to the employed substrates. The morphology of the ZnO films constituted by rice-like and flower-like structures shows differences in form and size depending on the substrate. The UV–Vis spectroscopy results show that the substrate did not influence the band gap energy value obtained from films.

  9. Morphology and thermal properties of PLA films plasticized with aliphatic oligoesters; Morfologia e propriedades termicas de filmes de PLA plastificados com oligoesteres alifaticos

    Energy Technology Data Exchange (ETDEWEB)

    Inacio, Erika M.; Dias, Marcos L., E-mail: erika.minacio@ima.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil); Lima, Maria Celiana P. [Instituto Federal do Rio de Janeiro (IFRJ), Duque de Caxias, RJ (Brazil)

    2015-07-01

    The addition of plasticizers to poly(lactic acid) (PLA) is one of the known ways of changing its ductility, making possible the modification of its mechanical and thermal properties. In this work, it was synthesized two biodegradable aliphatic oligoesters: oligo(trimethylene sebacate) (OST) and oligo(trimethylene malonate) (OMT), and these oligomers were used as plasticizer in cast films of commercial film grade PLA at concentrations of 1, 5 and 10 wt% of each plasticizer. X-ray diffraction (XRD) was used to investigate the morphology and differential scanning calorimetry (DSC) was also used aiming the evaluation of the thermal properties of these films. The PLA films containing no plasticizer showed an amorphous behavior, and the addition of PMT on the PLA films acted, simultaneously, decreasing the Tg, and rising the material's crystallinity. In contrast, the increased addition of OST to the PLA films did not change the Tg, and equally, did not have a significant changes in the material's crystallinity. Therefore, it was possible to observe the effect of the concentration of oligomers on the crystallinity of the films as well as the no plasticizer effect of the OST. (author)

  10. Morphology and thermal properties of PLA films plasticised with aliphatic oligoesters; Morfologia e propriedades termicas de filmes de PLA plastificados com oligoesteres alifaticos

    Energy Technology Data Exchange (ETDEWEB)

    Inacio, Erika M.; Dias, Marcos L., E-mail: erika.minacio@ima.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil); Lima, Maria Celiana P. [Instituto Federal do Rio de Janeiro (IFRJ), Duque de Caxias, RJ (Brazil)

    2013-07-01

    The addition of plasticizers to poly(lactic acid) (PLA) is one of the known ways of changing its ductility, making possible the modification of its mechanical and thermal properties. In this work, it was synthesized two biodegradable aliphatic oligoesters: oligo(trimethylene sebacate) (OST) and oligo(trimethylene malonate) (OMT), and these oligomers were used as plasticizer in cast films of commercial film grade PLA at concentrations of 1, 5 and 10 wt% of each plasticizer. X-ray diffraction (XRD) was used to investigate the morphology and differential scanning calorimetry (DSC) was also used aiming the evaluation of the thermal properties of these films. The PLA films containing no plasticizer showed an amorphous behavior, and the addition of PMT on the PLA films acted, simultaneously, decreasing the Tg, and rising the material's crystallinity. In contrast, the increased addition of OST to the PLA films did not change the Tg, and equally, did not have a significant changes in the material's crystallinity. Therefore, it was possible to observe the effect of the concentration of oligomers on the crystallinity of the films as well as the no plasticizer effect of the OST. (author)

  11. Optical, Electrical, and Morphological Effects of Yttrium Doping of Cadmium Oxide Thin Films Grown by Ultrasonic Spray Pyrolysis

    Science.gov (United States)

    Tombak, Ahmet; Baturay, Silan; Kilicoglu, Tahsin; Ocak, Yusuf Selim

    2017-04-01

    CdO films doped with Y concentrations of 0%, 1%, 2%, and 3% were deposited onto soda lime glass using ultrasonic spray pyrolysis. The effect of the doping level on the structural, morphological, optical, and electrical properties of the films was characterized. X-ray diffraction analysis was used to establish that all of the samples were polycrystalline and to determine the structural parameters, i.e., lattice spacing ( d), phases and associated ( hkl) planes, grain size ( D), and dislocation density ( δ). The films possessed high conductivity and carrier concentration, showing n-type semiconducting behavior. The films were almost transparent over the range from 600 nm to 1100 nm. The energy bandgap was 2.43 eV, 2.53 eV, 2.68 eV, and 2.70 eV for Y doping of 0%, 1%, 2%, and 3%, respectively. The refractive index and extinction coefficient of the films over the range from 700 nm to 1100 nm were determined by spectroscopic ellipsometry. Atomic force microscopy revealed the effect of Y doping on the surface morphology of the CdO films.

  12. Morphology, composition and electrical properties of SnO{sub 2}:Cl thin films grown by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Hsyi-En, E-mail: sean@mail.stust.edu.tw; Wen, Chia-Hui; Hsu, Ching-Ming [Department of Electro-Optical Engineering, Southern Taiwan University of Science and Technology, Tainan 71005, Taiwan (China)

    2016-01-15

    Chlorine doped SnO{sub 2} thin films were prepared using atomic layer deposition at temperatures between 300 and 450 °C using SnCl{sub 4} and H{sub 2}O as the reactants. Composition, structure, surface morphology, and electrical properties of the as-deposited films were examined. Results showed that the as-deposited SnO{sub 2} films all exhibited rutile structure with [O]/[Sn] ratios between 1.35 and 1.40. The electrical conductivity was found independent on [O]/[Sn] ratio but dependent on chlorine doping concentration, grain size, and surface morphology. The 300 °C-deposited film performed a higher electrical conductivity of 315 S/cm due to its higher chlorine doping level, larger grain size, and smoother film surface. The existence of Sn{sup 2+} oxidation state was demonstrated to minimize the effects of chlorine on raising the electrical conductivity of films.

  13. Regenerated silk fibroin films with controllable nanostructure size and secondary structure for drug delivery.

    Science.gov (United States)

    Zhou, Juan; Zhang, Bin; Shi, Lijun; Zhong, Jian; Zhu, Jun; Yan, Juan; Wang, Ping; Cao, Chuanbao; He, Dannong

    2014-12-24

    The ability of drug release from SF materials was governed largely by their secondary structure. It is known that the breakage degree of the peptide chain during the silk fibroin (SF) dissolution can affect the structure, property, and applications of SF materials. To deeply understand this effect, we designed a reaction system based on CaCl2/H2O/C2H5OH ternary solvent with different ethanol content to obtain the regenerated SF films with different morphologies and secondary structures. The results showed that the globule-like nanostructure was observed in all regenerated SF films, and their size decreased significantly with reducing the ethanol content in the solvent. Correspondingly, the β-sheet structure content of the SF films increased. In addition, the contact angle and the elongation ratio increased, and water absorption decreased significantly with decreasing the ethanol content in the solvent. The accumulated release percents of doxorubicin from these SF films were significantly different with increasing the time. With smaller nanostructure size and more β-sheet content, the SF films had a slower drug release at the beginning. This study indicated the importance of the ethanol content in the solvent in controlling the structure and properties of the regenerated SF films, which would improve the application of SF in drug delivery.

  14. Morphological Control of the Photoactive Layer in Bulk Heterojunction Organic Solar Cells

    KAUST Repository

    Su, Yisong

    2011-07-23

    For its inherent advantages, such as lightweight, low cost, flexibility, and opportunity to cover large surface areas, organic solar cells have attracted more and more attention in both academia and industry. However, the efficiency of organic solar cell is still much lower than silicon solar cells, but steadily rising as it now stands above 8%. The architecture of bulk heterojunction solar cells can improve the performance of organic solar cell a lot, but these improvements are highly dependent on the morphology of photoactive layer. Therefore, by controlling the morphology of photoactive layer, most commonly composed of a P3HT donor polymer and PCBM small molecule, the performance of organic solar cells could be optimized. The use of solvent additives in the solution formulation is particularly interesting, because it is a low cost method of controlling the phase separation of the photoactive layer and possibly removing the need for subsequent thermal and solvent vapor annealing. However, the role of the solvent additive remains not well understood and much debate remains on the mechanisms by which it impacts phase separation. In the first part of this thesis, we investigate the role of the solvent additive on the individual components (solvent, donor and acceptor) of the solution and the photoactive layer both in the bulk solution, during solution-processing and in the post-processing solid state of the film. In the second part of this thesis, we investigate the role of the additive on the blended solution state and resulting thin film phase separation. Finally, we propose a new method of controlling phase separation based on the insight into the role of the solvent additive. In the first part, we used an additive [octandiethiol (OT)] in the solvent to help the aggregation of P3HT in the solution. From the UV-vis experiments, the crystallinity of P3HT in the solutions increased while it decreased in thin films with steady increase of additive concentration. This

  15. Formation Mechanism and Control of Perovskite Films from Solution to Crystalline Phase Studied by in Situ Synchrotron Scattering.

    Science.gov (United States)

    Chang, Chun-Yu; Huang, Yu-Ching; Tsao, Cheng-Si; Su, Wei-Fang

    2016-10-12

    Controlling the crystallization and morphology of perovskite films is crucial for the fabrication of high-efficiency perovskite solar cells. For the first time, we investigate the formation mechanism of the drop-cast perovskite film from its precursor solution, PbCl2 and CH3NH3I in N,N-dimethylformamide, to a crystalline CH3NH3PbI3-xClx film at different substrate temperatures from 70 to 180 °C in ambient air and humidity. We employed an in situ grazing-incidence wide-angle X-ray scattering (GIWAXS) technique for this study. When the substrate temperature is at or below 100 °C, the perovskite film is formed in three stages: the initial solution stage, transition-to-solid film stage, and transformation stage from intermediates into a crystalline perovskite film. In each stage, the multiple routes for phase transformations are preceded concurrently. However, when the substrate temperature is increased from 100 to 180 °C, the formation mechanism of the perovskite film is changed from the "multistage formation mechanism" to the "direct formation mechanism". The proposed mechanism has been applied to understand the formation of a perovskite film containing an additive. The result of this study provides a fundamental understanding of the functions of the solvent and additive in the solution and transition states to the crystalline film. It provides useful knowledge to design and fabricate crystalline perovskite films for high-efficiency solar cells.

  16. Birefringence control of solution-cast film of cellulose triacetate

    Science.gov (United States)

    Kiyama, Ayumi; Nobukawa, Shogo; Yamaguchi, Masayuki

    2017-10-01

    We controlled the optical anisotropy of a solution-cast film composed of cellulose triacetate (CTA) by adding ferrocene. Owing to the molecular orientation in the film plane of solution-cast films, which results from the normal stress applied during the solvent evaporation process, the average refractive index is usually higher in the plane of the film than in the thickness direction. We found that the addition of ferrocene, which is miscible with CTA, reduced the optical anisotropy by nematic interaction; i.e., ferrocene molecules are forcibly embedded into the film plane accompanying the CTA chains. Because the direction of anisotropic polarizability of ferrocene is perpendicular to the long axis of the molecule, the refractive index in the thickness direction is reduced. Furthermore, the stress-optical coefficient in the glassy state is reduced by the addition of ferrocene.

  17. (0 0 2-oriented growth and morphologies of ZnO thin films prepared by sol-gel method

    Directory of Open Access Journals (Sweden)

    Guo Dongyun

    2016-09-01

    Full Text Available Zinc acetate was used as a starting material to prepare Zn-solutions from solvents and ligands with different boiling temperature. The ZnO thin films were prepared on Si(1 0 0 substrates by spin-coating method. The effect of baking temperature and boiling temperature of the solvents and ligands on their morphologies and orientation was investigated. The solvents and ligands with high boiling temperature were favorable for relaxation of mechanical stress to form the smooth ZnO thin films. As the solvents and ligands with low boiling temperature were used to prepare Zn-solutions, the prepared ZnO thin films showed (0 0 2 preferred orientation. As n-propanol, 2-methoxyethanol, 2-(methylaminoethanol and monoethanolamine were used to prepare Zn-solutions, highly (0 0 2-oriented ZnO thin films were formed by adjusting the baking temperature.

  18. Influence of air annealing on the structural, morphological, optical and electrical properties of chemically deposited ZnSe thin films

    Science.gov (United States)

    Kale, R. B.; Lokhande, C. D.

    2005-11-01

    Zinc selenide nanocrystalline thin films are grown onto amorphous glass substrate from an aqueous alkaline medium, using chemical bath deposition (CBD) method. The ZnSe thin films are annealed in air for 4 h at various temperatures and characterized by structural, morphological, optical and electrical properties. The as-deposited ZnSe film grew with nanocrystalline cubic phase alongwith some amorphous phase present in it. After annealing metastable nanocrystalline cubic phase was transformed into stable polycrystalline hexagonal phase with partial conversion of ZnSe into ZnO. The optical band gap, Eg, of as-deposited film is 2.85 eV and electrical resistivity of the order of 10 6-10 7 Ω cm. Depending upon annealing temperature, decrease up to 0.15 eV and 10 2 Ω cm were observed in the optical band gap, Eg, and electrical resistivity, respectively.

  19. Preparation of CuInSe2 films by ultrasonic electrodeposition-selenization and the improvement of their surface morphology

    Institute of Scientific and Technical Information of China (English)

    WANG Yanlai; NIE Hongbo; GUO Shiju

    2010-01-01

    The CuInSe2 compound was prepared by selenization of Cu-In precursor,which was ultrasonic electrodeposited at constant current.CuInSe2films were compacted to improve surface morphology.The films were characterized by X-ray diffractometry(XRD),scanning electron microscopy(SEM),and energy dispersive spectroscopy(EDS).It is indicated that ideal stoichiometric CuInSe2 films can be obtained by the selanization of Cu-In precursor deposited at a current density of 20 mA/cm2.Single-phase CuInSe2 is formed in the selenization process,and it exhibits preferred orientation along the(112)plane.The CuInSe2 films with smooth surface can be obtained under the pressure of 500 MPa at 60℃.

  20. Morphological Control of Multifunctional Mesoporous Silica Nanomaterials for Catalysis Applications

    Energy Technology Data Exchange (ETDEWEB)

    Huh, Seong [Iowa State Univ., Ames, IA (United States)

    2004-12-19

    I found an efficient method to control the morphology of the organically monofunctionalized mesoporous silica materials by introducing different types of organoalkoxysilanes in a base-catalyzed co-condensation reaction. The monofunctionalized materials exhibit different particle morphologies relative to the pure MCM-41 material. The concentration dependence of the morphology is a critical factor to determine the final particle shape. A proposed mechanism of the shape evolution is also offered. After understanding the role of organoalkoxysilanes in producing various well-shaped nanomaterials, I also obtained a series of bifunctional mesoporous silica materials with certain particle morphology. A series of bifunctional mesoporous silica nanospheres (MSNs) whose physicochemical properties was investigated via solid state NMR techniques and Cu2+ adsorption capacity tests, The ratio of two different organic groups inside of mesopores of these MSNs could be fine-tuned. These MSNs serve as a useful model system to study substrate selectivity in catalytic reactions and sorption phenomena. For example, the Cu2+ adsorption capacity of these materials was dictated by the chemical nature of the mesopores generated by the different organic functional groups. An investigation of the substrate selectivity of the bifunctionalized MSNs in a competitive nitroaldol reaction using an equimolar amount of two competing 4-nitrobenzaldehyde derivatives was performed. Shape-controlled bifunctional MSNs were employed as the catalysts. The properties of the MSNs were investigated using various spectroscopic methods and electron microscopy. The more hydrophobic the surface organic groups are, the higher the ratio of hydrophobic final product. This is the first example to demonstrate the selection of substrate using physicochemical nature of the mesopore surface other than the conventional shape selection in zeolite systems. I also created a cooperative dual catalyst

  1. Temporal evolution of surface structure and morphology in thin-film growth and etching processes

    Science.gov (United States)

    Drotar, Jason Todd

    plasma etching and chemical vapor deposition processes, which could not be explained by any of the previously known universality classes. More generally, these universality classes can help uncover what processes are most important in certain experimental systems. The temporal evolution of copper films thermally evaporated onto silicon oxide has also been studied. The structure of the film was monitored, during deposition, using reflection high-energy electron diffraction (RHEED). The films are found to be polycrystalline with face-centered cubic (fcc) grains. The crystal structure and surface morphology are studied as functions of time, and it is found that competitive texture evolution occurs, leading to an absence of (111), (200), and (220) oriented grains. The growth of facets is also studied, and it is found that the facet size grows exponentially with time. This behavior is explained in terms of facet coalescence. The results presented here illustrate several new methods of analyzing RHEED patterns and demonstrate the usefulness of RHEED for real-time characterization of polycrystalline films.

  2. Improved morphology control using a modified two-step method for efficient perovskite solar cells.

    Science.gov (United States)

    Bi, Dongqin; El-Zohry, Ahmed M; Hagfeldt, Anders; Boschloo, Gerrit

    2014-11-12

    A two-step wet chemical synthesis method for methylammonium lead(II) triiodide (CH3NH3PbI3) perovskite is further developed for the preparation of highly reproducible solar cells, with the following structure: fluorine-doped tin oxide (FTO)/TiO2 (compact)/TiO2 (mesoporous)/CH3NH3PbI3/spiro-OMeTAD/Ag. The morphology of the perovskite layer could be controlled by careful variation of the processing conditions. Specifically, by modifying the drying process and inclusion of a dichloromethane treatment, more uniform films could be prepared, with longer emission lifetime in the perovskite material and longer electron lifetime in solar cell devices, as well as faster electron transport and enhanced charge collection at the selective contacts. Solar cell efficiencies up to 13.5% were obtained.

  3. Metal nanostructures with complex surface morphology: The case of supported lumpy Pd and Pt nanoparticles produced by laser processing of metal films

    Science.gov (United States)

    Ruffino, F.; Maugeri, P.; Cacciato, G.; Zimbone, M.; Grimaldi, M. G.

    2016-09-01

    In this work we report on the formation of lumpy Pd and Pt nanoparticles on fluorine-doped tin oxide/glass (FTO/glass) substrate by a laser-based approach. In general, complex-surface morphology metal nanoparticles can be used in several technological applications exploiting the peculiarities of their physical properties as modulated by nanoscale morphology. For example plasmonic metal nanoparticles presenting a lumpy morphology (i.e. larger particles coated on the surface by smaller particles) can be used in plasmonic solar cell devices providing broadband scattering enhancement over the smooth nanoparticles leading, so, to the increase of the device efficiency. However, the use of plasmonic lumpy nanoparticles remains largely unexplored due to the lack of simply, versatile, low-cost and high-throughput methods for the controllable production of such nanostructures. Starting from these considerations, we report on the observation that nanoscale-thick Pd and Pt films (17.6 and 27.9 nm, 12.1 and 19.5 nm, respectively) deposited on FTO/glass surface irradiated by nanosecond pulsed laser at fluences E in the 0.5-1.5 J/cm2 range, produce Pd and Pt lumpy nanoparticles on the FTO surface. In addition, using scanning electron microscopy analyses, we report on the observation that starting from each metal film of fixed thickness h, the fraction F of lumpy nanoparticles increases with the laser fluence E and saturates at the higher fluences. For each fixed fluence, F was found higher starting from the Pt films (at each starting film thickness h) with respect to the Pd films. For each fixed metal and fluence, F was found to be higher decreasing the starting thickness of the deposited film. To explain the formation of the lumpy Pd and Pt nanoparticles and the behavior of F as a function of E and h both for Pd and Pt, the thermodynamic behavior of the Pd and Pt films and nanoparticles due to the interaction with the nanosecond laser is discussed. In particular, the

  4. Effect of thickness on surface morphology, optical and humidity sensing properties of RF magnetron sputtered CCTO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Ahmadipour, Mohsen [Structural Materials Niche Area, School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Penang (Malaysia); Ain, Mohd Fadzil [School of Electrical and Electronic Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Penang (Malaysia); Ahmad, Zainal Arifin, E-mail: srzainal@usm.my [Structural Materials Niche Area, School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Penang (Malaysia)

    2016-11-01

    Highlights: • CCTO thin film was synthesized by RF magnetron sputtering successfully. • Increase in thickness lead to increase in grain size and decrease in band gap. • Short response times and recovery times of lead CCTO humidity sensor. • Sensor could detect humidity range (30–90%). - Abstract: In this study, calcium copper titanate (CCTO) thin films were deposited on ITO substrates successfully by radio frequency (RF) magnetron sputtering method in argon atmosphere. The CCTO thin films present a polycrystalline, uniform and porous structure. The surface morphology, optical and humidity sensing properties of the synthesized CCTO thin films have been studied by X-ray diffraction (XRD), atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), UV–vis spectrophotometer and current-voltage (I–V) analysis. XRD and AFM confirmed that the intensity of peaks and pore size of CCTO thin films were enhanced by increasing the thin films. Tauc plot method was adopted to estimate the optical band gaps. The surface structure and energy band gaps of the deposited films were affected by film thickness. Energy band gap of the layers were 3.76 eV, 3.68 eV and 3.5 eV for 200 nm, 400 nm, and 600 nm CCTO thin films layer, respectively. The humidity sensing properties were measured by using direct current (DC) analysis method. The response times were 12 s, 22 s, and 35 s while the recovery times were 500 s, 600 s, and 650 s for 200 nm, 400 nm, and 600 nm CCTO thin films, respectively at humidity range of 30–90% relative humidity (RH).

