Electrical conductivity study on polythiophenes films

International Nuclear Information System (INIS)

Youm, I.; Cadene, M.

1994-10-01

The electrical conduction mechanism of two classes of polythiophenes: polythiophene (PT) and poly(3-methylthiophene) (PMT) films containing various levels of doping counter-ions was investigated. The temperature dependence of electrical conductivity obeys the Mott equation based on variable range hopping. The dimension of the variable range hopping is correlated with the structure of the conducting polymer. It seems for these polymers that carrier transport via mobile conjugational defects does not play a detectable role. (author). 17 refs, 3 figs, 1 tab

Charge transport in films of Geobacter sulfurreducens on graphite electrodes as a function of film thickness

KAUST Repository

Jana, Partha Sarathi; Katuri, Krishna; Kavanagh, Paul; Kumar, Amit Ravi Pradeep; Leech, Dó nal

2014-01-01

Harnessing, and understanding the mechanisms of growth and activity of, biofilms of electroactive bacteria (EAB) on solid electrodes is of increasing interest, for application to microbial fuel and electrolysis cells. Microbial electrochemical cell technology can be used to generate electricity, or higher value chemicals, from organic waste. The capability of biofilms of electroactive bacteria to transfer electrons to solid anodes is a key feature of this emerging technology, yet the electron transfer mechanism is not fully characterized as yet. Acetate oxidation current generated from biofilms of an EAB, Geobacter sulfurreducens, on graphite electrodes as a function of time does not correlate with film thickness. Values of film thickness, and the number and local concentration of electrically connected redox sites within Geobacter sulfurreducens biofilms as well as a charge transport diffusion co-efficient for the biofilm can be estimated from non-turnover voltammetry. The thicker biofilms, of 50 ± 9 μm, display higher charge transport diffusion co-efficient than that in thinner films, as increased film porosity of these films improves ion transport, required to maintain electro-neutrality upon electrolysis. This journal is © the Partner Organisations 2014.

Influence of functional group on the electrical transport properties of polyvinyl alcohol grafted multiwall carbon nanotube composite thick film

Science.gov (United States)

Kumar Das, Amit; Dharmana, Reuben; Mukherjee, Ayan; Baba, Koumei; Hatada, Ruriko; Kumar Meikap, Ajit

2018-04-01

We present a novel technique to obtain a higher or lower value of dielectric constant due to the variation of a functional group on the surface of multiwall carbon nanotube (MWCNTs) for a polyvinyl alcohol (PVA) grafted MWCNT system. We have prepared PVA grafted pristine and different types of functionalized (-COOH, -OH, and -NH2) MWCNT nanocomposite films. The strong interfacial interaction between the host PVA matrix and nanofiller is characterized by different experimental techniques. The frequency variation of the electrical transport properties of the composite films is investigated in a wide temperature range (303 ≤ T ≤ 413 K) and frequency range (20 Hz ≤ f ≤ 1 MHz). The dielectric constant of the amine (-NH2) functionalized MWCNT incorporated PVA film is about 2 times higher than that of the pristine MWCNT embedded PVA film. The temperature variation of the dielectric constant shows an anomalous behaviour. The modified Cole-Cole equation simulated the experimentally observed dielectric spectroscopy at high temperature. The ac conductivity of the composite films obeys the correlated barrier hopping model. The imaginary part of the electric modulus study shows the ideal Debye-type behaviour at low frequency and deviation of that at high frequency. To illustrate the impedance spectroscopy of the nanocomposite films, we have proposed an impedance based battery equivalent circuit model. The current-voltage characteristic shows hysteresis behaviour of the nanocomposite films. The trap state height for all composite films is evaluated by simulating the current density-electric field data with the Poole-Frenkel emission model. This investigation opens a new avenue for designing electronic devices with a suitable combination of cost effective soft materials.

Effect of annealing temperature on the electrical transport properties of CaRuO3-δ thin films directly deposited on the Si substrate

International Nuclear Information System (INIS)

Paik, Hanjong; Kim, Youngha; No, Kwangsoo; Cann, David P.; Yoon, DongJoo; Kim, ByungIl; Kim, Yangsoo

2007-01-01

We investigate the effect of annealing temperature on the preferentially (110)-oriented CaRuO 3-δ (CRO) thin films directly prepared on Si(100) substrate by rf magnetron sputtering. Crystalline quality and electrical transport properties of the CRO thin films were modified by post-annealing treatment. It was obvious that 700 C post-annealing brought about excellent metallic characteristics with the elevation of carrier concentration and mobility. From this result, we suggested that enhanced (110) orientation, and the ratio of chemical composition Ru 4+ /Ca 2+ ion were responsible for the transport properties of CRO thin film. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Electrical transport properties of V2O5 thin films obtained by thermal annealing of layers grown by RF magnetron sputtering at room temperature

International Nuclear Information System (INIS)

Giannetta, H.M.R.; Calaza, C.; Lamas, D.G.; Fonseca, L.; Fraigi, L.

2015-01-01

The present study investigates the main electrical transport mechanism in V 2 O 5 thin films deposited by RF magnetron sputtering on the basis of the Mott's small polaron hopping model. The material under test was obtained at room temperature from a V 2 O 5 target and then oxidized at high temperature under air atmosphere to obtain the desired V 2 O 5 phase. The dependence of the electrical conductivity of the V 2 O 5 thin films with temperature was analyzed using the Mott's small polarons hopping transport model under the Schnakenberg form. Model results suggest a polaron binding energy W H = 0.1682 eV, with a structural disorder energy W D = 0.2241 eV and an optical phonon frequency ν 0 = 0.468 × 10 13 s −1 . These results are in agreement with data reported in literature for single crystal V 2 O 5 . However, the carrier mobility μ = 1.5019 × 10 −5 cm 2 /Vs computed in the non-adiabatic regime is significantly smaller than that of the single crystal, suggesting a strong electron–phonon coupling in the V 2 O 5 thin films obtained with the proposed deposition method. - Highlights: • A two-stage deposition method compatible with lift-off patterning is proposed. • V 2 O 5 films are deposited by RF magnetron sputtering and then annealed in air. • Films are analyzed by SEM and its pure phase nature is confirmed by XRD. • Electrical conductivity was fitted using Mott's model for small polarons. • Fit derived parameters confirm charge transport through small-polarons hopping

Electrical Transport Ability of Nanostructured Potassium-Doped Titanium Oxide Film

Science.gov (United States)

Lee, So-Yoon; Matsuno, Ryosuke; Ishihara, Kazuhiko; Takai, Madoka

2011-02-01

Potassium-doped nanostructured titanium oxide films were fabricated using a wet corrosion process with various KOH solutions. The doped condition of potassium in TiO2 was confirmed by Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Nanotubular were synthesized at a dopant concentration of 0.27%, these structures disappeared. To investigate the electrical properties of K-doped TiO2, pseudo metal-oxide-semiconductor field-effect transistor (MOSFET) samples were fabricated. The samples exhibited a distinct electrical behavior and p-type characteristics. The electrical behavior was governed by the volume of the dopant when the dopant concentration was 0.18%.

Nanocrystalline SnO2 thin films: Structural, morphological, electrical transport and optical studies

International Nuclear Information System (INIS)

Sakhare, R.D.; Khuspe, G.D.; Navale, S.T.; Mulik, R.N.; Chougule, M.A.; Pawar, R.C.; Lee, C.S.; Sen, Shashwati; Patil, V.B.

2013-01-01

Highlights: ► Novel chemical route of synthesis of SnO 2 films. ► Physical properties SnO 2 are influenced by process temperature. ► The room temperature electrical conductivity of SnO 2 is of 10 −7 –10 −5 (Ω cm) −1 . ► SnO 2 exhibit high absorption coefficient (10 4 cm −1 ). -- Abstract: Sol–gel spin coating method has been successfully employed for preparation of nanocrystalline tin oxide (SnO 2 ) thin films. The effect of processing temperature on the structure, morphology, electrical conductivity, thermoelectric power and band gap was studied using X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, selected area electron diffraction pattern, atomic force microscopy, two probe technique and UV–visible spectroscopy. X-ray diffraction (XRD) analysis showed that SnO 2 films are crystallized in the tetragonal phase and present a random orientation. Field emission scanning electron microscopy (FESEM) analysis revealed that surface morphology of the tin oxide film consists nanocrystalline grains with uniform coverage of the substrate surface. Transmission electron microscopy (TEM) of SnO 2 film showed nanocrystals having diameter ranging from 5 to 10 nm. Selected area electron diffraction (SAED) pattern confirms tetragonal phase evolution of SnO 2 . Atomic force microscopy (AFM) analysis showed surface morphology of SnO 2 film is smooth. The dc electrical conductivity showed the semiconducting nature with room temperature electrical conductivity increased from 10 −7 to 10 −5 (Ω cm) −1 as processing temperature increased from 400 to 700 °C. Thermo power measurement confirms n-type conduction. The band gap energy of SnO 2 film decreased from 3.88 to 3.60 eV as processing temperature increased from 400 to 700 °C

Modeling the transport properties of epitaxially grown thermoelectric oxide thin films using spectroscopic ellipsometry

KAUST Repository

Sarath Kumar, S. R.

2012-02-01

The influence of oxygen vacancies on the transport properties of epitaxial thermoelectric (Sr,La)TiO3 thin films is determined using electrical and spectroscopic ellipsometry (SE) measurements. Oxygen vacancy concentration was varied by ex-situ annealing in Ar and Ar/H2. All films exhibited degenerate semiconducting behavior, and electrical conductivity decreased (258–133 S cm−1) with increasing oxygen content. Similar decrease in the Seebeck coefficient is observed and attributed to a decrease in effective mass (7.8–3.2 me ), as determined by SE. Excellent agreement between transport properties deduced from SE and direct electrical measurements suggests that SE is an effective tool for studying oxide thin film thermoelectrics.

Modeling the transport properties of epitaxially grown thermoelectric oxide thin films using spectroscopic ellipsometry

KAUST Repository

Sarath Kumar, S. R.; Abutaha, Anas I.; Hedhili, Mohamed N.; Alshareef, Husam N.

2012-01-01

The influence of oxygen vacancies on the transport properties of epitaxial thermoelectric (Sr,La)TiO3 thin films is determined using electrical and spectroscopic ellipsometry (SE) measurements. Oxygen vacancy concentration was varied by ex-situ annealing in Ar and Ar/H2. All films exhibited degenerate semiconducting behavior, and electrical conductivity decreased (258–133 S cm−1) with increasing oxygen content. Similar decrease in the Seebeck coefficient is observed and attributed to a decrease in effective mass (7.8–3.2 me ), as determined by SE. Excellent agreement between transport properties deduced from SE and direct electrical measurements suggests that SE is an effective tool for studying oxide thin film thermoelectrics.

Electrical properties and transport mechanisms in phase change memory thin films of quasi-binary-line GeTe–Sb{sub 2}Te{sub 3} chalcogenide semiconductors

Energy Technology Data Exchange (ETDEWEB)

Sherchenkov, A. A. [National Research University of Electronic Technology (Russian Federation); Kozyukhin, S. A., E-mail: sergkoz@igic.ras.ru [Russian Academy of Sciences, Kurnakov Institute of General and Inorganic Chemistry (Russian Federation); Lazarenko, P. I.; Babich, A. V. [National Research University of Electronic Technology (Russian Federation); Bogoslovskiy, N. A. [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation); Sagunova, I. V.; Redichev, E. N. [National Research University of Electronic Technology (Russian Federation)

2017-02-15

The temperature dependences of the resistivity and current–voltage (I–V) characteristics of phase change memory thin films based on quasi-binary-line GeTe–Sb{sub 2}Te{sub 3} chalcogenide semiconductors Ge{sub 2}Sb{sub 2}Te{sub 5}, GeSb{sub 2}Te{sub 5}, and GeSb{sub 4}Te{sub 7} are investigated. The effect of composition variation along the quasibinary line on the electrical properties and transport mechanisms of the thin films is studied. The existence of three ranges with different I–V characteristics is established. The position and concentration of energy levels controlling carrier transport are estimated. The results obtained show that the electrical properties of the thin films can significantly change during a shift along the quasi-binary line GeTe–Sb{sub 2}Te{sub 3}, which is important for targeted optimization of the phase change memory technology.

Electrical transport properties of MoO3 thin films prepared by laser assisted evaporation

International Nuclear Information System (INIS)

Lopez-Carreno, L.D.; Pardo, A.; Zuluaga, M.; Torres, J.; Alfonso, J.E.; Cortes-Bracho, O.L.

2007-01-01

In the present paper the growth of MoO 3 thin films on common glass substrates are described. The films were prepared by evaporation of a MoO 3 target with a CO 2 laser (10.6 μm), operating in the continuous wave mode. The effect of substrate temperature on the crystallographic structure and electrical properties of MoO 3 thin films was studied. The chemical composition of the different species formed on the films surface was obtained by X-ray photoelectron spectroscopy (XPS) and the crystalline structure was studied with X-ray diffraction (XRD). The electrical conductivity of the films was determined using the standard four-points method. Conductivity of the films varied from de 10 -9 to 10 -5 (Ωcm) -1 in the 300-600 K temperature range. Arrhenius-type plots for the electrical conductivity indicate the presence of at least two different conduction mechanisms. The I-V characteristic curve shows an ohmic behavior only in the 4.5-60 V range. Outside this interval the I-V curve has a behavior described by a power law. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Electrical transport in (103) YBa2Cu3O7-x thin films

International Nuclear Information System (INIS)

Divin, Yu.Ya.; Poppe, U.; Faley, M.I.; Soltner, H.; Seo, J.W.; Kabius, B.; Urban, K.

1993-01-01

We have studied the electrical and structural properties of (103) YBa 2 Cu 3 O 7-x thin films to estimate the applicability of these films as base electrodes of planar-type Josephson junctions. (orig.)

Electrical transport characterization of Al and Sn doped Mg 2 Si thin films

KAUST Repository

Zhang, Bo; Zheng, Tao; Sun, Ce; Guo, Zaibing; Kim, Moon J.; Alshareef, Husam N.; Quevedo-Lopez, Manuel; Gnade, Bruce E.

2017-01-01

Thin-film Mg2Si was deposited using radio frequency (RF) magnetron sputtering. Al and Sn were incorporated as n-type dopants using co-sputtering to tune the thin-film electrical properties. X-ray diffraction (XRD) analysis confirmed

Electrical transport and pinning properties of Nb thin films patterned with focused ion beam-milled washboard nanostructures

International Nuclear Information System (INIS)

Dobrovolskiy, O V; Begun, E; Huth, M; Shklovskij, V A

2012-01-01

A careful analysis of the magneto-transport properties of epitaxial nanostructured Nb thin films in the normal and the mixed state is performed. The nanopatterns were prepared by focused ion beam (FIB) milling. They provide a washboard-like pinning potential landscape for vortices in the mixed state and simultaneously cause a resistivity anisotropy in the normal state. Two matching magnetic fields for the vortex lattice with the underlying nanostructures have been observed. By applying these fields, the most likely pinning sites along which the flux lines move through the samples have been selected. By this, either the background isotropic pinning of the pristine film or the enhanced isotropic pinning originating from the nanoprocessing have been probed. Via an Arrhenius analysis of the resistivity data the pinning activation energies for three vortex lattice parameters have been quantified. The changes in the electrical transport and the pinning properties have been correlated with the results of the microstructural and topographical characterization of the FIB-patterned samples. Accordingly, along with the surface processing, FIB milling has been found to alter the material composition and the degree of disorder in as-grown films. The obtained results provide further insight into the pinning mechanisms at work in FIB-nanopatterned superconductors, e.g. for fluxonic applications. (paper)

Subthreshold electrical transport in amorphous phase-change materials

International Nuclear Information System (INIS)

Gallo, Manuel Le; Kaes, Matthias; Sebastian, Abu; Krebs, Daniel

2015-01-01

Chalcogenide-based phase-change materials play a prominent role in information technology. In spite of decades of research, the details of electrical transport in these materials are still debated. In this article, we present a unified model based on multiple-trapping transport together with 3D Poole–Frenkel emission from a two-center Coulomb potential. With this model, we are able to explain electrical transport both in as-deposited phase-change material thin films, similar to experimental conditions in early work dating back to the 1970s, and in melt-quenched phase-change materials in nanometer-scale phase-change memory devices typically used in recent studies. Experimental measurements on two widely different device platforms show remarkable agreement with the proposed mechanism over a wide range of temperatures and electric fields. In addition, the proposed model is able to seamlessly capture the temporal evolution of the transport properties of the melt-quenched phase upon structural relaxation. (paper)

Nanostructured ZnO films: A study of molecular influence on transport properties by impedance spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Sappia, Luciano D.; Trujillo, Matias R. [Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET, Chacabuco 461, T4000ILI San Miguel de Tucumán (Argentina); Laboratorio de Medios e Interfases (LAMEIN), Departamento de Bioingeniería, Fac. de Cs. Exactas y Tecnología, Universidad Nacional de Tucumán, Av. Independencia 1800, 4000 San Miguel de Tucumán (Argentina); Lorite, Israel [Division of Superconductivity and Magnetism, Institute for Experimental Physics II, University of Leipzig, Linnéstrasse 5, 04103 Leipzig (Germany); Madrid, Rossana E., E-mail: rmadrid@herrera.unt.edu.ar [Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET, Chacabuco 461, T4000ILI San Miguel de Tucumán (Argentina); Laboratorio de Medios e Interfases (LAMEIN), Departamento de Bioingeniería, Fac. de Cs. Exactas y Tecnología, Universidad Nacional de Tucumán, Av. Independencia 1800, 4000 San Miguel de Tucumán (Argentina); Tirado, Monica [NanoProject and Laboratorio de Nanomateriales y Propiedades Dieléctricas, Departamento de Física, Universidad Nacional de Tucumán, Avenida Independencia 1800, Tucumán (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) (Argentina); and others

2015-10-15

Graphical abstract: - Highlights: • We study electrical transport in nanostructured ZnO films by impedance spectroscopy. • Bioaggregates on the surface produce strong changes in film transport properties. • This behavior is explained by modeling data with RC parallel circuits. • Electrical responses of ZnO films to aggregates are promising for biosensing. - Abstract: Nanomaterials based on ZnO have been used to build glucose sensors due to its high isoelectric point, which is important when a protein like Glucose Oxidase (GOx) is attached to a surface. It also creates a biologically friendly environment to preserve the activity of the enzyme. In this work we study the electrical transport properties of ZnO thin films (TFs) and single crystals (SC) in contact with different solutions by using impedance spectroscopy. We have found that the composition of the liquid, by means of the charge of the ions, produces strong changes in the transport properties of the TF. The enzyme GOx and phosphate buffer solutions have the major effect in the conduction through the films, which can be explained by the entrapment of carriers at the grain boundaries of the TFs. These results can help to design a new concept in glucose biosensing.

Electrical transport, electrothermal transport, and effective electron mass in single-crystalline In2O3 films

Science.gov (United States)

Preissler, Natalie; Bierwagen, Oliver; Ramu, Ashok T.; Speck, James S.

2013-08-01

A comprehensive study of the room-temperature electrical and electrothermal transport of single-crystalline indium oxide (In2O3) and indium tin oxide (ITO) films over a wide range of electron concentrations is reported. We measured the room-temperature Hall mobility μH and Seebeck coefficient S of unintentionally doped and Sn-doped high-quality, plasma-assisted molecular-beam-epitaxy-grown In2O3 for volume Hall electron concentrations nH from 7×1016 cm-3 (unintentionally doped) to 1×1021 cm-3 (highly Sn-doped, ITO). The resulting empirical S(nH) relation can be directly used in other In2O3 samples to estimate the volume electron concentration from simple Seebeck coefficient measurements. The mobility and Seebeck coefficient were modeled by a numerical solution of the Boltzmann transport equation. Ionized impurity scattering and polar optical phonon scattering were found to be the dominant scattering mechanisms. Acoustic phonon scattering was found to be negligible. Fitting the temperature-dependent mobility above room temperature of an In2O3 film with high mobility allowed us to find the effective Debye temperature (ΘD=700 K) and number of phonon modes (NOPML=1.33) that best describe the polar optical phonon scattering. The modeling also yielded the Hall scattering factor rH as a function of electron concentration, which is not negligible (rH≈1.4) at nondegenerate electron concentrations. Fitting the Hall-scattering-factor corrected concentration-dependent Seebeck coefficient S(n) for nondegenerate samples to the numerical solution of the Boltzmann transport equation and to widely used, simplified equations allowed us to extract an effective electron mass of m*=(0.30±0.03)me (with free electron mass me). The modeled mobility and Seebeck coefficient based on polar optical phonon and ionized impurity scattering describes the experimental results very accurately up to electron concentrations of 1019 cm-3, and qualitatively explains a mobility plateau or local

Substrate-dependent post-annealing effects on the strain state and electrical transport of epitaxial La5/8-yPryCa3/8MnO3 films

International Nuclear Information System (INIS)

Hu, Sixia; Wang, Haibo; Dong, Yongqi; Hong, Bing; He, Hao; Bao, Jun; Huang, Haoliang; Yang, Yuanjun; Luo, Zhenlin; Yang, Mengmeng; Gao, Chen

2014-01-01

Large scale electronic phase separation (EPS) between ferromagnetic metallic and charge-ordered insulating phases in La 5/8-y Pr y Ca 3/8 MnO 3 (y = 0.3) (LPCMO) is very sensitive to the structural changes. This work investigates the effects of post-annealing on the strain states and electrical transport properties of LPCMO films epitaxially grown on (001) pc SrTiO 3 (tensile strain), LaAlO 3 (compressive strain) and NdGaO 3 (near-zero strain) substrates. Before annealing, all the films are coherent-epitaxial and insulating through the measured temperature range. Obvious change of film lattice is observed during the post-annealing: the in-plane strain in LPCMO/LAO varies from −1.5% to −0.1% while that in LPCMO/STO changes from 1.6% to 1.3%, and the lattice of LPCMO/NGO keeps constant because of the good lattice-match between LPCMO and NGO. Consequently, the varied film strain leads to the emergence of metal-insulator transitions (MIT) and shift of the critical transition temperature in the electrical transport. These results demonstrate that lattice-mismatch combined with post-annealing is an effective approach to tune strain in epitaxial LPCMO films, and thus to control the EPS and MIT in the films

Electronic and magneto-transport in chirality sorted carbon nanotube films

Science.gov (United States)

Janas, Dawid; Czechowski, Nikodem; Adamus, Zbigniew; GiŻewski, Tomasz

2018-01-01

This research details electronic and magneto-transport in unsorted and chirality-enriched carbon nanotube (CNT) films. By measuring the electrical conductivity from 4 K to 297 K, we were able to assign the governing mechanism of electronic transport. Fluctuation-induced tunnelling was in accordance with the obtained data and very well matched the underlying physics. We demonstrated how a change in the type of CNT to make the film affects its electrical performance. As the temperature was decreased down to cryogenic conditions, up to a 56-fold increase in resistance was noted. Moreover, the measurement of magnetoresistance (MR) revealed a non-monotonic dependence on the applied magnetic field. The initial negative component of MR was eventually overpowered by the positive MR component as the field strength was increased beyond a certain threshold.

Electrical transport properties of V{sub 2}O{sub 5} thin films obtained by thermal annealing of layers grown by RF magnetron sputtering at room temperature

Energy Technology Data Exchange (ETDEWEB)

Giannetta, H.M.R., E-mail: hgiann@inti.gov.ar [Centro de Micro y Nano Electrónica del Bicentenario (CMNB), Instituto Nacional de Tecnología Industrial (INTI), San Martín, Buenos Aires (Argentina); Universidad Tecnológica Nacional (UTN) — Facultad Regional Buenos Aires (FRBA) (Argentina); Calaza, C. [Instituto de Microelectrónica de Barcelona, Centro Nacional de Microelectrónica (IMB-CNM, CSIC), Campus UAB, Bellaterra, 08193 Barcelona (Spain); Lamas, D.G. [Universidad Nacional del Comahue CONICET-CITEFA — Laboratorio de Caracterización de Materiales, Facultad de Ingeniería, Neuquen (Argentina); Fonseca, L. [Instituto de Microelectrónica de Barcelona, Centro Nacional de Microelectrónica (IMB-CNM, CSIC), Campus UAB, Bellaterra, 08193 Barcelona (Spain); Fraigi, L. [Centro de Micro y Nano Electrónica del Bicentenario (CMNB), Instituto Nacional de Tecnología Industrial (INTI), San Martín, Buenos Aires (Argentina); Universidad Tecnológica Nacional (UTN) — Facultad Regional Buenos Aires (FRBA) (Argentina)

2015-08-31

The present study investigates the main electrical transport mechanism in V{sub 2}O{sub 5} thin films deposited by RF magnetron sputtering on the basis of the Mott's small polaron hopping model. The material under test was obtained at room temperature from a V{sub 2}O{sub 5} target and then oxidized at high temperature under air atmosphere to obtain the desired V{sub 2}O{sub 5} phase. The dependence of the electrical conductivity of the V{sub 2}O{sub 5} thin films with temperature was analyzed using the Mott's small polarons hopping transport model under the Schnakenberg form. Model results suggest a polaron binding energy W{sub H} = 0.1682 eV, with a structural disorder energy W{sub D} = 0.2241 eV and an optical phonon frequency ν{sub 0} = 0.468 × 10{sup 13}s{sup −1}. These results are in agreement with data reported in literature for single crystal V{sub 2}O{sub 5}. However, the carrier mobility μ = 1.5019 × 10{sup −5} cm{sup 2}/Vs computed in the non-adiabatic regime is significantly smaller than that of the single crystal, suggesting a strong electron–phonon coupling in the V{sub 2}O{sub 5} thin films obtained with the proposed deposition method. - Highlights: • A two-stage deposition method compatible with lift-off patterning is proposed. • V{sub 2}O{sub 5} films are deposited by RF magnetron sputtering and then annealed in air. • Films are analyzed by SEM and its pure phase nature is confirmed by XRD. • Electrical conductivity was fitted using Mott's model for small polarons. • Fit derived parameters confirm charge transport through small-polarons hopping.

Electrical transport properties of MoO{sub 3} thin films prepared by laser assisted evaporation

Energy Technology Data Exchange (ETDEWEB)

Lopez-Carreno, L.D.; Pardo, A.; Zuluaga, M.; Torres, J.; Alfonso, J.E. [Group of Materials with Technological Applications, GMAT, Physics Department, Universidad Nacional de Colombia, Bogota (Colombia); Cortes-Bracho, O.L. [Group of Materials with Technological Applications, GMAT, Physics Department, Universidad Nacional de Colombia, Bogota (Colombia); Electronic Engineering Department, Universidad Nacional de Colombia, Bogota (Colombia)

2007-07-01

In the present paper the growth of MoO{sub 3} thin films on common glass substrates are described. The films were prepared by evaporation of a MoO{sub 3} target with a CO{sub 2} laser (10.6 {mu}m), operating in the continuous wave mode. The effect of substrate temperature on the crystallographic structure and electrical properties of MoO{sub 3} thin films was studied. The chemical composition of the different species formed on the films surface was obtained by X-ray photoelectron spectroscopy (XPS) and the crystalline structure was studied with X-ray diffraction (XRD). The electrical conductivity of the films was determined using the standard four-points method. Conductivity of the films varied from de 10{sup -9} to 10{sup -5} ({omega}cm){sup -1} in the 300-600 K temperature range. Arrhenius-type plots for the electrical conductivity indicate the presence of at least two different conduction mechanisms. The I-V characteristic curve shows an ohmic behavior only in the 4.5-60 V range. Outside this interval the I-V curve has a behavior described by a power law. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

TUNABLE MAGNETIC AND ELECTRICAL PROPERTIES OF Co-DOPED ZnO FILMS BY VARYING OXYGEN PARTIAL PRESSURE

OpenAIRE

L. G. WANG; H. W. ZHANG; X. L. TANG; Y. X. LI; Z. Y. ZHONG

2011-01-01

High quality Co-doped ZnO films with good reproducibility have been prepared under different oxygen partial pressure by radio-frequency magnetron sputtering. These films were characterized using numerous characterization techniques including X-ray diffraction, electrical transport, and magnetization measurements. The effect of oxygen partial pressure on the structural, magnetic, and electrical properties of Co-doped ZnO films has been systematically studied. It was found that the structural, ...