  5. Influence of thermal annealing on microstructural, morphological, optical properties and surface electronic structure of copper oxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Akgul, Funda Aksoy, E-mail: fundaaksoy01@gmail.com [Department of Physics, Nigde University, 51240 Nigde (Turkey); Center for Solar Energy Research and Applications, Middle East Technical University, 06800 Ankara (Turkey); Akgul, Guvenc, E-mail: guvencakgul@gmail.com [Bor Vocational School, Nigde University, 51700 Nigde (Turkey); Center for Solar Energy Research and Applications, Middle East Technical University, 06800 Ankara (Turkey); Yildirim, Nurcan [Department of Physics Engineering, Ankara University, 06100 Ankara (Turkey); Department of Metallurgical and Materials Engineering, Middle East Technical University, 06800 Ankara (Turkey); Unalan, Husnu Emrah [Department of Metallurgical and Materials Engineering, Middle East Technical University, 06800 Ankara (Turkey); Center for Solar Energy Research and Applications, Middle East Technical University, 06800 Ankara (Turkey); Turan, Rasit [Department of Physics, Middle East Technical University, 06800 Ankara (Turkey); Center for Solar Energy Research and Applications, Middle East Technical University, 06800 Ankara (Turkey)

    2014-10-15

    In this study, effect of the post-deposition thermal annealing on copper oxide thin films has been systemically investigated. The copper oxide thin films were chemically deposited on glass substrates by spin-coating. Samples were annealed in air at atmospheric pressure and at different temperatures ranging from 200 to 600°C. The microstructural, morphological, optical properties and surface electronic structure of the thin films have been studied by diagnostic techniques such as X-ray diffraction (XRD), Raman spectroscopy, ultraviolet–visible (UV–VIS) absorption spectroscopy, field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The thickness of the films was about 520 nm. Crystallinity and grain size was found to improve with annealing temperature. The optical bandgap of the samples was found to be in between 1.93 and 2.08 eV. Cupric oxide (CuO), cuprous oxide (Cu{sub 2}O) and copper hydroxide (Cu(OH){sub 2}) phases were observed on the surface of as-deposited and 600 °C annealed thin films and relative concentrations of these three phases were found to depend on annealing temperature. A complete characterization reported herein allowed us to better understand the surface properties of copper oxide thin films which could then be used as active layers in optoelectronic devices such as solar cells and photodetectors. - Highlights: • Effect of post-deposition annealing on copper oxide thin films was investigated. • Structural, optical, and electronic properties of the thin films were determined. • Oxidation states of copper oxide thin films were confirmed by XPS analysis. • Mixed phases of CuO and Cu{sub 2}O were found to coexist in copper oxide thin films.

  6. Structural, Morphological, and LPG Sensing Properties of Al-Doped ZnO Thin Film Prepared by SILAR

    Directory of Open Access Journals (Sweden)

    Shampa Mondal

    2013-01-01

    Full Text Available Undoped and aluminum doped zinc oxide (AZO thin films were deposited on glass substrates by successive ion layer adsorption and reaction (SILAR technique from ammonium zincate complex. The thin films are characterized by X-ray diffraction (XRD and scanning electron microscopy (SEM for their structural and morphological studies. Both undoped and Al-doped film show strong preferred c-axis orientation. The texture coefficient (TC of the film along (002 direction increases due to Al incorporation. SEM micrograph shows round shaped particles for pure ZnO. However AZO films show particles with off spherical shape and compact interconnected grains. Sensitivity of the film in presence of 80% LEL (lower explosive limit of LPG increases with temperature and is maximum at 325°C. Significantly high sensitivity of 87% with reasonably fast response was observed for 1% Al-doped ZnO (AZO film in presence of 1.6 vol% LPG at 325°C.

  7. Effect of spatial distribution of wax and PEG-isocyanate on the morphology and hydrophobicity of starch films.

    Science.gov (United States)

    Muscat, Delina; Adhikari, Raju; Tobin, Mark J; McKnight, Stafford; Wakeling, Lara; Adhikari, Benu

    2014-10-13

    This study proposes a novel method for improving surface hydrophobicity of glycerol plasticized high amylose (HAG) films. We used polyethylene glycol isocyanate (PEG-iso) crosslinker to link HAG and three natural waxes (beeswax, candelilla wax and carnauba wax) to produce HAG+wax+PEG-iso films. The spatial distributions of wax and PEG-iso across the thickness of these films were determined using Synchrotron-based Fourier transform infrared spectroscopy. The hydrophobicity and surface morphology of the films were determined using contact angle (CA) and scanning electron microscopic measurements, respectively. The distribution patterns of wax and the PEG-iso across the thickness of the film, and the nature of crystalline patterns formed on the surface of these films were found to be the key factors affecting surface hydrophobicity. The highest hydrophobicity (CA >90°) was created when the PEG-iso was primarily distributed in the interior of the films and a hierarchical circular pinnacle structure of solidified wax was formed on the surface.

  8. Morphology and Optical Properties of Zinc Oxide Films Grown on Metal Coated Glass Substrates by Aqueous Chemical Growth

    Science.gov (United States)

    Bakar, M. A.; Hamid, M. A. A.; Jalar, A.; Shamsudin, R.

    2013-04-01

    Zinc oxide films were deposited on three different metal coated substrates (gold, nickel and platinum) by aqueous chemical growth method. This paper discusses the effect of metal coated substrates on the morphology and optical properties of grown ZnO films. X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM) and UV-visible spectroscopy (UV-vis) were employed to characterize the samples. All the as-deposited ZnO films exhibit crystalline hexagonal wurzite structure. The crystallite size of the ZnO films were in the range of 29 to 32 nm. FESEM micrographs revealed hexagonal rod, oval-like and flower-like ZnO structures formed on all metal coated substrates. The Pt coated film contains higher density hexagonal rod as compared to others metal coated substrate. Most probably the Pt lattice parameter is the nearest to ZnO compared to nickel and gold. The optical band gap energy, Eg of ZnO films were estimated to be 3.30 eV which is near to bulk Eg, 3.37 eV. This indicates that the ZnO grown by aqueous chemical growth is able to produce similar quality properties to other conventional method either films or bulk size.

  9. Controlled delamination of metal films by hydrogen loading

    Energy Technology Data Exchange (ETDEWEB)

    Nikitin, Eugen

    2008-11-18

    n this work we quantitatively determine the adhesion energy between metal films and their substrates. Therefore a new controlled buckling technique is established, applying the strong compressive in-plane stress that results in thin films clamped on rigid substrates during hydrogen loading. When the elastic energy stored in the H-loaded thin film exceeds the adhesion energy between film and substrate, delamination occurs. At the onset of delamination, a critical hydrogen concentration, a critical stress value and a critical bending of the substrate are present, which are quantitative measures for the adhesion energy and permit its calculation. As the critical values are determined at the onset of delamination, plastic deformation is negligible, which denies the quantitative determination of adhesion energies in conventional test setups. In multilayer-systems, adhesion energies between substrates and films that hardly absorb hydrogen can be measured by the controlled buckling technique, when the films of interest are coated with hydrogen absorbing films (active layer). The measurements are performed easily and can be repeated under the same test conditions, while variables such as the thickness of the coating materials or the boundary surface structure can be varied and optimized. In this work the adhesion energies of different materials on polycarbonate and niobium on sapphire are investigated. (orig.)

  10. Electrospinning of nickel oxide nanofibers: Process parameters and morphology control

    Energy Technology Data Exchange (ETDEWEB)

    Khalil, Abdullah, E-mail: akhalil@masdar.ac.ae; Hashaikeh, Raed, E-mail: rhashaikeh@masdar.ac.ae

    2014-09-15

    In the present work, nickel oxide nanofibers with varying morphology (diameter and roughness) were fabricated via electrospinning technique using a precursor composed of nickel acetate and polyvinyl alcohol. It was found that the diameter and surface roughness of individual nickel oxide nanofibers are strongly dependent upon nickel acetate concentration in the precursor. With increasing nickel acetate concentration, the diameter of nanofibers increased and the roughness decreased. An optimum concentration of nickel acetate in the precursor resulted in the formation of smooth and continuous nickel oxide nanofibers whose diameter can be further controlled via electrospinning voltage. Beyond an optimum concentration of nickel acetate, the resulting nanofibers were found to be ‘flattened’ and ‘wavy’ with occasional cracking across their length. Transmission electron microscopy analysis revealed that the obtained nanofibers are polycrystalline in nature. These nickel oxide nanofibers with varying morphology have potential applications in various engineering domains. - Highlights: • Nickel oxide nanofibers were synthesized via electrospinning. • Fiber diameter and roughness depend on nickel acetate concentration used. • With increasing nickel acetate concentration the roughness of nanofibers decreased. • XRD and TEM revealed a polycrystalline structure of the nanofibers.

  11. The effects of deposition time on surface morphology, structural, electrical and optical properties of sputtered Ag-Cu thin films

    Science.gov (United States)

    Ahmadpourian, Azin; Luna, Carlos; Boochani, Arash; Arman, Ali; Achour, Amine; Rezaee, Sahare; Naderi, Sirvan

    2016-10-01

    The preparation of designed nanostructured thin films combining nano grains of different compositions and physical properties represents a promising avenue for the exploration of novel collective behaviors with technological potentials. Herein, nanostructured Ag-Cu thin films with different surface morphology properties were grown by magnetron sputtering varying the deposition time (4-24 min) and fixing the other deposition conditions. X-ray diffraction studies corroborated that Cu and Ag tend to appear as separated phases with nanometric sizes due to the fact that these elements are rather immiscible. The deposited Cu tended to be partially oxidized with crystal sizes of several tens of nm, whereas the deposited Ag phase displayed a poor crystallinity with an average crystal size of around 3nm. However, at deposition time of few minutes, the formation of Ag-Cu crystals with a preferable crystallization orientation along the [111] direction was detected. The surface morphology of the obtained thin films was studied by atomic force microscopy determining the surface roughness and average particle sizes of the samples. These parameters were correlated with the plasmon resonance extinction bands of the different Ag-Cu films and their electrical properties, providing a reproducible route to obtain thin films with tuned electrical resistances and optical properties.

  12. The influence of substrate temperature on the structure and morphology of sexiphenyl thin films on Au(111)

    Energy Technology Data Exchange (ETDEWEB)

    Muellegger, S.; Haber, T.; Frank, P.; Resel, R.; Winkler, A. [Graz University of Technology, Institute of Solid State Physics, Graz (Austria); Hlawacek, G.; Teichert, C. [University of Leoben, Institute of Physics, Leoben (Austria)

    2007-04-15

    The layer growth of ultra-thin films of sexiphenyl on Au(111) has been studied as a function of substrate temperature under well-defined ultra-high-vacuum conditions. In situ X-ray photoelectron spectroscopy in combination with thermal desorption spectroscopy was applied to reveal the kinetics of layer growth and recrystallisation. Ex situ atomic force microscopy and X-ray diffraction were used to determine the film morphology and film structure. A continuous small-grain film is obtained at 93 K. The crystalline structure of the grains has been confirmed by X-ray diffraction. However, the grains are not preferentially oriented with respect to the substrate. Around room temperature, recrystallisation takes place and the molecules within the crystallites orient parallel to the substrate surface. Further small substrate temperature changes during growth lead to further changes of the film morphology and to reorientation of the crystallites. However, the molecules in the crystallites stay aligned parallel to the surface. At temperatures greater than 350 K, terraced islands of standing molecules are observed, in addition to needle-like islands with flat-lying molecules. (orig.)

  13. Air-stable solution-processed n-channel organic thin film transistors with polymer-enhanced morphology

    Energy Technology Data Exchange (ETDEWEB)

    He, Zhengran; Shaik, Shoieb; Bi, Sheng; Li, Dawen, E-mail: dawenl@eng.ua.edu [Department of Electrical and Computer Engineering, Center for Materials for Information Technology, The University of Alabama, Tuscaloosa, Alabama 35487 (United States); Chen, Jihua [Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2015-05-04

    N,N′-1H,1H-perfluorobutyl dicyanoperylenecarboxydiimide (PDIF-CN{sub 2}) is an n-type semiconductor exhibiting high electron mobility and excellent air stability. However, the reported electron mobility based on spin-coated PDIF-CN{sub 2} film is much lower than the value of PDIF-CN{sub 2} single crystals made from vapor phase deposition, indicating significant room for mobility enhancement. In this study, various insulating polymers, including poly(vinyl alcohol), poly(methyl methacrylate) (PMMA), and poly(alpha-methylstyrene) (PαMS), are pre-coated on silicon substrate aiming to enhance the morphology of the PDIF-CN{sub 2} thin film, thereby improving the charge transport and air stability. Atomic force microscopy images reveal that with the pre-deposition of PαMS or PMMA polymers, the morphology of the PDIF-CN{sub 2} polycrystalline films is optimized in semiconducting crystal connectivity, domain size, and surface roughness, which leads to significant improvement of organic thin-film transistor (OTFT) performance. Particularly, an electron mobility of up to 0.55 cm{sup 2}/V s has been achieved from OTFTs based on the PDIF-CN{sub 2} film with the pre-deposition of PαMS polymer.

  14. Morphology and Structure Properties of Boron-doped Diamond Films Prepared by Hot Cathode Direct Current Plasma Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    Mengmei PAN

    2016-05-01

    Full Text Available Boron-doped diamond (BDD films were deposited by hot cathode direct current plasma chemical vapor deposition (HCDC-PCVD according to various mixture ratios of CH4/H2/B(OCH33 gas. The Raman performances and surface morphologies of the BDD films were then characterized by Raman spectroscopy and scanning electron microscopy (SEM. Results indicated that the flow rate of B(OCH33 had marked effects on the growth characteristics of the produced boron-doped diamond films. The presence and concentration of the doped boron atoms significantly altered both the surface morphologies and structures of the diamond films. With increasing flow rate of B(OCH33, the crystal grain surfaces became smooth as visible under SEM. The B-doping levels in these films increased from 1.75×1019cm-3 to a maximum of 2.4×1021cm-3, estimated from the Raman spectra. DOI: http://dx.doi.org/10.5755/j01.ms.22.2.12923

  15. Structural, morphological and mechanical properties of niobium nitride thin films grown by ion and electron beams emanated from plasma

    Science.gov (United States)

    Siddiqui, Jamil; Hussain, Tousif; Ahmad, Riaz; Umar, Zeeshan A.; Abdus Samad, Ubair

    2016-05-01

    The influence of variation in plasma deposition parameters on the structural, morphological and mechanical characteristics of the niobium nitride films grown by plasma-emanated ion and electron beams are investigated. Crystallographic investigation made by X-ray diffractometer shows that the film synthesized at 10 cm axial distance with 15 plasma focus shots (PFS) exhibits better crystallinity when compared to the other deposition conditions. Morphological analysis made by scanning electron microscope reveals a definite granular pattern composed of homogeneously distributed nano-spheroids grown as clustered particles for the film synthesized at 10 cm axial distance for 15 PFS. Roughness analysis demonstrates higher rms roughness for the films synthesized at shorter axial distance and by greater number of PFS. Maximum niobium atomic percentage (35.8) and maximum average hardness (19.4 ± 0.4 GPa) characterized by energy-dispersive spectroscopy and nano-hardness analyzer respectively are observed for film synthesized at 10 cm axial distance with 15 PFS.

  16. Effect of sol temperature on structural, morphological and magnetic properties of PZT thin films on alumina substrate

    Science.gov (United States)

    Sreelalitha, K.; Thyagarajan, K.

    2016-01-01

    In the present study, we investigate the structural, morphological and magnetic properties of sol-gel spin-coated PZT thin films on alumina substrate. The morphotropic phase boundary (MPB) of PZT [Pb (Zr1-xTix)03] between the tetragonal and rhombohedral phases occurs at the Zr/Ti ratio of 52/48. At the MPB the physical properties of PZT are of far-reaching importance due to their possible crystalline phases. In this study Pb(Zr0.52Ti0.48)03 sols are prepared at room temperature and at 125 °C. The gels are coated onto alumina substrate using a spin-coating unit as two and three layers. The structural studies using XRD confirm the perovskite phase formation at an annealing temperature of 660 °C for both films. The structural parameter grain size, dislocation density, lattice parameters and strain were dependent on the sol temperature. The SEM morphology of the samples represents well-developed dense grain structure and thickness in micrometer ranges. The VSM analysis shows diamagnetic and ferromagnetic hysteresis loop. The ferromagnetism at low fields in PZT films is confirmed by studying the magnetic properties of powder made of the same gel. The effect of heat treatment on the gel preparation is observed on structural, morphological and magnetic properties of PZT thin films. The ferromagnetism in PZT can be attributed to oxygen vacancies. The squareness ratio of the films shows the application of the films as a high-density recording medium.

  17. Investigating the effect of capping layers on final thin film morphology after a dewetting process

    Science.gov (United States)

    White, Benjamin C.

    Nanoparticles on a substrate have numerous applications in nanotechnology, from enhancements to solar cell efficiency to improvements in carbon nanotube growth. Producing nanoparticles in a cheap fashion with some control over size and spacing is difficult to do, but desired. This work presents a novel method for altering the radius and pitch distributions of nickel and gold nanoparticles in a scalable fashion. The introduction of alumina capping layers to thin nickel films during a pulsed laser-induced dewetting process has yielded reductions in the mean and standard deviation of radii and pitch for dewet nanoparticles. Carbon nanotube mats grown on these samples show a much thicker mat for the capped case. The same capping layers have produced an opposite effect of increased nanoparticle size and spacing during a solid state dewetting process of a gold film. These results also show a decrease in the magnitude of the effect as the capping layer thickness increases. Since the subject of research interest for using these nanoparticles has shifted towards producing ordered arrays with size and spacing control, the uncertainty in the values of these distributions needs to be quantified for any form of meaningful comparison to be made between fabrication methods. Presented here is a first step in the uncertainty analysis of such samples via synthetic images producing error distributions.

  18. Morphology control of polymer: Fullerene solar cells by nanoparticle self-assembly

    Science.gov (United States)

    Zhang, Wenluan

    During the past two decades, research in the field of polymer based solar cells has attracted great effort due to their simple processing, mechanical flexibility and potential low cost. A standard polymer solar cell is based on the concept of a bulk-heterojunction composed of a conducting polymer as the electron donor and a fullerene derivative as the electron acceptor. Since the exciton lifetime is limited, this places extra emphasis on control of the morphology to obtain improved device performance. In this thesis, detailed characterization and novel morphological design of polymer solar cells was studied, in addition, preliminary efforts to transfer laboratory scale methods to industrialized device fabrication was made. Magnetic contrast neutron reflectivity was used to study the vertical concentration distribution of fullerene nanoparticles within poly(2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2- b]thiophene (pBTTT) thin film. Due to the wide space between the side chains of polymer, these fullerene nanoparticles intercalate between them creating a stable co-crystal structure. Therefore, a high volume fraction of fullerene was needed to obtain optimal device performance as phase separated conductive pathways are required and resulted in a homogeneous fullerene concentration profile through the film. Small angle neutron scattering was used to find there is amorphous fullerene even at lower concentration since it was previously believed that all fullerene formed a co-crystal. These fullerene molecules evolve into approximately 15 nm sized agglomerates at higher concentrations to improve electron transport. Unfortunately, thermal annealing gives these agglomerates mobility to form micrometer sized crystals and reduce the device performance. In standard poly(3-hexylthiophene) (P3HT):[6,6]-phenyl-C61-butyric acid methyl ester (PCMBM) solar cells, a higher concentration of PCBM at the cathode interface is desired due to the band alignment structure. This was

  19. Investigation on the Optical and Surface Morphology of Conjugated Polymer MEH-PPV:ZnO Nanocomposite Thin Films

    OpenAIRE

    Nurul Zayana Yahya; Mohamad Rusop

    2012-01-01

    Thin films of red color poly(2-methoxy-5(2′-ethylhexyloxy)-phenylene vinylene) (MEH-PPV) containing different weight percent of ZnO nanoparticles were obtained by spin-coating techniques. The MEH-PPV:ZnO solutions were spin coated onto silicon and glass substrates. The spun MEH-PPV:ZnO thin films were then used to investigate optical properties by using ultraviolet-visible spectrometer (UV-Vis) and photoluminescence spectrophotometer (PL). The morphologies were investigated by using field emi...

  20. Effect of Annealing Temperature on the Formation of Silicides and the Surface Morphologies of PtSi Films

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The effect of annealing temperature on the formation of the PtSi phase, distribution of silicides and the surface morphologies of silicides films is investigated by XPS, AFM. It is shown that the phase sequences of the films change from Pt-Pt2Si-PtSi-Si to Pt+Pt2Si+PtSi-PtSi-Si or Pt+Pt2Si+PtSi-PtSi-Si with an increase of annealing temperature and the reason for the formation of mixed layers is discussed.

  1. Interface morphology studies of liquid phase epitaxy grown HgCdTe films by atomic force microscopy

    Science.gov (United States)

    Azoulay, M.; George, M. A.; Burger, A.; Collins, W. E.; Silberman, E.

    1994-04-01

    In this paper we report an investigation of the morphology of the interfaces of liquid phase epitaxy (LPE) grown HgCdTe thin films on CdTe and CdZnTe substrates by atomic force microscopy (AFM) on freshly cleaved (110) crystallographic planes. An empirical observation which may be linked to lattice mismatch was indicated by an angle between the cleavage steps of the substrate to those of the film. The precipitates with size ranging from 5 nm to 20 nm were found to be most apparent near the interface.

  2. Light scattering effect of ITO:Zr/AZO films deposited on periodic textured glass surface morphologies for silicon thin film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, Shahzada Qamar [Sungkyunkwan University, Department of Energy Science, Suwon (Korea, Republic of); COMSATS Institute of Information Technology, Department of Physics, Lahore (Pakistan); Kwon, Gi Duk; Kim, Sunbo; Balaji, Nagarajan; Shin, Chonghoon; Kim, Sangho; Khan, Shahbaz; Pribat, Didier [Sungkyunkwan University, Department of Energy Science, Suwon (Korea, Republic of); Ahn, Shihyun; Le, Anh Huy Tuan; Park, Hyeongsik; Raja, Jayapal; Lee, Youn-Jung [Sungkyunkwan University, College of Information and Communication Engineering, Suwon (Korea, Republic of); Razaq, Aamir [COMSATS Institute of Information Technology, Department of Physics, Lahore (Pakistan); Velumani, S. [Sungkyunkwan University, College of Information and Communication Engineering, Suwon (Korea, Republic of); Department of Electrical Engineering (SEES), Mexico City (Mexico); Yi, Junsin [Sungkyunkwan University, Department of Energy Science, Suwon (Korea, Republic of); Sungkyunkwan University, College of Information and Communication Engineering, Suwon (Korea, Republic of)

    2015-09-15

    Various SF{sub 6}/Ar plasma-textured periodic glass surface morphologies for high transmittance, haze ratio and low sheet resistance of ITO:Zr films are reported. The SF{sub 6}/Ar plasma-textured glass surface morphologies were changed from low aspect ratio to high aspect ratio with the increase in RF power from 500 to 600 W. The micro- and nano-size features of textured glass surface morphologies enhanced the haze ratio in visible as well as NIR wavelength region. Micro-size textured features also influenced the sheet resistance and electrical characteristics of ITO:Zr films due to step coverage. The ITO:Zr/AZO bilayer was used as front TCO electrode for p-i-n amorphous silicon thin film solar cells with current density-voltage characteristics as: V{sub oc} = 875 mV, FF = 70.90 %, J{sub sc} = 11.31 mA/cm{sup 2}, η = 7.02 %. (orig.)

  3. Correlation of film morphology and defect content with the charge-carrier transport in thin-film transistors based on ZnO nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Polster, S. [Chair of Electron Devices, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Cauerstrasse 6, 91058 Erlangen (Germany); Jank, M. P. M. [Fraunhofer Institute for Integrated Systems and Device Technology, Schottkystrasse 10, 91058 Erlangen (Germany); Frey, L. [Chair of Electron Devices, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Cauerstrasse 6, 91058 Erlangen (Germany); Fraunhofer Institute for Integrated Systems and Device Technology, Schottkystrasse 10, 91058 Erlangen (Germany)

    2016-01-14

    The correlation of defect content and film morphology with the charge-carrier transport in field-effect devices based on zinc oxide nanoparticles was investigated. Changes in the defect content and the morphology were realized by annealing and sintering of the nanoparticle thin films. Temperature-dependent electrical measurements reveal that the carrier transport is thermally activated for both the unsintered and sintered thin films. Reduced energetic barrier heights between the particles have been determined after sintering. Additionally, the energetic barrier heights between the particles can be reduced by increasing the drain-to-source voltage and the gate-to-source voltage. The changes in the barrier height are discussed with respect to information obtained by scanning electron microscopy and photoluminescence measurements. It is found that a reduction of surface states and a lower roughness at the interface between the particle layer and the gate dielectric lead to lower barrier heights. Both surface termination and layer morphology at the interface affect the barrier height and thus are the main criteria for mobility improvement and device optimization.

  4. Structural, morphological and electronic study of CVD SnO{sub 2}:Sb films

    Energy Technology Data Exchange (ETDEWEB)

    Haireche, S.; Boumeddiene, A. [Laboratoire LASICOM, Faculté des Sciences, Université Saâd Dahlab de Blida (Algeria); Guittoum, A. [Centre de Recherche Nucléaire d' Alger (CRNA), Alger 16000 (Algeria); El Hdiy, A. [Laboratoire LMEN, Universite de Reims Champagne ardenne, Reims, Cedex 2 (France); Boufelfel, A., E-mail: ahboufelfel@gmail.com [Laboratoire de physique, Université du 08 mai 45, Guelma 24000 (Algeria)

    2013-05-15

    We have prepared solid thin film samples of SnO{sub 2}:Sb in different ratios using atmospheric pressure chemical vapour deposition technique APCVD. The chemical composition was determined with Rutherford Backscattering Spectroscopy (RBS) within an error of 1%. X-ray diffraction was used to study the influence of Sb concentration on the lattice parameters and preferred orientations. We have found that sample of concentration 4% showed a (200) preferred orientation. The AFM and SEM images showed that the surface roughness of our samples was influenced by the doping concentrations. The lowest electrical surface resistance was 8.0 Ω □{sup −1} for a 3% concentration sample. We found that the contribution to the metallic state is influenced by oxygen vacancy and Sb doping. Also, the sample of good electrical conductive property has an optical gap of 3.60 eV band at room temperature. - Highlights: ► The thickness was a nonlinear function of the reaction time. ► Minimal value of 8.0 Ω □{sup −1} for a 3% concentration and 3.60 eV energy gap. ► Surface morphology is dopant dependant.

  5. Surface morphology of refractive-index waveguide gratings fabricated in polymer films

    Science.gov (United States)

    Dong, Yi; Song, Yan-fang; Ma, Lei; Gao, Fang-fang

    2016-09-01

    The characteristic modifications are reported on the surface of polymeric waveguide film in the process of volume- grating fabrication. The light from a mode-locked 76 MHz femtosecond laser with pulse duration of 200 fs and wavelength of 800 nm is focused normal to the surface of the sample. The surface morphology modifications are ascribed to a fact that surface swelling occurs during the process. Periodic micro-structure is inscribed with increasing incident power. The laser-induced swelling threshold on the grating, which is higher than that of two-photon initiated photo-polymerization (TPIP) (8 mW), is verified to be about 20 mW. It is feasible to enhance the surface smoothness of integrated optics devices for further encapsulation. The variation of modulation depth is studied for different values of incident power and scan spacing. Ablation accompanied with surface swelling appears when the power is higher. By optimizing the laser carving parameters, highly efficient grating devices can be fabricated.

  6. Effects of Solution-Based Fabrication Conditions on Morphology of Lead Halide Perovskite Thin Film Solar Cells

    Directory of Open Access Journals (Sweden)

    Jeremy L. Barnett

    2016-01-01

    Full Text Available We present a critical review of the effects of processing conditions on the morphology of methylammonium lead iodide (CH3NH3PbI3 perovskite solar cells. Though difficult to decouple from synthetic and film formation effects, a single morphological feature, specifically grain size, has been evidently linked to the photovoltaic performance of this class of solar cells. Herein, we discuss experimental aspects of optimizing the (a temperature and time of annealing, (b spin-coating parameters, and (c solution temperature of methylammonium iodide (MAI solution.

  7. Exceptional Morphology-Preserving Evolution of Formamidinium Lead Triiodide Perovskite Thin Films via Organic-Cation Displacement.

    Science.gov (United States)

    Zhou, Yuanyuan; Yang, Mengjin; Pang, Shuping; Zhu, Kai; Padture, Nitin P

    2016-05-04

    Here we demonstrate a radically different chemical route for the creation of HC(NH2)2PbI3 (FAPbI3) perovskite thin films. This approach entails a simple exposure of as-synthesized CH3NH3PbI3 (MAPbI3) perovskite thin films to HC(═NH)NH2 (formamidine or FA) gas at 150 °C, which leads to rapid displacement of the MA(+) cations by FA(+) cations in the perovskite structure. The resultant FAPbI3 perovskite thin films preserve the microstructural morphology of the original MAPbI3 thin films exceptionally well. Importantly, the myriad processing innovations that have led to the creation of high-quality MAPbI3 perovskite thin films are directly adaptable to FAPbI3 through this simple, rapid chemical-conversion route. Accordingly, we show that efficiencies of perovskite solar cells fabricated with FAPbI3 thin films created using this route can reach ∼18%.

  8. Exceptional Morphology-Preserving Evolution of Formamidinium Lead Triiodide Perovskite Thin Films via Organic-Cation Displacement

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yuanyuan; Yang, Mengjin; Pang, Shuping; Zhu, Kai; Padture, Nitin P.

    2016-05-04

    Here we demonstrate a radically different chemical route for the creation of HC(NH2)2PbI3 (FAPbI3) perovskite thin films. This approach entails a simple exposure of as-synthesized CH3NH3PbI3 (MAPbI3) perovskite thin films to HC(=NH)NH2 (formamidine or FA) gas at 150 degrees C, which leads to rapid displacement of the MA+ cations by FA+ cations in the perovskite structure. The resultant FAPbI3 perovskite thin films preserve the microstructural morphology of the original MAPbI3 thin films exceptionally well. Importantly, the myriad processing innovations that have led to the creation of high-quality MAPbI3 perovskite thin films are directly adaptable to FAPbI3 through this simple, rapid chemical-conversion route. Accordingly, we show that efficiencies of perovskite solar cells fabricated with FAPbI3 thin films created using this route can reach -18%.

  9. Preparation and investigation of optical, structural, and morphological properties of nanostructured ZnO:Mn thin films

    Indian Academy of Sciences (India)

    E Amoupour; F E Ghodsi; H Andarva; A Abdolahzadeh Ziabari

    2013-08-01

    Nanostructured ZnO:Mn thin films have been prepared by sol–gel dip coating method. The content of Mn in the sol was varied from 0 to 12 wt%. The effect of Mn concentration on the optical, structural, and morphological properties of ZnO thin films were studied by using Fourier transform infrared (FTIR), UV–visible and photoluminescence (PL) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD results showed that the films have hexagonal wurtzite structure at lower content of Mn. The diffraction peaks corresponding to ZnO disappeared and two diffraction peaks of MnO2 and Mn3O4 appeared at the highest value of doping concentration (viz., 12 wt\\%). SEM results revealed that the surface smoothness of the films improved at higher content of Mn. The optical band gap of the films decreased from 3.89 to 3.15 eV when the Mn concentration increased from 0 to 12 wt\\%. The PL spectra of the films showed the characteristic peaks linked to band-to-band, green and yellow emissions. Besides, the PL intensity of the samples decreased with increase in Mn concentration.

  10. Effects of temperature on the morphology and optical properties of ZnS thin films deposited by chemical bath

    Science.gov (United States)

    Martín-Várguez, P. E.; Ceh, O.; González-Panzo, I. J.; Tec-Yam, S.; Patiño, R.; Oliva, A. I.

    2013-06-01

    Zinc sulphide thin films were deposited on Corning glass substrates by the chemical bath deposition technique at different temperatures. The influence of the bath temperature and deposition time on the morphological and optical properties of the ZnS films are herein investigated. ZnS films were deposited by changing the bath-temperature from 50 °C to 90 °C, and deposition times from 60 to 160 min. Thin and transparent films were obtained with thicknesses from 10 to 90 nm with the increment of the bath temperature, meanwhile the band gap energy Eg values diminishes from 4.15 to 3.4 eV. The quality of the ZnS film surfaces was also influenced by increasing the bath temperature, as showed by the reduced grain size and the increase of roughness, obtained from atomic force microscopy images. ZnS films of good optical quality were obtained at 90 °C with a mean value of Eg = 3.56 ± 0.03 eV.

  11. Characterization and morphology analysis of degradable poly(L-lactide) film in in-vitro gastric juice incubation

    Science.gov (United States)

    Chang, Hao-Ming; Huang, Chun-Chiang; Tsai, Hsieh-Chih; Imae, Toyoko; Hong, Po-Da

    2012-12-01

    The purpose of this study was to evaluate the use of the biodegradable poly(L-lactide) (PLLA) as a gastro-jejunal tube anchored in the duodenum for duodenal exclusion. PLLA film was fabricated using a hot melting process to a thickness of around 40-50 μm and was then immersed in human gastric juice to estimate the in vitro biodegradability behavior. PLLA film was more biodegradable in human gastric juice than in HCl and PBS. Measurements of weight loss indicated that 60% of original the PLLA was lost after 42 days of incubation. Surface functional group characterization, thermal stability, and surface morphology of the degraded PLLA film in human gastric juice showed that the decomposed sections of the PLLA film were primarily from the amorphous region. The degradation of the PLLA film in human gastric juice began with the erosion of continuous nanocavities in the range of 100-200 nm on the PLLA surface over the course of 21 days. The PLLA film collapsed and spiral PLLA fiber was obtained after 42 days of decomposing in human gastric juice.

  12. Glancing angle deposition of SiO{sub 2} thin film microstructures: Investigations of optical and morphological properties

    Energy Technology Data Exchange (ETDEWEB)

    Tokas, R. B., E-mail: tokasstar@gmail.com, E-mail: tokasstar@gmail.com; Jena, S., E-mail: tokasstar@gmail.com, E-mail: tokasstar@gmail.com; Sarkar, P., E-mail: tokasstar@gmail.com, E-mail: tokasstar@gmail.com; Thakur, S., E-mail: tokasstar@gmail.com, E-mail: tokasstar@gmail.com; Sahoo, N. K., E-mail: tokasstar@gmail.com, E-mail: tokasstar@gmail.com [Atomic and Molecular Physics Division, Bhabha Atomic Research Centre, Mumbai-400085 (India)

    2014-04-24

    In present work, the optical and the morphological properties of micro-structured SiO{sub 2} thin films fabricated by using glancing angle deposition (GLAD) technique has been carried out. The results are compared with the normally deposited SiO{sub 2} films for the gained advantages. The influence of the glancing angle on the refractive index of porous SiO{sub 2} film was investigated by the spectral transmission measurement in 400–950 nm wavelength regimes. The refractive index has been found to be 1.14@532 nm for the porous SiO{sub 2} film deposited at a glancing angle of 85°. The density and surface qualities of these samples were primarily investigated by using grazing angle X-ray reflectivity (GIXR) and atomic force microscope (AFM) measurements. Results indicate a substantial decrease in film density and refractive index and increase in surface roughness and grain size for GLAD SiO{sub 2} compared to normally deposited SiO{sub 2} films.

  13. High-Efficiency Nonfullerene Polymer Solar Cell Enabling by Integration of Film-Morphology Optimization, Donor Selection, and Interfacial Engineering.

    Science.gov (United States)

    Zhang, Xin; Li, Weiping; Yao, Jiannian; Zhan, Chuanlang

    2016-06-22

    Carrier mobility is a vital factor determining the electrical performance of organic solar cells. In this paper we report that a high-efficiency nonfullerene organic solar cell (NF-OSC) with a power conversion efficiency of 6.94 ± 0.27% was obtained by optimizing the hole and electron transportations via following judicious selection of polymer donor and engineering of film-morphology and cathode interlayers: (1) a combination of solvent annealing and solvent vapor annealing optimizes the film morphology and hence both hole and electron mobilities, leading to a trade-off of fill factor and short-circuit current density (Jsc); (2) the judicious selection of polymer donor affords a higher hole and electron mobility, giving a higher Jsc; and (3) engineering the cathode interlayer affords a higher electron mobility, which leads to a significant increase in electrical current generation and ultimately the power conversion efficiency (PCE).

  14. Exploiting the hierarchical morphology of single-walled and multi-walled carbon nanotube films for highly hydrophobic coatings

    Directory of Open Access Journals (Sweden)

    Francesco De Nicola

    2015-02-01

    Full Text Available Self-assembled hierarchical solid surfaces are very interesting for wetting phenomena, as observed in a variety of natural and artificial surfaces. Here, we report single-walled (SWCNT and multi-walled carbon nanotube (MWCNT thin films realized by a simple, rapid, reproducible, and inexpensive filtration process from an aqueous dispersion, that was deposited at room temperature by a dry-transfer printing method on glass. Furthermore, the investigation of carbon nanotube films through scanning electron microscopy (SEM reveals the multi-scale hierarchical morphology of the self-assembled carbon nanotube random networks. Moreover, contact angle measurements show that hierarchical SWCNT/MWCNT composite surfaces exhibit a higher hydrophobicity (contact angles of up to 137° than bare SWCNT (110° and MWCNT (97° coatings, thereby confirming the enhancement produced by the surface hierarchical morphology.

  15. Controlling film topography to form highly hydrophobic waterborne coatings.

    Science.gov (United States)

    López, Ana B; de la Cal, José C; Asua, José M

    2016-08-17

    Coatings have a tremendous impact on economy as they reduce corrosion that has an estimated cost of 3% of the world's GDP. Hydrophobic coatings are particularly efficient for this purpose and the challenge is to produce cost effective and environmentally friendly, highly hydrophobic, cohesive and non-porous coatings applicable to large and irregular surfaces. This work shows that this goal can be achieved by forming wrinkles on the surface of waterborne coatings through fine-tuning of the film forming conditions. The proof of concept was demonstrated by using waterborne dispersions of copolymers of 1H,1H,2H,2H-perfluorodecyl acrylate and 2-ethylhexyl acrylate, and using the temperature and hardness of the copolymer as control variables during film formation. This allowed the formation of transparent films with a wrinkled surface that had a contact angle of 133°, which represents an increase of 20° with respect to the film cast under standard conditions.

  16. On the future of controllable fluid film bearings

    DEFF Research Database (Denmark)

    Santos, Ilmar

    2011-01-01

    This work gives an overview of the theoretical and experimental achievements of mechatronics applied to fluid film bearings. Compressible and uncompressible fluids are addressed. Rigid and elastic (deformable) bearing profiles are investigated. Hydraulic, pneumatic, magnetic and piezoelectric...... controllable fluid film bearings is to improve the overall machine performance by: controlling the lateral vibration of rigid and flexible rotating shafts; modifying bearing dynamic characteristics, such as stiffness and damping properties; increasing the rotational speed ranges by enhancing damping...... and eliminating instability problems, for example, by compensating cross-coupling destabilizing effects; reducing start-up torque and energy dissipation in bearings; compensating thermal effects. It is shown that such controllable fluid film bearings can act as “smart” machine components and be applied...