Electrical doping: the impact on interfaces of π-conjugated molecular films

International Nuclear Information System (INIS)

Gao Weiying; Kahn, Antoine

2003-01-01

Organic-metal and organic-organic interfaces play crucial roles in charge injection in, and transport through, organic thin film devices. Their electronic structure, chemical properties and electrical behaviour must be fully characterized and understood if engineering and control of organic devices are to reach the levels attained for inorganic semiconductor devices. Recent fundamental, as well as device, work has demonstrated that electrical doping provides a very interesting way to improve carrier injection into molecular films and, eventually, control molecular level alignment at their interfaces. This brief review emphasizes the current understanding of the effects of doping on organic interfaces

Electrical initiation of an energetic nanolaminate film

Science.gov (United States)

Tringe, Joseph W.; Gash, Alexander E.; Barbee, Jr., Troy W.

2010-03-30

A heating apparatus comprising an energetic nanolaminate film that produces heat when initiated, a power source that provides an electric current, and a control that initiates the energetic nanolaminate film by directing the electric current to the energetic nanolaminate film and joule heating the energetic nanolaminate film to an initiation temperature. Also a method of heating comprising providing an energetic nanolaminate film that produces heat when initiated, and initiating the energetic nanolaminate film by directing an electric current to the energetic nanolaminate film and joule heating the energetic nanolaminate film to an initiation temperature.

Ultra-violet absorption induced modifications in bulk and nanoscale electrical transport properties of Al-doped ZnO thin films

Energy Technology Data Exchange (ETDEWEB)

Kumar, Mohit; Basu, Tanmoy; Som, Tapobrata, E-mail: tsom@iopb.res.in [SUNAG Laboratory, Institute of Physics, Sachivalaya Marg, Bhubaneswar 751 005 (India)

2015-08-07

Using conductive atomic force microscopy and Kelvin probe force microscopy, we study local electrical transport properties in aluminum-doped zinc oxide (ZnO:Al or AZO) thin films. Current mapping shows a spatial variation in conductivity which corroborates well with the local mapping of donor concentration (∼10{sup 20 }cm{sup −3}). In addition, a strong enhancement in the local current at grains is observed after exposing the film to ultra-violet (UV) light which is attributed to persistent photocurrent. Further, it is shown that UV absorption gives a smooth conduction in AZO film which in turn gives rise to an improvement in the bulk photoresponsivity of an n-AZO/p-Si heterojunction diode. This finding is in contrast to the belief that UV absorption in an AZO layer leads to an optical loss for the underneath absorbing layer of a heterojunction solar cell.

Electric Transport Phenomena of Nanocomposite Organic Polymer Thin Films

Science.gov (United States)

Jira, Nicholas C.; Sabirianov, Ildar; Ilie, Carolina C.

We discuss herein the nanocomposite organic thin film diodes for the use of plasmonic solar cells. This experimental work follows the theoretical calculations done for plasmonic solar cells using the MNPBEM toolbox for MatLab. These calculations include dispersion curves and amount of light scattering cross sections for different metallic nanoparticles. This study gives us clear ideas on what to expect from different metals, allowing us to make the best choice on what to use to obtain the best results. One specific technique for light trapping in thin films solar cells utilizes metal nanoparticles on the surface of the semiconductor. The characteristics of the metal, semiconductor interface allows for light to be guided in between them causing it to be scattered, allowing for more chances of absorption. The samples were fabricated using organic thin films made from polymers and metallic nanoparticles, more specifically Poly(1-vinylpyrrolidone-co-2-dimethylaminoethyl methacrylate) copolymer and silver or gold nanoparticles. The two fabrication methods applied include spin coating and Langmuir-Blodgett technique. The transport properties are obtained by analyzing the I-V curves. We will also discuss the resistance, resistivity, conductance, density of charge carriers. SUNY Oswego SCAC Grant.

Electrical transport characterization of Al and Sn doped Mg 2 Si thin films

KAUST Repository

Zhang, Bo

2017-05-22

Thin-film Mg2Si was deposited using radio frequency (RF) magnetron sputtering. Al and Sn were incorporated as n-type dopants using co-sputtering to tune the thin-film electrical properties. X-ray diffraction (XRD) analysis confirmed that the deposited films are polycrystalline Mg2Si. The Sn and Al doping concentrations were measured using Rutherford backscattering spectroscopy (RBS) and energy dispersive X-ray spectroscopy (EDS). The charge carrier concentration and the charge carrier type of the Mg2Si films were measured using a Hall bar structure. Hall measurements show that as the doping concentration increases, the carrier concentration of the Al-doped films increases, whereas the carrier concentration of the Sn-doped films decreases. Combined with the resistivity measurements, the mobility of the Al-doped Mg2Si films is found to decrease with increasing doping concentration, whereas the mobility of the Sn-doped Mg2Si films is found to increase.

Study of Electrical Transport Properties of Thin Films Used as HTL and as Active Layer in Organic Solar Cells, through Impedance Spectroscopy Measurements

Directory of Open Access Journals (Sweden)

Camilo A. Otalora

2016-01-01

Full Text Available Impedance spectroscopy (IS is used for studying the electrical transport properties of thin films used in organic solar cells with structure ITO/HTL/active layer/cathode, where PEDOT:PSS (poly(3,4-ethylenedioxythiophene:polystyrene sulfonic acid and CuPC (tetrasulfonated copper-phthalocyanine were investigated as HTL (hole transport layer and P3HT:PCBM (poly-3-hexylthiophene:phenyl-C61-butyric acid methyl ester blends prepared from mesitylene and chlorobenzene based solutions were studied as active layer and Ag and Al were used as cathode. The study allowed determining the influence of the type of solvent used for the preparation of the active layer as well as the speed at which the solvents are removed on the carriers mobility. The effect of exposing the layer of P3HT to the air on its mobility was also studied. It was established that samples of P3HT and P3HT:PCBM prepared using mesitylene as a solvent have mobility values significantly higher than those prepared from chlorobenzene which is the solvent most frequently used. It was also determined that the mobility of carriers in P3HT films strongly decreases when this sample is exposed to air. In addition, it was found that the electrical properties of P3HT:PCBM thin films can be improved by removing the solvent slowly which is achieved by increasing the pressure inside the system of spin-coating during the film growth.

Structural, magnetic and electrical transport properties in electron-doped La{sub 0.85}Hf{sub 0.15}MnO{sub 3} epitaxial film

Energy Technology Data Exchange (ETDEWEB)

Han, Li-an; Zhu, Hua-ze; Zhang, Tao [Xi' an University of Science and Technology, Department of Applied Physics, Xi' an (China); Ma, Zi-wei [Yuncheng University, Department of Physics and Electronic Engineering, Yuncheng (China); Chen, Chang-le [Northwestern Polytechnical University, Department of Applied Physics, Xi' an (China)

2017-03-15

Using a pulsed laser deposition method, the electron-doped La{sub 0.85}Hf{sub 0.15}MnO{sub 3} (LHMO) film with the thickness of 90 nm was epitaxially grown on LaAlO{sub 3} (001) single crystal substrate. The structural, magnetic and electrical transport properties of the film have been studied comprehensively. The X-ray diffraction patterns confirm that LHMO film is of single phase, good quality and c axis orientation. The film undergoes a ferromagnetic-like ordering to paramagnetic states at T{sub C} =280 K. Moreover, a spin glass behavior observed in the film may be attributed to the strain effects. Using the percolation theory, we have analyzed the resistivity data ρ (T) of the film and given an excellent fit in the whole temperature range. Particularly, large temperature coefficient of resistance of 11.27% K{sup -} {sup 1} has been discovered near sub-room-temperature, indicating that LHMO film could be useful for bolometric applications. (orig.)

Effects of electric-field-induced piezoelectric strain on the electronic transport properties of La0.9Ce0.1MnO3 thin films

International Nuclear Information System (INIS)

Zheng, R.K.; Dong, S.N.; Wu, Y.Q.; Zhu, Q.X.; Wang, Y.; Chan, H.L.W.; Li, X.M.; Luo, H.S.; Li, X.G.

2012-01-01

The authors constructed multiferroic structures by growing La 0.9 Ce 0.1 MnO 3 (LCEMO) thin films on piezoelectric 0.68Pb(Mg 1/3 Nb 2/3 )O 3 –0.32PbTiO 3 (PMN-PT) single-crystal substrates. Due to the efficient elastic coupling at the interface, the electric-field-induced piezoelectric strain in PMN-PT substrates is effectively transferred to LCEMO films and thus, leads to a decrease in the resistance and an increase in the magnetoresistance of the films. Particularly, it was found that the resistance-strain coefficient [(ΔR/R) film /(Δε zz ) film ] of the LCEMO film was considerably enhanced by the application of magnetic fields, demonstrating strong coupling between the lattice and the spin degrees of freedom. (ΔR/R) film /(Δε zz ) film at 122 K was enhanced by ∼ 28.8% by a magnetic field of 1.2 T. An analysis of the overall results demonstrates that the phase separation is crucial to understand strain-mediated modulation of electronic transport properties of manganite film/PMN-PT multiferroic structures. - Highlights: ► La 0.9 Ce 0.1 Mn O3 films were epitaxially grown on piezoelectric single crystals. ► Piezoelectric strain influences the electronic transport properties of films. ► Magnetic field enhances the piezoelectric strain effect. ► Phase separation is crucial to understand the piezoelectric strain effect.

Investigation of the structural, optical and electrical transport properties of n-doped CdSe thin films

Science.gov (United States)

Ali, H. M.; Abd El-Ghanny, H. A.

2008-04-01

Thin films of (CdSe)90(In2O3)10, (CdSe)90(SnO2)10 and (CdSe)90(ZnO)10 have been grown on glass substrates by the electron beam evaporation technique. It has been found that undoped and Sn or In doped CdSe films have two direct transitions corresponding to the energy gaps Eg and Eg+Δ due to spin-orbit splitting of the valence band. The electrical resistivity for n-doped CdSe thin films as a function of light exposure time has been studied. The influence of doping on the structural, optical and electrical characteristics of In doped CdSe films has been investigated in detail. The lattice parameters, grain size and dislocation were determined from x-ray diffraction patterns. The optical transmittance and band gap of these films were determined using a double beam spectrophotometer. The DC conductivity of the films was measured in vacuum using a two-probe technique.

Electric field induced instabilities in free emulsion films

Energy Technology Data Exchange (ETDEWEB)

Tchoukov, P.; Dabros, T. [Natural Resources Canada, Devon, AB (Canada); Mostowfi, F. [Schlumberger DBR Technology Center, Edmonton, AB (Canada); Panchev, N. [Champion Technologies Inc., Houston, TX (United States); Czarnecki, J. [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemical and Materials Engineering

2009-07-01

This presentation reported on a study that investigated the mechanism of electric field-induced breakdown of free emulsion films. Instability patterns were observed on the plane of a water-oil-water film following electric polarization. The length-scales of the instabilities were measured by analyzing images immediately after applying the electric field. Linear stability analysis was used to calculate the theoretical dominant wavelengths. The calculated values were found to be in good agreement with measured values. The films were formed in a thin film apparatus modified so that the oil film separated 2 aqueous phase compartments, each in contact with a platinum electrode. This enabled the measurement of disjoining pressure while applying the electric field to the film. It was concluded that breakdown of thin films induced by electric field has many applications, including electrostatic de-emulsification/desalination of crude oil and emulsion stability measurements. It was concluded that electroporation and dielectric breakdown may be responsible for electric field-induced breakdown. This study also presented evidence of an increase in electric field-induced instabilities in emulsion films resulting in rupture. tabs., figs.

Acousto-electric transport in MgO/ZnO-covered graphene on SiC

Science.gov (United States)

Liou, Y.-T.; Hernández-Mínguez, A.; Herfort, J.; Lopes, J. M. J.; Tahraoui, A.; Santos, P. V.

2017-11-01

We investigate the acousto-electric transport induced by surface acoustic waves (SAWs) in epitaxial graphene (EG) coated by a MgO/ZnO film. The deposition of a thin MgO layer protects the EG during the sputtering of a piezoelectric ZnO film for the efficient generation of SAWs. We demonstrate by Raman and electric measurements that the coating does not harm the EG structural and electronic properties. We report the generation of two SAW modes with frequencies around 2 GHz. For both modes, we measure acousto-electric currents in EG devices placed in the SAW propagation path. The currents increase linearly with the SAW power, reaching values up to almost two orders of magnitude higher than in previous reports for acousto-electric transport in EG on SiC. Our results agree with the predictions from the classical relaxation model of the interaction between SAWs and a two dimensional electron gas.

Magnetoelectric and transport properties of (GaMn)Sb thin films: A ferrimagnetic phase in dilute alloys

Energy Technology Data Exchange (ETDEWEB)

Calderón, Jorge A. [Universidad Nacional de Colombia – Bogotá, Dpto. de Física, Grupo de Materiales Nanoestructurados y sus Aplicaciones, Cra. 30 No. 45-03 Edificio 404 Lab. 121C Ciudad Universitaria, Bogotá (Colombia); Mesa, F., E-mail: fredy.mesa@urosario.edu.co [Grupo NanoTech, Facultad de Ciencias Naturales y Matemáticas, Universidad del Rosario, Cra. 24 No. 63C-69, Bogotá (Colombia); Dussan, A. [Universidad Nacional de Colombia – Bogotá, Dpto. de Física, Grupo de Materiales Nanoestructurados y sus Aplicaciones, Cra. 30 No. 45-03 Edificio 404 Lab. 121C Ciudad Universitaria, Bogotá (Colombia)

2017-02-28

Highlights: • (GaMn)Sb thin films were fabricated using the direct current (DC) magnetron co-sputtering. • Presence of ferrimagnetic (Mn{sub 2}Sb) and ferromagnetic (Mn{sub 2}Sb{sub 2}) phases. • A minor difference of 1% was found with respect to percolation theory, which confirmed the validity of the diffusional model in semiconductor alloys with magnetic properties. • Increase in the localized states density (N{sub F}) with increasing substrate temperature. - Abstract: We studied the electrical, magnetic, and transport properties of (GaMn)Sb thin films fabricated by the direct current magnetron co-sputtering method. Using X-ray powder diffraction measurements, we identified the presence of ferrimagnetic (Mn{sub 2}Sb) and ferromagnetic (Mn{sub 2}Sb{sub 2}) phases within the films. We also measured the magnetization of the films versus an applied magnetic field as well as their hysteresis curves at room temperature. We determined the electrical and transport properties of the films through temperature-dependent resistivity measurements using the Van Der Pauw method. The main contribution to the transport process was variable range hopping. Hopping parameters were calculated using percolation theory and refined using the diffusional model. In addition, we determined that all samples had p type semiconductor behavior, that there was an increase in the density of localized states near the Fermi level, and that the binary magnetic phases influenced the electrical properties and transport mechanisms.

Droplet manipulation by an external electric field for crystalline film growth.

Science.gov (United States)

Komino, Takeshi; Kuwabara, Hirokazu; Ikeda, Masaaki; Yahiro, Masayuki; Takimiya, Kazuo; Adachi, Chihaya

2013-07-30

Combining droplet manipulation by the application of an electric field with inkjet printing is proposed as a unique technique to control the surface wettability of substrates for solution-processed organic field-effect transistors (FETs). With the use of this technique, uniform thin films of 2,7-dioctyl[1]benzothieno[2,3,-b][1]benzothiopene (C8-BTBT) could be fabricated on the channels of FET substrates without self-assembled monolayer treatment. High-speed camera observation revealed that the crystals formed at the solid/liquid interface. The coverage of the crystals on the channels depended on the ac frequency of the external electric field applied during film formation, leading to a wide variation in the carrier transport of the films. The highest hole mobility of 0.03 cm(2) V(-1) s(-1) was obtained when the coverage was maximized with an ac frequency of 1 kHz.

High magnetic field quantum transport in Au nanoparticle–cellulose films

International Nuclear Information System (INIS)

Turyanska, L; Makarovsky, O; Patanè, A; Kozlova, N V; Liu, Z; Li, M; Mann, S

2012-01-01

We report the magneto-transport properties of cellulose films comprising interconnected networks of gold nanoparticles (Au NPs). Cellulose is a biopolymer that can be made electrically conducting by cellulose regeneration in Au NP dispersions. The mechanism of electronic conduction in the Au–cellulose films changes from variable range hopping to metallic-like conduction with decreasing resistivity. Our experiments in high magnetic fields (up to 45 T) reveal negative magnetoresistance in the highly resistive films. This is attributed to the spin polarization of the Au NPs and the magnetic field induced suppression of electron spin flips during spin-polarized tunneling in the NP network. (paper)

Electrical transport properties of thermally evaporated phthalocyanine (H 2Pc) thin films

Science.gov (United States)

El-Nahass, M. M.; Farid, A. M.; Attia, A. A.; Ali, H. A. M.

2006-08-01

Thin films of H 2Pc of various thicknesses have been deposited onto glass substrates using thermal evaporation technique at room temperature. The dark electrical resistivity measurements were carried out at different temperatures in the range 298-473 K. An estimation of mean free path ( lo) of charge carriers in H 2Pc thin films was attempted. Measurements of thermoelectric power confirm that H 2Pc thin films behave as a p-type semiconductor. The current density-voltage characteristics of Au/H 2Pc/Au at room temperature showed ohmic conduction mechanism at low voltages. At higher voltages the space-charge-limited conduction (SCLC) accompanied by an exponential trap distribution was dominant. The temperature dependence of current density allows the determination of some essential parameters such as the hole mobility ( μh), the total trap concentration ( Nt), the characteristic temperature ( Tt) and the trap density P( E).

Nonlinear Transport in Organic Thin Film Transistors with Soluble Small Molecule Semiconductor.

Science.gov (United States)

Kim, Hyeok; Song, Dong-Seok; Kwon, Jin-Hyuk; Jung, Ji-Hoon; Kim, Do-Kyung; Kim, SeonMin; Kang, In Man; Park, Jonghoo; Tae, Heung-Sik; Battaglini, Nicolas; Lang, Philippe; Horowitz, Gilles; Bae, Jin-Hyuk

2016-03-01

Nonlinear transport is intensively explained through Poole-Frenkel (PF) transport mechanism in organic thin film transistors with solution-processed small molecules, which is, 6,13-bis(triisopropylsilylethynyl) (TIPS) pentacene. We outline a detailed electrical study that identifies the source to drain field dependent mobility. Devices with diverse channel lengths enable the extensive exhibition of field dependent mobility due to thermal activation of carriers among traps.

Electric current induced forward and anomalous backward mass transport

International Nuclear Information System (INIS)

Somaiah, Nalla; Sharma, Deepak; Kumar, Praveen

2016-01-01

Multilayered test samples were fabricated in form of standard Blech structure, where W was used as the interlayer between SiO 2 substrate and Cu film. Electromigration test was performed at 250 °C by passing an electric current with a nominal density of 3.9  ×  10 10 A m −2 . In addition to the regular electromigration induced mass transport ensuing from the cathode towards the anode, we also observed anomalous mass transport from the anode to the cathode, depleting Cu from the anode as well. We propose an electromigration-thermomigration coupling based reasoning to explain the observed mass transport. (letter)

Electrical conduction of organic ultrathin films evaluated by an independently driven double-tip scanning tunneling microscope.

Science.gov (United States)

Takami, K; Tsuruta, S; Miyake, Y; Akai-Kasaya, M; Saito, A; Aono, M; Kuwahara, Y

2011-11-02

The electrical transport properties of organic thin films within the micrometer scale have been evaluated by a laboratory-built independently driven double-tip scanning tunneling microscope, operating under ambient conditions. The two tips were used as point contact electrodes, and current in the range from 0.1 pA to 100 nA flowing between the two tips through the material can be detected. We demonstrated two-dimensional contour mapping of the electrical resistance on a poly(3-octylthiophene) thin films as shown below. The obtained contour map clearly provided an image of two-dimensional electrical conductance between two point electrodes on the poly(3-octylthiophene) thin film. The conductivity of the thin film was estimated to be (1-8) × 10(-6) S cm(-1). Future prospects and the desired development of multiprobe STMs are also discussed.

Synthesis and electrical characterization of Graphene Oxide films

International Nuclear Information System (INIS)

Yasin, Muhammad; Tauqeer, T.; Zaidi, Syed M.H.; San, Sait E.; Mahmood, Asad; Köse, Muhammet E.; Canimkurbey, Betul; Okutan, Mustafa

2015-01-01

In this work, we have synthesized Graphene Oxide (GO) using modified Hummers method and investigated its electrical properties using parallel plate impedance spectroscopic technique. Graphene Oxide films were prepared using drop casting method on Indium Tin Oxide (ITO) coated glass substrate. Atomic force microscopy was used to characterize the films' microstructure and surface topography. Electrical characterization was carried out using LCR meter in frequency regime (100 Hz to 10 MHz) at different temperatures. AC conductivity σ ac of the films was observed to be varied with angular frequency, ω as ω S , with S < 1. The electrical properties of GO were found to be both frequency and temperature dependent. Analysis showed that GO film contains direct current (DC) and Correlated Barrier Hopping (CBH) conductivity mechanisms at low and high frequency ranges, respectively. Photon absorption and transmittance capability in the visible range and excellent electrical parameters of solution processed Graphene Oxide suggest its suitability for the realization of low cost flexible organic solar cells and organic Thin Film Transistors, respectively. - Highlights: • Synthesize and electrical characterization of Graphene Oxide (GO) Film was undertaken. • Temperature dependent impedance spectroscopy was used for electrical analysis. • AFM was used to characterize films' microstructure and surface topography. • Electrical parameters were found to vary with both temperature and frequency. • GO showed DC and CBH conductivity mechanisms at low and high frequency, respectively

Soap-film flow induced by electric fields in asymmetric frames

Science.gov (United States)

Mollaei, S.; Nasiri, M.; Soltanmohammadi, N.; Shirsavar, R.; Ramos, A.; Amjadi, A.

2018-04-01

Net fluid flow of soap films induced by (ac or dc) electric fields in asymmetric frames is presented. Previous experiments of controllable soap film flow required the simultaneous use of an electrical current passing through the film and an external electric field or the use of nonuniform ac electric fields. Here a single voltage difference generates both the electrical current going through the film and the electric field that actuates on the charge induced on the film. The film is set into global motion due to the broken symmetry that appears by the use of asymmetric frames. If symmetric frames are used, the film flow is not steady but time dependent and irregular. Finally, we study numerically these film flows by employing the model of charge induction in ohmic liquids.

Substrate-dependent post-annealing effects on the strain state and electrical transport of epitaxial La{sub 5/8-y}Pr{sub y}Ca{sub 3/8}MnO{sub 3} films

Energy Technology Data Exchange (ETDEWEB)

Hu, Sixia; Wang, Haibo; Dong, Yongqi; Hong, Bing; He, Hao; Bao, Jun [National Synchrotron Radiation Laboratory and School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026 (China); Huang, Haoliang [CAS Key Laboratory of Materials for Energy Conversion and Collaborative Innovation Center of Chemistry for Energy Materials, University of Science and Technology of China, Hefei, Anhui 230026 (China); Yang, Yuanjun; Luo, Zhenlin, E-mail: zlluo@ustc.edu.cn; Yang, Mengmeng; Gao, Chen, E-mail: cgao@ustc.edu.cn [National Synchrotron Radiation Laboratory and School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026 (China); CAS Key Laboratory of Materials for Energy Conversion and Collaborative Innovation Center of Chemistry for Energy Materials, University of Science and Technology of China, Hefei, Anhui 230026 (China)

2014-06-15

Large scale electronic phase separation (EPS) between ferromagnetic metallic and charge-ordered insulating phases in La{sub 5/8-y}Pr{sub y}Ca{sub 3/8}MnO{sub 3} (y = 0.3) (LPCMO) is very sensitive to the structural changes. This work investigates the effects of post-annealing on the strain states and electrical transport properties of LPCMO films epitaxially grown on (001){sub pc} SrTiO{sub 3} (tensile strain), LaAlO{sub 3} (compressive strain) and NdGaO{sub 3} (near-zero strain) substrates. Before annealing, all the films are coherent-epitaxial and insulating through the measured temperature range. Obvious change of film lattice is observed during the post-annealing: the in-plane strain in LPCMO/LAO varies from −1.5% to −0.1% while that in LPCMO/STO changes from 1.6% to 1.3%, and the lattice of LPCMO/NGO keeps constant because of the good lattice-match between LPCMO and NGO. Consequently, the varied film strain leads to the emergence of metal-insulator transitions (MIT) and shift of the critical transition temperature in the electrical transport. These results demonstrate that lattice-mismatch combined with post-annealing is an effective approach to tune strain in epitaxial LPCMO films, and thus to control the EPS and MIT in the films.

The effects of thermal annealing on the structure and the electrical transport properties of ultrathin gadolinia-doped ceria films grown by pulsed laser deposition

Energy Technology Data Exchange (ETDEWEB)

Rodrigo, K.; Pryds, N.; Theil Kuhn, L.; Esposito, V.; Linderoth, S. [Technical University of Denmark, Fuel Cells and Solid State Chemistry Division, Risoe DTU, Roskilde (Denmark); Heiroth, S.; Lippert, T. [Paul Scherrer Institute, General Energy Research Department, Villigen PSI (Switzerland); Schou, J. [Technical University of Denmark, Department of Photonics Engineering, Roskilde (Denmark)

2011-09-15

Ultrathin crystalline films of 10 mol% gadolinia-doped ceria (CGO10) are grown on MgO (100) substrates by pulsed laser deposition at a moderate temperature of 400 C. As-deposited CGO10 layers of approximately 4 nm, 14 nm, and 22 nm thickness consist of fine grains with dimensions {<=}{proportional_to}11 nm. The films show high density within the thickness probed in the X-ray reflectivity experiments. Thermally activated grain growth, density decrease, and film surface roughening, which may result in the formation of incoherent CGO10 islands by dewetting below a critical film thickness, are observed upon heat treatment at 400 C and 800 C. The effect of the grain coarsening on the electrical characteristics of the layers is investigated and discussed in the context of a variation of the number density of grain boundaries. The results are evaluated with regard to the use of ultrathin CGO10 films as seeding templates for the moderate temperature growth of thick solid electrolyte films with improved oxygen transport properties. (orig.)

Curvature effects on the electronic and transport properties of semiconductor films

Science.gov (United States)

Batista, F. F.; Chaves, Andrey; da Costa, D. R.; Farias, G. A.

2018-05-01

Within the effective mass approximation, we study the curvature effects on the electronic and transport properties of semiconductor films. We investigate how the geometry-induced potential resulting exclusively from periodic ripples in the film induces electronic confinement and a superlattice band structure. For fixed curvature parameters, such a confinement can be easily tuned by an external electric field, hence features of the superlattice band structure such as its energy gaps and band curvature can be controlled by an external parameter. We also show that, for some values of curvature and electric field, it is possible to obtain massless Dirac bands for a smooth curved structure. Moreover, we use a wave packet propagation method to demonstrate that the ripples are responsible for a significant inter-sub-band transition, specially for moderate values of the ripple height.

Interface effects on the electronic transport properties in highly epitaxial LaBaCo2O(5.5+δ) films.

Science.gov (United States)

Ma, C R; Liu, M; Liu, J; Collins, G; Zhang, Y M; Wang, H B; Chen, C L; Lin, Y; He, J; Jiang, J C; Meletis, E I; Jacobson, A J

2014-02-26

Single-crystalline perovskite LaBaCo2O5.5+δ thin films were grown on a (110) NdGaO3 single-crystal substrate in order to systematically investigate the effect of lattice mismatch on the electrical transport properties in comparison to the films on LaAlO3, SrTiO3, and MgO substrates. Microstructure studies reveal that all of the LaBaCo2O5.5+δ films are of excellent quality with atomically sharp interface structures. The electrical and magnetic transport property studies indicate that the resistivity, magnetoresistance, and magnetic moment of the film are very sensitive to the substrate materials because of the lattice mismatch/interface strain. The Curie temperature, however, is almost independent of the strain imposed by the substrate, probably because of the strong coupling between the nanodomain boundary and interface strain.