  17. Structural and morphological modifications of the Co-thin films caused by magnetic field and pH variation

    Energy Technology Data Exchange (ETDEWEB)

    Franczak, Agnieszka [LISM EA 4695, Universite de Reims Champagne-Ardenne, UFR Sciences et Naturelles, Bat. 6, Moulin de la Housse, BP 1039, 51687 Reims Cedex 2 (France); Levesque, Alexandra, E-mail: alexandra.levesque@univ-reims.fr [LISM EA 4695, Universite de Reims Champagne-Ardenne, UFR Sciences et Naturelles, Bat. 6, Moulin de la Housse, BP 1039, 51687 Reims Cedex 2 (France); Bohr, Frederic; Douglade, Jacques; Chopart, Jean-Paul [LISM EA 4695, Universite de Reims Champagne-Ardenne, UFR Sciences et Naturelles, Bat. 6, Moulin de la Housse, BP 1039, 51687 Reims Cedex 2 (France)

    2012-09-01

    Highlights: Black-Right-Pointing-Pointer Co electrodeposits were obtained at high electrolyte temperature under applied magnetic field. Black-Right-Pointing-Pointer The temperature is commonly used in the industrial process. Black-Right-Pointing-Pointer The effects of magnetic field up to 1 T and pH on structure and morphology were investigated. Black-Right-Pointing-Pointer The high process temperature enhances HER which is diminishing by the magnetic field application. - Abstract: Cobalt films were deposited by use of the electrochemical process from a cobalt (II) sulfate solution on a titanium electrode and characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD). The experiments at electrolyte temperature of 50 Degree-Sign C were performed which is commonly used in the industrial process. The effects of pH and low uniform magnetic field up to 1 T on structure and morphology changes were investigated. The detected phase composition indicates the presence of both phases: hexagonal centered packed and face centered cubic independent on the pH value and the applied magnetic field amplitude. Calculation of the orientation index of Co phase shows the preferential orientation in the films obtained at higher pH. SEM micro-imagines have shown the nucleus shape transition from coarse-grained to needle-shaped dependent on the application of B-field as well as on the pH variation in the case of higher pH level. Co-films obtained from the electrolyte of low pH were characterized by the fine-grained morphology which was not modified by the influence of magnetic field. AFM images proved the effect on roughness of the Co-films which is closely related with the obtained morphology.

  18. Spectroscopic, morphological and electrochromic characterization of layer-by-layer hybrid films of polyaniline and hexaniobate nanoscrolls

    OpenAIRE

    Silva, Claudio H. B.; Galiote, Nelson A.; Huguenin,Fritz; Teixeira-Neto, Erico; Constantino, Vera R. L.; Marcia L. A. Temperini

    2012-01-01

    The combination of semiconducting oxides and polyaniline in the nanoscale range may result in hybrid materials having enhanced properties, such as electrochromism and charge capacity. This paper reports the spectroscopic, morphological and electrochromic characterization of hybrid films made up of hexaniobate one-dimensional (1D) nanoscrolls and polyaniline prepared by the layer-by-layer assembly technique (LbL). Secondary electron imaging and backscattered electron imaging techniques perform...

  19. Morphology and Photoelectrochemical Characterization of MEH-PPV/PCBM Composite Film Doped with TiO2 Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    Farid Habelhames; Zerguine Wided; Leila Lamiri; Belkacem Nessark; Hassina Derbal-Habak

    2013-01-01

    Poly[2-methoxy-5-(20-ethylhexyloxy)-p-phenylenevinylene] (MEH-PPV),[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and titanium dioxide (TiO2) nanoparticles (n-type) were dissolved,mixed and deposited by physical methods (spin-coating) on indium tin-oxide (ITO) substrate.The incorporation of the titanium dioxide nanoparticles changed the morphology and increased the roughness of polymers film (MEH-PPV/PCBM),and the photocurrent density of the composite (MEH-PPV/PCBM +n-TiO2) was higher than that of single MEHPPV/PCBM film.The study showed that the presence of n-TiO2 particles in the polymeric film improves the photoelectrochemical properties of MEH-PPV/PCBM composite.

  20. Thin Film Morphology of Block Copolymers Containing Polydimethylsiloxane as a Function of the Surface Tension of the Opposing Block

    Science.gov (United States)

    Wadley, Maurice; Cavicchi, Kevin

    2008-03-01

    The self-assembly of block copolymers into ordered nanostructures such as spheres, cylinders, and lamellae in the range of 10-100 nm makes them interesting materials for patterning surfaces. Thin films of block copolymers containing poly(dimethylsiloxane) (PDMS) are attractive for patterning due to their high oxygen etch resistance compared to other polymers. The main disadvantage of these polymers for patterning is the low surface tension of PDMS. This causes the preferential migration of PDMS to the air/film interface driving the formation of domains parallel to the interface and surface wetting layers. In this work a series of AB block copolymers containing PDMS have been prepared where the surface tension of the opposing block was varied. The effect of changing the surface tension mismatch between the blocks on the thin film morphology will be discussed.

  1. Bath temperature impact on morphological evolution of Ni(OH)2 thin films and their supercapacitive behaviour

    Indian Academy of Sciences (India)

    U M Patil; K V Gurav; J H Kim; C D Lokhande; S C Jun

    2014-02-01

    Nanostructured Ni(OH)2 thin films were deposited over stainless steel (SS) and glass substrate via simple chemical bath deposition (CBD) method. NiCl2 :6H2O were used as source of nickel and aqueous ammonia as a complexing agent. The coating process of Ni(OH)2 material over substrate is based on the decomposition of ammonia complexed nickel ions at two different bath temperatures. The changes in structural, morphological and electro-chemical properties are examined as an impact of bath temperature. XRD studies reveal formation of mixed phase of and at lower bath temperature (313 K) while, pure phase of Ni(OH)2 thin films deposited was observed at higher bath temperature (353 K). The morphological evolution from honeycomb structure to vertically aligned flakes over the substrate is observed as the influence of bath temperature. The supercapacitive performance based on the morphology examined by using cyclic voltammetric measurements in 1 M KOH. The maximum specific capacitances of 610 and 460 F/g were observed for the vertical flake and honeycomb structured Ni(OH)2 thin films, respectively.

  2. The role of cationic precursors in structural, morphological and optical properties of PbS thin films

    Science.gov (United States)

    Preetha, K. C.; Murali, K. V.; Ragina, A. J.; Deepa, K.; Dhanya, A. C.; Remadevi, T. L.

    2013-05-01

    Thin films of Lead sulphide (PbS) were grown on soda lime glass substrate by Successive Ionic Layer Adsorption and Reaction (SILAR) method using lead acetate, lead chloride, lead nitrate, and lead sulphate as cationic precursors and thioacetamide as sulphur source. The experiments were carried out at room temperature under normal pressure utilizing aqueous conditions. The structural and morphological aspects of the as prepared samples were investigated by means of XRD and SEM results. The prepared samples were polycrystalline with nanometer-sized grains and identified as galena type cubic structure (FCC). The values of average crystallite size were found to be in the range 22 to 30 nm. The SEM micrographs show variations in morphology. Optical studies revealed that the absorption edges of the films indicated strong blue shifts with respect to bulk sample. In this work, we establish that the cationic precursor sources and in turn the size of the crystallites affects the structural, morphological and optical properties of PbS thin films.

  3. Structural, morphological and optical characterizations of ZnO:Al thin films grown on silicon substrates by pulsed laser deposition

    Science.gov (United States)

    Alyamani, A.; Sayari, A.; Albadri, A.; Albrithen, H.; El Mir, L.

    2016-09-01

    The pulsed laser deposition (PLD) technique is used to grow Al-doped ZnO (AZO) thin films at 500 ° C on silicon substrates under vacuum or oxygen gas background from ablating AZO nanoparticle targets synthesized via the sol-gel process. The structural, morphological and optical properties were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM) and spectroscopic ellipsometry (SE) techniques. XRD and TEM images show that AZO powder has a wurtzite-type structure and is composed of small prismatic-like shape nanoparticles with an average size of 30nm. The structural properties of the AZO films grown under oxygen show no significant changes compared to those of the film grown under vacuum. However, the optical properties show a dependence on the growth conditions of the AZO films. Highly c -axis-oriented AZO thin films were obtained with grain size ˜ 15 nm. The stress in the AZO films is tensile as measured from the c -parameter. The dielectric function, the refractive index and the extinction coefficient as a function of the photon energy for the AZO films were determined by using spectroscopic ellipsometry measurements in the photon energy region from 1 to 6eV. The band gap energy was observed to slightly decrease in the presence of the O2 gas background and this may be attributed to the stress. The surface and volume energy loss functions are calculated and exhibit different behaviors in the energy range 1-6eV. Refractive indices of 1.9-2.1 in the visible region were obtained for the AZO films. Also, the electronic carrier concentration appears to be related to the presence of O2 during the growth process.

  4. Effect of Annealing on Structure, Morphology, Electrical and Optical Properties of Nanocrystalline TiO2 Thin Films

    Directory of Open Access Journals (Sweden)

    B.T. Raut

    2011-01-01

    Full Text Available Semi-transparent and highly conducting nanostructured titanium oxide thin films have been prepared by sol-gel method. Thin films of TiO2 deposited on glass substrates using spin coating technique and the effect of annealing temperature (400 - 700 °C on structural, microstructural, electrical and optical properties were studied. The X-ray diffraction and Atomic force microscopy measurements confirmed that the films grown by this technique have good crystalline tetragonal mixed anatase and rutile phase structure and homogeneous surface. The study also reveals that the rms value of thin film roughness increases from 7 to 19 nm. HRTEM image of TiO2 thin film (annealed at 700 °C shows that a grain of about 50 - 60 nm in size is really aggregate of many small crystallites of around 10 - 15 nm. Electron diffraction pattern shows that the TiO2 films exhibited tetragonal structure. The surface morphology (SEM of the TiO2 film showed that the nanoparticles are fine with an average grain size of about 50 - 60 nm. The optical band gap slightly decreases from 3.26 - 3.24 eV and the dc electrical conductivity was found in the range of 10-6 to 10-5(Ω·cm-1 when the annealing temperature is changed from 400 to 700 °C. It is observed that TiO2 thin film annealed at 700 °C after deposition provide a smooth and flat texture suited for optoelectronic applications.

  5. Effect of Deposition Rate on Structure and Surface Morphology of Thin Evaporated Al Films on Dielectrics and Semiconductors

    Directory of Open Access Journals (Sweden)

    Kirill BORDO

    2012-12-01

    Full Text Available Aluminum (Al films with thickness of 100 nm were grown on unheated glass, silicon and mica substrates by electron beam evaporation. The deposition rates were adjusted in the range between 0.1 nm/s and 2 nm/s, the pressure in the vac­uum chamber during deposition was lower than 1·10–3 Pa. The structure and surface morphology of the as-deposited Al films were studied using scanning electron microscopy (SEM and atomic force microscopy (AFM. SEM imaging of the films showed that the mean grain size of thin Al films on all of the substrates increased from 20 nm – 30 nm to 50 nm – 70 nm with increase of the deposition rate. Quantitative AFM characterization showed that for all substrates the root mean square surface roughness increases monotonically with increasing the deposition rate from 0.1 nm/s to 2 nm/s. The observed effects of the deposition rate on the grain size and surface roughness are explained by the fundamental characteristics of the island growth mode, the influence of the background gases and the surface morphology of the bare substrates.DOI: http://dx.doi.org/10.5755/j01.ms.18.4.3088

  6. Structural, morphological, optical and electrical properties of NiO films prepared on Si (100) and glass substrates at different thicknesses

    Science.gov (United States)

    Ahmed, Anas A.; Afzal, Naveed; Devarajan, Mutharasu; Subramani, Shanmugan

    2016-11-01

    In this work, structural, surface, optical and electrical properties of NiO films were studied at different film thicknesses. The NiO films of different thicknesses in the range 330-920 nm were prepared on Si (100) and glass substrates by using radiofrequency magnetron sputtering of NiO target at 100 °C. The structural study through XRD indicated polycrystalline NiO films with preferred orientation along (200) plane. The crystalline quality of the films was improved with increase of the film thickness on both substrates, however, the films prepared on Si (100) displayed better crystallinity as compared to the films prepared on the glass. The morphological features of the film as studied through FE-SEM displayed an increase of grain size with increase of its thickness, however, the grain size of the film on Si (100) was found to be slightly larger than that of the glass. The band gap of NiO film was decreased with increase of the film thickness on both the substrates. The films grown on Si (100) exhibited superior electrical properties as compared to the films prepared on glass at all film thicknesses.

  7. Effect of morphology of thin DNA films on the electron stimulated desorption of anions

    Science.gov (United States)

    Mirsaleh-Kohan, Nasrin; Bass, Andrew D.; Sanche, Léon

    2011-01-01

    We present a comparison between the electron stimulated desorption (ESD) of anions from DNA samples prepared by lyophilization (an example of poorly organized or nonuniform films) and molecular self-assembly (well-ordered films). The lyophilization (or freeze- drying) method is perhaps the most frequently employed technique for forming DNA films for studies of low-energy electron (LEE) interactions leading to DNA damage; however, this technique usually produces nonuniform films with considerable clustering which may affect DNA configuration and enhance sample charging when the film is irradiated. Our results confirm the general validity of ESD measurements obtained with lyophilized samples, but also reveal limitations of lyophilization for LEE studies on DNA films. Specifically we observe some modulation of structures, associated with dissociative electron attachment, in the anion yield functions from different types of DNA film, confirming that conformational factors play a role in the LEE induced damage to DNA.

  8. New Method for Fabrication of Co3O4 Thin Film Sensors: Structural, Morphological and Optoelectronic Properties

    Directory of Open Access Journals (Sweden)

    Vikas PATIL

    2011-05-01

    Full Text Available Nanocrystalline Co3O4 thin films have been deposited by spin coating technique and then have been analyzed to test their application in NH3 gas-sensing technology. In particular, spectrophotometric and conductivity measurements have been performed in order to determine the optical and electrical properties of Co3O4 thin films. The structure and the morphology of such material have been investigated by X ray diffraction and Scanning electron microscopy. The X-ray diffraction studies confirmed that the films grown by this technique have good crystalline cubic spinel structure and present a random orientation. The morphology of the sol gel derived Co3O4 shows nanocrystalline grains with some overgrown clusters .The optical band gap has been determined from the absorption coefficient. We found that the optical band gap energy decreases from 2.58 eV to 2.07 eV with increasing annealing temperature between 400-700 oC. These mean that the optical quality of Co3O4 films is improved by annealing. The dc electrical conductivity of Co3O4 thin films were increased from 10-4 to 10-2(Ω cm-1 with increase in annealing temperature. The electron carrier concentration (n and mobility (μ of Co3O4 films annealed at 400-700 oC were estimated to be of the order of 2.4 to 4.5 x 1019 cm-3 and 5.2 to 7.0 x 10-5 cm2 V-1 s-1 respectively. It is observed that Co3O4 thin film annealing at 700 oC after deposition provide a smooth and flat texture suited for optoelectronic applications. Gas sensing properties showed that the Co3O4 films (at 700 oC were sensitive as well as fast in responding to NH3. A high sensitivity for ammonia indicates that the Co3O4 films are selective for this gas.

  9. Effect of Blend Composition and Additives on the Morphology of PCPDTBT:PC71BM Thin Films for Organic Photovoltaics.

    Science.gov (United States)

    Schaffer, Christoph J; Schlipf, Johannes; Dwi Indari, Efi; Su, Bo; Bernstorff, Sigrid; Müller-Buschbaum, Peter

    2015-09-30

    The use of solvent additives in the fabrication of bulk heterojunction polymer:fullerene solar cells allows to boost efficiencies in several low bandgap polymeric systems. It is known that solvent additives tune the nanometer scale morphology of the bulk heterojunction. The full mechanism of efficiency improvement is, however, not completely understood. In this work, we investigate the influences of blend composition and the addition of 3 vol % 1,8-octanedithiol (ODT) as solvent additive on polymer crystallization and both, vertical and lateral morphologies of poly[2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta [2,1-b;3,4-b']dithiophene)-alt-4,7(2,1,3-benzothiadiazole)] and [6,6]-phenyl C71-butyric acid methyl ester (PCPDTBT:PC71BM) blend thin films processed from chlorobenzene-based solutions. The nanoscale morphology is probed with grazing incidence small- and wide-angle X-ray scattering as well as X-ray reflectivity and complemented with UV/vis spectroscopy. In PCPDTBT:PC71BM films the use of ODT is found to lower the solubility of fullerene in the polymer matrix and to promote polymer crystallization, both vertical and lateral microphase separation with morphological coarsening, and formation of a fullerene-rich topping layer. The enhanced photovoltaic performance is explained by these findings.

  10. Bread crispness and morphology can be controlled by proving conditions

    NARCIS (Netherlands)

    Primo Martin, C.; Dalen, van G.; Meinders, M.B.J.; Don, A.; Hamer, R.H.; Vliet, van T.

    2010-01-01

    Bread crust crispness is lost when water migrates from crumb to crust during storage. To what extent water migration is influenced by morphology is not known. Therefore, the effect of crispy rolls morphology on crust crispness was studied. Crispy rolls were prepared at three proving volumes: 300 mL

  11. Controllable growth and characterization of highly aligned ZnO nanocolumnar thin films

    Science.gov (United States)

    Onuk, Zuhal; Rujisamphan, Nopporn; Murray, Roy; Bah, Mohamed; Tomakin, Murat; Shah, S. Ismat

    2017-02-01

    We investigated the effects of growth conditions during magnetron sputtering on the structural, morphological, and optical properties of nanostructured ZnO thin films. Undoped ZnO thin films are deposited onto p-type Si (100) and corning 7059 glass substrates by RF magnetron sputtering using a ZnO target in combination with various Ar-O2 sputtering gas mixtures at room temperature. The effect of the partial pressure of oxygen on the morphology of ZnO thin film structure and band alignment were investigated. Thickness, and therefore the growth rate of the samples measured from the cross-sectional SEM micrographs, is found to be strongly correlated with the oxygen partial pressure in the sputtering chamber. The optical transmittance spectrometry results show that the absorption edge shifts towards the longer wavelength at higher oxygen partial pressure. X-ray photoelectron spectroscopy (XPS) used for determining the surface chemical structure and valence band offsets show that conduction band can be controlled by changing the sputtering atmosphere.

  12. Modification of the morphology and optical properties of SnS films using glancing angle deposition technique

    Science.gov (United States)

    Sazideh, M. R.; Dizaji, H. Rezagholipour; Ehsani, M. H.; Moghadam, R. Zarei

    2017-05-01

    Tin sulfide (SnS) films were prepared by thermal evaporation method using Glancing Angle Deposition (GLAD) technique at zero and different oblique incident flux angles (α = 45°, 55°, 65°, 75° and 85°). The physical properties of prepared films were systematically investigated. The X-ray diffraction analysis indicated that the film deposited at α = 0° formed as single phase with an orthorhombic structure. However, the layers became amorphous at α = 45°, 55°, 65°, 75° and 85°. Beside the appearance of amorphous feature in the film prepared at α higher than zero, Sn2S3 phase was also observed. The top and cross-sectional field emission scanning electron microscope (FESEM) images of the samples showed noticeable changes in the structure and morphology of individual nano-plates as a function of incident angle. The band gap and refractive index values of the films were calculated by optical transmission measurements. The optical band-gap values were observed to increase with increasing the incident flux angle. This can be due to presence of Sn2S3 phase observed in the samples produced at α values other than zero. The effective refractive index and porosity exhibit an opposite evolution as the incident angle α rises. At α = 85° the layers show a considerable change in effective refractive index (Δn = 1.7) at near-IR spectral range.

  13. Morphology, structural properties and reducibility of size-selected CeO2−x nanoparticle films

    Directory of Open Access Journals (Sweden)

    Maria Chiara Spadaro

    2015-01-01

    Full Text Available Non-stoichiometric ceria nanoparticles (NPs were obtained by a gas aggregation source with a magnetron and were mass-selected with a quadrupole mass filter. By varying magnetron power, Ar gas flow, and the length of the aggregation tube, NPs with an average diameter of 6, 9, and 14 nm were synthesized and deposited onto a substrate, thus obtaining NP films. The morphology of the films was studied with scanning electron microscopy, while high resolution transmission electron microscopy was used to gain a deeper insight into the atomic structure of individual NPs. By using X-ray photoelectron spectroscopy we analyzed the degree of reduction of the NPs of different diameters, before and after thermal treatments in vacuum (reduction cycle and in O2 atmosphere (oxidation cycle at different temperatures. From this analysis we inferred that the size is an important parameter only at intermediate temperatures. As a comparison, we evaluated the reducibility of an ultra-thin ceria film with the same surface to volume ratio as the 9 nm diameter NPs film, observing that NPs are more reducible than the ceria film.

  14. Structural, morphological, and optical properties of TiO2 thin films synthesized by the electro phoretic deposition technique.

    Science.gov (United States)

    Ghrairi, Najla; Bouaicha, Mongi

    2012-07-01

    In this work, we report the structural, morphological, and optical properties of TiO2 thin films synthesized by the electro phoretic deposition technique. The TiO2 film was formed on a doped fluorine tin oxide (SnO2:F, i.e., FTO) layer and used as a photo electrode in a dye solar cell (DSC). Using spectroscopic ellipsometry measurements in the 200 to 800 nm wavelengths domain, we obtain a thickness of the TiO2 film in the range of 70 to 80 nm. Characterizations by X-ray diffraction and atomic force microscopy (AFM) show a polycrystalline film. In addition, AFM investigation shows no cracks in the formed layer. Using an ultraviolet-visible near-infrared spectrophotometer, we found that the transmittance of the TiO2 film in the visible domain reaches 75%. From the measured current-voltage or I-V characteristic under AM1.5 illumination of the formed DSC, we obtain an open circuit voltage Voc = 628 mV and a short circuit current Isc = 22.6 μA, where the surface of the formed cell is 3.14 cm2.

  15. Effect of Polyvinylpyrrolidone on the Morphologies of Latex Films and Air Permeability of the Latex Finished Fabrics

    Institute of Scientific and Technical Information of China (English)

    SHEN Yi-feng; YE Jia-jia; YANG Lei; WU Ming-hua; NI Tian-xiang

    2010-01-01

    Low air permeability is a common problem happening to the coating finished and pigment dyed fabrics.To tackle the problem,styrene and butyl acrylate copolymer latex was prepared and used as substitute for the binder.Then,polyvinylpyrrolidoue(PVP)was fed into the latex.It was expected that pores could form in the resulting latex film after being rinsed.The morphologies of the latex films were analysized by scanning electric microscope(SEM).It was found that the continuity of the latex films decreased greatly because of the addition of PVP,leading to the loss of the stress at break of the films.After rinsing with methanol aqueous solution,PVP was easily leached off and(macro)void was formed in the latex films.The size of the void decreased with the increase of the PVP concentration.Then,the latex with and without PVP was used to finish the cotton fabrics and engaged as binder in pigment dyeing.After PVP was rinsed out,the air permeability of the fabrics improved greatly,which recovered to that of the unfinished one.In the meantime,the color fastness to rubbing was little affected.So,the method of PVP addition could be termed as an efficient way to improve the air permeability in coating and dyeing industry.

  16. Role of precursors on morphology and optical properties of ZnS thin films prepared by chemical spray pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Fenollosa, M.A. [Departamento de Fisica Aplicada, Universidad Politecnica de Valencia, Cami de Vera s/n, 46071 - Valencia (Spain)], E-mail: mhernan@fis.upv.es; Lopez, M.C. [Laboratorio de Materiales y Superficie (Unidad Asociada al CSIC), Dptos Fisica Aplicada and Dpto. Ingenieria Quimica, Facultad de Ciencias, Unversidad de Malaga, E29071 Malaga (Spain); Donderis, V. [Departamento de Ingenieria Electrica, Universidad Politecnica de Valencia, Cami de Vera s/n, 46071 - Valencia (Spain); Gonzalez, M.; Mari, B. [Departamento de Fisica Aplicada, Universidad Politecnica de Valencia, Cami de Vera s/n, 46071 - Valencia (Spain); Ramos-Barrado, J.R. [Laboratorio de Materiales y Superficie (Unidad Asociada al CSIC), Dptos Fisica Aplicada and Dpto. Ingenieria Quimica, Facultad de Ciencias, Unversidad de Malaga, E29071 Malaga (Spain)

    2008-02-15

    This study investigates the effect of different growth parameters on the structural and optical properties of ZnS thin films, prepared using spray pyrolysis. The films were prepared using different Zn:S ratios (between 1:1 and 1:6) and in different growth solutions: (A), zinc chloride and thiourea and (B) dehydrated zinc acetate and thiourea, both in distilled water. By varying the Zn:S ratio in the films, the optical properties (absorption and photoluminescence) show that different species are created during film growth. This was deduced from the wide emission band appearing in the green region of the photoluminescence spectra, and from the change in band gap, which varies between 3.2 and 3.5 eV. Films formed from solution (A) with a Zn:S ratio of 1:3 or 1:4 show the best morphology and transmission. ZnS has a wider band gap than other conventional II-VI semiconductors utilized in various electronic and optical devices and can be expected to provide a useful window layer of solar cells which leads to an improvement in overall efficiency by decreasing absorption loss.

  17. Water effect on the surface morphology of TiO2 thin film modified by polyethylene glycol

    Science.gov (United States)

    Wang, Sheng-Hung; Wang, Kuo-Hua; Dai, Yong-Ming; Jehng, Jih-Mirn

    2013-01-01

    Water effect on the surface morphology of TiO2 thin film was investigated by using PEG-6000 as a template to form the porous structure. The porous TiO2 thin films were characterized by thermo-gravimetric analysis (TGA), X-ray diffraction (XRD), n&k Analyzer, UV-vis spectrophotometer, field-emission scanning electron microscopy (FE-SEM), and atomic forced microscopy (AFM) as a function of water content in the preparation of TiO2 thin film. The various water contents result in the TiO2 thin films possessing different surface structures, grain sizes, and thicknesses. The grain sizes were varied with changing the water content, and the thickness increased with increasing water content due to the enhancement of the cross-linking speed. In addition, the cratered surface structure transformed into cracked surface structure upon the water content beyond stoichiometric quantity because the excess water causes the aggregation of polyethylene glycol (PEG-6000). The photocatalysis has been performed by the degradation of methyl blue with corresponding structural characteristics of the TiO2 thin film. The best photocatalytic activity has been obtained when the ratio of water to titanium precursor is equal to 2 referred as TiO2-W2.

  18. Influence of the substrate on the morphological evolution of gold thin films during solid-state dewetting

    Science.gov (United States)

    Nsimama, Patrick D.; Herz, Andreas; Wang, Dong; Schaaf, Peter

    2016-12-01

    The evolution of electron-beam evaporated Au thin films deposited on crystalline TiO2 (c-TiO2) and amorphous TiO2 (a-TiO2) as well as amorphous SiO2 substrates are investigated. The kinetic of dewetting is clearly dependent on the type of substrate and is faster on TiO2 substrates than on SiO2 substrates. This difference can result from the difference in adhesion energy. Furthermore, the kinetic of dewetting is faster on a-TiO2 than on c-TiO2, possibly due to the crystallization of TiO2 during annealing induced dewetting process. The morphologies of dewetted Au films deposited on crystalline TiO2 are characterized by branched holes. The XRD patterns of the Au films deposited on TiO2 substrates constituted peaks from both metallic Au and anatase TiO2. The activation energy of Au films deposited on crystalline TiO2 substrates was higher than that that of the films deposited on amorphous TiO2 substrates.

  19. Investigation of optical, structural and morphological properties of nanostructured boron doped TiO2 thin films

    Indian Academy of Sciences (India)

    Savaş Sönmezoǧlu; Banu Erdoǧan; İskender Askeroǧlu

    2013-12-01

    Pure and different ratios (1, 3, 5, 7 and 10%) of boron doped TiO2 thin films were grown on the glass substrate by using sol–gel dip coating method having some benefits such as basic and easy applicability compared to other thin film production methods. To investigate the effect of boron doped on the physical properties of TiO2, structural, morphological and optical properties of growth thin films were examined. 1% boron-doping has no effect on optical properties of TiO2 thin film; however, optical properties vary with > 1%. From X-ray diffraction spectra, it is seen that TiO2 thin films together with doping of boron were formed along with TiB2 hexagonal structure having (111) orientation, B2O3 cubic structure having (310) orientation, TiB0.024O2 tetragonal structure having rutile phase (110) orientation and polycrystalline structures. From SEM images, it is seen that particles together with doping of boron have homogeneously distributed and held onto surface.

  20. Effect of chlorine doping on the structural, morphological, optical and electrical properties of spray deposited CdS thin films

    Directory of Open Access Journals (Sweden)

    T. Sivaraman

    2015-10-01

    Full Text Available CdS and chlorine doped CdS (CdS:Cl thin films with different Cl-doping levels (0, 2, 4, 6 and 8 at% have been deposited on glass substrates by a spray pyrolysis technique using a perfume atomizer. The effect of Cl doping on the structural, morphological, optical and electrical properties of the films was investigated. XRD patterns revealed that all the films exhibit hexagonal crystal structure with a preferential orientation along the (0 0 2 plane irrespective of the Cl doping level. The particle size value decreases from 22.03 nm to 18.12 nm with increase in Cl concentration. Optical band gap is blue-shifted from 2.48 eV to 2.73 eV with increase in Cl doping concentration. All the films have resistivity in the order of 104 Ω cm. The obtained results confirm that chlorine as an anionic dopant material can enhance the physical properties of CdS thin films to a large extent.

  1. Controllable preparation of nanosized TiO2 thin film and relationship between structure of film and its photocatalytic activity

    Institute of Scientific and Technical Information of China (English)

    WEI; Gang; (魏刚); ZHANG; Yuanjing; (张元晶); XIONG; Rongchun; (熊蓉春)

    2003-01-01

    TiO2 nano-crystalline film and fixed bed photocatalytic reactor were prepared by the sol-gel process using tetrabutylorthotitanate as a precursor and glass tube as the substrate. XRD, AFM, SEM and thickness analysis results indicate that the preparation of nano-crystalline film can be controlled by optimizing experiment process. Under the optimized process, the phase of TiO2 in film is anatase, and the grain size is 3-4 nm. The size of particles, which is about 20-80 nm, can be controlled. The thickness of monolayer film is in nanometer grade. The thickness and particles size in films growing on nanometer film can also be controlled in nanometer grade. As a result, the crack of film can be effectively avoided. Rhodamine B degradation results using UV-Vis spectrophotometer show that the activity of nano-crystalline film in the photocatalytic reactor has a good relation with the diameter of TiO2 particles, that is, the film shows high activity when the size is 20-30 nm and greatly reduced when the size is above 60 nm. The activity of film does not decrease with the increase of film thickness, and this result indicates that nano-crystalline film has no ill influence on the transmissivity of ultraviolet light.

  2. Morphology control of ordered mesoporous carbons for high capacity lithium sulfur batteries

    Energy Technology Data Exchange (ETDEWEB)

    Schuster, Joerg David

    2011-06-07

    The focus of this thesis concerns the morphology control of ordered mesoporous carbon (OMC) materials. Ordered mesoporous carbons with diverse morphologies, that are thin films, fibers - embedded in anodic alumina membranes and free-standing - or spherical nanoparticles, have been successfully prepared by soft-templating procedures. The mechanisms of structure formation and processing were investigated with in-situ SAXS measurements and their application in high capacity lithium-sulfur batteries was successfully tested in cooperation with Guang He and Linda Nazar from the University of Waterloo in Canada. The Li-S batteries receive increasing attention due to their high theoretical energy density which is 3 to 5 times higher than from lithium-ion batteries. For this type of battery the specific pore volume is crucial for the content of the active component (sulfur) in the cathode and therefore correlates with the capacity and gravimetric energy density of the battery. At first, mesoporous thin films with 2D-hexagonal structure were obtained through organic-organic self-assembly of a preformed oligomeric resol precursor and the triblock copolymer template Pluronic P123. The formation of a condensed-wall material through thermopolymerization of the precursor oligomers resulted in mesostructured phenolic resin films. Subsequent decomposition of the surfactant and partial carbonization were achieved through thermal treatment in inert atmosphere. The films were crack-free with tunable homogenous thicknesses, and showed either 2D-hexagonal or lamellar mesostructure. An additional, yet unknown 3D-mesostructure was also found. In the second part, cubic and circular hexagonal mesoporous carbon phases in the confined environment of tubular anodic alumina membrane (AAM) pores were obtained by self-assembly of the mentioned resol precursor and the triblock copolymer templates Pluronic F127 or P123, respectively. Casting and solvent-evaporation were also followed by

  3. Influence of water content in mixed solvent on surface morphology, wettability, and photoconductivity of ZnO thin films.

    Science.gov (United States)

    Zhao, Min; Shang, Fengjiao; Lv, Jianguo; Song, Ying; Wang, Feng; Zhou, Zhitao; He, Gang; Zhang, Miao; Song, Xueping; Sun, Zhaoqi; Wei, Yiyong; Chen, Xiaoshuang

    2014-01-01

    ZnO thin films have been synthesized by means of a simple hydrothermal method with different solvents. The effect of deionized water content in the mixed solvents on the surface morphology, crystal structure, and optical property has been investigated by scanning electron microscopy, X-ray diffraction, and UV-Vis spectrophotometer. A large number of compact and well-aligned hexagonal ZnO nanorods and the maximal texture coefficient have been observed in the thin film, which is grown in the mixed solvent with x = 40%. A lot of sparse, diagonal, and pointed nanorods can be seen in the ZnO thin film, which is grown in the 40-mL DI water solution. The optical band gap decreases firstly and then increases with the increase of x. Reversible wettability of ZnO thin films were studied by home-made water contact angle apparatus. Reversible transition between hydrophobicity and hydrophilicity may be attributed to the change of surface chemical composition, surface roughness and the proportion of nonpolar planes on the surface of ZnO thin films. Photocurrent response of ZnO thin films grown at different solvents were measured in air. The response duration of the thin film, which is grown in the solvent with x = 40%, exhibits a fast growth in the beginning but cannot approach the saturate current value within 100 s. The theoretical mechanism for the slower growth or decay duration of the photocurrent has been discussed in detail.

  4. Surface morphological changes and magnetic properties of Sc-substituted Y 3Fe 5O 12 epitaxial films deposited on the GGG substrate

    Science.gov (United States)

    Syvorotka, I. I.; Syvorotka, I. M.; Kityk, I. V.

    2010-11-01

    Sc-doped YIG films were grown on (1 1 1) oriented GGG crystalline substrate with disorientation angle within the range 0-25'. Sc 3+ ion substitution was varied within the range 0.25-0.3 per formula unit. The films demonstrate different types of surface morphology versus film growth rate and substrate disorientation. Conditions for existence of these types of the surface morphology were defined. The field dependence of magnetic susceptibility at magnetization reversal in film plane and Faraday rotation at wavelength 633 nm for a magnetic field applied in perpendicular direction were measured to characterize the films grown. Films with "mirror-like" surface demonstrate a planar magnetization at room temperature.

  5. Effect of clay concentration on morphology and properties of hydroxypropylmethylcellulose films.

    Science.gov (United States)

    Mondal, Dibyendu; Bhowmick, Biplab; Mollick, Md Masud R; Maity, Dipanwita; Mukhopadhyay, Asis; Rana, Dipak; Chattopadhyay, Dipankar

    2013-07-01

    Hydroxypropylmethylcellulose (HPMC)/montmorillonite (MMT) nanocomposite films are prepared by solution intercalation method. Mechanical, thermal, moisture absorption, optical clarity and water vapor permeability of HPMC/MMT nanocomposite films are measured. X-ray diffraction (XRD) and transmission electron microscopic (TEM) results establish formation of partially intercalated and partially exfoliated HPMC/MMT nanocomposite films. In presence of MMT, the tensile strength, tensile modulus and elongation at break of HPMC films are improved. The thermal stability of HPMC/MMT nanocomposites is better than pure HPMC. The moisture absorption of HPMC film measured in 75% of constant relative humidity is reduced with loading of MMT. Optical clarity of HPMC film is almost unaffected in presence of MMT. Water vapor permeability of HPMC decreases in presence of nanoclay due to increasing tortuous path for diffusion.

  6. Effect of reaction conditions on film morphology of polyaniline composite membranes for gas separation

    KAUST Repository

    Blinova, Natalia V.

    2012-04-21

    Composite membranes combining polyaniline as an active layer with a polypropylene support have been prepared using an in situ deposition technique. The protonated polyaniline layer with a thickness in the range of 90-200 nm was prepared using precipitation, dispersion, or emulsion polymerization of aniline with simultaneous deposition on top of the porous polypropylene support, which was immersed in the reaction mixture. Variables such as temperature, concentration of reagents, presence of steric stabilizers, surfactants, and heteropolyacid were found to control both the formation and the quality of the polyaniline layers. Both morphology and thickness of the layers were characterized using scanning electron microscopy. Selective separation of carbon dioxide from its mixture with methane is used to illustrate potential application of these composite membranes. © 2012 Wiley Periodicals, Inc.

  7. Sol–gel synthesis of nanostructured indium tin oxide with controlled morphology and porosity

    Energy Technology Data Exchange (ETDEWEB)

    Kőrösi, László, E-mail: ltkorosi@gmail.com [Department of Biotechnology, Nanophage Therapy Center, Enviroinvest Corporation, Kertváros u. 2, H-7632 Pécs (Hungary); Scarpellini, Alice [Department of Nanochemistry, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova (Italy); Petrik, Péter [Institute for Technical Physics and Materials Science, Konkoly-Thege út 29-33, H-1121 Budapest (Hungary); Papp, Szilvia [Department of Biotechnology, Nanophage Therapy Center, Enviroinvest Corporation, Kertváros u. 2, H-7632 Pécs (Hungary); Dékány, Imre [MTA-SZTE Supramolecular and Nanostructured Materials Research Group, University of Szeged, Dóm tér 8, H-6720 Szeged (Hungary)

    2014-11-30

    Graphical abstract: - Highlights: • Nanocrystalline ITO thin films and powders were prepared by a sol–gel method. • The nature of the compounds used for hydrolysis plays a key role in the morphology. • Hydrolysis of In{sup 3+}/Sn{sup 4+} with EA led to a rod-like morphology. • Monodisperse spherical ITO nanoparticles were obtained on the use of AC. • ITO{sub E}A was highly porous, while ITO{sub A}C contained densely packed nanocrystals. - Abstract: Nanostructured indium tin oxide (ITO) powders and thin films differing in morphology and porosity were prepared by a sol–gel method. In{sup 3+} and Sn{sup 4+} were hydrolyzed in aqueous medium through the use of ethanolamine (EA) or sodium acetate (AC). X-ray diffraction measurements demonstrated that both EA and AC furnished indium tin hydroxide, which became nanocrystalline after aging for one day. The indium tin hydroxide samples calcined at 550 °C afforded ITO with a cubic crystal structure, but the morphology differed significantly, depending on the agent used for hydrolysis. Electron microscopy revealed the formation of round monodisperse nanoparticles when AC was used, whereas the application of EA led to rod-like ITO nanoparticles. Both types of nanoparticles were suitable for the preparation of transparent and conductive ITO thin films. The influence of the morphology and porosity on the optical properties is discussed.

  8. Stoichiometry controlled oxide thin film growth by pulsed laser deposition

    NARCIS (Netherlands)

    Groenen, Rik; Smit, Jasper; Orsel, Kasper; Vailionis, Arturas; Bastiaens, Bert; Huijben, Mark; Boller, Klaus; Rijnders, Guus; Koster, Gertjan

    2015-01-01

    The oxidation of species in the plasma plume during pulsed laser deposition controls both the stoichiometry as well as the growth kinetics of the deposited SrTiO3 thin films, instead of the commonly assumed mass distribution in the plasma plume and the kinetic energy of the arriving species. It was

  9. Control and optimization of sealing layer in films

    Science.gov (United States)

    Najarzadeh, Zahra

    Heat sealing is the process to achieve the hermetic closure of a package by applying heat and pressure on two polymer films for a specified dwell time. The heat sealing process has been used in packaging of a wide spectrum of products, in particular for food packaging. During the past two decades, heat sealing machinery has been developed for very high speed line production which requires very precise process condition and material optimization. Heat seal process conditions, including temperature, dwell time, and pressure as well as film characteristics such as molecular weight, molecular weight distribution, long and short chain branching are the key factors that control the final quality of the joint. In the first part of this study, we have investigated the interrelated influence of heat seal process parameters on the strengthening of the interface as well as the micro mechanisms involved. The effects of heat seal temperature, pressure, and dwell time on seal strength of LLDPE were illustrated in "time-temperature" and "pressure-temperature" 3D maps, a methodology that is easily applicable to other systems. The interfacial adhesion of semicrystalline polymers was not well understood. We thus studied the adhesion behaviour of LLDPE as a semicrystalline polymer. The results indicated that the time and temperature dependence of seal strength is a consequence of the fraction of amorphous phase available at the interface of films. The seal strength had a linear correlation with the square root of sealing time which was also supported by the welding models. The slope of this linear correlation increased with temperature. This work was followed concurrently by two main approaches: analysis of polymer chain behaviour from microscopic point of view based on reptation theory and conventional macroscopic analysis based on bulk properties of the polymer. Failure mechanisms and fractured surfaces were also analyzed after peeling. Moreover, the topography and morphology of

  10. Correction: β-Sialon nanowires, nanobelts and hierarchical nanostructures: morphology control, growth mechanism and cathodoluminescence properties

    Science.gov (United States)

    Huang, Juntong; Huang, Zhaohui; Liu, Yangai; Fang, Minghao; Chen, Kai; Huang, Yaoting; Huang, Saifang; Ji, Haipeng; Yang, Jingzhou; Wu, Xiaowen; Zhang, Shaowei

    2016-07-01

    Correction for `β-Sialon nanowires, nanobelts and hierarchical nanostructures: morphology control, growth mechanism and cathodoluminescence properties' by Juntong Huang, et al., Nanoscale, 2014, 6, 424-432.