Electrical transport through single-wall carbon nanotube-anodic aluminum oxide-aluminum heterostructures

International Nuclear Information System (INIS)

Kukkola, Jarmo; Rautio, Aatto; Sala, Giovanni; Pino, Flavio; Toth, Geza; Leino, Anne-Riikka; Maeklin, Jani; Jantunen, Heli; Uusimaeki, Antti; Kordas, Krisztian; Gracia, Eduardo; Terrones, Mauricio; Shchukarev, Andrey; Mikkola, Jyri-Pekka

2010-01-01

Aluminum foils were anodized in sulfuric acid solution to form thick porous anodic aluminum oxide (AAO) films of thickness ∼6 μm. Electrodes of carboxyl-functionalized single-wall carbon nanotube (SWCNT) thin films were inkjet printed on the anodic oxide layer and the electrical characteristics of the as-obtained SWCNT-AAO-Al structures were studied. Nonlinear current-voltage transport and strong temperature dependence of conduction through the structure was measured. The microstructure and chemical composition of the anodic oxide layer was analyzed using transmission and scanning electron microscopy as well as x-ray photoelectron spectroscopy. Schottky emission at the SWCNT-AAO and AAO-Al interfaces allowed by impurity states in the anodic aluminum oxide film together with ionic surface conduction on the pore walls of AAO gives a reasonable explanation for the measured electrical conduction. Calcined AAO is proposed as a dielectric material for SWCNT-field effect transistors.

Phonon transport across nano-scale curved thin films

Energy Technology Data Exchange (ETDEWEB)

Mansoor, Saad B.; Yilbas, Bekir S., E-mail: bsyilbas@kfupm.edu.sa

2016-12-15

Phonon transport across the curve thin silicon film due to temperature disturbance at film edges is examined. The equation for radiative transport is considered via incorporating Boltzmann transport equation for the energy transfer. The effect of the thin film curvature on phonon transport characteristics is assessed. In the analysis, the film arc length along the film centerline is considered to be constant and the film arc angle is varied to obtain various film curvatures. Equivalent equilibrium temperature is introduced to assess the phonon intensity distribution inside the curved thin film. It is found that equivalent equilibrium temperature decay along the arc length is sharper than that of in the radial direction, which is more pronounced in the region close to the film inner radius. Reducing film arc angle increases the film curvature; in which case, phonon intensity decay becomes sharp in the close region of the high temperature edge. Equivalent equilibrium temperature demonstrates non-symmetric distribution along the radial direction, which is more pronounced in the near region of the high temperature edge.

Phonon transport across nano-scale curved thin films

International Nuclear Information System (INIS)

Mansoor, Saad B.; Yilbas, Bekir S.

2016-01-01

Phonon transport across the curve thin silicon film due to temperature disturbance at film edges is examined. The equation for radiative transport is considered via incorporating Boltzmann transport equation for the energy transfer. The effect of the thin film curvature on phonon transport characteristics is assessed. In the analysis, the film arc length along the film centerline is considered to be constant and the film arc angle is varied to obtain various film curvatures. Equivalent equilibrium temperature is introduced to assess the phonon intensity distribution inside the curved thin film. It is found that equivalent equilibrium temperature decay along the arc length is sharper than that of in the radial direction, which is more pronounced in the region close to the film inner radius. Reducing film arc angle increases the film curvature; in which case, phonon intensity decay becomes sharp in the close region of the high temperature edge. Equivalent equilibrium temperature demonstrates non-symmetric distribution along the radial direction, which is more pronounced in the near region of the high temperature edge.

Effects of phosphorus on the electrical characteristics of plasma deposited hydrogenated amorphous silicon carbide thin films

Science.gov (United States)

Alcinkaya, Burak; Sel, Kivanc

2018-01-01

The properties of phosphorus doped hydrogenated amorphous silicon carbide (a-SiCx:H) thin films, that were deposited by plasma enhanced chemical vapor deposition technique with four different carbon contents (x), were analyzed and compared with those of the intrinsic a-SiCx:H thin films. The carbon contents of the films were determined by X-ray photoelectron spectroscopy. The thickness and optical energies, such as Tauc, E04 and Urbach energies, of the thin films were determined by UV-Visible transmittance spectroscopy. The electrical properties of the films, such as conductivities and activation energies were analyzed by temperature dependent current-voltage measurements. Finally, the conduction mechanisms of the films were investigated by numerical analysis, in which the standard transport mechanism in the extended states and the nearest neighbor hopping mechanism in the band tail states were taken into consideration. It was determined that, by the effect of phosphorus doping the dominant conduction mechanism was the standard transport mechanism for all carbon contents.

Electrical transport properties of sputtered Nd2-xCexCuO4±δ thin films

Science.gov (United States)

Guarino, Anita; Leo, Antonio; Avella, Adolfo; Avitabile, Francesco; Martucciello, Nadia; Grimaldi, Gaia; Romano, Alfonso; Pace, Sandro; Romano, Paola; Nigro, Angela

2018-05-01

Thin films of the electron-doped high-temperature superconductor Nd2-xCexCuO4±δ have been deposited by dc sputtering technique on (100) SrTiO3 substrates. A tuning of the oxygen content in the as-grown non-superconducting samples has been achieved by changing the oxygen partial pressure during the growth in the Argon sputtering atmosphere. All samples show the superconducting transition after a suitable two-step thermal treatment in an oxygen-reducing environment. Structural and electrical transport properties on the as-grown as well as on the superconducting samples have been investigated. We find that the structural properties are consistent with a deficiency of the oxygen content with respect to optimally annealed samples, and that the transition to the superconducting phase is always accompanied by an increase of the c-axis lattice parameter. Measurements of the Hall coefficient RH as a function of temperature and in the normal state of our epitaxial films are presented and discussed. RH results negative for all the films regardless of the oxygen content and it decreases with the temperature. In particular, the Hall coefficient is only about 10% lower than the value measured in the as-grown oxygen-deficient phase, in contrast to the results reported in literature. The removal of the excess oxygen in as-grown samples seems not to be the only requirement for triggering the superconducting transition in electron-doped compounds. The microstructural change associated with the increase of the c-axis parameter in our deoxygenated samples could help in understanding the microscopic mechanism underlying the reduction process of n-type superconductors, which is still under debate.

Temperature-dependent charge injection and transport in pentacene thin-film transistors

International Nuclear Information System (INIS)

Kim, Dong Wook; Shin, Hyunji; Choi, Jong Sun; Park, Ji-Ho; Park, Jaehoon

2015-01-01

The electrical characteristics of p-channel pentacene thin-film transistors (TFTs) were analyzed at different operating temperatures ranging from 253 to 353 K. An improvement in the drain current and field-effect mobility of the pentacene TFTs is observed with increasing temperature. From the Arrhenius plots of field-effect mobility extracted at various temperatures, a lower activation energy of 99.34 meV was obtained when the device is operating in the saturation region. Such observation is ascribed to the thermally activated hole transport through the pentacene grain boundaries. On the other hand, it was found that the Au/pentacene contact significantly affects the TFTs electrical characteristics in the linear region, which resulted in a higher activation energy. The activation energy based on the linear field-effect mobility, which increased from 344.61 to 444.70 meV with decreasing temperature, implies the charge-injection-limited electrical behavior of pentacene TFTs at low temperatures. The thermally induced electrical characteristic variations in pentacene TFTs can thus be studied through the temperature dependence of the charge injection and transport processes. (paper)

Effect of microstructure on the electronic transport properties of epitaxial CaRuO{sub 3} thin films

Energy Technology Data Exchange (ETDEWEB)

Daptary, Gopi Nath; Sow, Chanchal; Sarkar, Suman; Chiniwar, Santosh; Kumar, P.S. Anil [Department of Physics, Indian Institute of Science, Bangalore 560012 (India); Sil, Anomitra [Center For Nano Science And Engineering, Indian Institute of Science, Bangalore 560012 (India); Bid, Aveek, E-mail: aveek.bid@physics.iisc.ernet.in [Department of Physics, Indian Institute of Science, Bangalore 560012 (India)

2017-04-15

We have carried out extensive comparative studies of the structural and transport properties of CaRuO{sub 3} thin films grown under various oxygen pressure. We find that the preferred orientation and surface roughness of the films are strongly affected by the oxygen partial pressure during growth. This in turn affects the electrical and magnetic properties of the films. Films grown under high oxygen pressure have the least surface roughness and show transport characteristics of a good metal down to the lowest temperature measured. On the other hand, films grown under low oxygen pressures have high degree of surface roughness and show signatures of ferromagnetism. We could verify that the low frequency resistance fluctuations (noise) in these films arise due to thermally activated fluctuations of local defects and that the defect density matches with the level of disorder seen in the films through structural characterizations.

Study of the charge transport characteristics of dendrimer molecular thin films

Energy Technology Data Exchange (ETDEWEB)

Li, J.C., E-mail: jcli@mail.neu.edu.cn; Han, N.; Wang, S.S.; Ba, D.C.

2011-05-31

In this work, we systematically studied the electrical characteristics of two types of dendritic arylamine thin film devices. We observed that, for devices with different interfacial structures, their charge injection barriers and transport properties are obviously different. The smallest charge injection barrier is observed in dendrimer devices without charge-transfer interfacial layers. The Richardson-Schottky thermionic emission model can be well used to fit the experimental current-voltage characteristics at a lower voltage region. The charge injection barrier increases about 0.4 eV and 0.5 eV when a 1-decanethiol self-assembly layer and -CN terminated dendrimer thin films are inserted as the interfacial layer, respectively. It is shown that the molecule/electrode charge-transfer interfaces can largely affect the device charge injection/transport process and consequently change the device performance. In this case, the space charge limited conduction theory is more applicable to simulate the device conduction mechanism. Owing to its ultra-thin thickness, the self-assembly monolayer technique is proved to be an efficient approach in engineering the interfacial electronic structures of dendrimer thin film devices.

Study of the charge transport characteristics of dendrimer molecular thin films

International Nuclear Information System (INIS)

Li, J.C.; Han, N.; Wang, S.S.; Ba, D.C.

2011-01-01

In this work, we systematically studied the electrical characteristics of two types of dendritic arylamine thin film devices. We observed that, for devices with different interfacial structures, their charge injection barriers and transport properties are obviously different. The smallest charge injection barrier is observed in dendrimer devices without charge-transfer interfacial layers. The Richardson-Schottky thermionic emission model can be well used to fit the experimental current-voltage characteristics at a lower voltage region. The charge injection barrier increases about 0.4 eV and 0.5 eV when a 1-decanethiol self-assembly layer and -CN terminated dendrimer thin films are inserted as the interfacial layer, respectively. It is shown that the molecule/electrode charge-transfer interfaces can largely affect the device charge injection/transport process and consequently change the device performance. In this case, the space charge limited conduction theory is more applicable to simulate the device conduction mechanism. Owing to its ultra-thin thickness, the self-assembly monolayer technique is proved to be an efficient approach in engineering the interfacial electronic structures of dendrimer thin film devices.

Electrical Conductivity of CUXS Thin Film Deposited by Chemical ...

African Journals Online (AJOL)

Thin films of CuxS have successfully been deposited on glass substrates using the Chemical Bath Deposition (CBD) technique. The films were then investigated for their electrical properties. The results showed that the electrical conductivities of the CuxS films with different molarities (n) of thiourea (Tu), determined using ...

Effect of large compressive strain on low field electrical transport in La0.88Sr0.12MnO3 thin films

International Nuclear Information System (INIS)

Prasad, Ravikant; Gaur, Anurag; Siwach, P K; Varma, G D; Kaur, A; Singh, H K

2007-01-01

We have investigated the effect of large in-plane compressive strain on the electrical transport in La 0.88 Sr 0.12 MnO 3 in thin films. For achieving large compressive strain, films have been deposited on single crystal LaAlO 3 (LAO, a = 3.798 A) substrate from a polycrystalline bulk target having average in-plane lattice parameter a av = (a b + b b )/2 = 3.925 A. The compressive strain was further relaxed by varying the film thickness in the range ∼6-75 nm. In the film having least thickness (∼6 nm) large increase (c = 3.929 A) in the out-of-plane lattice parameter is observed which gradually decreases towards the bulk value (c bulk = 3.87 A) for ∼75 nm thick film. This shows that the film having the least thickness is under large compressive strain, which partially relaxes with increasing film thickness. The T IM of the bulk target ∼145 K goes up to ∼235 K for the ∼6 nm thin film and even for partially strain relaxed ∼75 nm thick film T IM is as high as ∼200 K. This enhancement in T IM is explained in terms of suppression of Jahn-Teller distortion of the MnO 6 octahedra by the large in-plane compressive strain. We observe a large enhancement in the low field magnetoresistance (MR) just below T IM in the films having partial strain relaxation. Thick films of 6 and 20 nm have MR ∼14% at 3 kOe that almost doubles in 35 nm film to ∼27%. Similar enhancement is also obtained in the case of the temperature coefficient of resistivity. The near doubling of low field MR is explained in terms of delocalization of weakly localized carriers around T IM by small magnetic fields

Photodiode Based on CdO Thin Films as Electron Transport Layer

Science.gov (United States)

Soylu, M.; Kader, H. S.

2016-11-01

Cadmium oxide (CdO) thin films were synthesized by the sol-gel method. The films were analyzed by means of XRD, AFM, and UV/Vis spectrophotometry. X-ray diffraction patterns confirm that the films are formed from CdO with cubic crystal structure and consist of nano-particles. The energy gap of the prepared film was found to be 2.29 eV. The current-voltage ( I- V) characteristics of the CdO/ p-Si heterojunction were examined in the dark and under different illumination intensities. The heterojunction showed high rectifying behavior and a strong photoresponse. Main electrical parameters of the photodiode such as series and shunt resistances ( R s and R sh), saturation current I 0, and photocurrent I ph, were extracted considering a single diode equivalent circuit of a photovoltaic cell. Results indicate that the application of CdO thin films as an electron transport layer on p-Si acts as a photodetector in the field of the UV/visible.

Impact of the Topological Surface State on the Thermoelectric Transport in Sb2Te3 Thin Films.

Science.gov (United States)

Hinsche, Nicki F; Zastrow, Sebastian; Gooth, Johannes; Pudewill, Laurens; Zierold, Robert; Rittweger, Florian; Rauch, Tomáš; Henk, Jürgen; Nielsch, Kornelius; Mertig, Ingrid

2015-04-28

Ab initio electronic structure calculations based on density functional theory and tight-binding methods for the thermoelectric properties of p-type Sb2Te3 films are presented. The thickness-dependent electrical conductivity and the thermopower are computed in the diffusive limit of transport based on the Boltzmann equation. Contributions of the bulk and the surface to the transport coefficients are separated, which enables to identify a clear impact of the topological surface state on the thermoelectric properties. When the charge carrier concentration is tuned, a crossover between a surface-state-dominant and a Fuchs-Sondheimer transport regime is achieved. The calculations are corroborated by thermoelectric transport measurements on Sb2Te3 films grown by atomic layer deposition.

Metallic transport and large anomalous Hall effect at room temperature in ferrimagnetic Mn4N epitaxial thin film

International Nuclear Information System (INIS)

Shen, Xi; Shigematsu, Kei; Chikamatsu, Akira; Fukumura, Tomoteru; Hirose, Yasushi; Hasegawa, Tetsuya

2014-01-01

We report the electrical transport properties of ferrimagnetic Mn 4 N (001) epitaxial thin films grown by pulsed laser deposition on MgO (001) substrates. The Mn 4 N thin films were tetragonally distorted with a ratio of out-of-plane to in-plane lattice constants of 0.987 and showed perpendicular magnetic anisotropy with an effective magnetic anisotropy constant of 0.16 MJ/m 3 , which is comparable with that of a recently reported molecular-beam-epitaxy-grown film. The thin films exhibited metallic transport with a room temperature resistivity of 125 μΩ cm in addition to a large anomalous Hall effect with a Hall angle tangent of 0.023.

Lattice dynamics and substrate-dependent transport properties of (In, Yb)-doped CoSb3 skutterudite thin films

KAUST Repository

Sarath Kumar, S. R.

2011-10-24

Lattice dynamics, low-temperature electrical transport, and high-temperature thermoelectric properties of (In, Yb)-doped CoSb3thin films on different substrates are reported. Pulsed laser deposition under optimized conditions yielded single-phase polycrystalline skutterudite films. Raman spectroscopy studies suggested that In and Yb dopants occupy the cage sites in the skutterudite lattice. Low-temperature electrical transport studies revealed the n-type semiconducting nature of the films with extrinsic and intrinsic conduction mechanisms, in sharp contrast to the degenerate nature reported for identical bulk samples. Calculations yielded a direct bandgap close to 50 meV with no evidence of an indirect gap. The carrier concentration of the films was identical to that reported for the bulk and increased with temperature beyond 250 K. The higher resistivity exhibited is attributed to the enhanced grain boundary scattering in films with a high concentration of grains. The maximum power factor of ∼0.68 W m−1 K−1 obtained at 660 K for the film on glass is found to be nearly four times smaller compared to that reported for the bulk. The observed difference in the power factors of the films on different substrates is explained on the basis of the diffusion of oxygen from the substrates and the formation of highly conducting CoSb2 phase upon the oxidation of CoSb3.

Lattice dynamics and substrate-dependent transport properties of (In, Yb)-doped CoSb3 skutterudite thin films

KAUST Repository

Sarath Kumar, S. R.; Cha, Dong Kyu; Alshareef, Husam N.

2011-01-01

Lattice dynamics, low-temperature electrical transport, and high-temperature thermoelectric properties of (In, Yb)-doped CoSb3thin films on different substrates are reported. Pulsed laser deposition under optimized conditions yielded single

Electric field tuning of phase separation in manganite thin films

KAUST Repository

Lourembam, James; Wu, Jianchun; Ding, Junfeng; Lin, Weinan; Wu, Tao

2014-01-01

In this paper, we investigate the electric field effect on epitaxial Pr0.65(Ca0.75Sr0.25)0.35MnO3 thin films in electric double-layer transistors. Different from the conventional transistors with semiconducting channels, the sub(micrometer)-scale phase separation in the manganite channels is expected to result in inhomogeneous distribution of mobile carriers and local enhancement of electric field. The field effect is much larger in the low-temperature phase separation region compared to that in the high-temperature polaron transport region. Further enhancement of electroresistance is achieved by applying a magnetic field, and a 250% modulation of resistance is observed at 80 K, equivalent to an increase of the ferromagnetic metallic phase fraction by 0.51%, as estimated by the general effective medium model. Our results illustrate the complementary nature of electric and magnetic field effects in phase-separated manganites, providing insights on such novel electronic devices based on complex oxides.

Electric field tuning of phase separation in manganite thin films

KAUST Repository

Lourembam, James

2014-01-29

In this paper, we investigate the electric field effect on epitaxial Pr0.65(Ca0.75Sr0.25)0.35MnO3 thin films in electric double-layer transistors. Different from the conventional transistors with semiconducting channels, the sub(micrometer)-scale phase separation in the manganite channels is expected to result in inhomogeneous distribution of mobile carriers and local enhancement of electric field. The field effect is much larger in the low-temperature phase separation region compared to that in the high-temperature polaron transport region. Further enhancement of electroresistance is achieved by applying a magnetic field, and a 250% modulation of resistance is observed at 80 K, equivalent to an increase of the ferromagnetic metallic phase fraction by 0.51%, as estimated by the general effective medium model. Our results illustrate the complementary nature of electric and magnetic field effects in phase-separated manganites, providing insights on such novel electronic devices based on complex oxides.

Structural and morphological changes in P3HT thin film transistors applying an electric field

Energy Technology Data Exchange (ETDEWEB)

Tiwari, Deepak Kumar; Grigorian, Souren; Pietsch, Ullrich [University of Siegen (Germany); Flesch, Heinz; Resel, Roland [University of Siegen (Germany); Graz University of Technology (Austria)

2010-07-01

We report on electric field dependent crystalline structure and morphological changes of drop casting and spin coated poly(3-hexylthiophene) (P3HT) thin films. In order to probe the morphological changes induced by an applied electric field the samples were covered with thin source/drain electrodes separated by a small channel of 2 mm width. A series of x-ray reflectivity, X-ray grazing incidence out-of-plane and in-plane scans have been performed as function of the applied electric voltage. The (100) peak shows a decrease in intensity with increase of the applied electric field. This might be caused by Joule heating and the creation of current induced defects in the P3HT film. On other hand the (020) peak intensity shows much stronger changes with applied field. Considering the *-* stacking direction the measured effect can be directly related to a change in the electric transport. The observed changes in structure are reversible and the current-voltage cycle can be repeated several times. For X-ray reflectivity major changes have been found close to critical angle of total external reflection indicating the film becomes less dense and increases in surface roughness with increase of the voltage. This change in surface behaviour could be confirmed by in-situ AFM measurements.

Microstructure and opto-electric properties of Cu/ITO thin films

International Nuclear Information System (INIS)

Wang Xian; Li Junlei; Shi Shiwei; Song Xueping; Cui Jingbiao; Sun Zhaoqi

2012-01-01

Highlights: ► We prepared Cu/ITO films with different Cu layer thickness. ► We analyzed the relation between opto-electric properties and roughness of the films. ► The Cu-16.1 nm/ITO film shows excellent optical and electric properties. ► Cu/ITO films have great application prospects in new-type transflective displays. - Abstract: Cu/ITO thin films were deposited on glass and silicon substrates by DC and RF magnetron sputtering at room temperature. X-ray diffraction results showed that the films were amorphous. Both of SEM images and 3D Profilometer images indicated that the surface morphology of the ITO films had been affected by the Cu layer. The optical and electric properties of the Cu/ITO films changed significantly with the variation of Cu layer thickness. Cu-5.4 nm/ITO film exhibited the highest optical transmittance of 62.9% at 550 nm and the lowest sheet resistance of 96 Ω/□, whereas Cu-16.1 nm/ITO film showed the highest average reflectance of 24.0% and the lowest resistance of 27.4 Ω/□. Based on our analysis, it was evaluated that Cu layer had an important effect on the electrical and optical properties of ITO thin films.

Memory and Electrical Properties of (100-Oriented AlN Thin Films Prepared by Radio Frequency Magnetron Sputtering

Directory of Open Access Journals (Sweden)

Maw-Shung Lee

2014-01-01

Full Text Available The (100-oriented aluminum nitride (AlN thin films were well deposited onto p-type Si substrate by radio frequency (RF magnetron sputtering method. The optimal deposition parameters were the RF power of 350 W, chamber pressure of 9 mTorr, and nitrogen concentration of 50%. Regarding the physical properties, the microstructure of as-deposited (002- and (100-oriented AlN thin films were obtained and compared by XRD patterns and TEM images. For electrical properties analysis, we found that the memory windows of (100-oriented AlN thin films are better than those of (002-oriented thin films. Besides, the interface and interaction between the silicon and (100-oriented AlN thin films was serious important problem. Finally, the current transport models of the as-deposited and annealed (100-oriented AlN thin films were also discussed. From the results, we suggested and investigated that large memory window of the annealed (100-oriented AlN thin films was induced by many dipoles and large electric field applied.

Methods for producing thin film charge selective transport layers

Science.gov (United States)

Hammond, Scott Ryan; Olson, Dana C.; van Hest, Marinus Franciscus Antonius Maria

2018-01-02

Methods for producing thin film charge selective transport layers are provided. In one embodiment, a method for forming a thin film charge selective transport layer comprises: providing a precursor solution comprising a metal containing reactive precursor material dissolved into a complexing solvent; depositing the precursor solution onto a surface of a substrate to form a film; and forming a charge selective transport layer on the substrate by annealing the film.

Metal-insulator transition in tin doped indium oxide (ITO) thin films: Quantum correction to the electrical conductivity

OpenAIRE

Deepak Kumar Kaushik; K. Uday Kumar; A. Subrahmanyam

2017-01-01

Tin doped indium oxide (ITO) thin films are being used extensively as transparent conductors in several applications. In the present communication, we report the electrical transport in DC magnetron sputtered ITO thin films (prepared at 300 K and subsequently annealed at 673 K in vacuum for 60 minutes) in low temperatures (25-300 K). The low temperature Hall effect and resistivity measurements reveal that the ITO thin films are moderately dis-ordered (kFl∼1; kF is the Fermi wave vector and l ...

Metallic transport and large anomalous Hall effect at room temperature in ferrimagnetic Mn{sub 4}N epitaxial thin film

Energy Technology Data Exchange (ETDEWEB)

Shen, Xi; Shigematsu, Kei [Department of Chemistry, The University of Tokyo, Tokyo 113-0033 (Japan); Chikamatsu, Akira, E-mail: chikamatsu@chem.s.u-tokyo.ac.jp; Fukumura, Tomoteru [Department of Chemistry, The University of Tokyo, Tokyo 113-0033 (Japan); CREST, Japan Science and Technology Agency (JST), Tokyo 113-0033 (Japan); Hirose, Yasushi; Hasegawa, Tetsuya [Department of Chemistry, The University of Tokyo, Tokyo 113-0033 (Japan); CREST, Japan Science and Technology Agency (JST), Tokyo 113-0033 (Japan); Kanagawa Academy of Science and Technology (KAST), Kawasaki 213-0012 (Japan)

2014-08-18

We report the electrical transport properties of ferrimagnetic Mn{sub 4}N (001) epitaxial thin films grown by pulsed laser deposition on MgO (001) substrates. The Mn{sub 4}N thin films were tetragonally distorted with a ratio of out-of-plane to in-plane lattice constants of 0.987 and showed perpendicular magnetic anisotropy with an effective magnetic anisotropy constant of 0.16 MJ/m{sup 3}, which is comparable with that of a recently reported molecular-beam-epitaxy-grown film. The thin films exhibited metallic transport with a room temperature resistivity of 125 μΩ cm in addition to a large anomalous Hall effect with a Hall angle tangent of 0.023.

Electrical properties and conduction mechanisms of Ru-based thick-film (cermet) resistors

International Nuclear Information System (INIS)

Pike, G.E.; Seager, C.H.

1977-01-01

This paper presents an experimental study of the electrical conduction mechanisms in thick-film (cermet) resistor. The resistors were made from one custom and three commercially formulated inks with sheet resistivities ranging from 10 2 to 10 6 Ω/D 7 Alembertian in decade increments. Their microstructure and composition have been examined using optical and scanning electron microscopy, electron microprobe analysis, x-ray diffraction, and various chemical analyses. This portion of our study shows that the resistors are heterogeneous mixtures of metallic metal oxide particles (approx.4 x 10 -5 cm in diameter) and a lead silicate glass. The metal oxide particles are ruthenium containing pyrochlores, and are joined to form a continuous three-dimensional network of chain segments. The principal experimental work reported here is an extensive study of the electrical transport properties of the resistors. The temperature dependence of conductance has been measured from 1.2 to 400 K, and two features common to all resistors are found. There is a pronounced decrease in conductance at low temperatures and a shallow maximum at several hundred Kelvin. Within the same range of temperatures the reversible conductance as a function of electric field from 0 to 28 kV/cm has been studied. The resistors are non-Ohmic at all temperatures, but particularly at cryogenic temperatures for low fields. At higher fields the conductance shows a linear variation with electric field. The thick-film resistors are found to have a small dielectric constant and a (nearly) frequency-independent conductance from dc to 50 MHz. The magnetoresistance to 100 kG, the Hall mobility, and the Seebeck coefficient of most of the resistors have been measured and discovered to be quite small. Many of the electrical transport properties have also been determined for the metal oxide particles which were extracted from the fired resistors

Electric field-induced hole transport in copper(i) thiocyanate (CuSCN) thin-films processed from solution at room temperature

KAUST Repository

Pattanasattayavong, Pichaya; Ndjawa, Guy Olivier Ngongang; Zhao, Kui; Chou, Kang Wei; Yaacobi-Gross, Nir; O'Regan, Brian C.; Amassian, Aram; Anthopoulos, Thomas D.

2013-01-01

The optical, structural and charge transport properties of solution-processed films of copper(i) thiocyanate (CuSCN) are investigated in this work. As-processed CuSCN films of ∼20 nm in thickness are found to be nano-crystalline, highly transparent and exhibit intrinsic hole transporting characteristics with a maximum field-effect mobility in the range of 0.01-0.1 cm2 V-1 s-1. © 2013 The Royal Society of Chemistry.