  11. Thin-film morphology of inkjet-printed single-droplet organic transistors using polarized Raman spectroscopy: effect of blending TIPS-pentacene with insulating polymer

    NARCIS (Netherlands)

    James, D.T.; Kjellander, B.K.C.; Smaal, W.T.T.; Gelinck, G.H.; Combe, C.; McCulloch, I.; Wilson, R.; Burroughes, J.H.; Bradley, D.D.C.; Kim, J.S.

    2011-01-01

    We report thin-film morphology studies of inkjet-printed single-droplet organic thin-film transistors (OTFTs) using angle-dependent polarized Raman spectroscopy. We show this to be an effective technique to determine the degree of molecular order as well as to spatially resolve the orientation of th

  12. Multifractal Analysis of Morphology of TiO2 Nano-films

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The SEM and AFM images of three TiO2 nano-films prepared at different conditions were obtained and transformed into digital format.The multifractal analyses for three films were made using height from a depth of thickness of film B and q from 55 to -55.The scale- invariance is very good for all lnχq(ε)~ln( plots and τ(q)~q plots at least close to three orders of magnitude.But the multifractal spectra f(a) of the films are quite distinct due to their different height distribution.

  13. AFM investigations of the morphology features and local mechanical properties of HTS YBCO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Soifer, Yakov M.; Verdyan, Armen; Lapsker, Igor; Azoulay, Jacob

    2004-08-01

    In the paper presented here the application of the atomic force microscope (AFM) is considered for evaluation of hardness and Young's modulus of high T{sub c} superconducting YBCO thin films of different thickness (from 0.05 to 1 {mu}m) grown on unbuffered SrTiO{sub 3} (film I) and on sapphire with a buffer layer of CeO{sub 2} (film II). The best film features a transition temperature T{sub c} of 90 K, critical current density J{sub c} (H=0) of 3 x 10{sup 7} A/cm{sup 2} at 4.2 K and 2 x 10{sup 6} A/cm{sup 2} at 77 K. The relationship between mechanical properties and microstructure of these films was investigated. It was found that all the films comprised well-defined Cu-rich precipitates of different size and with different density on their surface. For both type of films the hardness was measured to be in the range of 12-18 GPa. The Young's modulus of the films was about 180-200 GPa. The nanoindentation and nanoscratching measurements showed that the mechanical strength of the films studied was determined mainly by mechanical failure and surface defects (secondary phases)

  14. AFM investigations of the morphology features and local mechanical properties of HTS YBCO thin films

    Science.gov (United States)

    Soifer, Yakov M.; Verdyan, Armen; Lapsker, Igor; Azoulay, Jacob

    2004-08-01

    In the paper presented here the application of the atomic force microscope (AFM) is considered for evaluation of hardness and Young's modulus of high Tc superconducting YBCO thin films of different thickness (from 0.05 to 1 μm) grown on unbuffered SrTiO 3 (film I) and on sapphire with a buffer layer of CeO 2 (film II). The best film features a transition temperature Tc of 90 K, critical current density Jc ( H=0) of 3 × 10 7 A/cm 2 at 4.2 K and 2 × 10 6 A/cm 2 at 77 K. The relationship between mechanical properties and microstructure of these films was investigated. It was found that all the films comprised well-defined Cu-rich precipitates of different size and with different density on their surface. For both type of films the hardness was measured to be in the range of 12-18 GPa. The Young's modulus of the films was about 180-200 GPa. The nanoindentation and nanoscratching measurements showed that the mechanical strength of the films studied was determined mainly by mechanical failure and surface defects (secondary phases).

  15. Grain growth and morphology of In{sub 2}O{sub 3}:Pd nanocomposite films

    Energy Technology Data Exchange (ETDEWEB)

    Amani, Matin; Gregory, Otto J., E-mail: gregory@egr.uri.edu

    2013-09-02

    Thin film nanocomposites based on semiconducting oxides and palladium have been systematically studied using combinatorial chemistry techniques to optimize their thermoelectric properties. These nanocomposites have considerable potential for energy harvesting applications in harsh environments and were prepared by embedding palladium nanoparticles into an indium oxide matrix via co-sputtering from metal and ceramic targets. The as-deposited films were largely amorphous and thus were subsequently heat treated in nitrogen ambients to produce crystalline nanocomposites. These nanocomposite films were screened for their thermoelectric properties at room temperature as a function of composition, and the resulting films exhibited thermoelectric power factors that were significantly greater than the semiconducting oxides deposited directly from ceramic targets. Based on these rapid screening protocols employing hundreds of micro-thermocouples, the most promising nanocomposite films in terms of thermoelectric power factor were down-selected. Transmission electron microscopy, selected area electron diffraction, and scanning electron microscopy were then used to study the microstructural changes in these films as a function of temperature. When thermally cycled to 800 °C, an abrupt transition from normal, equiaxed grain growth to abnormal (spherulitic growth) was observed at a threshold palladium loading which was also optimal for thermoelectric energy harvesting. - Highlights: • Films consisting of Pd nanoparticles in an In{sub 2}O{sub 3} matrix were grown by sputtering. • These films have previously shown promising thermoelectric properties. • Transmission and scanning electron microscopy were used to investigate the films • This was determined for various compositions and annealing temperatures.

  16. Photoelectrochemical, photophysical and morphological studies of electrostatic layer-by-layer thin films based on poly(p-phenylenevinylene) and single-walled carbon nanotubes

    OpenAIRE

    Almeida, LCP; Zucolotto, V.; Domingues, RA; ATVARS, TDZ; Nogueira, AF

    2011-01-01

    The preparation of multilayer films based on poly(p-phenylenevinylene) (PPV) and carboxylic-functionalized single-walled carbon nanotubes (SWNT-COOH) by electrostatic interaction using the layer-by-layer (LbL) deposition method is reported herein. The multilayer build-up, monitored by UV-Vis and photoluminescence (PL) spectroscopies, displayed a linear behavior with the number of PPV and SWNT-COOH layers deposited that undergo deviation and spectral changes for thicker films. Film morphology ...

  17. Morphology and Curie temperature engineering in crystalline La{sub 0.7}Sr{sub 0.3}MnO{sub 3} films on Si by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Nori, Rajashree, E-mail: rajsre@ee.iitb.ac.in; Ganguly, U.; Ravi Chandra Raju, N.; Pinto, R.; Ramgopal Rao, V. [Centre of Excellence in Nanoelectronics, Department of Electrical Engineering, Indian Institute of Technology-Bombay (IIT-B), Mumbai 400076 (India); Kale, S. N. [Department of Applied Physics, Defence Institute of Advanced Technology (DIAT), Pune 411025 (India); Sutar, D. S. [Central Surface Analytical Facility, Indian Institute of Technology-Bombay (IIT-B), Mumbai 400076 (India)

    2014-01-21

    Of all the colossal magnetoresistant manganites, La{sub 0.7}Sr{sub 0.3}MnO{sub 3} (LSMO) exhibits magnetic and electronic state transitions above room temperature, and therefore holds immense technological potential in spintronic devices and hybrid heterojunctions. As the first step towards this goal, it needs to be integrated with silicon via a well-defined process that provides morphology and phase control, along with reproducibility. This work demonstrates the development of pulsed laser deposition (PLD) process parameter regimes for dense and columnar morphology LSMO films directly on Si. These regimes are postulated on the foundations of a pressure-distance scaling law and their limits are defined post experimental validation. The laser spot size is seen to play an important role in tandem with the pressure-distance scaling law to provide morphology control during LSMO deposition on lattice-mismatched Si substrate. Additionally, phase stability of the deposited films in these regimes is evaluated through magnetometry measurements and the Curie temperatures obtained are 349 K (for dense morphology) and 355 K (for columnar morphology)—the highest reported for LSMO films on Si so far. X-ray diffraction studies on phase evolution with variation in laser energy density and substrate temperature reveals the emergence of texture. Quantitative limits for all the key PLD process parameters are demonstrated in order enable morphological and structural engineering of LSMO films deposited directly on Si. These results are expected to boost the realization of top-down and bottom-up LSMO device architectures on the Si platform for a variety of applications.

  18. Modification of the morphology of P(S-b-EO) templated thin TiO2 films by swelling with PS homopolymer.

    Science.gov (United States)

    Perlich, J; Schulz, L; Abul Kashem, M M; Cheng, Y-J; Memesa, M; Gutmann, J S; Roth, S V; Müller-Buschbaum, P

    2007-09-25

    For the controlled modification of sol-gel-templated polymer nanocomposites, which are transferred to a nanostructured, crystalline TiO2 phase by a calcination process, the addition of a single homopolymer was investigated. For the preparation, the homopolymer polystyrene (PS) is added in different amounts to the diblock copolymer P(S-b-EO) acting as a templating agent. The homopolymer/diblock copolymer blend system is combined with sol-gel chemistry to provide and attach the TiO2 nanoparticles to the diblock copolymer. So-called good-poor solvent-pair-induced phase separation leads to the formation of nanostructures by film preparation via spin coating. The fabricated morphologies are studied as a function of added homopolymer before and after calcination with atomic force microscopy, field emission scanning electron microscopy, and grazing incidence small-angle X-ray scattering. The observed behavior is discussed in the framework of controlling the block copolymer morphologies by the addition of homopolymers. At small homopolymer concentrations, the increase in homopolymer concentration changes the structure size, whereas at high homopolymer concentrations, a change in morphology is triggered. Thus, the behavior of a pure polymer system is transferred to a more complex hybrid system.

  19. Effect of gelatinization and additives on morphology and thermal behavior of corn starch/PVA blend films.

    Science.gov (United States)

    Luo, Xuegang; Li, Jiwei; Lin, Xiaoyan

    2012-11-06

    The blend films of ungelatinized and gelatinized starch/polyvinyl alcohol (PVA) were prepared with a solution casting method by the introduction of additives (glycerol/urea) or not. The phase morphologies and thermal behaviors of the blends were carefully analyzed. A droplet phase was observed in the blends containing ungelatinized starch and a laminated phase was observed in the blends containing gelatinized starch. For both ungelatinized and gelatinized starch/PVA blends, the melting temperature (T(m)) (210-230 °C) of PVA was detected, and the T(m) of gelatinized starch/PVA blends was higher than that of the ungelatinized starch/PVA blends. Blend films containing 16.8 wt% of glycerol or urea exhibited a decreased T(m). The introduction of additives (glycerol or urea) reduced the decomposition onset temperature of the blend films. These various morphologies and thermal behaviors could be attributed to the different hydrogen bonding interaction characteristics between starch and polyvinyl alcohol at different conditions. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  20. Effect of Energy Alignment, Electron Mobility, and Film Morphology of Perylene Diimide Based Polymers as Electron Transport Layer on the Performance of Perovskite Solar Cells.

    Science.gov (United States)

    Guo, Qiang; Xu, Yingxue; Xiao, Bo; Zhang, Bing; Zhou, Erjun; Wang, Fuzhi; Bai, Yiming; Hayat, Tasawar; Alsaedi, Ahmed; Tan, Zhan'ao

    2017-03-29

    For organic-inorganic perovskite solar cells (PerSCs), the electron transport layer (ETL) plays a crucial role in efficient electron extraction and transport for high performance PerSCs. Fullerene and its derivatives are commonly used as ETL for p-i-n structured PerSCs. However, these spherical small molecules are easy to aggregate with high annealing temperature and thus induce morphology stability problems. N-type conjugated polymers are promising candidates to overcome these problems due to the tunable energy levels, controllable aggregation behaviors, and good film formation abilities. Herein, a series of perylene diimide (PDI) based polymers (PX-PDIs), which contain different copolymeried units (X), including vinylene (V), thiophene (T), selenophene (Se), dibenzosilole (DBS), and cyclopentadithiophene (CPDT), are introduced as ETL for p-i-n structured PerSCs. The effect of energy alignment, electron mobility, and film morphology of these ETLs on the photovoltaic performance of the PerSCs are fully investigated. Among the PX-PDIs, PV-PDI demonstrates the deeper LUMO energy level, the highly delocalized LUMO electron density, and a better planar structure, making it the best electron transport material for PerSCs. The planar heterojunction PerSC with PV-PDI as ETL achieves a power conversion efficiency (PCE) of 10.14%, among the best values for non-fullerene based PerSCs.

  1. Ion-beam modifications of the surface morphology and conductivity in some polymer thin films

    Indian Academy of Sciences (India)

    M Ramakrishna Murthy; E Venkateshwar Rao

    2002-10-01

    Studies on the surface micromorphology and surface conductivity in thin polymer films of poly vinyl alcohol (PVA) and poly ethylene oxide (PEO) in both as-grown and ion-implanted polymer films have been carried out to reveal certain specific features of the ordered state in these materials. Optical microscopic investigations revealed the existence and enhanced formation in number of spherulites and dendrites in ionimplanted films relative to the as-grown films. The number and rate of formation of spherulites indicated an increase in the degree of crystallinity in these films. Measurements of surface conductivity of as-grown and ion-implanted polymer films, employing four-point probe method, indicated a decrease in electrical conductivity on ion-implantation. Photomicrographic analysis of the PVA and PEO thin film surfaces, has enabled to propose a temperature–stress induced mechanism of crystallization in conjunction with the surface conductivity measurements. The decrease in surface conductivity on ion-implantation in both PVA and PEO thin films, is attributed to a decrease in mobility of macromolecular charged species due to an increase in degree of crystallinity as has been observed by optical microscopy.

  2. Modifications of surfactant distributions and surface morphologies in latex films due to moisture exposure

    Science.gov (United States)

    Guizhen H. Xu; Jinping Dong; Steven J. Severtson; Carl J. Houtman; Larry E. Gwin

    2009-01-01

    Migration of surfactants in water-based, pressure-sensitive adhesive (PSA) films exposed to static and cyclic relative humidity conditions was investigated using confocal Raman microscopy (CRM) and atomic force microscopy (AFM). Studied PSA films contain monomers n-butyl acrylate, vinyl acetate, and methacrylic acid and an equal mass mixture of anionic and nonionic...

  3. Structural, morphological, optical and electrical properties of spray deposited lithium doped CdO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Velusamy, P.; Babu, R. Ramesh, E-mail: rampap2k@yahoo.co.in [Crystal Growth and Thin Films Laboratory, Department of Physics, Bharathidasan University, Tiruchirappalli-620 024, Tamil Nadu (India); Ramamurthi, K. [Crystal Growth and Thin Films Laboratory, Department of Physics and Nanotechnology, Faculty of Engineering and Technology, SRM University, Kattankulathur – 603 203, Tamil Nadu (India)

    2016-05-23

    In the present work, CdO and Li doped CdO thin films were deposited on microscopic glass substrates at 300°C by a spray pyrolysis experimental setup. The deposited CdO and Li doped CdO thin films were subjected to XRD, SEM, UV-VIS spectroscopy and Hall measurement analyses. XRD studies revealed the polycrystalline nature of the deposited films and confirmed that the deposited CdO and Li doped CdO thin films belong to cubic crystal system. The Scanning electron microscopy analysis revealed the information on shape of CdO and Li doped CdO films. Electrical study reveals the n-type semiconducting nature of CdO and the optical band gap is varied between 2.38 and 2.44 eV, depending on the Li doping concentrations.

  4. Structural, morphological, optical and electrical properties of spray deposited lithium doped CdO thin films

    Science.gov (United States)

    Velusamy, P.; Babu, R. Ramesh; Ramamurthi, K.

    2016-05-01

    In the present work, CdO and Li doped CdO thin films were deposited on microscopic glass substrates at 300˚C by a spray pyrolysis experimental setup. The deposited CdO and Li doped CdO thin films were subjected to XRD, SEM, UV-VIS spectroscopy and Hall measurement analyses. XRD studies revealed the polycrystalline nature of the deposited films and confirmed that the deposited CdO and Li doped CdO thin films belong to cubic crystal system. The Scanning electron microscopy analysis revealed the information on shape of CdO and Li doped CdO films. Electrical study reveals the n-type semiconducting nature of CdO and the optical band gap is varied between 2.38 and 2.44 eV, depending on the Li doping concentrations.

  5. Assessment of morphology and property of graphene oxide-hydroxypropylmethylcellulose nanocomposite films.

    Science.gov (United States)

    Ghosh, Tapas Kumar; Gope, Shirshendu; Mondal, Dibyendu; Bhowmik, Biplab; Mollick, Md Masud Rahaman; Maity, Dipanwita; Roy, Indranil; Sarkar, Gunjan; Sadhukhan, Sourav; Rana, Dipak; Chakraborty, Mukut; Chattopadhyay, Dipankar

    2014-05-01

    Graphene oxide (GO) was synthesized by Hummer's method and characterized by using Fourier transform infrared spectroscopy and Raman spectroscopy. The as synthesized GO was used to make GO/hydroxypropylmethylcellulose (HPMC) nanocomposite films by the solution mixing method using different concentrations of GO. The nanocomposite films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and thermo-gravimetric analysis. Mechanical properties, water absorption property and water vapor transmission rate were also measured. XRD analysis showed the formation of exfoliated HPMC/GO nanocomposites films. The FESEM results revealed high interfacial adhesion between the GO and HPMC matrix. The tensile strength and Young's modulus of the nanocomposite films containing the highest weight percentage of GO increased sharply. The thermal stability of HPMC/GO nanocomposites was slightly better than pure HPMC. The water absorption and water vapor transmission rate of HPMC film was reduced with the addition of up to 1 wt% GO.

  6. Optical, electrochemical and morphological investigations of poly (3,4-propylenedioxythiophene)–sultone (PProDOT–S) thin films

    Indian Academy of Sciences (India)

    S Sindhu; C R Siju; S K Sharma; K N Rao; E S R Gopal

    2012-08-01

    In this paper, we have carried out thin film characterization of poly(3,4-propylenedioxythiophene)–sultone (PProDOT–S), a derivative of electrochromic poly(3,4-propylenedioxythiophene) (PProDOT). PProDOT–S was deposited onto transparent conducting oxide coated glass substrates by solution casting method. Single wavelength spectrophotometry is used to monitor the switching speed and contrast ratio at maximum wavelength (max). The percentage transmittance at the max of the neutral polymer is monitored as a function of time when the polymer film is repeatedly switched. This experiment gives a quantitative measure of the speed with which a film is able to switch between the two states i.e. the coloured and the bleached states. PProDOT–S films were switched at a voltage of 1.9 V with a switching speed of 2 s at max of 565 nm and showed a contrast of ∼37%. Cyclic voltammetry performed at different scan rates have shown the characteristic anodic and cathodic peaks. The structural investigations of PProDOT–S films by IR spectra were in good agreement with previously reported results. Raman spectra of PProDOT–S showed a strong Raman peak at 1509 cm-1 and a weak peak at 1410 cm-1 due to the C = C asymmetric and symmetric stretching vibrations of thiophene rings. The morphological investigations carried out by using scanning electron microscope (SEM) of polymer films have shown that these polymers are found to be arranged in dense packed clusters with non-uniform distribution having an average width and length of 95 nm and 160 nm, respectively.