Electrically aligned cellulose film for electro-active paper and its piezoelectricity

International Nuclear Information System (INIS)

Yun, Sungryul; Jang, Sangdong; Yun, Gyu-Young; Kim, Jaehwan

2009-01-01

Electrically aligned regenerated cellulose films were fabricated and the effect of applied electric field was investigated for the piezoelectricity of electro-active paper (EAPap). The EAPap was fabricated by coating gold electrodes on both sides of regenerated cellulose film. The cellulose film was prepared by dissolving cotton pulp in LiCl/N,N-dimethylacetamide solution followed by a cellulose chain regeneration process. During the regeneration process an external electric field was applied in the direction of mechanical stretching. Alignment of cellulose fiber chains was investigated as a function of applied electric field. The material characteristics of the cellulose films were analyzed by using an x-ray diffractometer, a field emission scanning electron microscope and a high voltage electron microscope. The application of external electric fields was found to induce formation of nanofibers in the cellulose, resulting in an increase in the crystallinity index (CI) values. It was also found that samples with higher CI values showed higher in-plane piezoelectric constant, d 31 , values. The piezoelectricity of the current EAPap films was measured to be equivalent or better than that of ordinary PVDF films. Therefore, an external electric field applied to a cellulose film along with a mechanical stretching during the regeneration process can enhance the piezoelectricity. (technical note)

Correlation of nanostructure and charge transport properties of oxidized a -SiC:H films

Energy Technology Data Exchange (ETDEWEB)

Gordienko, S.O.; Nazarov, A.N.; Vasin, A.V.; Rusavsky, A.V.; Lysenko, V.S. [Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, Prospekt Nauki 41, 03028 Kyiv (Ukraine)

2012-06-15

This paper considers the influence of low temperature oxidation on structural and electrical properties of amorphous carbon-rich a -Si{sub 1-x}C{sub x}:H thin films fabricated by reactive RF magnetron sputtering. It is shown that oxidation leads to formation of SiO{sub x} matrix with graphite-like carbon inclusions. Such conductive precipitates has a strong effect on charge transport in oxidized a -Si{sub 1-x}C{sub x}:H films (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Spin transport, magnetoresistance, and electrically detected magnetic resonance in amorphous hydrogenated silicon nitride

Energy Technology Data Exchange (ETDEWEB)

Mutch, Michael J. [Intercollege Program of Materials, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Lenahan, Patrick M. [Intercollege Program of Materials, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); King, Sean W. [Logic Technology Development, Intel Corporation, Hillsboro, Oregon 97124 (United States)

2016-08-08

We report on a study of spin transport via electrically detected magnetic resonance (EDMR) and near-zero field magnetoresistance (MR) in silicon nitride films. Silicon nitrides have long been important materials in solid state electronics. Although electronic transport in these materials is not well understood, electron paramagnetic resonance studies have identified a single dominating paramagnetic defect and have also provided physical and chemical descriptions of the defects, called K centers. Our EDMR and MR measurements clearly link the near-zero field MR response to the K centers and also indicate that K center energy levels are approximately 3.1 eV above the a-SiN:H valence band edge. In addition, our results suggest an approach for the study of defect mediated spin-transport in inorganic amorphous insulators via variable electric field and variable frequency EDMR and MR which may be widely applicable.

Electrical resistivity of sputtered molybdenum films

International Nuclear Information System (INIS)

Nagano, J.

1980-01-01

The electrical resistivity of r.f. sputtered molybdenum films of thickness 5-150 nm deposited on oxidized silicon substrates was resolved into the three electron scattering components: isotropic background scattering, scattering at grain boundaries and scattering at surfaces. It was concluded that the isotropic background scattering is almost equal to that of bulk molybdenum and is not influenced by sputtering and annealing conditions. When the film thickness is sufficient that surface scattering can be ignored, the decrease in film resistivity after annealing is caused by the decrease in scattering at the grain boundaries for zero bias sputtered films, and is caused by an increase of the grain diameter for r.f. bias sputtered films. (Auth.)

Electron transport determines the electrochemical properties of tetrahedral amorphous carbon (ta-C) thin films

International Nuclear Information System (INIS)

Palomäki, Tommi; Wester, Niklas; Caro, Miguel A.; Sainio, Sami; Protopopova, Vera; Koskinen, Jari; Laurila, Tomi

2017-01-01

Amorphous carbon based electrodes are very promising for electrochemical sensing applications. In order to better understand their structure-function relationship, the effect of film thickness on the electrochemical properties of tetrahedral amorphous carbon (ta-C) electrodes was investigated. ta-C thin films of 7, 15, 30, 50 and 100 nm were characterized in detail with Raman spectroscopy, transmission electron microscopy (TEM), conductive atomic force microscopy (c-AFM), scanning tunneling spectroscopy (STS) and X-ray absorption spectroscopy (XAS) to assess (i) the surface properties of the films, (ii) the effect of film thickness on their structure and electrical properties and (iii) the subsequent correlation with their electrochemistry. The electrochemical properties were investigated by cyclic voltammetry (CV) using two different outer-sphere redox probes, Ru(NH 3 ) 6 3+/2+ and FcMeOH, and by electrochemical impedance spectroscopy (EIS). Computational simulations using density functional theory (DFT) were carried out to rationalize the experimental findings. The characterization results showed that the sp 2 /sp 3 ratio increased with decreasing ta-C film thickness. This correlated with a decrease in mobility gap value and an increase in the average current through the films, which was also consistent with the computational results. XAS indicated that the surface of the ta-C films was always identical and composed of a sp 2 -rich layer. The CV measurements indicated reversible reaction kinetics for both outer-sphere redox probes at 7 and 15 nm ta-C films with a change to quasi-reversible behavior at a thickness of around 30 nm. The charge transfer resistance, obtained from EIS measurements, decreased with decreasing film thickness in accordance with the CV results. Based on the characterization and electrochemical results, we conclude that the reaction kinetics in the case of outer-sphere redox systems is determined mainly by the electron transport through the

Study on the electrical transport properties of La{sub 2/3}Ba{sub 1/3}MnO{sub 3}:Ag{sub 0.04}/LaAlO{sub 3} (001) films

Energy Technology Data Exchange (ETDEWEB)

Liu, Xiang, E-mail: lxjim@126.com; Zhao, Shuang; Zhang, Shao-Chun

2017-01-01

La{sub 2/3}Ba{sub 1/3}MnO{sub 3}: wt%Ag{sub x} (LBMO:Ag{sub x}, x=0.04) films were prepared on single crystalline (001)-orientated LaAlO{sub 3} substrates by pulsed laser deposition technique. All the samples show along the (00l) orientation in rhombohedral structure with R3c space group. The surface roughness (Ra), insulator-metal transition temperature (Tp) and resistivity at Tp (ρ{sub Tp}) of the LBMO:Ag{sub 0.04} films reached optimal values of 3.29 nm, 288 K and 0.033 Ω cm at 740 °C, respectively. The improvement of electrical transport properties in the films are attributed to the optimal growth temperature and Ag-doping improve the microstructure of the surfaces, grain boundaries (GBs) in connectivity and better crystallization. In addition, the electrical conduction behaviors can be well fitted with the grain/domain boundary, electron–electron and magnon scattering mechanisms in the ferromagnetic metallic region (TTp).

Electrical and optical properties of zinc oxide: thin films

International Nuclear Information System (INIS)

Zuhairusnizam Md Darus; Abdul Jalil Yeop Majlis; Anis Faridah Md Nor; Burhanuddin Kamaluddin

1992-01-01

Zinc oxide films have been prepared by high temperature oxidation of thermally evaporated zinc films on glass substrates. The resulting films are characterized using X-ray diffraction, optical absorption and electrical conductivity measurements. These zinc oxide films are very transparent and photoconductive

The Electrical Properties of Plasma-Deposited Thin Films Derived from Pelargonium graveolens

Directory of Open Access Journals (Sweden)

Ahmed Al-Jumaili

2017-10-01

Full Text Available Inherently volatile at atmospheric pressure and room temperature, plant-derived precursors present an interesting human-health-friendly precursor for the chemical vapour deposition of thin films. The electrical properties of films derived from Pelargonium graveolens (geranium were investigated in metal–insulator–metal (MIM structures. Thin polymer-like films were deposited using plasma-enhanced synthesis under various plasma input power. The J–V characteristics of thus-fabricated MIM were then studied in order to determine the direct current (DC conduction mechanism of the plasma polymer layers. It was found that the capacitance of the plasma-deposited films decreases at low frequencies (C ≈ 10−11 and remains at a relatively constant value (C ≈ 10−10 at high frequencies. These films also have a low dielectric constant across a wide range of frequencies that decreases as the input RF power increases. The conductivity was determined to be around 10−16–10−17 Ω−1 m−1, which is typical for insulating materials. The Richardson–Schottky mechanism might dominate charge transport in the higher field region for geranium thin films.

Electrical Switching of Perovskite Thin-Film Resistors

Science.gov (United States)

Liu, Shangqing; Wu, Juan; Ignatiev, Alex

2010-01-01

Electronic devices that exploit electrical switching of physical properties of thin films of perovskite materials (especially colossal magnetoresistive materials) have been invented. Unlike some related prior devices, these devices function at room temperature and do not depend on externally applied magnetic fields. Devices of this type can be designed to function as sensors (exhibiting varying electrical resistance in response to varying temperature, magnetic field, electric field, and/or mechanical pressure) and as elements of electronic memories. The underlying principle is that the application of one or more short electrical pulse(s) can induce a reversible, irreversible, or partly reversible change in the electrical, thermal, mechanical, and magnetic properties of a thin perovskite film. The energy in the pulse must be large enough to induce the desired change but not so large as to destroy the film. Depending on the requirements of a specific application, the pulse(s) can have any of a large variety of waveforms (e.g., square, triangular, or sine) and be of positive, negative, or alternating polarity. In some applications, it could be necessary to use multiple pulses to induce successive incremental physical changes. In one class of applications, electrical pulses of suitable shapes, sizes, and polarities are applied to vary the detection sensitivities of sensors. Another class of applications arises in electronic circuits in which certain resistance values are required to be variable: Incorporating the affected resistors into devices of the present type makes it possible to control their resistances electrically over wide ranges, and the lifetimes of electrically variable resistors exceed those of conventional mechanically variable resistors. Another and potentially the most important class of applications is that of resistance-based nonvolatile-memory devices, such as a resistance random access memory (RRAM) described in the immediately following article

Electrical and Optical Properties of GeSi−:H Thin Films Prepared by Thermal Evaporation Method

Directory of Open Access Journals (Sweden)

A. A. J. Al-Douri

2010-01-01

Full Text Available Thin a-GeSi1−:H films were grown successfully by fabrication of designated ingot followed by evaporation onto glass slides. A range of growth conditions, Ge contents, dopant concentration (Al and As, and substrate temperature, were employed. Stoichiometry of the thin films composition was confirmed using standard surface techniques. The structure of all films was amorphous. Film composition and deposition parameters were investigated for their bearing on film electrical and optical properties. More than one transport mechanism is indicated. It was observed that increasing substrate temperature, Ge contents, and dopant concentration lead to a decrease in the optical energy gap of those films. The role of the deposition conditions on values of the optical constants was determined. Accordingly, models of the density of states for the Ge0.5Si0.5:H thin films as pure, doped with 3.5% of Al (p-type and that doped with 3.5% As (n-type, were proposed.

Electron transport in disordered films of metal nanoparticles linked by organic molecules

International Nuclear Information System (INIS)

Mueller, K.H.; Wei, G.; Herrmann, J.; Raguse, B.; Baxter, G.

2004-01-01

Full text: We have investigated theoretically and experimentally the mechanism of electron transport in films made of ∼10 nm sized gold nanoparticles linked by alkanedithiol molecules. Conduction in these films is due to linker-molecule assisted single-electron tunnelling between neighbouring nanoparticles where electrons have to overcome the Coulomb blockade energy. Strong disorder in our films in the form of separation gap fluctuations between adjacent nanoparticles and variations in Coulomb blockade energies cause electron current percolation. We have found that the dependence of the conduction on the length of the alkanedithiol molecules is affected by the degree of disorder. In addition, we have observed that percolation leads to a non-Arrhenius-like temperature dependence of the conduction and to a film-thickness dependent conductivity. I-V characteristics at low temperatures reveal Coulomb blockade effects. The strong dependence of the electrical conduction on the separation gaps between adjacent nanoparticles can be utilized in strain gauge and gas sensor applications

Enhancement of electrical conductivity of ion-implanted polymer films

International Nuclear Information System (INIS)

Brock, S.

1985-01-01

The electrical conductivity of ion-implanted films of Nylon 66, Polypropylene (PP), Poly(tetrafluoroethylene) (Teflon) and mainly Poly (ethylene terephthalate) (PET) was determined by DC measurements at voltages up to 4500 V and compared with the corresponding values of pristine films. Measurements were made at 21 0 C +/- 1 0 C and 65 +/- 2% RH. The electrical conductivity of PET films implanted with F + , Ar + , or As + ions at energies of 50 keV increases by seven orders of magnitude as the fluence increases from 1 x 10 18 to 1 x 10 20 ions/m 2 . The conductivity of films implanted with As + was approximately one order greater than those implanted with Ar + , which in turn was approximately one-half order greater than those implanted with F + . The conductivity of the most conductive film ∼1 S/m) was almost 14 orders of magnitude greater than the pristine PET film. Except for the three PET samples implanted at fluences near 1 x 10 20 ions/m 2 with F + , Ar + , and As + ions, all implanted films were ohmic up to an electric field strength of 600 kV/m. The temperature dependence of the conductivity of the three PET films implanted near a fluence of 1 x 10 20 ions/m 2 was measured over the range of 80 K < T < 300 K

Tariff structures for the transport of electricity

International Nuclear Information System (INIS)

Frenken, R.M.L.; Van de Water, C.J.

1995-01-01

Some possible tariff structures for electricity transport are discussed. First, the costs associated with the transport of electricity are explained. The fixed and variable costs of a transport are illustrated with some examples. Furthermore, the most common tariff structures (contract path, megawatt mile, postage stamp) and negotiated Third Party Access are discussed. Finally, the way the tariff structures reflect the costs of electricity transport are reviewed. 3 figs., 1 tab., 7 refs

Electrical transport in crystalline phase change materials

International Nuclear Information System (INIS)

Woda, Michael

2012-01-01

In this thesis, the electrical transport properties of crystalline phase change materials are discussed. Phase change materials (PCM) are a special class of semiconducting and metallic thin film alloys, typically with a high amount of the group five element antimony or the group six element tellurium, such as Ge 2 Sb 2 Te 5 . The unique property portfolio of this material class makes it suitable for memory applications. PCMs reveal fast switching between two stable room-temperature phases (amorphous and crystalline) realized by optical laser or electrical current pulses in memory devices. Additionally, a pronounced property contrast in form of optical reflectivity and electrical conductivity between the amorphous and crystalline phase is the characteristic fingerprint of PCMs. The emerging electrical solid state memory PCRAM is a very promising candidate to replace Flash memory in the near future or to even become a universal memory, which is non-volatile and shows the speed and cyclability of DRAM. One of the main technological challenges is the switching process into the amorphous state, which is the most power demanding step. In order to reduce the switching power, the crystalline resistivity needs to be increased at a given voltage. Thus understanding and tayloring of this property is mandatory. In this work, first the technological relevance, i.e. optical and electrical memory concepts based on PCMs are introduced. Subsequently a description of the physical properties of PCMs in four categories is given. Namely, structure, kinetics, optical properties and electrical properties are discussed. Then important recent developments such as the identification of resonant bonding in crystalline PCMs and a property predicting coordination scheme are briefly reviewed. The following chapter deals with the theoretical background of electrical transport, while the next chapter introduces the experimental techniques: Sputtering, XRR, XRD, DSC, thermal annealing

Metal-insulator transition in tin doped indium oxide (ITO thin films: Quantum correction to the electrical conductivity

Directory of Open Access Journals (Sweden)

Deepak Kumar Kaushik

2017-01-01

Full Text Available Tin doped indium oxide (ITO thin films are being used extensively as transparent conductors in several applications. In the present communication, we report the electrical transport in DC magnetron sputtered ITO thin films (prepared at 300 K and subsequently annealed at 673 K in vacuum for 60 minutes in low temperatures (25-300 K. The low temperature Hall effect and resistivity measurements reveal that the ITO thin films are moderately dis-ordered (kFl∼1; kF is the Fermi wave vector and l is the electron mean free path and degenerate semiconductors. The transport of charge carriers (electrons in these disordered ITO thin films takes place via the de-localized states. The disorder effects lead to the well-known ‘metal-insulator transition’ (MIT which is observed at 110 K in these ITO thin films. The MIT in ITO thin films is explained by the quantum correction to the conductivity (QCC; this approach is based on the inclusion of quantum-mechanical interference effects in Boltzmann’s expression of the conductivity of the disordered systems. The insulating behaviour observed in ITO thin films below the MIT temperature is attributed to the combined effect of the weak localization and the electron-electron interactions.

Metal-insulator transition in tin doped indium oxide (ITO) thin films: Quantum correction to the electrical conductivity

Science.gov (United States)

Kaushik, Deepak Kumar; Kumar, K. Uday; Subrahmanyam, A.

2017-01-01

Tin doped indium oxide (ITO) thin films are being used extensively as transparent conductors in several applications. In the present communication, we report the electrical transport in DC magnetron sputtered ITO thin films (prepared at 300 K and subsequently annealed at 673 K in vacuum for 60 minutes) in low temperatures (25-300 K). The low temperature Hall effect and resistivity measurements reveal that the ITO thin films are moderately dis-ordered (kFl˜1; kF is the Fermi wave vector and l is the electron mean free path) and degenerate semiconductors. The transport of charge carriers (electrons) in these disordered ITO thin films takes place via the de-localized states. The disorder effects lead to the well-known `metal-insulator transition' (MIT) which is observed at 110 K in these ITO thin films. The MIT in ITO thin films is explained by the quantum correction to the conductivity (QCC); this approach is based on the inclusion of quantum-mechanical interference effects in Boltzmann's expression of the conductivity of the disordered systems. The insulating behaviour observed in ITO thin films below the MIT temperature is attributed to the combined effect of the weak localization and the electron-electron interactions.

Evolution of structural and electrical properties of carbon films from amorphous carbon to nanocrystalline graphene on quartz glass by HFCVD.

Science.gov (United States)

Zhai, Zihao; Shen, Honglie; Chen, Jieyi; Li, Xuemei; Jiang, Ye

2018-04-25

Direct growth of graphene films on glass is of great importance but has so far met with limited success. The non-catalytic property of glass results in the low decomposition ability of hydrocarbon precursors, especially at reduced temperatures (structural and electrical properties of carbon films deposited on quartz glass at 850 °C by hot-filament chemical vapor deposition (HFCVD). The results revealed that the obtained a-C films were all graphite-like carbon films. Structural transition of the deposited films from a-C to nanocrystalline graphene was achieved by raising the hydrogen dilution ratios from 10 % to over 80 %. Based on systematically structural and chemical characterizations, a schematic process with three steps including sp2 chains aggregation, aromatic rings formation and sp3 bonds etch was proposed to interpret the structural evolution. The nanocrystalline graphene films grown on glass by HFCVD exhibited good electrical performance with a carrier mobility of 36.76 cm2/(V·s) and a resistivity of 5.24×10-3 Ω·cm over an area of 1 cm2. Temperature-dependent electrical characterizations revealed that the electronic transport in carbon films was dominated by defect, localised and extended states respectively when increasing the temperature from 75 K to 292 K. The nanocrystalline graphene films presented higher carrier mobility and lower carrier concentration than a-C films, which was mainly attributed to their smaller conductive activation energy. The present investigation provides an effective way for direct growth of graphene films on glass at reduced temperatures and also offers useful insights into the understanding of structural and electrical relationship between a-C and graphene.

Optical, electrical and sensing properties of β-ketoimine calix[4]arene thin films

Energy Technology Data Exchange (ETDEWEB)

Echabaane, M., E-mail: mosaab.echabaane@yahoo.fr [Laboratoire des Interfaces et Matériaux Avancés (LIMA), Faculté des Sciences de Monastir, Avenue de l' environnement, 5000 Monastir (Tunisia); Rouis, A. [Laboratoire des Interfaces et Matériaux Avancés (LIMA), Faculté des Sciences de Monastir, Avenue de l' environnement, 5000 Monastir (Tunisia); Bonnamour, I. [Institut de Chimie and Biochimie Moléculaires and Supramoléculaires (ICBMS), UMR CNRS 5246, 43 Boulevard du 11 Novembre 1918, Université Claude Bernard Lyon 1, 69100 Villeurbanne (France); Ben Ouada, H. [Laboratoire des Interfaces et Matériaux Avancés (LIMA), Faculté des Sciences de Monastir, Avenue de l' environnement, 5000 Monastir (Tunisia)

2013-09-16

Optical, electrical and ion sensing properties of β-ketoimine calix[4]arene thin films have been investigated. These calix[4]arene derivative films exhibit absorption spectra with a resolved electronic structure in the UV–vis and the energy gap was found to be 3.65 eV. Electrical properties of ITO/β-ketoimine calix[4]arene/Al devices have been investigated by I–V characteristics and impedance spectroscopy measurements. The conduction is governed by space-charge-limited current (SCLC) mechanism. The impedance spectroscopy study showed a hopping transport process, a typical behavior of disordered materials. The device was modeled by a single parallel resistor and capacitor network in series with a resistance. The β-ketoimine calix[4]arene was used for the conception of the novel optical chemical sensor and the detection of Cu{sup 2+} ions was monitored by UV–visible spectroscopy. The linear dynamic range for the determination of Cu{sup 2+} has been 10{sup −5}–10{sup −3.7} M with a detection limit of 10{sup −5} M. The characteristics of this optode such as regeneration, repeatability, reproducibility, short-term stability, life time and ion selectivity have been discussed. - Highlights: • We examine optical properties of β-ketoimine calix[4]arene ligand. • We investigate the electric properties of ITO/β-ketoimine calix[4]arene/Al device. • We study the sensing properties of optode films for the detection of copper (II)

Electrical properties of tungsten trioxide films

International Nuclear Information System (INIS)

Xu, Z.; Vetelino, J.F.; Lec, R.; Parker, D.C.

1990-01-01

Selectively doped semiconducting metal oxide (SMO) films have been shown to have applications as the sensing element in gas microsensors. Critical to the design and operation of these sensors is the SMO film. In the present work, the electrical properties of both intrinsic and extrinsic (doped with gold) tungsten trioxide (WO 3 ) films, which selectively sorb hydrogen sulfide (H 2 S), are investigated. Hall effect measurements are performed as a function of film thickness, temperature, gold-doping concentration, and H 2 S gas concentration. The conductivity was found to be n type and strongly dependent on temperature, gold doping concentration, and H 2 S gas concentration and less dependent on film thickness. The mobility was relatively high while the intrinsic carrier concentration was low when compared to typical semiconductor materials. The conductivity was shown to exhibit anomalous behavior at certain temperatures and H 2 S gas concentrations

Structural and electrical properties of ZnO/Zn0.85Mg0.15O thin film prepared by pulsed laser deposition

Science.gov (United States)

Yang, Jing-Jing; Wang, Gang; Du, Wen-Han; Xiong, Chao

2017-07-01

The electrical transport properties are the key factors to determine the performance of ZnO-based quantum effect device. ZnMgO is a typical material to regulate the band of ZnO. In order to investigate the electrical properties of the interface of ZnO/Zn0.85Mg0.15O films, three kinds of ZnO/Zn0.85Mg0.15O films have been fabricated with different thickness. After comparing the structural and electrical properties of the samples, we found that the independent Zn0.85Mg0.15O hexagonal wurtzite structure (002) peak can be detected in XRD spectra. Hall-effect test data confirmed that the two-dimensional electron gas (2DEG) became lower because of the decrease of thickness of Zn0.85Mg0.15O films, increase of impurity scattering and lattice structure distortion caused by the increase of Mg content.

Effects of ZnO addition on electrical and structural properties of amorphous SnO2 thin films

International Nuclear Information System (INIS)

Ko, J.H.; Kim, I.H.; Kim, D.; Lee, K.S.; Lee, T.S.; Jeong, J.-H.; Cheong, B.; Baik, Y.J.; Kim, W.M.

2006-01-01

Amorphous Zn-Sn-O (ZTO) thin films with relative Zn contents (= [at.% Zn]/([at.% Zn] + [at.% Sn])) of 0, 0.08 and 0.27 were fabricated by co-sputtering of SnO 2 and ZnO targets at room temperature. Changes in structural, electrical and optical properties together with electron transport properties were examined upon post-annealing treatment in the temperature range from 200 to 600 deg. C in vacuum and in air. Characterization by XRD showed that an amorphous ZTO thin film crystallized at higher temperatures with increasing Zn content. Crystallized ZTO films with a relative Zn content of 0.27 might not contain a single SnO 2 phase which is observed in the films of the other compositions. Amorphous ZTO films showed decreasing electrical resistivities with increasing annealing temperature, having a minimum value of 1 x 10 - 3 Ω cm. Upon crystallization, the resistivities increased drastically, which was attributed to poor crystallinity of the crystallized films. All the ZTO films were found to be degenerate semiconductors with non-parabolic conduction bands having effective masses varying from 0.15 to 0.3 in the carrier concentration range of 6 x 10 18 to 2 x 10 2 cm - 3 . As for a ZTO film with a relative Zn content of 0.27, the degree of non-parabolicity was much lower compared with films of the other compositions, leading to a relatively stable mobility over a wide range of carrier concentration

Hydroxyapatite screen-printed thick films: optical and electrical properties

International Nuclear Information System (INIS)

Silva, C.C.; Rocha, H.H.B.; Freire, F.N.A.; Santos, M.R.P.; Saboia, K.D.A.; Goes, J.C.; Sombra, A.S.B.

2005-01-01

In this paper, we did a study on the structural and electrical properties of bioceramic hydroxiapatite (HA) thick films. The films were prepared in two layers using the screen-printing technique on Al 2 O 3 substrates. Mechanical alloying has been used successfully to produce nanocrystalline powders of hydroxyapatite to be used in the films. We also look for the effect of the grain size of the HA in the final properties of the film. The samples were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), infrared and Raman scattering spectroscopy and electrical measurements. We did a study of the dielectric permittivity and the loss of the films in the radio-frequency of the spectra. The X-ray diffraction patterns of the films indicate that all the peaks associated to HA phase is present in the films. One can notice that, for all the films there is a decrease of the DC (dielectric constant) with the increase of the frequency. The values of the dielectric constant of the films are in between 4 and 9 (at 1 kHz), as a function of the flux concentration. The loss is decreasing as we increase the frequency for all the films. These results strongly suggest that the screen-printing HA thick films are good candidates for applications in biocompatible coatings of implant materials

Hydroxyapatite screen-printed thick films: optical and electrical properties

Energy Technology Data Exchange (ETDEWEB)

Silva, C.C. [Laboratorio de Telecomunicaco-tilde es e Ciencia e Engenharia de Materiais (LOCEM), Departamento de Fisica, Universidade Federal do Ceara, Campus do Pici, Caixa Postal 6030, 60455-760 Fortaleza, Ceara (Brazil); Rocha, H.H.B. [Laboratorio de Telecomunicaco-tilde es e Ciencia e Engenharia de Materiais (LOCEM), Departamento de Fisica, Universidade Federal do Ceara, Campus do Pici, Caixa Postal 6030, 60455-760 Fortaleza, Ceara (Brazil); Freire, F.N.A. [Departamento de Quimica Orga-circumflex nica e Inorga-circumflex nica-UFC, Caixa Postal 6030, CEP 60455-760, Fortaleza, Ceara (Brazil); Santos, M.R.P. [Laboratorio de Telecomunicaco-tilde es e Ciencia e Engenharia de Materiais (LOCEM), Departamento de Fisica, Universidade Federal do Ceara, Campus do Pici, Caixa Postal 6030, 60455-760 Fortaleza, Ceara (Brazil); Saboia, K.D.A. [Laboratorio de Telecomunicaco-tilde es e Ciencia e Engenharia de Materiais (LOCEM), Departamento de Fisica, Universidade Federal do Ceara, Campus do Pici, Caixa Postal 6030, 60455-760 Fortaleza, Ceara (Brazil); Goes, J.C. [Laboratorio de Telecomunicaco-tilde es e Ciencia e Engenharia de Materiais (LOCEM), Departamento de Fisica, Universidade Federal do Ceara, Campus do Pici, Caixa Postal 6030, 60455-760 Fortaleza, Ceara (Brazil); Sombra, A.S.B. [Laboratorio de Telecomunicaco-tilde es e Ciencia e Engenharia de Materiais (LOCEM), Departamento de Fisica, Universidade Federal do Ceara, Campus do Pici, Caixa Postal 6030, 60455-760 Fortaleza, Ceara (Brazil)]. E-mail: sombra@fisica.ufc.br

2005-07-15

In this paper, we did a study on the structural and electrical properties of bioceramic hydroxiapatite (HA) thick films. The films were prepared in two layers using the screen-printing technique on Al{sub 2}O{sub 3} substrates. Mechanical alloying has been used successfully to produce nanocrystalline powders of hydroxyapatite to be used in the films. We also look for the effect of the grain size of the HA in the final properties of the film. The samples were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), infrared and Raman scattering spectroscopy and electrical measurements. We did a study of the dielectric permittivity and the loss of the films in the radio-frequency of the spectra. The X-ray diffraction patterns of the films indicate that all the peaks associated to HA phase is present in the films. One can notice that, for all the films there is a decrease of the DC (dielectric constant) with the increase of the frequency. The values of the dielectric constant of the films are in between 4 and 9 (at 1 kHz), as a function of the flux concentration. The loss is decreasing as we increase the frequency for all the films. These results strongly suggest that the screen-printing HA thick films are good candidates for applications in biocompatible coatings of implant materials.

Optical and electrical properties of chemical bath deposited cobalt sulphide thin films

Energy Technology Data Exchange (ETDEWEB)

Govindasamy, Geetha [R& D Centre, Bharathiar University, Coimbatore (India); Murugasen, Priya, E-mail: priyamurugasen15@gmail.com [Department of Physics, Saveetha Engineering, Chennai, Tamil Nadu (India); Sagadevan, Suresh [Department of Physics, AMET University, Chennai, Tamil Nadu (India)

2017-01-15

Cobalt sulphide (CoS) thin films were synthesized using the Chemical Bath Deposition (CBD) technique. X-ray diffraction (XRD) analysis was used to study the structure and the crystallite size of CoS thin film. Scanning Electron Microscope (SEM) studies reveal the surface morphology of these films. The optical properties of the CoS thin films were determined using UV-Visible absorption spectrum. The optical band gap of the thin films was found to be 1.6 eV. Optical constants such as the refractive index, the extinction coefficient and the electric susceptibility were determined. The dielectric studies were carried out at different frequencies and at different temperatures for the prepared CoS thin films. In addition, the plasma energy of the valence electron, Penn gap or average energy gap, the Fermi energy and electronic polarizability of the thin films were determined. The AC electrical conductivity measurement was also carried out for the thin films. The activation energy was determined by using DC electrical conductivity measurement. (author)

Electrical transport in crystalline phase change materials

Energy Technology Data Exchange (ETDEWEB)

Woda, Michael

2012-01-06

In this thesis, the electrical transport properties of crystalline phase change materials are discussed. Phase change materials (PCM) are a special class of semiconducting and metallic thin film alloys, typically with a high amount of the group five element antimony or the group six element tellurium, such as Ge{sub 2}Sb{sub 2}Te{sub 5}. The unique property portfolio of this material class makes it suitable for memory applications. PCMs reveal fast switching between two stable room-temperature phases (amorphous and crystalline) realized by optical laser or electrical current pulses in memory devices. Additionally, a pronounced property contrast in form of optical reflectivity and electrical conductivity between the amorphous and crystalline phase is the characteristic fingerprint of PCMs. The emerging electrical solid state memory PCRAM is a very promising candidate to replace Flash memory in the near future or to even become a universal memory, which is non-volatile and shows the speed and cyclability of DRAM. One of the main technological challenges is the switching process into the amorphous state, which is the most power demanding step. In order to reduce the switching power, the crystalline resistivity needs to be increased at a given voltage. Thus understanding and tayloring of this property is mandatory. In this work, first the technological relevance, i.e. optical and electrical memory concepts based on PCMs are introduced. Subsequently a description of the physical properties of PCMs in four categories is given. Namely, structure, kinetics, optical properties and electrical properties are discussed. Then important recent developments such as the identification of resonant bonding in crystalline PCMs and a property predicting coordination scheme are briefly reviewed. The following chapter deals with the theoretical background of electrical transport, while the next chapter introduces the experimental techniques: Sputtering, XRR, XRD, DSC, thermal annealing

Transport in reversibly laser-modified YBa2Cu3O/sub 7-//sub x/ superconducting thin films

International Nuclear Information System (INIS)

Krchnavek, R.R.; Chan, S.; Rogers, C.T.; De Rosa, F.; Kelly, M.K.; Miceli, P.F.; Allen, S.J.

1989-01-01

A focused argon ion laser beam in a controlled ambient is used to modify the transport properties of superconducting YBa 2 Cu 3 O/sub 7-//sub x/ thin films. The laser-modified region shows a sharp transition temperature (T/sub c/≅76 K) that is reduced from the unmodified regions of the film (T/sub c/≅87 K). In situ monitoring of the room-temperature electrical resistance is used to control the laser processing and prevent formation of the semiconducting phase. The original properties of the superconducting film can be recovered by plasma oxidation indicating that the laser-induced phase is oxygen deficient

Electronic transport properties of nanostructured MnSi-films

Science.gov (United States)

Schroeter, D.; Steinki, N.; Scarioni, A. Fernández; Schumacher, H. W.; Süllow, S.; Menzel, D.

2018-05-01

MnSi, which crystallizes in the cubic B20 structure, shows intriguing magnetic properties involving the existence of skyrmions in the magnetic phase diagram. Bulk MnSi has been intensively investigated and thoroughly characterized, in contrast to MnSi thin film, which exhibits widely varying properties in particular with respect to electronic transport. In this situation, we have set out to reinvestigate the transport properties in MnSi thin films by means of studying nanostructure samples. In particular, Hall geometry nanostructures were produced to determine the intrinsic transport properties.

Optical transparency and electrical conductivity of nonstoichiometric ultrathin InxOy films

International Nuclear Information System (INIS)

Joseph, Shay; Berger, Shlomo

2011-01-01

The effect of thickness and composition on the electrical conductivity and optical transparency, mainly in the infrared, of ultrathin In x O y films was studied. In x O y films 35-470 A thick with oxygen atomic fractions of ∼0.3 and ∼0.5 were prepared via dc magnetron sputtering. All films were polycrystalline, consisting of only the cubic bixbiyte phase of In 2 O 3 . The average grain size of the films increased from 30 to 95 nm as the film thickness increased. The weak dependence of the electrical conductivity on the frequency and the low activation energies for conduction, a few hundredths of an eV, provided an indication that free band conduction was the primary electrical conduction mechanism in the case of all ultrathin In x O y films. It was found that introducing a high degree of nonstoichiometry in the form of oxygen deficiency did not help improve the electrical conductivity, since not all vacancies contributed two free electrons for conduction and due to impurity scattering. The optical nature of these films, studied mainly by ellipsometry, was found to be dependent on the film's composition and thickness. In the infrared, the dielectric function of all In x O y films was consistent with the Drude model, inferring that the transparency loss in this region was a result of free charge carriers. In the visible however, In x O y films under 170 A, which had an oxygen atomic fraction of ∼0.5, were modeled by extending the Drude model to the shorter wavelengths. Films over 170 A, with the same composition, were modeled using the Cauchy dispersion model, meaning that no absorption was measured. These results indicate that, optically, under specific compositions, ultrathin In x O y films undergo a transition from metalliclike behavior to dielectric behavior with increasing film thickness. Using a figure of merit approach, it was determined that a nonstoichiometric 230 A thick In x O y film, with an oxygen atomic fraction of ∼0.3, had the best combination

An analytical expression of electric potential and field of organic thin film transistors

International Nuclear Information System (INIS)

Pankalla, S; Glesner, M

2012-01-01

The two-dimensional electric potential and field of an organic thin-film transistor (OTFT) is derived by conformal mapping using the Schwarz-Christoffel-transformation of the Poisson equation. In this paper we compare this analytical closed-form solution to field simulation results from Silvaco TCAD. Inter alia the potential close to the surface is calculated and we found excellent accordance to the numerical simulations and thus proofed its usability for charge transport calculations. Thus, it is used for calculation of the drain-source-current in the channel.

Correlation between structural and electrical properties of ZnO thin films

International Nuclear Information System (INIS)

Asadov, A.; Gao, W.; Li, Z.; Lee, J.; Hodgson, M.

2005-01-01

Thin ZnO films were deposited by radio frequency (r.f.) and direct current (d.c.) magnetron sputtering techniques onto glass substrates. Microstructural and electrical properties of ZnO films were studied using X-ray diffractometer (XRD), scanning electron microscope (SEM) and resistivity measurements. It was found that the size of the crystallites in the d.c. deposited films increased with increasing film thickness, while the crystallite size of r.f. deposited films remained unchanged. The d.c. deposited grains also had much stronger orientation related to the substrate than the r.f. films. XRD data indicated that the thin films with d<350 nm for r.f. and <750 nm for d.c. films have a very high degree of ZnO nonstoichiometry. This agreed well with the conductivity measurements and R(T) behaviour of the films with different resistance R. It was also found that the electrical resistivity of the samples increased exponentially with the thickness of films

Electricity: an indigenous transport fuel

Energy Technology Data Exchange (ETDEWEB)

Byers, D J

1978-12-25

Potential reserves of hydro and geothermal power are adequate to power all road-transport vehicles should these be converted to electric drives in the future. Conversion of petrol vehicles to electric drives results in a significant increase in energy-utilization efficiency coupled with a decrease in costs, both to the country in overseas funds and to the driver in operating costs. As yet, however, New Zealand has no plan to use these resources in a transport role and is supporting no feasibility research.

Development of micro-four-point probe in a scanning tunneling microscope for in situ electrical transport measurement.

Science.gov (United States)

Ge, Jian-Feng; Liu, Zhi-Long; Gao, Chun-Lei; Qian, Dong; Liu, Canhua; Jia, Jin-Feng

2015-05-01

Electrons at surface may behave differently from those in bulk of a material. Multi-functional tools are essential in comprehensive studies on a crystal surface. Here, we developed an in situ microscopic four-point probe (4PP) transport measurement system on the basis of a scanning tunneling microscope (STM). In particular, convenient replacement between STM tips and micro-4PPs enables systematic investigations of surface morphology, electronic structure, and electrical transport property of a same sample surface. Performances of the instrument are demonstrated with high-quality STM images, tunneling spectra, and low-noise electrical I-V characteristic curves of a single-layer FeSe film grown on a conductive SrTiO3 surface.

Development of micro-four-point probe in a scanning tunneling microscope for in situ electrical transport measurement

Energy Technology Data Exchange (ETDEWEB)

Ge, Jian-Feng; Liu, Zhi-Long; Gao, Chun-Lei; Qian, Dong; Liu, Canhua, E-mail: canhualiu@sjtu.edu.cn, E-mail: jfjia@sjtu.edu.cn; Jia, Jin-Feng, E-mail: canhualiu@sjtu.edu.cn, E-mail: jfjia@sjtu.edu.cn [Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China)

2015-05-15

Electrons at surface may behave differently from those in bulk of a material. Multi-functional tools are essential in comprehensive studies on a crystal surface. Here, we developed an in situ microscopic four-point probe (4PP) transport measurement system on the basis of a scanning tunneling microscope (STM). In particular, convenient replacement between STM tips and micro-4PPs enables systematic investigations of surface morphology, electronic structure, and electrical transport property of a same sample surface. Performances of the instrument are demonstrated with high-quality STM images, tunneling spectra, and low-noise electrical I-V characteristic curves of a single-layer FeSe film grown on a conductive SrTiO{sub 3} surface.

Structural, chemical and electrical characterisation of conductive graphene-polymer composite films

Energy Technology Data Exchange (ETDEWEB)

Brennan, Barry; Spencer, Steve J.; Belsey, Natalie A. [National Physical Laboratory, Teddington, TW11 0LW (United Kingdom); Faris, Tsegie [DZP Technologies Ltd., Future Business Centre, Cambridge, CB4 2HY (United Kingdom); Cronin, Harry [DZP Technologies Ltd., Future Business Centre, Cambridge, CB4 2HY (United Kingdom); Advanced Technology Institute (ATI), University of Surrey, Guildford, GU2 7XH (United Kingdom); Silva, S. Ravi P. [Advanced Technology Institute (ATI), University of Surrey, Guildford, GU2 7XH (United Kingdom); Sainsbury, Toby; Gilmore, Ian S. [National Physical Laboratory, Teddington, TW11 0LW (United Kingdom); Stoeva, Zlatka [DZP Technologies Ltd., Future Business Centre, Cambridge, CB4 2HY (United Kingdom); Pollard, Andrew J., E-mail: andrew.pollard@npl.co.uk [National Physical Laboratory, Teddington, TW11 0LW (United Kingdom)

2017-05-01

Graphical abstract: Secondary Ion Mass Spectrometry (SIMS) imaging of the dispersion of graphene within graphene-polymer composites using the Na{sup +} signal. - Highlights: • Relation of properties of graphene flakes with electrical properties of composite. • Standardised characterisation method for structural properties of graphene flakes. • Structural and chemical characterisation of commercial graphene flakes. • ToF-SIMS used to determine dispersion of graphene in polymer. - Abstract: Graphene poly-acrylic and PEDOT:PSS nanocomposite films were produced using two alternative commercial graphene powders to explore how the graphene flake dimensions and chemical composition affected the electrical performance of the film. A range of analytical techniques, including scanning electron microscopy (SEM), atomic force microscopy (AFM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS), were employed to systematically analyse the initial graphene materials as well as the nanocomposite films. Electrical measurements indicated that the sheet resistance of the films was affected by the properties of the graphene flakes used. To further explore the composition of the films, ToF-SIMS mapping was employed and provided a direct means to elucidate the nature of the graphene dispersion in the films and to correlate this with the electrical analysis. These results reveal important implications for how the dispersion of the graphene material in films produced from printable inks can be affected by the type of graphene powder used and the corresponding effect on electrical performance of the nanocomposites. This work provides direct evidence for how accurate and comparable characterisation of the graphene material is required for real-world graphene materials to develop graphene enabled films and proposes a measurement protocol for comparing graphene materials that can be used for international

Annealing temperature effect on structure and electrical properties of films formed of Ge nanoparticles in SiO2

International Nuclear Information System (INIS)

Stavarache, Ionel; Lepadatu, Ana-Maria; Stoica, Toma; Ciurea, Magdalena Lidia

2013-01-01

Ge–SiO 2 films with high Ge/Si atomic ratio of about 1.86 were obtained by co-sputtering of Ge and SiO 2 targets and subsequently annealed at different temperatures between 600 and 1000 °C in a conventional furnace in order to show how the annealing process influences the film morphology concerning the Ge nanocrystal and/or amorphous nanoparticle formation and to study their electrical behaviour. Atomic force microscopy (AFM) imaging, Raman spectroscopy and electrical conductance measurements were performed in order to find out the annealing effect on the film surface morphology, as well as the Ge nanoparticle formation in correlation with the hopping conductivity of the films. AFM images show that the films annealed at 600 and 700 °C present a granular surface with particle height of about 15 nm, while those annealed at higher temperatures have smoother surface. The Raman investigations evidence Ge nanocrystals (including small ones) coexisting with amorphous Ge in the films annealed at 600 °C and show that almost all Ge is crystallized in the films annealed at 700 °C. The annealing at 800 °C disadvantages the Ge nanocrystal formation due to the strong Ge diffusion. This transition in Ge nanocrystals formation process by annealing temperature increase from 700 to 800 °C revealed by AFM and Raman spectroscopy measurements corresponds to a change in the electrical transport mechanism. Thus, in the 700 °C annealed films, the current depends on temperature according to a T −1/2 law which is typical for a tunnelling mechanism between neighbour Ge nanocrystals. In the 800 °C annealed films, the current–temperature characteristic has a T −1/4 dependence showing a hopping mechanism within an electronic band of localized states related to diffused Ge in SiO 2 .

Electrical contacts on polyimide substrates for flexible thin film photovoltaic devices

Energy Technology Data Exchange (ETDEWEB)

Guillen, C.; Herrero, J

2003-05-01

Both frontal and back electrical contacts have been developed onto polyimide sheets (Kapton KJ[reg]) as alternative substrates to the conventional glasses, for application in lightweight and flexible thin film photovoltaic devices. Transparent and conductive indium tin oxide (ITO) thin films have been deposited by r.f.-magnetron sputtering as the frontal electrical contact. On the other hand, Mo, Cr and Ni layers have been prepared by e-gun evaporation for the back electrical connections. ITO films deposited onto polyimide have shown similar optical transmittance and higher electrical conductivity than onto glass substrates. The transmittance decreases and the conductivity increases after heating at 400 sign C in vacuum atmosphere. Mo, Cr and Ni layers deposited onto polyimide showed similar structure and electrical conductivity than onto conventional glasses. The properties of Mo and Cr layers remained unchanged after heating at 400 sign C in selenium atmosphere.

Electrical conductivity of free-standing mesoporous silicon thin films

International Nuclear Information System (INIS)

Khardani, M.; Bouaicha, M.; Dimassi, W.; Zribi, M.; Aouida, S.; Bessais, B.

2006-01-01

The effective electrical conductivity of free-standing p + -type porous silicon layers having porosities ranging from 30% to 80% was studied at both experimental and theoretical sides. An Effective Medium Approximation (EMA) model was used as a theoretical support. The porous silicon (PS) films were prepared by the electrochemical etching method for different values of the anodic current density. In order to model the PS electrical conductivity, the free-standing porous layer was assumed to be formed of three phases; vacuum, oxide and Si nanocrystallites. The analytical expression of the electrical conductivity of the Si nanocrystallites was established using the quantum confinement theory. This enables us to correlate the electrical conductivity of the mesoporous film to the value of the effective band gap energy estimated from the absorption coefficient. A perfect agreement between the theoretical and the experimental electrical conductivity values was obtained for all prospected PS porosities

Electrical and optical transport characterizations of electron beam evaporated V doped In{sub 2}O{sub 3} thin films

Energy Technology Data Exchange (ETDEWEB)

Islam, Md. Ariful, E-mail: arifapee19@gmail.com [Department of Physics, Rajshahi University of Engineering & Technology (RUET), Rajshahi (Bangladesh); Roy, Ratan Chandra; Hossain, Jaker; Julkarnain, Md.; Khan, Khairul Alam [Department of Applied Physics & Electronic Engineering, University of Rajshahi (Bangladesh)

2017-01-15

Vanadium (5 at. %) doped Indium Oxide (V: In{sub 2}O{sub 3}) thin films with different thicknesses (50 nm, 100 nm and 150 nm) were prepared onto glass substrate by electron beam evaporation technique in a vacuum of about 4 x 10{sup -3} Pa. X-ray diffraction (XRD) pattern revealed that the prepared films of thickness 50 nm are amorphous in nature. Temperature dependence of electrical resistivity was studied in the 300 < T < 475 K temperature range. The films exhibit a metallic behavior in the 300 < T < 380 K range with a positive temperature coefficient of the resistivity (TCR), whereas at T > 380 K, the conduction behavior turns into a semiconductor with a negative TCR. Optical studies revealed that the films of thickness 50 nm possess high transmittance of about 86 % in the near-infrared spectral region. The direct optical band gap lies between 3.26 and 3.00 eV depending on the film thickness. (author)

Surface proton transport of fully protonated poly(aspartic acid) thin films on quartz substrates

Energy Technology Data Exchange (ETDEWEB)

Nagao, Yuki, E-mail: ynagao@jaist.ac.jp; Kubo, Takahiro

2014-12-30

Graphical abstract: - Highlights: • Proton transport of fully protonated poly(aspartic acid) thin film was investigated. • The thin film structure differed greatly from the partially protonated one. • Proton transport occurs on the surface, not inside of the thin film. • This result contributes to biological transport systems such as bacteriorhodopsin. - Abstract: Thin film structure and the proton transport property of fully protonated poly(aspartic acid) (P-Asp100) have been investigated. An earlier study assessed partially protonated poly(aspartic acid), highly oriented thin film structure and enhancement of the internal proton transport. In this study of P-Asp100, IR p-polarized multiple-angle incidence resolution (P-MAIR) spectra were measured to investigate the thin film structure. The obtained thin films, with thicknesses of 120–670 nm, had no oriented structure. Relative humidity dependence of the resistance, proton conductivity, and normalized resistance were examined to ascertain the proton transport property of P-Asp100 thin films. The obtained data showed that the proton transport of P-Asp100 thin films might occur on the surface, not inside of the thin film. This phenomenon might be related with the proton transport of the biological system.

Surface proton transport of fully protonated poly(aspartic acid) thin films on quartz substrates

International Nuclear Information System (INIS)

Nagao, Yuki; Kubo, Takahiro

2014-01-01

Graphical abstract: - Highlights: • Proton transport of fully protonated poly(aspartic acid) thin film was investigated. • The thin film structure differed greatly from the partially protonated one. • Proton transport occurs on the surface, not inside of the thin film. • This result contributes to biological transport systems such as bacteriorhodopsin. - Abstract: Thin film structure and the proton transport property of fully protonated poly(aspartic acid) (P-Asp100) have been investigated. An earlier study assessed partially protonated poly(aspartic acid), highly oriented thin film structure and enhancement of the internal proton transport. In this study of P-Asp100, IR p-polarized multiple-angle incidence resolution (P-MAIR) spectra were measured to investigate the thin film structure. The obtained thin films, with thicknesses of 120–670 nm, had no oriented structure. Relative humidity dependence of the resistance, proton conductivity, and normalized resistance were examined to ascertain the proton transport property of P-Asp100 thin films. The obtained data showed that the proton transport of P-Asp100 thin films might occur on the surface, not inside of the thin film. This phenomenon might be related with the proton transport of the biological system

Electric Vehicle Grid Integration | Transportation Research | NREL

Science.gov (United States)

Electric Vehicle Grid Integration Electric Vehicle Grid Integration Illustration of a house with a in the garage, is connected via a power cord to a household outlet. A sustainable transportation sustainable transportation technologies to increase the capacity, efficiency, and stability of the grid

Effects of lithium doping on microstructure, electrical properties, and chemical bonds of sol-gel derived NKN thin films

International Nuclear Information System (INIS)

Lin, Chun-Cheng; Chen, Chan-Ching; Weng, Chung-Ming; Chu, Sheng-Yuan; Hong, Cheng-Shong; Tsai, Cheng-Che

2015-01-01

Highly (100/110) oriented lead-free Li x (Na 0.5 K 0.5 ) 1−x NbO 3 (LNKN, x = 0, 0.02, 0.04, and 0.06) thin films are fabricated on Pt/Ti/SiO 2 /Si substrates via a sol-gel processing method. The lithium (Li) dopants modify the microstructure and chemical bonds of the LNKN films, and therefore improve their electrical properties. The optimal values of the remnant polarization (P r  = 14.3 μC/cm 2 ), piezoelectric coefficient (d 33  = 48.1 pm/V), and leakage current (<10 −5 A/cm 2 ) are obtained for a lithium addition of x = 0.04 (i.e., 4 at. %). The observation results suggest that the superior electrical properties are the result of an improved crystallization, a larger grain size, and a smoother surface morphology. It is shown that the ion transport mechanism is dominated by an Ohmic behavior under low electric fields and the Poole-Frenkel emission effect under high electric fields

All-metallic electrically gated 2H-TaSe2 thin-film switches and logic circuits

International Nuclear Information System (INIS)

Renteria, J.; Jiang, C.; Yan, Z.; Samnakay, R.; Goli, P.; Pope, T. R.; Salguero, T. T.; Wickramaratne, D.; Lake, R. K.; Khitun, A. G.; Balandin, A. A.

2014-01-01

We report the fabrication and performance of all-metallic three-terminal devices with tantalum diselenide thin-film conducting channels. For this proof-of-concept demonstration, the layers of 2H-TaSe 2 were exfoliated mechanically from single crystals grown by the chemical vapor transport method. Devices with nanometer-scale thicknesses exhibit strongly non-linear current-voltage characteristics, unusual optical response, and electrical gating at room temperature. We have found that the drain-source current in thin-film 2H-TaSe 2 –Ti/Au devices reproducibly shows an abrupt transition from a highly resistive to a conductive state, with the threshold tunable via the gate voltage. Such current-voltage characteristics can be used, in principle, for implementing radiation-hard all-metallic logic circuits. These results may open new application space for thin films of van der Waals materials

All-metallic electrically gated 2H-TaSe2 thin-film switches and logic circuits

Science.gov (United States)

Renteria, J.; Samnakay, R.; Jiang, C.; Pope, T. R.; Goli, P.; Yan, Z.; Wickramaratne, D.; Salguero, T. T.; Khitun, A. G.; Lake, R. K.; Balandin, A. A.

2014-01-01

We report the fabrication and performance of all-metallic three-terminal devices with tantalum diselenide thin-film conducting channels. For this proof-of-concept demonstration, the layers of 2H-TaSe2 were exfoliated mechanically from single crystals grown by the chemical vapor transport method. Devices with nanometer-scale thicknesses exhibit strongly non-linear current-voltage characteristics, unusual optical response, and electrical gating at room temperature. We have found that the drain-source current in thin-film 2H-TaSe2-Ti/Au devices reproducibly shows an abrupt transition from a highly resistive to a conductive state, with the threshold tunable via the gate voltage. Such current-voltage characteristics can be used, in principle, for implementing radiation-hard all-metallic logic circuits. These results may open new application space for thin films of van der Waals materials.

Electrical railway transportation systems

CERN Document Server

Brenna, Morris; Zaninelli, Dario

2018-01-01

Allows the reader to deepen their understanding of various technologies for both fixed power supply installations of railway systems and for railway rolling stock. This book explores the electric railway systems that play a crucial role in the mitigation of congestion and pollution caused by road traffic. It is divided into two parts: the first covering fixed power supply systems, and the second concerning the systems for railway rolling stock. In particular, after a historical introduction to the framework of technological solutions in current use, the authors investigate electrification systems for the power supply of rail vehicles, trams, and subways. Electrical Railway Transportation Systems explores the direct current systems used throughout the world for urban and suburban transport, which are also used in various countries for regional transport. It provides a study of alternating current systems, whether for power supply frequency or for special railway frequency, that are used around the world for ...

An investigation on high-temperature electrical transport properties of graphene-oxide nano-thinfilms

International Nuclear Information System (INIS)

Venugopal, Gunasekaran; Krishnamoorthy, Karthikeyan; Kim, Sang-Jae

2013-01-01

High-temperature electrical transport properties are investigated for graphene-oxide nano thinfilms. The graphene-oxide nanoparticles are synthesized by modified Hummers method and characterized by UV–vis, Raman and X-ray diffraction techniques. The surface morphology of graphene-oxide film is analyzed using scanning electron and atomic force microscopy. The experimental results on high-temperature electrical studies of thinfilms exhibit metallic behavior followed by three-dimensional variable range hopping mechanism. The current–voltage characteristics at various temperatures (from 293 K to 573 K) were investigated. The effect of high-temperature on the functional groups of graphene-oxide film is evidently examined using X-ray photoelectron, thermal gravimetric analysis and Fourier transform infra-red spectroscopy. Transistor characteristics were performed after heat treatment resulting ambipolar behavior with holes and electron mobility of 127 and 66.9 cm 2 V −1 s −1 respectively. Our results are comparable to reduced graphene-oxide, indicating the advantage of our approach requires no further reduction to develop graphene-based transparent and conductive electrodes for dye-sensitized solar cells and ultra-capacitor applications.

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.

Magnetic and electrical transport properties of LaBaCo2O(5.5+δ) thin films on vicinal (001) SrTiO3 surfaces.

Science.gov (United States)

Ma, Chunrui; Liu, Ming; Collins, Gregory; Wang, Haibin; Bao, Shanyong; Xu, Xing; Enriquez, Erik; Chen, Chonglin; Lin, Yuan; Whangbo, Myung-Hwan

2013-01-23

Highly epitaxial LaBaCo(2)O(5.5+δ) thin films were grown on the vicinal (001) SrTiO(3) substrates with miscut angles of 0.5°, 3.0°, and 5.0° to systemically study strain effect on its physical properties. The electronic transport properties and magnetic behaviors of these films are strongly dependent on the miscut angles. With increasing the miscut angle, the transport property of the film changes from semiconducting to semimetallic, which results most probably from the locally strained domains induced by the surface step terraces. In addition, a very large magnetoresistance (34% at 60 K) was achieved for the 0.5°-miscut film, which is ~30% larger than that for the film grown on the regular (001) SrTiO(3) substrates.