  7. A novel in-situ technique to fabricate thin films with controlled lateral thickness modulations

    Science.gov (United States)

    Zhang, Chi

    Surfaces having well-defined morphologies like periodic arrays of dots or lines, promise useful applications. Magnetic nanodots of Co and Fe-alloys are useful in patterned magnetic recording media. Well controlled grain size and surface area of nanostructured TiO2 are useful to develop efficient photocatalysts. However, there is a continuing need to develop techniques to make such surfaces in a simple and economical manner. In this thesis, a previously unexplored in-situ approach to assemble lateral patterns in thin films was proposed and investigated. Simple models of film growth on a defect free surface show that under uniform areal deposition rates and surface temperatures, nucleation occurs at random positions on the surface. We proposed that by exposing a growing thin film to a spatially varying surface temperature distribution, nucleation and growth can be confined to specific spatial locations. Consequently, a film with a desired pattern or thickness modulation could be achieved. The experimental approach consists of irradiating the substrate surface with a laser interference pattern simultaneous with physical vapor deposition (PVD). To perform such film growth experiments, a vibration minimized and multifunctional ultra-high vacuum chamber was integrated with a Nd:YAG laser. The laser output is a beam of 266 nm with a coherence length of approximately 2 m and an area of ˜0.8 x 0.8 cm2. The laser has a pulse width of 9 ns, a constant repetition rate of 50 Hz, with a rated peak output of 44 mJ/pulse. The typical laser energy density used in this work was about 10 mJ/cm2. Since sub-micron length scales were of interest, vibration studies were performed by recording the interference patterns on kapton films. Results from the kapton films, measurements using a shear accelerometer and recent growth results showed that peak-to-peak vibration amplitudes on the substrate surface were less than +/-25 nm. Well-established PVD techniques like pulsed laser deposition

  8. Surface morphologies of MOCVD-grown GaN films on sapphire studied by scanning tunneling microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, J.; Reddic, J.E.; Sinha, M.; Ricker, W.S.; Karlinsey, J.; Yang, J.-W.; Khan, M.A.; Chen, D.A

    2002-12-30

    The surface morphologies of MOCVD GaN films grown on sapphire substrates have been investigated by scanning tunneling microscopy (STM). High quality STM images could not be obtained prior to cleaning the les in HF, hot HCl or 2 M NaOH. STM images of the GaN films showed that the surfaces consisted of curved step edges and interlocking terraces, which were roughly 224 nm wide. Surface pits approximately 2-5 nm deep and 50-80 nm wide were observed on the GaN films, and these pits were preferentially located at a juncture between two step edges. Previous studies in the literature involving MOCVD-grown GaN on sapphire have demonstrated that the surface pits are associated with screw-component threading dislocations. Therefore, the number of screw-component threading dislocations in these GaN films is estimated as 6.3x10{sup 8} cm{sup -2} from the number surface pits observed in the STM images. X-ray photoelectron studies indicated that the major surface contaminants before cleaning were carbon and oxygen. Treatment in HF or HCl removed oxygen from the surface while treatment in NaOH was more effective at removing surface carbon.

  9. Morphology-controlled In2O3 nanostructures enhance the performance of photoelectrochemical water oxidation

    Science.gov (United States)

    Chen, Changlong; Moir, Jonathon; Soheilnia, Navid; Mahler, Benoit; Hoch, Laura; Liao, Kristine; Hoepfner, Veronika; O'Brien, Paul; Qian, Chenxi; He, Le; Ozin, Geoffrey A.

    2015-02-01

    Nanotower- and nanowall-like indium oxide structures were grown directly on fluorine-doped tin oxide (FTO)/In2O3 seeded substrates and pristine FTO substrates, respectively, by a straightforward solvothermal method. The tower-like nanostructures are proposed to form via a self-assembly process on the In2O3 seeds. The wall-like nanostructures are proposed to form via epitaxial growth from the exposed edges of SnO2 crystals of the FTO substrate. The nanotowers and nanowalls are composed of highly crystalline and ordered nanocrystals with preferred orientations in the [111] and [110] directions, respectively. The two structures display remarkably different activities when used as photoanodes in solar light-driven water splitting. X-ray photoelectron spectroscopy results suggest an increased density of hydroxyl groups in the nanowalls, which results in a decrease of the work function and a concomitant shift in the onset potential of the photocurrent in the linear sweep voltammograms, which is further confirmed by Mott-Schottky and flat-band potential measurements, indicating the importance of hydroxyl content in determining the photoelectrochemical properties of the films. Morphology-controlled, nanostructured transparent conducting oxide electrodes of the kind described in this paper are envisioned to provide valuable platforms for supporting catalysts and co-catalysts that are intentionally tailored for efficient light-assisted oxidation of water and reduction of carbon dioxide.Nanotower- and nanowall-like indium oxide structures were grown directly on fluorine-doped tin oxide (FTO)/In2O3 seeded substrates and pristine FTO substrates, respectively, by a straightforward solvothermal method. The tower-like nanostructures are proposed to form via a self-assembly process on the In2O3 seeds. The wall-like nanostructures are proposed to form via epitaxial growth from the exposed edges of SnO2 crystals of the FTO substrate. The nanotowers and nanowalls are composed of

  10. Surface morphology and optical properties of cdse films obtained by the close-spaced vacuum sublimation technique

    Directory of Open Access Journals (Sweden)

    V.V. Starikov

    2009-01-01

    Full Text Available Investigation of the surface morphology, growth mechanisms and optical properties of CdSe films obtained by the close-spaced vacuum sublimation (CSVS technique, which are promising for use as the absorption layers of tandem solar cells and photodetectors, was carried out in the present paper. Measurements of the optical characteristics of the layers were performed by the spectrophotometric analysis method near the “red boundary” of semiconductor photoactivity. Performed investigations allowed to obtain the spectral distributions of the transmission T(λ, reflection R(λ, absorption α(λ, and refraction n(λ coefficients, and the real ε1(λ and imaginary ε2(λ parts of the optical dielectric constant of the samples and to define their dependence on the film deposition temperature.

  11. Growth Mechanism and Morphology of ZnO/eosin-Y Hybrid Thin Films

    Institute of Scientific and Technical Information of China (English)

    MAR(I) Bernabé; SINGH Krishan-Chander; MOLLAR Miguel; MOYA Mónica; RANA Ravi

    2012-01-01

    Thin hybrid films of ZnO/eosin-Y were prepared by electrodeposition at-0.8 and -0.9 V in aqueous and non-aqueous baths at temperatures ranging from 40 to 90 ℃ with dye concentrations of 100 and 400 μmol· L-1.The films were characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM),energy-dispersive X-ray analysis (EDX),and absorption spectroscopy.The films prepared in a non-aqueous bath were non-porous and did not adsorb dye molecules on their surface.However,the films grown in aqueous media were porous in nature and adsorbed dye during the deposition of ZnO.Preferential growth of the film along the (002) face was observed,and the highest crystallinity was achieved when the film was deposited at 60 ℃.The maximum absorption was achieved for the films grown at 60 to 70 ℃,a deposition potential of-0.9 V,and a dye concentration of 100 μmol· L-1.

  12. Morphology and photoresponse of crystalline antimony film grown on mica by physical vapor deposition

    Directory of Open Access Journals (Sweden)

    Shafa Muhammad

    2016-09-01

    Full Text Available Antimony is a promising material for the fabrication of photodetectors. This study deals with the growth of a photosensitive thin film by the physical vapor deposition (PVD of antimony onto mica surface in a furnace tube. The geometry of the grown structures was studied via scanning electron microscopy (SEM, X-ray diffraction (XRD, energy-dispersive X-ray spectroscopy (EDX and elemental diffraction analysis. XRD peaks of the antimony film grown on mica mostly matched with JCPDF Card. The formation of rhombohedral crystal structures in the film was further confirmed by SEM micrographs and chemical composition analysis. The Hall measurements revealed good electrical conductivity of the film with bulk carrier concentration of the order of 1022 Ω·cm-3 and mobility of 9.034 cm2/Vs. The grown film was successfully tested for radiation detection. The photoresponse of the film was evaluated using its current-voltage characteristics. These investigations revealed that the photosensitivity of the antimony film was 20 times higher than that of crystalline germanium.

  13. Controllable Curved Mirrors Made from Single-Layer EAP Films

    Science.gov (United States)

    Bao, Xiaoqi; Bar-Cohen, Yoseph; Sherrit, Stewart

    2004-01-01

    A document proposes that lightweight, deployable, large-aperture, controllable curved mirrors made of reflectively coated thin electroactive-polymer (EAP) films be developed for use in spaceborne microwave and optical systems. In these mirrors, the EAP films would serve as both structures and actuators. EAPs that are potentially suitable for such use include piezoelectric, electrostrictive, ferroelectric, and dielectric polymers. These materials exhibit strains proportional to the squares of applied electric fields. Utilizing this phenomenon, a curved mirror according to the proposal could be made from a flat film, upon which a nonuniform electrostatic potential (decreasing from the center toward the edge) would be imposed to obtain a required curvature. The effect would be analogous to that of an old-fashioned metalworking practice in which a flat metal sheet is made into a bowl by hammering it repeatedly, the frequency of hammer blows decreasing with distance from the center. In operation, the nonuniform electrostatic potential could be imposed by use of an electron gun. Calculations have shown that by use of a single- layer film made of a currently available EAP, it would be possible to control the focal length of a 2-m-diameter mirror from infinity to 1.25 m.

  14. Controlled release of ethylene via polymeric films for food packaging

    Science.gov (United States)

    Pisano, Roberto; Bazzano, Marco; Capozzi, Luigi Carlo; Ferri, Ada; Sangermano, Marco

    2015-12-01

    In modern fruit supply chain a common method to trigger ripening is to keep fruits inside special chambers and initiate the ripening process through administration of ethylene. Ethylene is usually administered through cylinders with inadequate control of its final concentration in the chamber. The aim of this study is the development of a new technology to accurately regulate ethylene concentration in the atmosphere where fruits are preserved: a polymeric film, containing an inclusion complex of α-cyclodextrin with ethylene, was developed. The complex was prepared by molecular encapsulation which allows the entrapment of ethylene into the cavity of α-cyclodextrin. After encapsulation, ethylene can be gradually released from the inclusion complex and its release rate can be regulated by temperature and humidity. The inclusion complex was dispersed into a thin polymeric film produced by UV-curing. This method was used because is solvent-free and involves low operating temperature; both conditions are necessary to prevent rapid release of ethylene from the film. The polymeric films were characterized with respect to thermal behaviour, crystalline structure and kinetics of ethylene release, showing that can effectively control the release of ethylene within confined volume.

  15. On Controllable Elastohydrodynamic Fluid Film Bearings

    DEFF Research Database (Denmark)

    Haugaard, Martin Asger

    This thesis gives a theoretical description of the active tilting-pad journal bearing (ATPJB). It provides the qualified reader with the tools to model an ATPJB, while staying clear of pitfalls. The model is based on well known techniques and allows for local stability analyses, harmonic stationary...... are performed for a tilting-pad journal bearing (TPJB) and an ATPJB under static conditions, followed by a generalisation to dynamic conditions (transient as well as stationary harmonic). These analyses will be of interest to experimentalists, since they permit experiments performed on scaled down test rigs...... the addition of a control system may just as well harm rotor-bearing performance as improve it....

  16. Surface morphology-dependent room-temperature LaFeO₃ nanostructure thin films as selective NO₂ gas sensor prepared by radio frequency magnetron sputtering.

    Science.gov (United States)

    Thirumalairajan, S; Girija, K; Mastelaro, Valmor R; Ponpandian, N

    2014-08-27

    In the present work, perovskite LaFeO3 thin films with unique morphology were obtained on silicon substrate using radio frequency magnetron sputtering technique. The effect of thickness and temperature on the morphological and structural properties of LaFeO3 films was systematically studied. The X-ray diffraction pattern explored the highly oriented orthorhombic perovskite phase of the prepared thin films along [121]. Electron micrograph images exposed the network and nanocube surface morphology of LaFeO3 thin films with average sizes of ∼90 and 70 nm, respectively. The developed LaFeO3 thin films not only possess unique morphology, but also influence the gas-sensing performance toward NO2. Among the two morphologies, nanocubes exhibited high sensitivity, good selectivity, fast response-recovery time, and excellent repeatability for 1 ppm level of NO2 gas at room temperature. The response time for nanocubes was 24-11 s with a recovery duration of 35-15 s less than the network structure. The sensitivity toward NO2 detection was found to be in the range 29.60-157.89. The enhancement in gas-sensing properties is attributed to their porous structure, surface morphology, numerous surface active sites, and the oxygen vacancies. The gas-sensing measurements demonstrate that the LaFeO3 sensing material is an outstanding candidate for NO2 detection.

  17. Study on micro-structure and morphological evolution of Fe/Pt nano-magnetic film.

    Science.gov (United States)

    Ishiguro, S; Ju, D Y; Ogatsu, R; Nakano, T

    2011-10-01

    One of the vertical magnetic recordings medium materials of the hard disk drive (HDD) is a Fe/Pt thin film. The development of ultra-high density magnetic recording medium in next generation is expected the magnetic disks such as HDD with capacity enlargement of the data. In order to study effectiveness of the proposed sputtering method, we evaluated micro structure, magnetic and the mechanical properties of a Fe/Pt thin film by some sputtering process conditions. From research results, effect sputtering conditions on micro-structure and mechanical properties of Fe/Pt nano film are verified.

  18. Bonding structure and morphology of chromium oxide films grown by pulsed-DC reactive magnetron sputter deposition

    Energy Technology Data Exchange (ETDEWEB)

    Gago, R., E-mail: rgago@icmm.csic.es [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas, E-28049 Madrid (Spain); Vinnichenko, M. [Fraunhofer-Institut für Keramische Technologien und Systeme IKTS, D-01277 Dresden (Germany); Hübner, R. [Helmholtz-Zentrum Dresden – Rossendorf, Institute of Ion Beam Physics and Materials Research, Bautzner Landstraße 400, 01328 Dresden (Germany); Redondo-Cubero, A. [Departamento de Física Aplicada and Centro de Microanálisis de Materiales, Universidad Autónoma de Madrid, E-28049 Madrid (Spain)

    2016-07-05

    Chromium oxide (CrO{sub x}) thin films were grown by pulsed-DC reactive magnetron sputter deposition in an Ar/O{sub 2} discharge as a function of the O{sub 2} fraction in the gas mixture (ƒ) and for substrate temperatures, T{sub s}, up to 450 °C. The samples were analysed by Rutherford backscattering spectrometry (RBS), spectroscopic ellipsometry (SE), atomic force microscopy (AFM), scanning (SEM) and transmission (TEM) electron microscopy, X-ray diffraction (XRD), and X-ray absorption near-edge structure (XANES). On unheated substrates, by increasing ƒ the growth rate is higher and the O/Cr ratio (x) rises from ∼2 up to ∼2.5. Inversely, by increasing T{sub s} the atomic incorporation rate drops and x falls to ∼1.8. XRD shows that samples grown on unheated substrates are amorphous and that nanocrystalline Cr{sub 2}O{sub 3} (x = 1.5) is formed by increasing T{sub s}. In amorphous CrO{sub x}, XANES reveals the presence of multiple Cr environments that indicate the growth of mixed-valence oxides, with progressive promotion of hexavalent states with ƒ. XANES data also confirms the formation of single-phase nanocrystalline Cr{sub 2}O{sub 3} at elevated T{sub s}. These structural changes also reflect on the optical and morphological properties of the films. - Highlights: • XANES of CrO{sub x} thin films grown by pulsed-DC reactive magnetron sputtering. • Identification of mixed-valence amorphous CrO{sub x} oxides on unheated substrates. • Promotion of amorphous chromic acid (Cr{sup VI}) by increasing O{sub 2} partial pressure. • Production of single-phase Cr{sub 2}O{sub 3} films by increasing substrate temperature. • Correlation of bonding structure with morphological and optical properties.

  19. Study of effect annealing temperature on the structure, morphology and photocatalytic activity of Si doped TiO{sub 2} thin films deposited by electron beam evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Lu Zhongdan [Key Lab of Soft Chemistry and Functional Materials of Ministry of Education, Nanjing University of Science and Technology, Xiaolingwei 200, Nanjing 210094 (China); Jiang Xiaohong, E-mail: jiangxh24@mail.njust.edu.cn [Key Lab of Soft Chemistry and Functional Materials of Ministry of Education, Nanjing University of Science and Technology, Xiaolingwei 200, Nanjing 210094 (China); Zhou Bing; Wu Xiaodong; Lu Lude [Key Lab of Soft Chemistry and Functional Materials of Ministry of Education, Nanjing University of Science and Technology, Xiaolingwei 200, Nanjing 210094 (China)

    2011-10-01

    Transparent Si-doped TiO{sub 2} thin films (Si-TiO{sub 2}) were deposited on quartz glasses using electron beam evaporation (EBE) and annealed at different temperature in an air atmosphere. The structure and morphology of these films were analyzed by X-ray diffraction (XRD), Raman microscopy (Raman), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Meanwhile the photocatalytic activity of the films has also been evaluated on the basis of the degradation degree of rhodamine B in aqueous solution. Our experimental results suggest that the annealing temperature impact a strong effect on the structure, morphology and photocatalytic activity of Si-TiO{sub 2} thin films. Furthermore the enhanced thermal stability of Si-TiO{sub 2} films enabled them to elevate the phase transformation temperature of TiO{sub 2} from anatase to rutile and enhanced the photocatalytic efficiency.

  20. Structural and morphological characterization of TiO2-SnO2 thin film prepared by combining doctor-blade and sol-gel techniques

    Science.gov (United States)

    Adawiyah, S. R.; Endarko

    2017-04-01

    The TiO2-SnO2 thin film has successfully been synthesized using the co-precipitation method and was coated on ITO (Indium Tin Oxide) substrate by doctor-blade technique. The structure and morphology of the film were investigated by XRD and SEM, respectively. The results showed that the film with SnO2 has a stronger formation of anatase phase compared to TiO2 film. The morphological study is also revealed that the TiO2-SnO2 film has a more porous nature and uniform particle aggregates, and the presence of SnO2 has been confirmed with EDX spectra.

  1. Stress and morphological development of CdS and ZnS thin films during the SILAR growth on (1 0 0)GaAs

    Science.gov (United States)

    Laukaitis, Giedrius; Lindroos, Seppo; Tamulevičius, Sigitas; Leskelä, Markku

    2001-12-01

    Cadmium sulfide and zinc sulfide films were grown on (1 0 0)GaAs substrate by successive ionic layer adsorption and reaction (SILAR) technique from aqueous precursor solutions at room temperature and normal pressure. The stress development of the thin films was characterized by laser interferometry as a function of the thickness of the films. The morphology and roughness of the films were monitored by atomic force microscopy. Additionally the crystallinity and crystallite size were analyzed by X-ray diffraction and composition by electron spectroscopy for chemical analysis. The CdS thin films had significantly higher stress level and also better crystallinity compared with ZnS thin films. Both films were polycrystalline and cubic, but the CdS thin films followed the substrate (1 0 0) orientation, whereas the ZnS films were (1 1 1) orientated. The roughness vs. film thickness curves of both films followed each other in shape, but the CdS films consisted of smaller particles.

  2. Composite films of arabinoxylan and fibrous sepiolite: Morphological, mechanical, and barrier properties

    CSIR Research Space (South Africa)

    Sarossy, Z

    2012-06-01

    Full Text Available . Consistent with these findings, mechanical testing showed increases in film stiffness and strength with sepiolite addition and the effect of poly(ethylene glycol) methyl ether (mPEG) plasticizer addition. Incorporation of sepiolite did not significantly...

  3. Optical and morphological properties of porous diamond-like-carbon films deposited by magnetron sputtering

    OpenAIRE

    Baroni, M. P. M. A.; Conceição, M. Ventura; Rosa, R. R.; Persson, C.; Arwin, H.; Silva Jr., E.F. da; Roman, L.S.; Nakamura, O.; I. Pepe; Silva, A. Ferreira da

    2006-01-01

    RESTRITO Porous diamond-like-carbon (PDLC) thin films obtained on silicon substrate by DC low energy magnetron sputtering have been investigated by photoluminescence, transmission and reflection spectroscopy, photoacoustic and spectroscopic ellipsometry. The absorption features observed for these films show similarities with those of porous silicon (PS) as well as in the performed gradient structural pattern classification of the SFM porosity, by means of the computational GPA-flyby enviro...

  4. Morphology and current-voltage characteristics of nanostructured pentacene thin films probed by atomic force microscopy.