Structural, magnetic and transport properties of Co2FeAl Heusler films with varying thickness

International Nuclear Information System (INIS)

Wang, Xiaotian; Li, Yueqing; Du, Yin; Dai, Xuefang; Liu, Guodong; Liu, Enke; Liu, Zhongyuan; Wang, Wenhong; Wu, Guangheng

2014-01-01

We report on a systematic study of the structural, magnetic properties and the anomalous Hall effect, in the Heusler alloy Co 2 FeAl (CFA) epitaxial films on MgO (001), as a function of film thickness. It was found that the epitaxial CFA films show a highly ordered B2 structure with an in-plane uniaxial magnetic anisotropy. The electrical transport properties reveal that the lattice and magnon scattering contributions to the longitudinal resistivity. Independent on the thickness of films, the anomalous Hall resistivity of CFA films is found to be dominated by skew scattering only. Moreover, the anomalous Hall resistivity shows weakly temperature dependent behavior, and its absolute value increases as the thickness decreases. We attribute this temperature insensitivity in the anomalous Hall resistivity to the weak temperature dependent of tunneling spin-polarization in the CFA films, while the thickness dependence behavior is likely due to the increasing significance of interface or free surface electronic states. - Highlights: ●Highly ordered CFA films with various thicknesses were prepared on MgO substrates. ●The magnon scattering contributions to the longitudinal resistivity in the CFA films. ●The anomalous Hall resistivity of the CFA films shows weakly temperature dependent. ●The CFA films show weak temperature dependent of tunneling spin-polarization

Polycrystalline Mg2Si thin films: A theoretical investigation of their electronic transport properties

International Nuclear Information System (INIS)

Balout, H.; Boulet, P.; Record, M.-C.

2015-01-01

The electronic structures and thermoelectric properties of a polycrystalline Mg 2 Si thin film have been investigated by first-principle density-functional theory (DFT) and Boltzmann transport theory calculations within the constant-relaxation time approximation. The polycrystalline thin film has been simulated by assembling three types of slabs each having the orientation (001), (110) or (111) with a thickness of about 18 Å. The effect of applying the relaxation procedure to the thin film induces disorder in the structure that has been ascertained by calculating radial distribution functions. For the calculations of the thermoelectric properties, the energy gap has been fixed at the experimental value of 0.74 eV. The thermoelectric properties, namely the Seebeck coefficient, the electrical conductivity and the power factor, have been determined at three temperatures of 350 K, 600 K and 900 K with respect to both the energy levels and the p-type and n-type doping levels. The best Seebeck coefficient is obtained at 350 K: the S yy component of the tensor amounts to about ±1000 μV K −1 , depending on the type of charge carriers. However, the electrical conductivity is much too small which results in low values of the figure of merit ZT. Structure–property relationship correlations based on directional radial distribution functions allow us to tentatively draw some explanations regarding the anisotropy of the electrical conductivity. Finally, the low ZT values obtained for the polycrystalline Mg 2 Si thin film are paralleled with those recently reported in the literature for bulk chalcogenide glasses. - Graphical abstract: Structure of the polycrystalline thin film of Mg 2 Si. - Author-Highlights: • Polycrystalline Mg 2 Si film has been modelled by DFT approach. • Thermoelectric properties have been evaluated by semi-classical Boltzmann theory. • The structure was found to be slightly disordered after relaxation. • The highest value of Seebeck

Electrical resistivity of ferrimagnetic magnetite thin film

International Nuclear Information System (INIS)

Varshney, Dinesh; Yogi, A.; Kaurav, N.; Gupta, R.P.; Phase, D.M.

2006-01-01

We have grown Fe 3 O 4 (III) epitaxial film on Al 2 O 3 (0001) substrate by pulsed laser deposition, with thickness of 130 nm. X-ray diffraction studies of magnetite show the spinel cubic structure of film with preferential (III) orientation. The electrical resistivity measurement demonstrates that the properties of thin film of magnetite are basically similar to those of bulk magnetite and clearly shows semiconductor-insulator transition at Verwey transition temperature (≅140 K). We have found higher Verwey transition temperature when compared with earlier reports on similar type of system. Possible causes for increase in transition temperature are discussed. (author)

The effect of the Grain-Boundary and surface scattering of charge carriers on electrical conductance of thin V and Re films

International Nuclear Information System (INIS)

Lakh, Kh.G.; Stasyuk, Z.V.

1994-01-01

Size effects in electrical conductivity and the Hall coefficient of thin V and Re films have been investigated. An analysis of experimental data was made within the framework of modified Mayadas -Shatzkes and Tellier - Tosser - Pichard models. The parameters of charge transport for V and Re have been found

Electron transport properties of some new 4-tert-butylcalix[4]arene derivatives in thin films

Energy Technology Data Exchange (ETDEWEB)

Leontie, Liviu, E-mail: lleontie@uaic.ro [Faculty of Physics, Alexandru Ioan Cuza University of Iasi, B-dul Carol I, Nr. 11, 700506 Iasi (Romania); Danac, Ramona [Faculty of Chemistry, Alexandru Ioan Cuza University of Iasi, B-dul Carol I, Nr. 11, 700506 Iasi (Romania); Girtan, Mihaela [Laboratoire LPhiA, Angers University, 2, Bd. Lavoisier, 49045, Angers (France); Carlescu, Aurelian; Rambu, Alicia Petronela; Rusu, Gheorghe I. [Faculty of Physics, Alexandru Ioan Cuza University of Iasi, B-dul Carol I, Nr. 11, 700506 Iasi (Romania)

2012-07-16

Temperature dependences of electric conductivity and thermoelectric power of some recently synthesized organic compounds, 4-tert-butylcalix[4]arene derivatives, are studied. Thin-film samples (d = 0.10-0.40 {mu}m) spin-coated from chloroform solutions onto glass substrates were used. Organic films with reproducible electron transport properties can be obtained if, after deposition, they are submitted to a heat treatment within temperature range of 295-575 K. The studied polycrystalline compounds show typical p-type semiconductor behavior. The activation energy of the electric conduction ranges between 0.82 and 1.12 eV, while the ratio of charge carrier mobilities was found in the range of 0.83-0.94. Some correlations between semiconducting parameters and molecular structure of the organic compounds have been discussed. In the higher temperature ranges (T > 420 K), the electron transport in examined compounds can be interpreted in terms of the band gap representation model, while in the lower temperature range, the Mott's variable-range hopping conduction model was found to be appropriate. The investigated compounds hold promise for thermistor applications. - Highlights: Black-Right-Pointing-Pointer 4-tert-butylcalix(4)arene derivatives in thin films are p-type semiconductors. Black-Right-Pointing-Pointer The electron transfer is favored by their extended conjugation and packing capacity. Black-Right-Pointing-Pointer The band gap representation is suitable in the higher temperature range. Black-Right-Pointing-Pointer The Mott's VRH conduction model may be applied in the lower temperature range. Black-Right-Pointing-Pointer As-prepared organic compounds are promising for thermistor applications.

Electron transport properties of some new 4-tert-butylcalix[4]arene derivatives in thin films

International Nuclear Information System (INIS)

Leontie, Liviu; Danac, Ramona; Girtan, Mihaela; Carlescu, Aurelian; Rambu, Alicia Petronela; Rusu, Gheorghe I.

2012-01-01

Temperature dependences of electric conductivity and thermoelectric power of some recently synthesized organic compounds, 4-tert-butylcalix[4]arene derivatives, are studied. Thin-film samples (d = 0.10–0.40 μm) spin-coated from chloroform solutions onto glass substrates were used. Organic films with reproducible electron transport properties can be obtained if, after deposition, they are submitted to a heat treatment within temperature range of 295–575 K. The studied polycrystalline compounds show typical p-type semiconductor behavior. The activation energy of the electric conduction ranges between 0.82 and 1.12 eV, while the ratio of charge carrier mobilities was found in the range of 0.83–0.94. Some correlations between semiconducting parameters and molecular structure of the organic compounds have been discussed. In the higher temperature ranges (T > 420 K), the electron transport in examined compounds can be interpreted in terms of the band gap representation model, while in the lower temperature range, the Mott's variable-range hopping conduction model was found to be appropriate. The investigated compounds hold promise for thermistor applications. - Highlights: ► 4-tert-butylcalix(4)arene derivatives in thin films are p-type semiconductors. ► The electron transfer is favored by their extended conjugation and packing capacity. ► The band gap representation is suitable in the higher temperature range. ► The Mott's VRH conduction model may be applied in the lower temperature range. ► As-prepared organic compounds are promising for thermistor applications.

Temperature dependent electrical properties of polyaniline film grown on paper through aniline vapor polymerization

International Nuclear Information System (INIS)

Deb, K.; Bera, A.; Saha, B.; Bhowmik, K. L.; Chattopadhyay, K. K.

2016-01-01

Polyaniline thin film has been prepared on paper by aniline vapor deposition technique. Ferric chloride has been used as polymerizing agent in this approach. The prepared films were studied through electrical resistivity and optical properties measurements. The electrical resistivity of the polyaniline film shows significant temperature dependence. The resistance sharply falls with the increase in temperature. The optical absorbance measurements shows characteristics absorbance peak indicating the formation of conducting emeraldine salt form of polyaniline. The optical energy band gap of the film was calculated from the transmittance spectra. The optical energy band gap and electrical conductivity of the polyaniline film is well suited for their applications in electronic devices.

Temperature dependent electrical properties of polyaniline film grown on paper through aniline vapor polymerization

Energy Technology Data Exchange (ETDEWEB)

Deb, K.; Bera, A.; Saha, B., E-mail: biswajit.physics@gmail.com [Department of Physics, National Institute of Technology Agartala, Jirania, West Tripura 799046 (India); Bhowmik, K. L. [Department of Physics, National Institute of Technology Agartala, Jirania, West Tripura 799046 (India); Department of Chemistry, Bir Bikram Memorial College, Agartala, West Tripura 799004 (India); Chattopadhyay, K. K. [Department of Physics, Jadavpur University, Kolkata 700 032 (India)

2016-05-23

Polyaniline thin film has been prepared on paper by aniline vapor deposition technique. Ferric chloride has been used as polymerizing agent in this approach. The prepared films were studied through electrical resistivity and optical properties measurements. The electrical resistivity of the polyaniline film shows significant temperature dependence. The resistance sharply falls with the increase in temperature. The optical absorbance measurements shows characteristics absorbance peak indicating the formation of conducting emeraldine salt form of polyaniline. The optical energy band gap of the film was calculated from the transmittance spectra. The optical energy band gap and electrical conductivity of the polyaniline film is well suited for their applications in electronic devices.

Temperature dependent electrical properties of polyaniline film grown on paper through aniline vapor polymerization

Science.gov (United States)

Deb, K.; Bhowmik, K. L.; Bera, A.; Chattopadhyay, K. K.; Saha, B.

2016-05-01

Polyaniline thin film has been prepared on paper by aniline vapor deposition technique. Ferric chloride has been used as polymerizing agent in this approach. The prepared films were studied through electrical resistivity and optical properties measurements. The electrical resistivity of the polyaniline film shows significant temperature dependence. The resistance sharply falls with the increase in temperature. The optical absorbance measurements shows characteristics absorbance peak indicating the formation of conducting emeraldine salt form of polyaniline. The optical energy band gap of the film was calculated from the transmittance spectra. The optical energy band gap and electrical conductivity of the polyaniline film is well suited for their applications in electronic devices.

Electrical properties of BiSrCaCuO films (2223)

International Nuclear Information System (INIS)

Okunev, V.D.; Pafomov, N.N.; Perekrestov, B.I.; Svistunov, V.M.

1996-01-01

The mechanisms of electrical conductivity of BiSrCaCuO films (2223) of different structural states are investigated. The films of an amorphous state (ρ = 10 3 - 10 10 Ohm centre dot cm) display a hopping conductivity with a variable hop length. Since the formation of a crystal structure (ρ = 10 - 10 3 Ohm centre dot cm) and up to the transition to a metal conductivity state (ρ ≅ 10 -2 Ohm centre dot cm) their electrical properties are similar to those of granular films featuring the exponential relation between specific resistance and separation between granules of metallic conductivity. In the vicinity of insulators-metal transition they feature the electrical conductivity-temperature relation with exponents 1/2 and 1/3. The transition to the metallic state is of a percolation nature and realized for a metal phase concentration of c m ≅ 0.2

Preparation, electrical and optical properties of evaporated thin films of CuPbI3

International Nuclear Information System (INIS)

Kuku, T.A.; Azi, S.O.

1995-10-01

Thin films of CuPbl 3 have been prepared by a vacuum evaporation process. X-ray analysis gives structural parameters in consonance with the bulk powder form of the material. The film however preferring a growth in the [002] direction. Electrical conductivity indicates an activated process with two activation energies being 0.45 eV for T ≤ 373 K, and 0.6 eV for T ≥ 373 K. Both are interpreted to be due to the transport of anionic carriers in the phases existing below and beyond 373 K respectively. Optical characterization reveals a material with high absorption coefficient, with α ≥ 10 4 cm -1 . The material is characterized by a direct absorption with the direct edge at 1.64 eV. (author). 13 refs, 5 figs

Comparison of four-probe thermal and thermoelectric transport measurements of thin films and nanostructures with microfabricated electro-thermal transducers

Science.gov (United States)

Kim, Jaehyun; Fleming, Evan; Zhou, Yuanyuan; Shi, Li

2018-03-01

Two different four-probe thermal and thermoelectric measurement methods have been reported for measuring the thermal conductivity, Seebeck coefficient, and electrical conductivity of suspended thin films and nanostructures with microfabricated electro-thermal transducers. The thermal contact resistance was extracted from the measured thermoelectric voltage drop at the contacts in the earlier four-probe method based on the assumption of constant thermal and thermoelectric properties along the sample. In comparison, the latter four-probe method can directly obtain the contact thermal resistance together with the intrinsic sample thermal resistance without making this assumption. Here, the measurement theory and data reduction processes of the latter four-probe measurement method are re-examined and improved. The measured thermal conductivity result of this improved method on representative thin film samples are found to agree with those obtained from the earlier four-probe method, which has obtained similar Seebeck coefficient and electrical conductivity as those measured with a different method for a supported thin film. The agreement provides further validation of the latest four-probe thermal transport measurement method of thin films and nanostructures.

All-metallic electrically gated 2H-TaSe{sub 2} thin-film switches and logic circuits

Energy Technology Data Exchange (ETDEWEB)

Renteria, J.; Jiang, C.; Yan, Z. [Nano-Device Laboratory, Department of Electrical Engineering, Bourns College of Engineering, University of California–Riverside, Riverside, California 92521 (United States); Samnakay, R.; Goli, P. [Materials Science and Engineering Program, Bourns College of Engineering, University of California–Riverside, Riverside, California 92521 (United States); Pope, T. R.; Salguero, T. T. [Department of Chemistry, University of Georgia, Athens, Georgia 30602 (United States); Wickramaratne, D.; Lake, R. K. [Laboratory for Terascale and Terahertz Electronics, Department of Electrical Engineering, Bourns College of Engineering, University of California–Riverside, Riverside, California 92521 (United States); Khitun, A. G. [Nano-Device Laboratory, Department of Electrical Engineering, Bourns College of Engineering, University of California–Riverside, Riverside, California 92521 (United States); Materials Science and Engineering Program, Bourns College of Engineering, University of California–Riverside, Riverside, California 92521 (United States); Balandin, A. A., E-mail: balandin@ee.ucr.edu [Nano-Device Laboratory, Department of Electrical Engineering, Bourns College of Engineering, University of California–Riverside, Riverside, California 92521 (United States); Department of Chemistry, University of Georgia, Athens, Georgia 30602 (United States)

2014-01-21

We report the fabrication and performance of all-metallic three-terminal devices with tantalum diselenide thin-film conducting channels. For this proof-of-concept demonstration, the layers of 2H-TaSe{sub 2} were exfoliated mechanically from single crystals grown by the chemical vapor transport method. Devices with nanometer-scale thicknesses exhibit strongly non-linear current-voltage characteristics, unusual optical response, and electrical gating at room temperature. We have found that the drain-source current in thin-film 2H-TaSe{sub 2}–Ti/Au devices reproducibly shows an abrupt transition from a highly resistive to a conductive state, with the threshold tunable via the gate voltage. Such current-voltage characteristics can be used, in principle, for implementing radiation-hard all-metallic logic circuits. These results may open new application space for thin films of van der Waals materials.

Thin film coatings for space electrical power system applications

Science.gov (United States)

Gulino, Daniel A.

1988-01-01

This paper examines some of the ways in which thin film coatings can play a role in aerospace applications. Space systems discussed include photovoltaic and solar dynamic electric power generation systems, including applications in environmental protection, thermal energy storage, and radiator emittance enhancement. Potential applications of diamondlike films to both atmospheric and space based systems are examined. Also, potential uses of thin films of the recently discovered high-temperature superconductive materials are discussed.

Transport of organic solutes through amorphous teflon AF films.

Science.gov (United States)

Zhao, Hong; Zhang, Jie; Wu, Nianqiang; Zhang, Xu; Crowley, Katie; Weber, Stephen G

2005-11-02

Fluorous media have great potential for selective extraction (e.g., as applied to organic synthesis). Fluorous polymer films would have significant advantages in fluorous separations. Stable films of Teflon AF 2400 were cast from solution. Films appear defect-free (SEM; AFM). Rigid aromatic solutes are transported (from chloroform solution to chloroform receiving phase) in a size-dependent manner (log permeability is proportional to -0.0067 times critical volume). Benzene's permeability is about 2 orders of magnitude higher than in comparable gas-phase experiments. The films show selectivity for fluorinated solutes in comparison to the hydrogen-containing control. Transport rates are dependent on the solvent making up the source and receiving phases. The effect of solvent is, interestingly, not due to changes in partition ratio, but rather it is due to changes in the solute diffusion coefficient in the film. Solvents plasticize the films. A less volatile compound, -COOH-terminated poly(hexafluoropropylene oxide) (4), plasticizes the films (T(g) = -40 degrees C). Permeabilities are decreased in comparison to 4-free films apparently because of decreased diffusivity of solutes. The slope of dependence of log permeability on critical volume is not changed, however.

Electrical Transport Mechanisms and Photoconduction in Undoped Crystalline Flash-Evaporated Lead Iodide Thin Films

Science.gov (United States)

Al-Daraghmeh, Tariq M.; Saleh, Mahmoud H.; Ahmad, Mais Jamil A.; Bulos, Basim N.; Shehadeh, Khawla M.; Jafar, Mousa M. Abdul-Gader

2018-03-01

The flash-evaporation technique was utilized to fabricate undoped 1.35-μm and 1.2-μm thick lead iodide films at substrate temperatures T_{{s}} = 150 °C and 200°C, respectively. The films were deposited onto a coplanar comb-like copper (Cu-) electrode pattern, previously coated on glass substrates to form lateral metal-semiconductor-metal (MSM-) structures. The as-measured constant- temperature direct-current (dc)-voltage ( I( {V;T} ) - V ) curves of the obtained lateral coplanar Cu-PbI2-Cu samples (film plus electrode) displayed remarkable ohmic behavior at all temperatures ( T = 18 - 90°C). Their dc electrical resistance R_{{dc}} (T ) revealed a single thermally-activated conduction mechanism over the temperature range with activation energy E_{{act}} ≈ 0.90 - 0.98 {eV} , slightly less than half of room-temperature bandgap energy E_{{g}} ( ≈ 2.3 {eV} ) of undoped 2H-polytype PbI2 single crystals. The undoped flash-evaporated {PbI}_{{x}} thin films were homogeneous and almost stoichiometric ( x ≈ 1.87 ), in contrast to findings on lead iodide films prepared by other methods, and were highly crystalline hexagonal 2H-polytypic structure with c-axis perpendicular to the surface of substrates maintained at T_{s} ≳ 150°C. Photoconductivity measurements made on these lateral Cu-PbI2-Cu-structures under on-off visible-light illumination reveal a feeble photoresponse for long wavelengths ( λ > 570 {nm} ), but a strong response to blue light of photon energy E_{{ph}} ≈ 2.73 {eV} ( > E_{{g}} ), due to photogenerated electron-hole (e-h) pairs via direct band-to-band electronic transitions. The constant-temperature/dc voltage current-time I( {T,V} ) - t curves of the studied lateral PbI2 MSM-structures at low ambient temperatures ( T < 50°C), after cutting off the blue-light illumination, exhibit two trapping mechanisms with different relaxation times. These strongly depend on V and T , with thermally generated charge carriers in the PbI2 mask photogenerated

Increasing the electrical anisotropy of solution-grown PbI2 thin films by addition of CdI2

International Nuclear Information System (INIS)

Ponpon, J.P.; Amann, M.

2010-01-01

In the present study up to 20% CdI 2 has been added to a lead iodide-water solution, which is used to grow PbI 2 polycrystalline thin films. As a result, a significant increase in the anisotropy of the lead iodide film's electrical properties has been observed: the resistivity in the direction parallel to the c-axis reached 10 15 Ω cm but did not change significantly in the orthogonal direction. This behavior can be explained by the modification of the transport properties related to the crystallographic structure of the films along the c-axis. As suggested by thermally stimulated current measurements, only a small number of the Cd atoms incorporated into the PbI 2 lattice could behave as dopants.

Surface proton transport of fully protonated poly(aspartic acid) thin films on quartz substrates

Science.gov (United States)

Nagao, Yuki; Kubo, Takahiro

2014-12-01

Thin film structure and the proton transport property of fully protonated poly(aspartic acid) (P-Asp100) have been investigated. An earlier study assessed partially protonated poly(aspartic acid), highly oriented thin film structure and enhancement of the internal proton transport. In this study of P-Asp100, IR p-polarized multiple-angle incidence resolution (P-MAIR) spectra were measured to investigate the thin film structure. The obtained thin films, with thicknesses of 120-670 nm, had no oriented structure. Relative humidity dependence of the resistance, proton conductivity, and normalized resistance were examined to ascertain the proton transport property of P-Asp100 thin films. The obtained data showed that the proton transport of P-Asp100 thin films might occur on the surface, not inside of the thin film. This phenomenon might be related with the proton transport of the biological system.

An easily accessible carbon material derived from carbonization of polyacrylonitrile ultrathin films: ambipolar transport properties and application in a CMOS-like inverter.

Science.gov (United States)

Jiao, Fei; Zhang, Fengjiao; Zang, Yaping; Zou, Ye; Di, Chong'an; Xu, Wei; Zhu, Daoben

2014-03-04

Ultrathin carbon films were prepared by carbonization of a solution processed polyacrylonitrile (PAN) film in a moderate temperature range (500-700 °C). The films displayed balanced hole (0.50 cm(2) V(-1) s(-1)) and electron mobilities (0.20 cm(2) V(-1) s(-1)) under ambient conditions. Spectral characterization revealed that the electrical transport is due to the formation of sp(2) hybridized carbon during the carbonization process. A CMOS-like inverter demonstrated the potential application of this material in the area of carbon electronics, considering its processability and low-cost.

Electroresistance Effect in Gold Thin Film Induced by Ionic-Liquid-Gated Electric Double Layer

NARCIS (Netherlands)

Nakayama, Hiroyasu; Ye, Jianting; Ohtani, Takashi; Fujikawa, Yasunori; Ando, Kazuya; Iwasa, Yoshihiro; Saitoh, Eiji

Electroresistance effect was detected in a metallic thin film using ionic-liquid-gated electric-double-layer transistors (EDLTs). We observed reversible modulation of the electric resistance of a Au thin film. In this system, we found that an electric double layer works as a nanogap capacitor with

Effects of lithium doping on microstructure, electrical properties, and chemical bonds of sol-gel derived NKN thin films

Energy Technology Data Exchange (ETDEWEB)

Lin, Chun-Cheng [Department of Electrical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Department of Mathematic and Physical Sciences, R.O.C. Air Force Academy, Kaohsiung 820, Taiwan (China); Chen, Chan-Ching; Weng, Chung-Ming [Department of Electrical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Chu, Sheng-Yuan, E-mail: chusy@mail.ncku.edu.tw [Department of Electrical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 701, Taiwan (China); Hong, Cheng-Shong [Department of Electronic Engineering, National Kaohsiung Normal University, Kaohsiung 802, Taiwan (China); Tsai, Cheng-Che [Department of Digital Game and Animation Design, Tung-Fang Design University, Kaohsiung 829, Taiwan (China)

2015-02-28

Highly (100/110) oriented lead-free Li{sub x}(Na{sub 0.5}K{sub 0.5}){sub 1−x}NbO{sub 3} (LNKN, x = 0, 0.02, 0.04, and 0.06) thin films are fabricated on Pt/Ti/SiO{sub 2}/Si substrates via a sol-gel processing method. The lithium (Li) dopants modify the microstructure and chemical bonds of the LNKN films, and therefore improve their electrical properties. The optimal values of the remnant polarization (P{sub r} = 14.3 μC/cm{sup 2}), piezoelectric coefficient (d{sub 33} = 48.1 pm/V), and leakage current (<10{sup −5} A/cm{sup 2}) are obtained for a lithium addition of x = 0.04 (i.e., 4 at. %). The observation results suggest that the superior electrical properties are the result of an improved crystallization, a larger grain size, and a smoother surface morphology. It is shown that the ion transport mechanism is dominated by an Ohmic behavior under low electric fields and the Poole-Frenkel emission effect under high electric fields.

Local electrical properties of thermally grown oxide films formed on duplex stainless steel surfaces

Science.gov (United States)

Guo, L. Q.; Yang, B. J.; He, J. Y.; Qiao, L. J.

2018-06-01

The local electrical properties of thermally grown oxide films formed on ferrite and austenite surfaces of duplex stainless steel at different temperatures were investigated by Current sensing atomic force microscopy, X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES). The current maps and XPS/AES analyses show that the oxide films covering austenite and ferrite surfaces formed at different temperatures exhibit different local electrical characteristics, thickness and composition. The dependence of electrical conductivity of oxide films covering austenite and ferrite surface on the formation temperature is attributed to the film thickness and semiconducting structures, which is intrinsically related to thermodynamics and kinetics process of film grown at different temperature. This is well elucidated by corresponding semiconductor band structures of oxide films formed on austenite and ferrite phases at different temperature.

Structural, magnetic and transport properties of Co{sub 2}FeAl Heusler films with varying thickness

Energy Technology Data Exchange (ETDEWEB)

Wang, Xiaotian [School of Material Sciences and Engineering, Hebei University Technology, Tianjin 300130 (China); Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Li, Yueqing [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); State Key Laboratory of Metastable Material Sciences and Technology, Yanshan University, Qinhuangdao 066004 (China); Du, Yin [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Dai, Xuefang; Liu, Guodong [School of Material Sciences and Engineering, Hebei University Technology, Tianjin 300130 (China); Liu, Enke [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Liu, Zhongyuan [State Key Laboratory of Metastable Material Sciences and Technology, Yanshan University, Qinhuangdao 066004 (China); Wang, Wenhong, E-mail: wenhong.wang@iphy.ac.cn [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Wu, Guangheng [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

2014-08-01

We report on a systematic study of the structural, magnetic properties and the anomalous Hall effect, in the Heusler alloy Co{sub 2}FeAl (CFA) epitaxial films on MgO (001), as a function of film thickness. It was found that the epitaxial CFA films show a highly ordered B2 structure with an in-plane uniaxial magnetic anisotropy. The electrical transport properties reveal that the lattice and magnon scattering contributions to the longitudinal resistivity. Independent on the thickness of films, the anomalous Hall resistivity of CFA films is found to be dominated by skew scattering only. Moreover, the anomalous Hall resistivity shows weakly temperature dependent behavior, and its absolute value increases as the thickness decreases. We attribute this temperature insensitivity in the anomalous Hall resistivity to the weak temperature dependent of tunneling spin-polarization in the CFA films, while the thickness dependence behavior is likely due to the increasing significance of interface or free surface electronic states. - Highlights: ●Highly ordered CFA films with various thicknesses were prepared on MgO substrates. ●The magnon scattering contributions to the longitudinal resistivity in the CFA films. ●The anomalous Hall resistivity of the CFA films shows weakly temperature dependent. ●The CFA films show weak temperature dependent of tunneling spin-polarization.

Effect of thickness on structural and electrical properties of Al-doped ZnO films

Energy Technology Data Exchange (ETDEWEB)

Garcés, F.A., E-mail: felipe.garces@santafe-conicet.gov.ar [Instituto de Física del Litoral (CONICET-UNL), Güemes 3450, Santa Fe S3000GLN (Argentina); Budini, N. [Instituto de Física del Litoral (CONICET-UNL), Güemes 3450, Santa Fe S3000GLN (Argentina); Arce, R.D.; Schmidt, J.A. [Instituto de Física del Litoral (CONICET-UNL), Güemes 3450, Santa Fe S3000GLN (Argentina); Facultad de Ingeniería Química, Universidad Nacional del Litoral, Santiago del Estero 2829, Santa Fe S3000AOM (Argentina)

2015-01-01

In this work, we have investigated the influence of thickness on structural and electrical properties of Al-doped ZnO films. Transparent conducting oxide films were grown by the spray pyrolysis technique from precursors prepared via the sol–gel method. We determined the structural properties of the films by performing X-ray diffraction and mosaicity measurements, which evidenced an increase of disorder and inhomogeneity between crystalline domains as the films thickened. This behavior was contrasted with results obtained from electrical measurements and was attributed to plastic deformation of the films as their thickness increased. As a result, the carrier mobility, the optical gap and the activation energy are affected due to emerging grain boundaries and a higher degree of disorder. - Highlights: • Al-doped ZnO thin films on glass with different thicknesses • Film thickness affects the morphological and electrical properties. • Increasing time deposition allows modification of resistivity and Hall mobility. • Mosaicity between crystalline domains increases with film thickness.

Effect of thickness on structural and electrical properties of Al-doped ZnO films

International Nuclear Information System (INIS)

Garcés, F.A.; Budini, N.; Arce, R.D.; Schmidt, J.A.

2015-01-01

In this work, we have investigated the influence of thickness on structural and electrical properties of Al-doped ZnO films. Transparent conducting oxide films were grown by the spray pyrolysis technique from precursors prepared via the sol–gel method. We determined the structural properties of the films by performing X-ray diffraction and mosaicity measurements, which evidenced an increase of disorder and inhomogeneity between crystalline domains as the films thickened. This behavior was contrasted with results obtained from electrical measurements and was attributed to plastic deformation of the films as their thickness increased. As a result, the carrier mobility, the optical gap and the activation energy are affected due to emerging grain boundaries and a higher degree of disorder. - Highlights: • Al-doped ZnO thin films on glass with different thicknesses • Film thickness affects the morphological and electrical properties. • Increasing time deposition allows modification of resistivity and Hall mobility. • Mosaicity between crystalline domains increases with film thickness

The role of electric field during spray deposition on fluorine doped tin oxide film

Energy Technology Data Exchange (ETDEWEB)

Kumar, Anuj, E-mail: anujkumarom@gmail.com; Swami, Sanjay Kumar; Dutta, Viresh

2014-03-05

Highlights: • Fluorine doped tin oxide deposition by spray technique. • The growth reaction of tin oxide, controlled by the electric field on the substrate surface. • Deposit on large scale substrate 10 cm × 10 cm by single nozzle. • Obtained good quality of thin film. -- Abstract: The fluorine doped tin oxide film has been deposited on 10 cm × 10 cm glass substrate by using spray technique with a voltage applied between the nozzle and an annular electrode placed 2 mm below the nozzle. The effect of the electric field thus created during the spray deposition on structural, optical and electrical properties of SnO{sub 2}:F (FTO) film was studied. X-ray diffraction pattern revealed the presence of cassiterite structure with (2 0 0) orientation for all the FTO film. SEM study revealed the formation of smooth and uniform surface FTO film under the electric field over the entire substrate area. The electrical measurements show that the film prepared under the electric field (for an applied voltage of 2000 V) had a resistivity ∼1.2 × 10{sup −3} Ω cm, carrier concentration ∼4.21 × 10{sup 20} cm{sup −3} and mobility ∼14.48 cm{sup 2} V{sup −1} s{sup −1}. The sprayed FTO film have the average transmission in the visible region of more than about 80%.

Electrical properties of multilayer (DLC-TiC) films produced by pulsed laser deposition

Science.gov (United States)

Alawajji, Raad A.; Kannarpady, Ganesh K.; Nima, Zeid A.; Kelly, Nigel; Watanabe, Fumiya; Biris, Alexandru S.

2018-04-01

In this work, pulsed laser deposition was used to produce a multilayer diamond like carbon (ML (DLC-TiC)) thin film. The ML (DLC-TiC) films were deposited on Si (100) and glass substrates at various substrate temperatures in the range of 20-450 °C. Raman spectroscopy, x-ray photoelectron spectroscopy (XPS), and atomic force microscopy were utilized to characterize the prepared films. Raman analysis revealed that as the substrate temperature increased, the G-peak position shifted to a higher raman shift and the full width at half maximum of the G and D bands decreased. XPS analysis indicated a decrease in sp3/sp2 ratio and an increase in Ti-C bond intensity when the substrate temperature was increased. Additionally, the surface roughness of ML (DLC-TiC) filmswas affected by the type and temperature of the substrate. The electrical measurement results indicated that the electrical resistivity of the ML (DLC-TiC) film deposited on Si and glass substrates showed the same behavior-the resistivity decreased when substrate temperature increased. Furthermore, the ML (DLC-TiC) films deposited on silicon showed lower electrical resistivity, dropping from 8.39E-4 Ω-cm to 5.00E-4 Ω-cm, and, similarly, the films on the glass substrate displayed a drop in electrical resistivity from 1.8E-2 Ω-cm to 1.2E-3 Ω-cm. These enhanced electrical properties indicate that the ML (DLC-TiC) films have widespread potential as transducers for biosensors in biological research; electrochemical electrodes, because these films can be chemically modified; biocompatible coatings for medicals tools; and more.

Effect of laser energy on the electrical transport properties of La{sub 0.67}Ca{sub 0.33}MnO{sub 3}:Ag{sub 0.2} films by pulsed laser deposition technique

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yalin; Chen, Qingming; Jin, Fei; Chen, Xiaohui; Li, Zhiyu; Li, Di; Zhang, Hui [Kunming University of Science and Technology, Faculty of Materials Science and Engineering, Kunming (China)

2017-09-15

La{sub 0.67}Ca{sub 0.33}MnO{sub 3} (LCMO):Ag{sub 0.2} films were grown on LaAlO{sub 3} (LAO) substrates (100) by pulsed laser deposition (PLD) technique with various incident laser energies. The surface morphologies and the thicknesses of the films were studied by atomic force microscopy (AFM) and scanning electron microscopy (SEM), respectively. The crystal structures were analyzed by X-ray, diffraction (XRD), and the temperature dependence of the resistivity (ρ-T) of the films was studied by the standard four-probe method. It can be found that the crystal quality, surface morphology, metal-insulator transition temperature (T{sub p}), and temperature coefficient of resistance (TCR) of the LCMO:Ag{sub 0.2} films are changed with various laser energy. The highest T{sub p} 287 K is obtained with 300 mJ laser energy; meanwhile, the optimal TCR 13.5% K{sup -1} is achieved. The results suggest that the electrical transport properties of LCMO:Ag{sub 0.2} films are affected by the interface-induced compressive stress, the oxygen balance, and the double exchange between Mn{sup 3+}-O-Mn{sup 4+}. (orig.)

Infrared transparency and electrical conductivity of non-stoichiometric InxOy films

International Nuclear Information System (INIS)

Joseph, Shay; Berger, Shlomo

2010-01-01

In an effort to achieve both high infrared transparency and electrical conductivity, In x O y films having different oxygen atomic fractions, ranging from 0.27 to 0.6 were prepared. From AC electrical measurements it was determined that conductivity of In x O y films, having oxygen atomic fraction near 0.6, is governed by the hopping conduction mechanism via energy states located in the band gap. Conductivity of In x O y films having non-stoichiometric compositions was found to be governed by the free band conduction mechanism. The conduction activation energy was decreased from about 0.47 eV to about 0.02 eV as the deviation of the oxygen atomic fraction from the stoichiometric value of 0.6 was increased. The dielectric function of the films was determined by applying the Drude-Lorentz model to ellipsometric measurements in the infrared and visible wavelengths. In the visible range, the major source for optical transmission loss is interband absorption, which was modeled by the Lorentz model. In the infrared range, optical absorption was measured and attributed to the presence of free charge carriers according to the Drude model. Fitting the model to the optical measurements required a correction factor, which was correlated with the films polarizability. In order to determine the optimal tradeoff between optical transparency in the infrared and electrical conductivity, which were found to be affected mainly by the oxygen concentration in the films, a figure of merit parameter was established. It was found that by introducing non-stoichiometry in the form of oxygen deficiency, the electrical conductivity was improved by as much as two orders of magnitude while the infrared transparency was decreased by no more than 30% with respect to stoichiometric In 2 O 3 films.

Coupled electric and transport phenomena in porous media

NARCIS (Netherlands)

Li, Shuai

2014-01-01

The coupled electrical and transport properties of clay-containing porous media are the topics of interest in this study. Both experimental and numerical (pore network modeling) techniques are employed to gain insight into the macro-scale interaction between electrical and solute transport phenomena

Spin dependent transport of hot electrons through ultrathin epitaxial metallic films

Energy Technology Data Exchange (ETDEWEB)

Heindl, Emanuel

2010-06-23

In this work relaxation and transport of hot electrons in thin single crystalline metallic films is investigated by Ballistic Electron Emission Microscopy. The electron mean free paths are determined in an energy interval of 1 to 2 eV above the Fermi level. While fcc Au-films appear to be quite transmissive for hot electrons, the scattering lengths are much shorter for the ferromagnetic alloy FeCo revealing, furthermore, a strong spin asymmetry in hot electron transport. Additional information is gained from temperature dependent studies in combination with golden rule approaches in order to disentangle the impact of several relaxation and transport properties. It is found that bcc Fe-films are much less effective in spin filtering than films made of the FeCo-alloy. (orig.)

Nature of Dielectric Properties, Electric Modulus and AC Electrical Conductivity of Nanocrystalline ZnIn2Se4 Thin Films

Science.gov (United States)

El-Nahass, M. M.; Attia, A. A.; Ali, H. A. M.; Salem, G. F.; Ismail, M. I.

2018-02-01

The structural characteristics of thermally deposited ZnIn2Se4 thin films were indexed utilizing x-ray diffraction as well as scanning electron microscopy techniques. Dielectric properties, electric modulus and AC electrical conductivity of ZnIn2Se4 thin films were examined in the frequency range from 42 Hz to 106 Hz. The capacitance, conductance and impedance were measured at different temperatures. The dielectric constant and dielectric loss decrease with an increase in frequency. The maximum barrier height was determined from the analysis of the dielectric loss depending on the Giuntini model. The real part of the electric modulus revealed a constant maximum value at higher frequencies and the imaginary part of the electric modulus was characterized by the appearance of dielectric relaxation peaks. The AC electrical conductivity obeyed the Jonscher universal power law. Correlated barrier hopping model was the appropriate mechanism for AC conduction in ZnIn2Se4 thin films. Estimation of the density of states at the Fermi level and activation energy, for AC conduction, was carried out based on the temperature dependence of AC electrical conductivity.

A model of film boiling in the presence of electric fields

Energy Technology Data Exchange (ETDEWEB)

Carrica, P.M.; Masson, V.; Clausse, A. [Centro Atomico Bariloche and Instituto Balseiro, Barilochi (Argentina)

1995-09-01

Recently it was found that, when a strong electric field is applied around a heated wire, two distinct film boiling heat transfer regimes are observed. In this paper, a semi-empirical model is derived to analyze the pool boiling process in the presence of non uniform electric field. The model takes into account the dielectrophoretic force acting on the bubbles as they grow and the effect of the electric field on the most dangerous wavelength. It is shown how the transition between the two film boiling regimes is possible for high strength electric fields. The threshold voltage for transition, transition heat fluxes and hysteresis values are compared with experimental outcomes showing a satisfactory agreement.

Effects of iron content on electrical resistivity of oxide films on Zr-base alloys

International Nuclear Information System (INIS)

Kubo, Toshio; Uno, Masayoshi

1991-01-01

Measurements of electrical resistivity were made for oxide films formed by anodic oxidation and steam oxidation (400degC/12 h) on Zr plates with different Fe contents. When the Fe content was higher than about 1,000 ppm the electrical resistivity of the steam oxide films was almost equivalent to that of the anodic oxide films, while at lower Fe content the former exhibited lower electrical resistivity than the latter by about 1∼3 orders of magnitude. The anodic oxide film was an almost homogeneous single oxide layer. The steam oxide films, on the other hand, were composed of duplex oxide layers. The oxide layer formed in the vicinity of the oxide/metal interface had higher electrical resistivity than the near-surface oxide layer by about 1∼4 orders of magnitude. The oxide layer in the vicinity of the interface could act as a protective film against corrosion and its electrical resistivity is one important factor controlling the layer protectiveness. The electrical resistivity of the oxide/metal interfacial layer was strongly dependent on the Fe content. One possible reason for Fe to improve the corrosion resistance is that Fe ions would tend to stabilize the tetragonal (or cubic) phase and consequently suppress the formation of open pores and cracks in the interfacial layer. (author)

Reinforced carbon nanotubes as electrically conducting and flexible films for space applications.

Science.gov (United States)

Atar, Nurit; Grossman, Eitan; Gouzman, Irina; Bolker, Asaf; Hanein, Yael

2014-11-26

Chemical vapor deposition (CVD)-grown entangled carbon nanotube (CNT) sheets are characterized by high electrical conductivity and durability to bending and folding. However, since freestanding CNT sheets are mechanically weak, they cannot be used as stand-alone flexible films. In this work, polyimide (PI) infiltration into entangled cup-stacked CNT (CSCNT) sheets was studied to form electrically conducting, robust, and flexible films for space applications. The infiltration process preserved CNTs' advantageous properties (i.e., conductivity and flexibility), prevented CNT agglomeration, and enabled CNT patterning. In particular, the CNT-PI films exhibited ohmic electrical conductance in both the lateral and vertical directions, with a sheet resistivity as low as 122 Ω/□, similar to that of as-grown CNT sheets, with minimal effect of the insulating matrix. Moreover, this high conductivity was preserved under mechanical and thermal manipulations. These properties make the reported CNT-PI films excellent candidates for applications where flexibility, thermal stability, and electrical conductivity are required. Particularly, the developed CNT-PI films were found to be durable in space environment hazards such as high vacuum, thermal cycling, and ionizing radiation, and hence they are suggested as an alternative for the electrostatic discharge (ESD) protection layer in spacecraft thermal blankets.

Correlation between the transport mechanisms in conductive filaments inside Ta2O5-based resistive switching devices and in substoichiometric TaOx thin films

Science.gov (United States)

Rosário, Carlos M. M.; Thöner, Bo; Schönhals, Alexander; Menzel, Stephan; Wuttig, Matthias; Waser, Rainer; Sobolev, Nikolai A.; Wouters, Dirk J.

2018-05-01

Conductive filaments play a key role in redox-based resistive random access memory (ReRAM) devices based on the valence change mechanism, where the change of the resistance is ascribed to the modulation of the oxygen content in a local region of these conductive filaments. However, a deep understanding of the filaments' composition and structure is still a matter of debate. We approached the problem by comparing the electronic transport, at temperatures from 300 K down to 2 K, in the filaments and in TaOx films exhibiting a substoichiometric oxygen content. The filaments were created in Ta (15 nm)/Ta2O5 (5 nm)/Pt crossbar ReRAM structures. In the TaOx thin films with various oxygen contents, the in-plane transport was studied. There is a close similarity between the electrical properties of the conductive filaments in the ReRAM devices and of the TaOx films with x ˜ 1, evidencing also no dimensionality difference for the electrical transport. More specifically, for both systems there are two different conduction processes: one in the higher temperature range (from 50 K up to ˜300 K), where the conductivity follows a √{ T } dependence, and one at lower temperatures (<50 K), where the conductivity follows the exp(-1 / √{ T } ) dependence. This suggests a strong similarity between the material composition and structure of the filaments and those of the substoichiometric TaOx films. We also discuss the temperature dependence of the conductivity in the framework of possible transport mechanisms, mainly of those normally observed for granular metals.

ELECTRICAL PROPERTIES OF DC REACTIVE MAGNETRON ...

African Journals Online (AJOL)

Mgina

value of the AC resistivity was given by the ZnO:Al film with the highest value of ... Compared to other thin film ... critical parameters in determining the ... approach in studying the electronic transport ..... J 2009 Electrical and optical studies of.

Electrical characterization of thin film ferroelectric capacitors

NARCIS (Netherlands)

Tiggelman, M.P.J.; Reimann, K.; Klee, M.; Beelen, D.; Keur, W.; Schmitz, Jurriaan; Hueting, Raymond Josephus Engelbart

2006-01-01

Tunable capacitors can be used to facilitate the reduction of components in wireless technologies. The tunability of the capacitors is caused by the sensitivity of the relative dielectric constant to a change in polarization with electric field. Thin film ferroelectric MIM capacitors on silicon

Charge transport in dye-sensibilized porous zinc oxide films; Ladungstransport in farbstoffsensibilisierten poroesen Zinkoxidfilmen

Energy Technology Data Exchange (ETDEWEB)

Reemts, J.

2006-05-18

During the last decades, zinc oxide has attracted a lot of attention as an important material in various electrical, chemical, and optical applications. In the present work results are discussed gained from investigations of highly porous electrochemically deposited zinc oxide, which is a promising electrode material both in the area of solar energy conversion and sensor technology. The films were prepared by adding detergents during the electrodeposition process. The detergents have a structure-directing influence during the film deposition and, therefore, on the morphology of the films. The obtained electrodes can easily be sensitized for light or different chemicals by a simple adsorption of different molecules. In the present work I discuss the fundamental charge transport properties of electrochemically deposited zinc oxide films. Temperature-dependent measurements of the current-voltage characteristics are carried out and the spectral response of the photoconductivity is investigated. In order to understand the charge transport properties of this highly porous material, it is necessary to get a deeper insight in the electrode morphology. Therefore, different optical and scanning probe microscopy methods are used to characterize the inner structure of the electrodes. The electrical conductivity of the zinc oxide films can be seen as a thermally activated process, which can be explained by electronic transitions from the valence band of the zinc oxide to two shallow impurity levels. The current-voltage characteristic unveils a nonlinear behavior which can be explained by a space-charge-limited current model with traps distributed in energy. Upon excitation with different wavelengths, the conductivity of the zinc oxide increases already under sub-band gap illumination due to widely distributed trap states within the band gap. The transients of the photoconductivity follow a stretched exponential law with time scales in the range of several hours, either if the

Electricity for road transport, flexible power systems and wind power

Energy Technology Data Exchange (ETDEWEB)

Nielsen, Lars Henrik; Ravn, H.; Meibom, P. (and others)

2011-12-15

The aim of the project is to analyse the potential synergistic interplay that may arise between the power sector and the transport sector, if parts of the road transport energy needs are based on electricity via the utilisation of plug-in hybrid electric vehicles and pure electric vehicles. The project focuses on the technical elements in the chain that comprises: 1: The electric vehicle status, potentials and expected development. Electric batteries are in focus in this part of the analysis. 2: Analysis of plug-in hybrid electric vehicle interacting with a local grid. 3: Analysis of grid-vehicle connection systems including technical regulation options and analysis of needs for standardisation. 4: Setting up scenarios covering potential developments for utilizing electric drive trains in road transport. Period: Up to year 2030. 5: Analysis of capacity constraints in the electricity grid (transmission and distribution) as consequence of increasing electricity demand, and new flexible consumption patterns from segments in the transport sector, and as consequence of increasing capacity on wind power in the system. 6: Setting up and analysis of combined scenarios covering both the heat and power system and the transport sector. (Author)

Semiconductor thin films directly from minerals—study of structural, optical, and transport characteristics of Cu2O thin films from malachite mineral and synthetic CuO

International Nuclear Information System (INIS)

Balasubramaniam, K.R.; Kao, V.M.; Ravichandran, J.; Rossen, P.B.; Siemons, W.; Ager, J.W.

2012-01-01

We demonstrate the proof-of-concept of using an abundantly occurring natural ore, malachite (Cu 2 CO 3 (OH) 2 ) to directly yield the semiconductor Cu 2 O to be used as an active component of a functional thin film based device. Cu 2 O is an archetype hole-conducting semiconductor that possesses several interesting characteristics particularly useful for solar cell applications, including low cost, non-toxicity, good hole mobility, large minority carrier diffusion length, and a direct energy gap ideal for efficient absorption. In this article, we compare the structural, optical, and electrical transport characteristics of Cu 2 O thin films grown from the natural mineral malachite and synthetic CuO targets. Growth from either source material results in single-phase, fully epitaxial cuprous oxide thin films as determined by x-ray diffraction. The films grown from malachite have strong absorption coefficients ( 10 4 cm −1 ), a direct allowed optical bandgap ( 2.4 eV), and majority carrier hole mobilities ( 35 cm 2 V −1 s −1 at room temperature) that compare well with films grown from the synthetic target as well as with previously reported values. Our work demonstrates that minerals could be useful to directly yield the active components in functional devices and suggests a route for the exploration of low cost energy conversion and storage technologies. - Highlights: ► Semiconductor thin films directly from minerals ► Chemistry and structure evolution of the films obtained from mineral target is very similar to that films obtained from high-purity synthetic targets. ► Quite interestingly, transport and optical characteristics are also found to be similar.

Resistivity of thiol-modified gold thin films

International Nuclear Information System (INIS)

Correa-Puerta, Jonathan; Del Campo, Valeria; Henríquez, Ricardo; Häberle, Patricio

2014-01-01

In this work, we study the effect of thiol self assembled monolayers on the electrical resistivity of metallic thin films. The analysis is based on the Fuchs–Sondheimer–Lucas theory and on electrical transport measurements. We determined resistivity change due to dodecanethiol adsorption on gold thin films. For this purpose, we controlled the deposition and annealing temperatures of the films to change the surface topography and to diminish the effect of electron grain boundary scattering. Results show that the electrical response to the absorption of thiols strongly depends on the initial topography of the surface. - Highlights: • We study the effect of self assembled monolayers on the resistivity of thin films. • Fuchs–Sondheimer theory reproduces the resistivity increase due to thiol deposition. • We determined resistivity change due to dodecanethiol deposition on gold thin films. • The electrical response strongly depends on the substrate surface topography

Resistivity of thiol-modified gold thin films

Energy Technology Data Exchange (ETDEWEB)

Correa-Puerta, Jonathan [Instituto de Física, Pontificia Universidad Católica de Valparaíso, Av. Universidad 330, Curauma, Valparaíso (Chile); Del Campo, Valeria [Departamento de Física, Universidad Técnica Federico Santa María, Av. España 1680, Valparaiso 2390123 (Chile); Henríquez, Ricardo, E-mail: ricardo.henriquez@usm.cl [Departamento de Física, Universidad Técnica Federico Santa María, Av. España 1680, Valparaiso 2390123 (Chile); Häberle, Patricio [Departamento de Física, Universidad Técnica Federico Santa María, Av. España 1680, Valparaiso 2390123 (Chile)

2014-11-03

In this work, we study the effect of thiol self assembled monolayers on the electrical resistivity of metallic thin films. The analysis is based on the Fuchs–Sondheimer–Lucas theory and on electrical transport measurements. We determined resistivity change due to dodecanethiol adsorption on gold thin films. For this purpose, we controlled the deposition and annealing temperatures of the films to change the surface topography and to diminish the effect of electron grain boundary scattering. Results show that the electrical response to the absorption of thiols strongly depends on the initial topography of the surface. - Highlights: • We study the effect of self assembled monolayers on the resistivity of thin films. • Fuchs–Sondheimer theory reproduces the resistivity increase due to thiol deposition. • We determined resistivity change due to dodecanethiol deposition on gold thin films. • The electrical response strongly depends on the substrate surface topography.

Electric field dependence of excess electrical conductivity below transition temperature in thin superconducting lead films

Energy Technology Data Exchange (ETDEWEB)

Ashwini Kumar, P K; Duggal, V P [Delhi Univ. (India). Dept. of Physics and Astrophysics

1976-01-26

Results of measurements of the electric field dependence of the excess electrical conductivity are reported in thin superconducting lead films below the transition temperature. It is observed that the normal state sheet resistance has some effect on the nonlinearity but the theory of Yamaji still fits well to the experimental data.

Electrical properties of SmB6 thin films prepared by pulsed laser deposition from a stoichiometric SmB6 target

Czech Academy of Sciences Publication Activity Database

Baťková, M.; Baťko, I.; Stobiecki, F.; Szymański, B.; Kuswik, P.; Macková, Anna; Malinský, Petr

2018-01-01

Roč. 744, č. 5 (2018), s. 821-827 ISSN 0925-8388 R&D Projects: GA ČR(CZ) GBP108/12/G108; GA MŠk LM2015056 Institutional support: RVO:61389005 Keywords : rare earth alloys and compounds * thin films * vapor deposition * electrical transport * valence fluctuations Subject RIV: JP - Industrial Processing OBOR OECD: Materials engineering Impact factor: 3.133, year: 2016

Recovery of electrical resistance in copper films on polyethylene terephthalate subjected to a tensile strain

International Nuclear Information System (INIS)

Glushko, O.; Marx, V.M.; Kirchlechner, C.; Zizak, I.; Cordill, M.J.

2014-01-01

Substantial recovery (decrease) of electrical resistance during and after unloading is demonstrated for copper films on polyethylene terephthalate substrates subjected to a tensile strain with different peak values. Particularly, the films strained to 5% exhibit full resistance recovery after unloading despite clearly visible plastic deformation of the film. The recovery of electrical resistance in connection with the mechanical behavior of film/substrate couple is discussed with the help of in situ scanning electron microscopy and X-ray diffraction analysis. - Highlights: • Tensile tests on 200 nm Cu films on PET substrate are performed. • Electrical resistance is recorded in-situ during loading and unloading. • Significant recovery (decrease) of resistance is observed during and after unloading. • Films strained to 5% demonstrate full resistance recovery. • Viscoelastic relaxation of PET is responsible for recovery of Cu film resistance

Strain-dependent electrical resistance of multi-walled carbon nanotube/polymer composite films

International Nuclear Information System (INIS)

Park, Myounggu; Kim, Hyonny; Youngblood, Jeffrey P

2008-01-01

The strain-dependent electrical resistance characteristics of multi-walled carbon nanotube (MWCNT)/polymer composite films were investigated. In this research, polyethylene oxide (PEO) is used as the polymer matrix. Two representative volume fractions of MWCNT/PEO composite films were selected: 0.56 vol% (near the percolation threshold) and 1.44 vol% (away from the percolation threshold) of MWCNT. An experimental setup which can measure electrical resistance and strain simultaneously and continuously has been developed. Unique and repeatable relationships in resistance versus strain were obtained for multiple specimens with different volume fractions of MWCNT. The overall pattern of electrical resistance change versus strain for the specimens tested consists of linear and nonlinear regions. A resistance change model to describe the combination of linear and nonlinear modes of electrical resistance change as a function of strain is suggested. The unique characteristics in electrical resistance change for different volume fractions imply that MWCNT/PEO composite films can be used as tunable strain sensors and for application into embedded sensor systems in structures

Recrystallization behaviour and electrical properties of germanium ion implanted polycrystalline silicon films

International Nuclear Information System (INIS)

Kang, Myeon-Koo; Matsui, Takayuki; Kuwano, Hiroshi

1996-01-01

The recrystallization behaviour of undoped and phosphorus-doped polycrystalline silicon films amorphized by germanium ion implantation at doses ranging from 1 x 10 15 to 1 x 10 16 cm -2 are investigated, and the electrical properties of phosphorus-doped films after recrystallization are studied. The phosphorus doping concentration ranges from 3 x 10 18 to 1 x 10 20 cm -3 . It is found that the nucleation rate decreases for undoped films and increases for phosphorus-doped films with increasing germanium dose; the growth rates decrease for both doped and undoped films. The decrease in nucleation rate is caused by the increase in implantation damage. The decrease in growth rate is considered to be due to the increase in lattice strain. The grain size increases with germanium dose for undoped films, but decreases for phosphorus-doped films. The dependence of the electrical properties of the recrystallized films as a function of phosphorus doping concentration with different germanium doses can be explained in terms of the grain size, crystallinity and grain boundary barrier height. (Author)

Electrical Field Effect Dependence of Hall Constant in Bi-films

International Nuclear Information System (INIS)

Butenko, A. V.; Sandomirsky, V.; Schlesinger, Y.; Shvarts, Dm.