    Science.gov (United States)

    Zorba, S; Le, Q T; Watkins, N J; Yan, L; Gao, Y

    2001-09-01

    Atomic force microscopy was used to study the growth modes (on SiO2, MoS2, and Au substrates) and the current-voltage (I-V) characteristics of organic semiconductor pentacene. Pentacene films grow on SiO2 substrate in a layer-by-layer manner with full coverage at an average thickness of 20 A and have the highest degree of molecular ordering with large dendritic grains among the pentacene films deposited on the three different substrates. Films grown on MoS2 substrate reveal two different growth modes, snowflake-like growth and granular growth, both of which seem to compete with each other. On the other hand, films deposited on Au substrate show granular structure for thinner coverages (no crystal structure) and dendritic growth for higher coverages (crystal structure). I-V measurements were performed with a platinum tip on a pentacene film deposited on a Au substrate. The I-V curves on pentacene film reveal symmetric tunneling type character. The field dependence of the current indicates that the main transport mechanism at high field intensities is hopping (Poole-Frenkel effect). From these measurements, we have estimated a field lowering coefficient of 9.77 x 10(-6) V-1/2 m1/2 and an ideality factor of 18 for pentacene.

  5. Controllable injector for local flux entry into superconducting films

    Energy Technology Data Exchange (ETDEWEB)

    Carmo, D.; Colauto, F.; de Andrade, A. M. H.; Oliveira, A. A. M.; Ortiz, W. A.; Johansen, T. H.

    2016-07-21

    A superconducting flux injector (SFI) has been designed to allow for controlled injections of magnetic flux into a superconducting film from a predefined location along the edge. The SFI is activated by an external current pulse, here chosen to be 200 ms long, and it is demonstrated on films of Nb that the amount of injected flux is controlled by the pulse height. Examples of injections at two different temperatures where the flux enters by stimulated flux-flow and by triggered thermomagnetic avalanches are presented. The boundary between the two types of injection is determined and discussed. The SFI opens up for active use of phenomena which up to now have been considered hazardous for a safe operation of superconducting devices.

  6. A Controlled Study on the Correlation between Tear Film Volume and Tear Film Stability in Diabetic Patients.

    Science.gov (United States)

    Eissa, Iman M; Khalil, Noha M; El-Gendy, Heba A

    2016-01-01

    Purpose. To assess the tear film quantity and correlate it with the quality and stability of the tear film in diabetics and compare them to age matched controls. Introduction. Diabetes affects tear film parameters in multiple ways. Poor metabolic control and neuropathy are postulated factors. To further understand how diabetes affects tear film parameters this study was conducted. Subjects and Methods. Tear meniscus height was measured by anterior segment OCT, along with tear thinning time, a subtype of noninvasive tear break-up time, and blinking rate per minute which were all recorded for 22 diabetic patients. Correlations between these tear film parameters were studied and then compared to 16 age matched controls. Results. A statistically significant difference was found in blinking rate between the diabetic and the control group (P = 0.002), with higher blinking rate among diabetics. All tear film parameters were negatively correlated with duration of diabetes. A positive correlation was found between tear film volume and stability. Conclusion. Diabetes affects the tear film in various ways. Diabetics should be examined for dry eye signs even in absence of symptoms which may be masked by associated neuropathy. Duration of diabetes has an impact on tear film status.

  7. Order-disorder criticality, wetting, and morphological phase transitions in the irreversible growth of far-from-equilibrium magnetic films

    Energy Technology Data Exchange (ETDEWEB)

    Candia, J.Julian; Albano, E.V.Ezequiel V. E-mail: ealbano@inifta.unlp.edu.ar

    2003-04-01

    An exhaustive numerical investigation of the growth of magnetic films in confined (d+1)-dimensional stripped geometries (d=1,2) is carried out by means of extensive Monte Carlo simulations. Films in contact with a thermal bath at temperature T, are grown by adding spins having two possible orientations and considering ferromagnetic (nearest-neighbor) interactions. At low temperatures, thin films of thickness L are constituted by a sequence of well-ordered domains of average length l{sub D}>>L. These domains have opposite magnetization. So, the films exhibit 'spontaneous magnetization reversal' during the growth process. Such reversal occurs within a short characteristic length l{sub R}, such that l{sub D}>>l{sub R}{approx}L. Furthermore, it is found that for d=1 the system is non-critical, while a continuous order-disorder phase transition at finite temperature takes place in the d=2 case. Using standard finite-size scaling procedures, the critical temperature and some relevant critical exponents are determined. Finally, the growth of magnetic films in (2+1) dimensions with competing short-range magnetic fields acting along the confinement walls is studied. Due to the antisymmetric condition considered, an interface between domains with spins having opposite orientation develops along the growing direction. Such an interface undergoes a localization-delocalization transition that is the precursor of a wetting transition in the thermodynamic limit. Furthermore, the growing interface also undergoes morphological transitions in the growth mode. A comparison between the well-studied equilibrium Ising model and the studied irreversible magnetic growth model is performed throughout. Although valuable analogies are encountered, it is found that the non-equilibrium nature of the latter introduces new and rich physical features of interest.

  8. Order-disorder criticality, wetting, and morphological phase transitions in the irreversible growth of far-from-equilibrium magnetic films

    Science.gov (United States)

    Candia, Julián; Albano, Ezequiel V.

    2003-04-01

    An exhaustive numerical investigation of the growth of magnetic films in confined ( d+1)-dimensional stripped geometries ( d=1,2) is carried out by means of extensive Monte Carlo simulations. Films in contact with a thermal bath at temperature T, are grown by adding spins having two possible orientations and considering ferromagnetic (nearest-neighbor) interactions. At low temperatures, thin films of thickness L are constituted by a sequence of well-ordered domains of average length lD≫ L. These domains have opposite magnetization. So, the films exhibit "spontaneous magnetization reversal" during the growth process. Such reversal occurs within a short characteristic length lR, such that lD≫ lR˜ L. Furthermore, it is found that for d=1 the system is non-critical, while a continuous order-disorder phase transition at finite temperature takes place in the d=2 case. Using standard finite-size scaling procedures, the critical temperature and some relevant critical exponents are determined. Finally, the growth of magnetic films in (2+1) dimensions with competing short-range magnetic fields acting along the confinement walls is studied. Due to the antisymmetric condition considered, an interface between domains with spins having opposite orientation develops along the growing direction. Such an interface undergoes a localization-delocalization transition that is the precursor of a wetting transition in the thermodynamic limit. Furthermore, the growing interface also undergoes morphological transitions in the growth mode. A comparison between the well-studied equilibrium Ising model and the studied irreversible magnetic growth model is performed throughout. Although valuable analogies are encountered, it is found that the non-equilibrium nature of the latter introduces new and rich physical features of interest.

  9. Structural, Morphological and Optical Properties of Sn3Sb2S6 Thin Films Synthesized by Oblique Angle Deposition

    Science.gov (United States)

    Larbi, A.; Chaffar Akkari, F.; Dahman, H.; Demaille, D.; Gallas, B.; Kanzari, M.

    2016-10-01

    The oblique angle deposition technique has attracted a lot attention in many different applications due to its unique advantage of programmable nanocolumns. In this work we use this technique to investigate the physical properties of obliquely thermal evaporated Sn3Sb2S6 thin films deposited onto unheated glass and silicon substrates, inclined from the flux vapor source at the deposition angles 0°, 40°, 60°, 75° and 85°. X-ray diffraction (XRD) and UV-Visible and near infrared (UV-Vis-IFR) analysis were used respectively to characterize the structural and optical properties of the layers. The influence of flux angle on the surface morphology and the microstructure was investigated by using scanning electron microscopy. The optical constants were obtained from analysis of the experimental recorded transmission and reflectance spectral data over the wavelength range 300 nm to 1800 nm. The band gaps of the synthesized thin films were found to be direct allowed transitions and increased from 1.44 eV to 1.66 eV with increasing γ from 0° to 85°, respectively. The absorption coefficients of the films are in the range of 105 cm-1 to 106 cm-1. The refractive indexes were evaluated in the transparent region in terms of the envelope method suggested by the Swanepoel model. It has been found that the refractive index decreases from 2.66 to 2.06 with increasing deposition angle from 0° to 85°, respectively. The relationship between the flux incident angles γ and the column angle β was also explored. The oblique angle deposition films showed an inclined columnar structure, with columns tilting in the direction of the incident flux. The effective packing densities of the synthesized Sn3Sb2S6 thin films were calculated using Bruggeman effective medium approximation.

  10. Temperature Controlled Lateral Pattern Formation in Confined Polymer Thin Films

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hao-li; David G. Bucknall

    2004-01-01

    The thermal induced topography change in a model system consisting of a polymer film on a Si substrate capped by a thin metal layer has been studied by using AFM. Regular lateral patterns over large areas were observed on the surface when the system was heated to a sufficiently high temperature. 2D-FFT analysis to the AFM images indicates that the patterns are isotropic and have well defined periodicities. The periodicities of the characteristic patterns are found to depend strongly on the annealing temperature. The study of the kinetics of the formation reveals that such a topography forms almost instantaneously once the critical temperature is reached. It is suggested that this wave-like surface morphology is driven by the thermal expansion coefficient mismatch of the different layers. This method for generating regular wave-like patterns could be used as a general method for patterning various organic materials into micro/nanostructures.

  11. Cyclopentadithiophene organic core in small molecule organic solar cells: morphological control of carrier recombination.

    Science.gov (United States)

    Domínguez, Rocío; Montcada, Núria F; de la Cruz, Pilar; Palomares, Emilio; Langa, Fernando

    2017-02-01

    Two new planar and symmetrical A-D-A (electron acceptor-electron donor-electron acceptor) small molecules based on a commercial cyclopentadithiophene derivative have been synthesized for solution processed small molecule organic solar cells. The aim was to synthesise the molecules to be energetically identical (similar HOMO-LUMO energy levels) in order to assign the differences observed to changes in the film morphology or to differences in the interfacial recombination kinetics or both. Devices were electrically characterized under one sun simulated (1.5 AM G) conditions by determining current-voltage curves, light harvesting efficiencies and external quantum efficiencies. Moreover, time-resolved photo-induced techniques such as photo-induced charge extraction and photo-induced transient photo-voltage were also performed. The results demonstrate that, despite having the same core, i.e. cyclopentadithiophene, the use of one hexyl chain instead of two in the organic molecule leads to a greater control of the molecular ordering using solvent vapour annealing techniques and also to better solar cell efficiency.

  12. Pulsed-laser printing of silver nanoparticles ink: control of morphological properties.

    Science.gov (United States)

    Rapp, Ludovic; Ailuno, Julie; Alloncle, Anne Patricia; Delaporte, Philippe

    2011-10-24

    Fine electrically-conductive patterns of silver nanoparticles ink have been laser printed using the laser-induced forward transfer (LIFT) technique. LIFT is a technique that offers the possibility of printing patterns with high spatial resolution from a wide range of materials in solid or liquid state. Influence of drying the ink film, previous to its transfer, on the printed droplet morphology is discussed. The laser pulse energy and donor-receiver substrate separation were systematically varied and their effects on the transferred droplets were analyzed. The use of an intermediate titanium dynamic release layer was also investigated and demonstrated the possibility of a better control of both the size and shape of the printed patterns. Conditions have been determined for printing flat-top droplets with sharp edges. 21 µm width silver lines with 80 nm thickness have been printed with a smooth convex profile. Electrical resistivities of the transferred patterns are only 5 times higher than the bulk silver. © 2011 Optical Society of America

  13. Morphological control of layered double hydroxide through a biomimetic approach using carboxylic and sulfonic acids

    Directory of Open Access Journals (Sweden)

    Taishi Yokoi

    2015-09-01

    Full Text Available Layered double hydroxides (LDHs have intercalation properties and are used in various applications. The performances of the LDH materials can be improved by controlling crystal morphology. Morphology of inorganic crystals is controlled by organic molecules in biomineralization. Inspired by biomineralization, we investigated the effect of the addition of mono, di and triacids as morphological control agents on crystal morphology of LDH synthesized by the homogeneous precipitation method. Morphology of LDH was changed from hexagonal plate to stacked disc by addition of monoacids, namely acetic acid and methanesulfonic acid, in the reaction solution. Flower-shaped LDH crystals were formed in the presence of diacids and a triacid, namely succinic acid, 1,2-ethanedisulfonic acid and 1,2,3-propanetricarboxylic acid. We found that the morphology of the LDH crystals was controlled by the number of functional group on the morphological control agent rather than the type of functional group. These findings can contribute for the development of novel and functional LDH materials with precisely controlled morphology.

  14. Controlled Mechanical Cracking of Metal Films Deposited on Polydimethylsiloxane (PDMS

    Directory of Open Access Journals (Sweden)

    Andreas Polywka

    2016-09-01

    Full Text Available Stretchable large area electronics conform to arbitrarily-shaped 3D surfaces and enables comfortable contact to the human skin and other biological tissue. There are approaches allowing for large area thin films to be stretched by tens of percent without cracking. The approach presented here does not prevent cracking, rather it aims to precisely control the crack positions and their orientation. For this purpose, the polydimethylsiloxane (PDMS is hardened by exposure to ultraviolet radiation (172 nm through an exposure mask. Only well-defined patterns are kept untreated. With these soft islands cracks at the hardened surface can be controlled in terms of starting position, direction and end position. This approach is first investigated at the hardened PDMS surface itself. It is then applied to conductive silver films deposited from the liquid phase. It is found that statistical (uncontrolled cracking of the silver films can be avoided at strain below 35%. This enables metal interconnects to be integrated into stretchable networks. The combination of controlled cracks with wrinkling enables interconnects that are stretchable in arbitrary and changing directions. The deposition and patterning does not involve vacuum processing, photolithography, or solvents.

  15. Accurately controlled sequential self-folding structures by polystyrene film

    Science.gov (United States)

    Deng, Dongping; Yang, Yang; Chen, Yong; Lan, Xing; Tice, Jesse

    2017-08-01

    Four-dimensional (4D) printing overcomes the traditional fabrication limitations by designing heterogeneous materials to enable the printed structures evolve over time (the fourth dimension) under external stimuli. Here, we present a simple 4D printing of self-folding structures that can be sequentially and accurately folded. When heated above their glass transition temperature pre-strained polystyrene films shrink along the XY plane. In our process silver ink traces printed on the film are used to provide heat stimuli by conducting current to trigger the self-folding behavior. The parameters affecting the folding process are studied and discussed. Sequential folding and accurately controlled folding angles are achieved by using printed ink traces and angle lock design. Theoretical analyses are done to guide the design of the folding processes. Programmable structures such as a lock and a three-dimensional antenna are achieved to test the feasibility and potential applications of this method. These self-folding structures change their shapes after fabrication under controlled stimuli (electric current) and have potential applications in the fields of electronics, consumer devices, and robotics. Our design and fabrication method provides an easy way by using silver ink printed on polystyrene films to 4D print self-folding structures for electrically induced sequential folding with angular control.

  16. Mechanisms of Morphology Development and Control in Polymer- Polymer Blends

    Science.gov (United States)

    Macosko, Christopher W.

    1998-03-01

    Polymer-polymer blends continue to be the most important method for achieving optimization of properties in plastics products. Over 30 percent of all plastics are blends. While miscible blends generally give average properties between the components, immiscible blends offer synergistic possibilities such as high modulus with high toughness; high flow with high impact strength or diffusion barriers with good mechanical properties and low cost. The key to performance of these immiscible blends is their morphology. There are several important types of morphology which can lead to valuable property improvement: emulsion - small polymer spheres well dispersed in a polymer matrix. double emulsion - spheres inside spheres which are dispersed in another matrix. microlayer - thin, parallel layers of one polymer in a matrix. cocontinuous - two (or more) continuous, interpenetrating polymer phases. To be economical it is desirable to create these morphologies via melt mixing of powder or pellets in conventional compounding equipment. The melting stage during compounding is very important for morphology development. This presentation will demonstrate the role of melting or softening of each phase as well as their viscosity, elasticity and interfacial tension in morphology development. Interfacial modification with premade block copolymers or reactively formed copolymers can greatly alter morphology formation and stability. Experimental results will be presented which quantify the role of these additives. References to recent work in this area by our group are listed below: DeBrule, M. B., L. Levitt and C.W. Macosko, "The Rheology and Morphology of Layered Polymer Melts in Shear," Soc. Plastics Eng. Tech Papers (ANTEC), 84-89 (1996). Guegan, P., C. W. Macosko, T. Ishizone, A. Hirao and S. Nakahama, "Kinetics of Chain Coupling at Melt Interfaces, Macromol. 27, 4993-4997 (1994). Lee, M. S., T.P. Lodge, and C. W. Macosko, "Can Random Copolymers Serve as Effective Polymeric

  17. Topographic control of sorted circle morphology on Svalbard

    Science.gov (United States)

    Voigt, Joana; Hauber, Ernst; Reiss, Dennis; Hiesinger, Harald; Johnsson, Andreas; van Gasselt, Stephan; Balme, Matt; Head, Jim; de Verra, Jean-Pierre; Steinbrügge, Gregor; Jaumann, Ralf

    2015-04-01

    Patterned ground is a typical phenomenon in polar, subpolar and alpine regions [1]. As it is commonly (but not necessarily!) related to freeze-thaw cycles, its presence on Mars could possibly point to locations and periods where and when liquid water existed in the recent past [2]. Sorted circles are a class of patterned ground that was tentatively identified in Elysium Planitia (Mars) [3], but this interpretation has been challenged on the basis of physical considerations [4]. Without direct access to potential patterned ground on Mars, the analysis of terrestrial analogues can inform the interpretation of Martian landforms. Svalbard (Norway) offers a wide variety of permafrost features that are morphologically analogous to Martian cold-climate landforms [5]. It hosts some of the best examples of sorted circles on Earth, which are located on the westernmost tip of Brøgger peninsula, on a broad strand flat that is characterized by a series of postglacial beach ridges [6]. Here we report on our analysis of sorted circle morphology (especially their plan-view shape, i.e. their "roundness" or ellipticity) and its correlation with local topography (slopes, curvature). Sorted circle morphology was determined from HRSC-AX images (for details on the flight campaign and image properties see ref [5]) and through field work. Topographic information comes from a 50 cm gridded DEM derived from HRSC-AX stereo images. We measured sorted circle morphology (ellipticity, azimuth of major axis) along a WNW-ESE traverse that runs from the inland towards the sea and is oriented perpendicular to the local beach ridge trend. Selected areas with homogeneous sorted circle appearance were visually mapped, and compared to the average slope, aspect, and the calculated topographic wetness index (TWI). Furthermore the whole traverse was classified into four different morphologies of the sorted patterned ground (sorted circles, sorted "ellipses", sorted nets and areas without patterned ground

  18. Protolytic carbon film technology

    Energy Technology Data Exchange (ETDEWEB)

    Renschler, C.L.; White, C.A.

    1996-04-01

    This paper presents a technique for the deposition of polyacrylonitrile (PAN) on virtually any surface allowing carbon film formation with only the caveat that the substrate must withstand carbonization temperatures of at least 600 degrees centigrade. The influence of processing conditions upon the structure and properties of the carbonized film is discussed. Electrical conductivity, microstructure, and morphology control are also described.

  19. Silicon nanocrystals on amorphous silicon carbide alloy thin films: Control of film properties and nanocrystals growth

    Energy Technology Data Exchange (ETDEWEB)

    Barbe, Jeremy, E-mail: jeremy.barbe@hotmail.com [CEA, Liten, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France); Universite de Toulouse, UPS, INPT, LAPLACE (Laboratoire Plasma et Conversion d' Energie), 118 route de Narbonne, 31062 Toulouse (France); Xie, Ling; Leifer, Klaus [Department of Engineering Sciences, Uppsala University, Box 534, S-751 21 Uppsala (Sweden); Faucherand, Pascal; Morin, Christine; Rapisarda, Dario; De Vito, Eric [CEA, Liten, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France); Makasheva, Kremena; Despax, Bernard [Universite de Toulouse, UPS, INPT, LAPLACE (Laboratoire Plasma et Conversion d' Energie), 118 route de Narbonne, 31062 Toulouse (France); CNRS, LAPLACE, F-31062 Toulouse (France); Perraud, Simon [CEA, Liten, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France)

    2012-11-01

    The present study demonstrates the growth of silicon nanocrystals on amorphous silicon carbide alloy thin films. Amorphous silicon carbide films</