1998-01-01

The Electrical Field Effect (EFE) was investigated on the capacitive structure Aumica (ns 10 μm ) - Bi films (L ∼ 350≥≥500 angstrem) in the temperature region 15 - 100 K. The thicknesses of Bi films lay in the region of the Quantum Size Effect (QSE). The transverse electric fields reach the value of 106 V/cm. The corresponding surface carrier concentrations are ns ∼ 10 13 [e]/cm 2 , i.e. the average change of carrier concentration in the 500 angstrem film is n s /L ∼ 10 17 cm -3 . The latter value is comparable with the original carrier concentration in Bi film, 3 f 1017 cm-3. However, EEE, the film resistance change Δ R is 0.5 %. On the other hand EFE change of Hall constant (2ΔR H ), that was observed for the first time in this work, is 5 - 30 % (depending on the film thickness). These results point to a small carrier mobility and to an essential change of carrier concentration in the EEE influence region (of the order of the screening length). The interpretation takes into account both classical and quantum versions of Bi film behavior under EFE conditions. A procedure to determine the surface charge carrier mobilities and concentrations from EFE-data (both ΔR and ORE) is propose

Physical-mechanical and electrical properties of aluminium anodic films

Energy Technology Data Exchange (ETDEWEB)

Dima, L. [Research and Design Inst. for Electr. Eng., Bucharest (Romania); Anicai, L. [Research and Design Inst. for Electr. Eng., Bucharest (Romania)

1995-11-01

Mechanical, thermal and electrical properties of aluminium anodic films obtained by continuously anodization of Al wires of 4.5 mm diameter and Al sheets of 40 x 0.2 mm (Al min.99.5% purity), using an electrolyte based on oxalic acid, citric acid, boric acid, isopropilic alcohol, were investigated. The thickness of Al anodic oxide layers was 5 {+-} 1{mu}, 10 {+-} 1{mu}, for Al sheet, respectively 5 {+-} 1{mu}, 10 {+-} 1{mu}, 15 {+-} 1{mu}, for Al wire. To establish the influence of anodic film formation on mechanical parameters, measurements of breaking strength and relative elongation at break for anodized and non-anodized Al conductors, were made. In order to electrically characterize the anodic films, the breakdown voltage for different curvature radii of the conductor, between 50 - 12.5 mm, were measured. The influence of the layer thickness, as well as of the cracking during its bending, was established, too. To test the thermal resistance of the insulating anodic films, the Al conductors were subjected to 1 - 5 cyclic thermal shocks at 500 C. After the experimentals were done, it was found that Al anodic films of 5 {+-} 1{mu} may assure a breakdown voltage of minimum 200 V, for coils having a curvature radius greater than 12.5 mm and operating temperatures up to 500 C. From mechanical point of view, anodic oxide film determines a relatively reinforcing of Al conductor, but it doesn`t influence its functional properties. (orig.)

Electric-field effects in optically generated spin transport

International Nuclear Information System (INIS)

Miah, M. Idrish

2009-01-01

Transport of spin-polarized electrons in semiconductors is studied experimentally. Spins are generated by optical excitation because of the selection rules governing optical transitions from heavy-hole and light-hole states to conduction-band states. Experiments designed for the control of spins in semiconductors investigate the bias-dependent spin transport process and detect the spin-polarized electrons during transport. A strong bias dependence is observed. The electric-field effects on the spin-polarized electron transport are also found to be depended on the excitation photon energy and temperature. Based on a field-dependent spin relaxation mechanism, the electric-field effects in the transport process are discussed.

Electric-field effects in optically generated spin transport

Energy Technology Data Exchange (ETDEWEB)

Miah, M. Idrish [Nanoscale Science and Technology Centre and School of Biomolecular and Physical Sciences, Griffith University, Nathan, Brisbane, QLD 4111 (Australia); Department of Physics, University of Chittagong, Chittagong 4331 (Bangladesh)], E-mail: m.miah@griffith.edu.au

2009-05-25

Transport of spin-polarized electrons in semiconductors is studied experimentally. Spins are generated by optical excitation because of the selection rules governing optical transitions from heavy-hole and light-hole states to conduction-band states. Experiments designed for the control of spins in semiconductors investigate the bias-dependent spin transport process and detect the spin-polarized electrons during transport. A strong bias dependence is observed. The electric-field effects on the spin-polarized electron transport are also found to be depended on the excitation photon energy and temperature. Based on a field-dependent spin relaxation mechanism, the electric-field effects in the transport process are discussed.

Influence of Microstructure on the Electrical Properties of Heteroepitaxial TiN Films

Science.gov (United States)

Xiang, Wenfeng; Liu, Yuan; Zhang, Jiaqi

2018-03-01

Heteroepitaxial TiN films were deposited on Si substrates by pulse laser deposition at different substrate temperature. The microstructure and surface morphology of the films were investigated by X-ray diffraction (θ-2θ scan, ω-scan, and ϕ-scan) and atomic force microscopy. The electrical properties of the prepared TiN films were studied using a physical property measurement system. The experimental results showed that the crystallinity and surface morphology of the TiN films were improved gradually with increasing substrate temperature below 700 °C. Specially, single crystal TiN films were prepared when substrate temperature is above 700 °C; However, the quality of TiN films gradually worsened when the substrate temperature was increased further. The electrical properties of the films were directly correlated to their crystalline quality. At the optimal substrate temperature of 700 °C, the TiN films exhibited the lowest resistivity and highest mobility of 25.7 μΩ cm and 36.1 cm2/V s, respectively. In addition, the mechanism concerning the influence of substrate temperature on the microstructure of TiN films is discussed in detail.

An Electricity-Alcohol Transportation Strategy

Energy Technology Data Exchange (ETDEWEB)

Morris, David [Inst. for Local Self-Reliance, Minneapolis (United States)

2006-07-15

In the United States, a dual fuel system may be emerging as a consensus strategy for a rapid transition to an oil free transportation system. The energy source for the vehicles will be a combination of electricity and alcohols. The technology will be a plug-in hybrid electric vehicle whose batteries can be charged from the national grid system, and a backup flexible fueled engine, primarily fueled by alcohols.

Comparison on electrically pumped random laser actions of hydrothermal and sputtered ZnO films

International Nuclear Information System (INIS)

Wang, Canxing; Jiang, Haotian; Li, Yunpeng; Ma, Xiangyang; Yang, Deren

2013-01-01

Random lasing (RL) in polycrystalline ZnO films is an intriguing research subject. Here, we have comparatively investigated electrically pumped RL behaviors of two metal-insulator-semiconductor structured devices using the hydrothermal and sputtered ZnO films as the semiconductor components, i.e., the light-emitting layers, respectively. It is demonstrated that the device using the hydrothermal ZnO film exhibits smaller threshold current and larger output optical power of the electrically pumped RL. The morphological characterization shows that the hydrothermal ZnO film is somewhat porous and is much rougher than the sputtered one, suggesting that in the former stronger multiple light scattering can occur. Moreover, the photoluminescence characterization indicates that there are fewer defects in the hydrothermal ZnO film than in the sputtered one, which means that the photons can pick up larger optical gain through stimulated emission in the hydrothermal ZnO film. Therefore, it is believed that the stronger multiple light scattering and larger optical gain contribute to the improved performance of the electrically pumped RL from the device using the hydrothermal ZnO film

Li ion transport in sputter deposited LiCoO{sub 2} thin films and glassy borate membranes

Energy Technology Data Exchange (ETDEWEB)

Stockhoff, Tobias; Gallasch, Tobias; Schmitz, Guido [Westfaelische Wilhelms-Universitaet Muenster, Institut fuer Materialphysik, Muenster (Germany)

2010-07-01

LiCoO{sub 2} membranes are key components of current battery technology. We investigate sputter-deposited thin films of these materials aiming at the application in all-solid-state thin film batteries. For this, LiCoO{sub 2} films (10-200 nm) were deposited onto ITO-coated glass substrates by ion beam sputtering. In addition, a part of these films are coated by an ion-conductive membrane of Li{sub 2}O-B{sub 2}O{sub 3} glasses in the thickness range of 50 to 300 nm. Structural, chemical and electrical properties of the layers are studied by means of TEM(EELS) and various electrical methods (cyclic voltammetry, chrono-amperometry/-potentiometry). Since the color of the LiCoO{sub 2} films changes from red-brown to grey during de-intercalation of Li and the substrate as well as the glassy membrane deposited on top are optical transparent, reversible Li de- and intercalation can be directly demonstrated and quantified by a measurement of light transmission through the layered system. Samples coated with an ion-conductive membrane reveal a characteristic delay in switching optical transparency which is due to the slower transport across the membrane. Varying the thickness of the glassy membrane, the d.c. ion-conductivity and permeation through the membrane is determined quantitatively. Using thin membranes in the range of a few tens of nanometers the critical current densities are way sufficient for battery applications.

Influence of the linear magneto-electric effect on the lateral shift of light reflected from a magneto-electric film

International Nuclear Information System (INIS)

Dadoenkova, Yu S; Petrov, R V; Bichurin, M I; Bentivegna, F F L; Dadoenkova, N N; Lyubchanskii, I L

2016-01-01

We present a theoretical investigation of the lateral shift of an infrared light beam reflected from a magnetic film deposited on a non-magnetic dielectric substrate, taking into account the linear magneto-electric interaction in the magnetic film. We use the stationary phase method to evaluate the lateral shift. It is shown that the magneto-electric coupling leads to a six-fold enhancement of the lateral shift amplitude of a p-(s-) polarized incident beam reflected into a s-(p-) polarized beam. A reversal of the magnetization in the film leads to a nonreciprocal sign change of the lateral shift. (paper)

Strain-induced properties of epitaxial VOx thin films

NARCIS (Netherlands)

Rata, AD; Hibma, T

We have grown VOx thin films on different substrates in order to investigate the influence of epitaxial strain on the transport properties. We found that the electric conductivity is much larger for films grown under compressive strain on SrTiO3 substrates, as compared to bulk material and VOx films

Enhanced electrical properties in bilayered ferroelectric thin films

Science.gov (United States)

Zhang, Hao; Long, WeiJie; Chen, YaQing; Guo, DongJie

2013-03-01

Sr2Bi4Ti5O18 (SBTi) single layered and Sr2Bi4Ti5O18/Pb(Zr0.53Ti0.47)O3 (SBTi/PZT) bilayered thin films have been prepared on Pt/TiO2/SiO2/Si substrates by pulsed-laser deposition (PLD). The related structural characterizations and electrical properties have been comparatively investigated. X-ray diffraction reveals that both films have crystallized into perovskite phases and scanning electron microscopy shows the sharp interfaces. Both films show well-saturated ferroelectric hysteresis loops, however, compared with the single layered SBTi films, the SBTi/PZT bilayered films have significantly increased remnant polarization ( P r) and decreased coercive field ( E c), with the applied field of 260 kV/cm. The measured P r and E c of SBTi and SBTi/PZT films were 7.9 μC/cm2, 88.1 kV/cm and 13.0 μC/cm2, 51.2 kV/cm, respectively. In addition, both films showed good fatigue-free characteristics, the switchable polarization decreased by 9% and 11% of the initial values after 2.2×109 switching cycles for the SBTi single layered films and the SBTi/PZT bilayered films, respectively. Our results may provide some guidelines for further optimization of multilayered ferroelectric thin films.

Doping dependence of electrical and thermal conductivity of nanoscale polyaniline thin films

Energy Technology Data Exchange (ETDEWEB)

Jin Jiezhu; Wang Qing [Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 (United States); Haque, M A [Department of Mechanical and Nuclear Engineering, Pennsylvania State University, University Park, PA 16802 (United States)

2010-05-26

We performed simultaneous characterization of electrical and thermal conductivity of 55 nm thick polyaniline (PANI) thin films doped with different levels of camphor sulfonic acids (CSAs). The effect of the doping level is more pronounced on electrical conductivity than on thermal conductivity of PANIs, thereby greatly affecting their ratio that determines the thermoelectric efficiency. At the 60% (the molar ratio of CSA to phenyl-N repeat unit of PANI) doping level, PANI exhibited the maximum electrical and thermal conductivity due to the formation of mostly delocalized structures. Whereas polarons are the charge carriers responsible for the electrical conduction, phonons are believed to play a dominant role in the heat conduction in nanoscale doped PANI thin films.

Interactions between Radial Electric Field, Transport and Structure in Helical Plasmas

International Nuclear Information System (INIS)

Ida, Katsumi and others

2006-01-01

Control of the radial electric field is considered to be important in helical plasmas, because the radial electric field and its shear are expected to reduce neoclassical and anomalous transport, respectively. Particle and heat transport, that determines the radial structure of density and electron profiles, sensitive to the structure of radial electric field. On the other hand, the radial electric field itself is determined by the plasma parameters. In general, the sign of the radial electric field is determined by the plasma collisionality, while the magnitude of the radial electric field is determined by the temperature and/or density gradients. Therefore the structure of radial electric field and temperature and density are strongly coupled through the particle and heat transport and formation mechanism of radial electric field. Interactions between radial electric field, transport and structure in helical plasmas is discussed based on the experiments on Large Helical Device

Solution processable semiconductor thin films: Correlation between morphological, structural, optical and charge transport properties

Science.gov (United States)

Isik, Dilek

This Ph.D. thesis is a result of multidisciplinary research bringing together fundamental concepts in thin film engineering, materials science, materials processing and characterization, electrochemistry, microfabrication, and device physics. Experiments were conducted by tackling scientific problems in the field of thin films and interfaces, with the aim to correlate the morphology, crystalline structure, electronic structure of thin films with the functional properties of the films and the performances of electronic devices based thereon. Furthermore, novel strategies based on interfacial phenomena at electrolyte/thin film interfaces were explored and exploited to control the electrical conductivity of the thin films. Three main chemical systems were the object of the studies performed during this Ph.D., two types of organic semiconductors (azomethine-based oligomers and polymers and soluble pentacene derivatives) and one metal oxide semiconductor (tungsten trioxide, WO3). To explore the morphological properties of the thin films, atomic force microscopy was employed. The morphological properties were further investigated by hyperspectral fluorescence microscopy and tentatively correlated to the charge transport properties of the films. X-ray diffraction (Grazing incidence XRD, GIXRD) was used to investigate the crystallinity of the film and the effect of the heat treatment on such crystallinity, as well as to understand the molecular arrangement of the organic molecules in the thin film. The charge transport properties of the films were evaluated in thin film transistor configuration. For electrolyte gated thin film transistors, time dependent transient measurements were conducted, in parallel to more conventional transistor characterizations, to explore the specific effects played on the gating by the anion and cation constituting the electrolyte. The capacitances of the electrical double layers at the electrolyte/WO3 interface were obtained from

Low-temperature transport in ultra-thin tungsten films

Energy Technology Data Exchange (ETDEWEB)

Chiatti, Olivio [Neue Materialien, Institut fuer Physik, Humboldt-Univ. Berlin (Germany); London Centre for Nanotechnology, University College London (United Kingdom); Nash, Christopher; Warburton, Paul [London Centre for Nanotechnology, University College London (United Kingdom)

2012-07-01

Tungsten-containing films, fabricated by focused-ion-beam-induced chemical vapour deposition, are known to have an enhanced superconducting transition temperature compared to bulk tungsten, and have been investigated previously for film thickness down to 25 nm. In this work, by using ion-beam doses below 50 pC/{mu}m{sup 2} on a substrate of amorphous silicon, we have grown continuous films with thickness below 20 nm. The electron transport properties were investigated at temperatures down to 350 mK and in magnetic fields up to 3 T, parallel and perpendicular to the films. The films in this work are closer to the limit of two-dimensional systems and are superconducting at low temperatures. Magnetoresistance measurements yield upper critical fields of the order of 1 T, and the resulting coherence length is smaller than the film thickness.

An international perspective on electric transportation. Survey on electric road transport 2012

Energy Technology Data Exchange (ETDEWEB)

Weeda, M; Kroon, P [ECN Policy Studies, Petten (Netherlands); Appels, D [Agentschap NL, Utrecht (Netherlands)

2012-09-15

To compare the Dutch governmental efforts and developments in the field of electric road transport, the Ministry of Economic Affairs, Agriculture and Innovation has asked ECN Policy Studies and NL Agency to conduct an international assessment on electric mobility. The countries that have been considered are: Austria, Belgium, Denmark, France, Germany, the Netherlands, Norway, Portugal, Spain, UK, China, USA and South Korea. The Netherlands has a high ambition level with regard to the number of electric vehicles and is one of the leaders as for the envisaged number of charging points. In the field of R and D, Germany, South Korea and China take the lead, followed by France, the UK, the USA and Austria. However, the assessment has only looked at specific funds for electric mobility, and has not looked at general R and D and innovation funds. The Netherlands has several electro-mobility field tests, but is not leading in number. Norway and Austria are leading countries when it comes to implementation of public charging infrastructure.

Aquatic biofouling prevention by electrically charged nanocomposite polymer thin film membranes.

Science.gov (United States)

de Lannoy, Charles-François; Jassby, David; Gloe, Katie; Gordon, Alexander D; Wiesner, Mark R

2013-03-19

Electrically conductive polymer-nanocomposite (ECPNC) tight nanofiltration (NF) thin film membranes were demonstrated to have biofilm-preventing capabilities under extreme bacteria and organic material loadings. A simple route to the creation and application of these polyamide-carbon nanotube thin films is also reported. These thin films were characterized with SEM and TEM as well as FTIR to demonstrate that the carbon nanotubes are embedded within the polyamide and form ester bonds with trimesoyl chloride, one of the monomers of polyamide. These polymer nanocomposite thin film materials boast high electrical conductivity (∼400 S/m), good NaCl rejection (>95%), and high water permeability. To demonstrate these membranes' biofouling capabilities, we designed a cross-flow water filtration vessel with insulated electrical leads connecting the ECPNC membranes to an arbitrary waveform generator. In all experiments, conducted in highly bacterially contaminated LB media, flux tests were run until fluxes decreased by 45 ± 3% over initial flux. Biofilm-induced, nonreversible flux decline was observed in all control experiments and a cross-flow rinse with the feed solution failed to induce flux recovery. In contrast, flux decrease for the ECPNC membranes with an electric potential applied to their surface was only caused by deposition of bacteria rather than bacterial attachment, and flux was fully recoverable following a short rinse with the feed solution and no added cleaning agents. The prevention of biofilm formation on the ECPNC membranes was a long-term effect, did not decrease with use, and was highly reproducible.

City electric transport preferences and motives of the Russian students

Science.gov (United States)

Romanova, Elena

2017-10-01

The share of electric transport in Russia is very small. Many cities refuse operation of urban electric passenger transportation. Basic reasons of it are high cost value and expensive operation. In Moscow the emphasis is placed on development of rail electric transport. It provides fast movement and pollutes the city environment less. The Moscow students understand that for an urban transportation ecological compatibility and safety are important but they choose buses and individual cars with the internal combustion engine for daily use. The main criteria of the choice are the speed and comfort. Ecological compatibility of the individual transport costs on one of the last places.

Logistic characteristics of phonon transport in silicon thin film: the S-curve

Energy Technology Data Exchange (ETDEWEB)

Yilbas, B.S., E-mail: bsyilbas@kfupm.edu.sa; Mansoor, S. Bin

2013-10-01

The logistic characteristics of the averaged heat flux are investigated across the thin film incorporating the S-curve. Temporal behaviour of the heat flux vector is computed using the Boltzmann transport equation. The dispersion relations are introduced to account for the frequency dependent phonon transport across the film. The influence of film width on the characteristics of the averaged heat flux is also examined. It is found that temporal behaviour of the averaged heat flux follows the S-curve. The S-curve characteristics change for different film widths. The time to reach 95% steady value of the averaged heat flux is short for the film with small widths, which is attributed to the ballistic behaviour of phonons in the film.

Logistic characteristics of phonon transport in silicon thin film: the S-curve

International Nuclear Information System (INIS)

Yilbas, B.S.; Mansoor, S. Bin

2013-01-01

The logistic characteristics of the averaged heat flux are investigated across the thin film incorporating the S-curve. Temporal behaviour of the heat flux vector is computed using the Boltzmann transport equation. The dispersion relations are introduced to account for the frequency dependent phonon transport across the film. The influence of film width on the characteristics of the averaged heat flux is also examined. It is found that temporal behaviour of the averaged heat flux follows the S-curve. The S-curve characteristics change for different film widths. The time to reach 95% steady value of the averaged heat flux is short for the film with small widths, which is attributed to the ballistic behaviour of phonons in the film

Structural and electrical properties of CuAlMo thin films prepared by magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Birkett, Martin, E-mail: martin.birkett@northumbria.ac.uk; Penlington, Roger; Wan, Chaoying; Zoppi, Guillaume

2013-07-01

The structural and electrical properties of a low resistivity CuAlMo thin film resistor material were investigated. The thin films were grown on Al{sub 2}O{sub 3} and glass substrates by direct current (dc) magnetron sputtering. The key electrical properties of sheet resistance, temperature coefficient of resistance (TCR) and resistance stability were investigated as a function of sputtering pressure and post-deposition heat treatment time and temperature. A low sputtering pressure range of 0.13 to 0.40 Pa produced CuAlMo films with sheet resistance in the range 0.1 to 0.2 Ω/□ and resistance stability of 0.45 to 0.65% with a TCR of − 90 ppm/°C which could be shifted to zero following annealing in air at 425 °C. Films grown at higher sputtering pressures of 0.53 to 0.80 Pa had increased sheet resistance in the range 0.4 to 0.6 Ω/□ and inferior stability of 0.8 to 1.7% with a more negative TCR of − 110 to − 180 ppm/°C which could not be shifted to zero following annealing. The stability of the films grown at 0.13 and 0.40 Pa could be further improved to < 0.25% with heat treatment, due to the formation of a protective aluminium oxide layer. A minimum dwell time of 3 h at 425 °C was required to stabilise the films and set the electrical properties. - Highlights: • Thin films of copper–aluminium–molybdenum were sputtered on alumina substrates. • Film properties were investigated with variation in process conditions. • Low sputtering pressure gave improved electrical performance. • Post deposition annealing in air further improved electrical performance.

Structural and electrical properties of CuAlMo thin films prepared by magnetron sputtering

International Nuclear Information System (INIS)

Birkett, Martin; Penlington, Roger; Wan, Chaoying; Zoppi, Guillaume

2013-01-01

The structural and electrical properties of a low resistivity CuAlMo thin film resistor material were investigated. The thin films were grown on Al 2 O 3 and glass substrates by direct current (dc) magnetron sputtering. The key electrical properties of sheet resistance, temperature coefficient of resistance (TCR) and resistance stability were investigated as a function of sputtering pressure and post-deposition heat treatment time and temperature. A low sputtering pressure range of 0.13 to 0.40 Pa produced CuAlMo films with sheet resistance in the range 0.1 to 0.2 Ω/□ and resistance stability of 0.45 to 0.65% with a TCR of − 90 ppm/°C which could be shifted to zero following annealing in air at 425 °C. Films grown at higher sputtering pressures of 0.53 to 0.80 Pa had increased sheet resistance in the range 0.4 to 0.6 Ω/□ and inferior stability of 0.8 to 1.7% with a more negative TCR of − 110 to − 180 ppm/°C which could not be shifted to zero following annealing. The stability of the films grown at 0.13 and 0.40 Pa could be further improved to < 0.25% with heat treatment, due to the formation of a protective aluminium oxide layer. A minimum dwell time of 3 h at 425 °C was required to stabilise the films and set the electrical properties. - Highlights: • Thin films of copper–aluminium–molybdenum were sputtered on alumina substrates. • Film properties were investigated with variation in process conditions. • Low sputtering pressure gave improved electrical performance. • Post deposition annealing in air further improved electrical performance

Polarization of electron-beam irradiated LDPE films: contribution to charge generation and transport

Science.gov (United States)

Banda, M. E.; Griseri, V.; Teyssèdre, G.; Le Roy, S.

2018-04-01

Electron-beam irradiation is an alternative way to generate charges in insulating materials, at controlled position and quantity, in order to monitor their behaviour in regard to transport phenomena under the space charge induced electric field or external field applied. In this study, low density polyethylene (LDPE) films were irradiated by a 80 keV electron-beam with a flux of 1 nA cm‑2 during 10 min in an irradiation chamber under vacuum conditions, and were then characterized outside the chamber using three experimental methods. The electrical behaviour of the irradiated material was assessed by space charge measurements using the pulsed electro-acoustic (PEA) method under dc stress. The influence of the applied electric field polarity and amplitude has been tested in order to better understand the charge behaviour after electron-beam irradiation. Fourier transform infra-red spectroscopy (FTIR) and photoluminescence (PL) measurements were performed to evaluate the impact of the electron beam irradiation, i.e. deposited charges and energy, on the chemical structure of the irradiated samples. The present results show that the electrical behaviour in LDPE after irradiation is mostly driven by charges, i.e. by physical process functions of the electric field, and that changes in the chemical structure seems to be mild.

Physical and electrical characteristics of silicon oxynitride films with various refractive indices

Energy Technology Data Exchange (ETDEWEB)

Liao, Jeng-Hwa; Hsieh, Jung-Yu; Lin, Hsing-Ju; Tang, Wei-Yao; Chiang, Chun-Ling; Yang, Ling-Wu; Yang, Tahone; Chen, Kuang-Chao; Lu, Chih-Yuan [Macronix International Co. Ltd, No 16, Li-Hsin Road, Hsinchu Science Park, Hsinchu 300, Taiwan (China); Lo, Yun-Shan; Wu, Tai-Bor, E-mail: jhliao@mxic.com.t [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300, Taiwan (China)

2009-09-07

This study explores the relationship between both the physical and the electrical characteristics of silicon oxynitride (SiON) films and the refractive index. The single wafer rapid thermal process modules were used for low pressure chemical vapour deposition of SiON films. A series of SiON films with refractive index between 1.50 and 1.83 were fabricated. Fourier transform infrared absorption spectroscopy and x-ray photoelectron spectroscopy identified the chemical bonding configurations of different SiON films: the Si-N bonds are replaced by Si-O bonds as the refractive index of the SiON films declines. Moreover, the Si atomic ratio is kept between 35% and 40% while the oxygen atomic ratio increases and the nitrogen atomic ratio decreases as the refractive index of the SiON film declines. The electrical characteristics of different SiON-based silicon-oxide-nitride-oxide-silicon (SONOS) devices suggest that (1) the dielectric constant increases with increasing refractive index of the SiON film and (2) the charge-trap density is inversely proportional to the oxygen concentration in the SiON film. Based on these results, the SiON films with various refractive indices can provide a wider application for silicon-based devices, such as SONOS and MOS devices.

Physical and electrical characteristics of silicon oxynitride films with various refractive indices

International Nuclear Information System (INIS)

Liao, Jeng-Hwa; Hsieh, Jung-Yu; Lin, Hsing-Ju; Tang, Wei-Yao; Chiang, Chun-Ling; Yang, Ling-Wu; Yang, Tahone; Chen, Kuang-Chao; Lu, Chih-Yuan; Lo, Yun-Shan; Wu, Tai-Bor

2009-01-01

This study explores the relationship between both the physical and the electrical characteristics of silicon oxynitride (SiON) films and the refractive index. The single wafer rapid thermal process modules were used for low pressure chemical vapour deposition of SiON films. A series of SiON films with refractive index between 1.50 and 1.83 were fabricated. Fourier transform infrared absorption spectroscopy and x-ray photoelectron spectroscopy identified the chemical bonding configurations of different SiON films: the Si-N bonds are replaced by Si-O bonds as the refractive index of the SiON films declines. Moreover, the Si atomic ratio is kept between 35% and 40% while the oxygen atomic ratio increases and the nitrogen atomic ratio decreases as the refractive index of the SiON film declines. The electrical characteristics of different SiON-based silicon-oxide-nitride-oxide-silicon (SONOS) devices suggest that (1) the dielectric constant increases with increasing refractive index of the SiON film and (2) the charge-trap density is inversely proportional to the oxygen concentration in the SiON film. Based on these results, the SiON films with various refractive indices can provide a wider application for silicon-based devices, such as SONOS and MOS devices.

Electrical properties of ZnO thin films grown by MOCVD

Energy Technology Data Exchange (ETDEWEB)

Pagni, O. [Department of Physics, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa); Somhlahlo, N.N. [Department of Physics, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa); Weichsel, C. [Department of Physics, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa); Leitch, A.W.R. [Department of Physics, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa)]. E-mail: andrew.leitch@nmmu.ac.za

2006-04-01

We report on the electrical characterization of ZnO films grown by MOCVD on glass and sapphire substrates. After correcting our temperature variable Hall measurements by applying the standard two-layer model, which takes into account an interfacial layer, scattering mechanisms in the ZnO films were studied as well as donor activation energies determined. ZnO films grown at different oxygen partial pressures indicated the importance of growth conditions on the defect structure by means of their conductivities and conductivity activation energies.

Electrical properties of ZnO thin films grown by MOCVD

International Nuclear Information System (INIS)

Pagni, O.; Somhlahlo, N.N.; Weichsel, C.; Leitch, A.W.R.

2006-01-01

We report on the electrical characterization of ZnO films grown by MOCVD on glass and sapphire substrates. After correcting our temperature variable Hall measurements by applying the standard two-layer model, which takes into account an interfacial layer, scattering mechanisms in the ZnO films were studied as well as donor activation energies determined. ZnO films grown at different oxygen partial pressures indicated the importance of growth conditions on the defect structure by means of their conductivities and conductivity activation energies

Enhanced and tunable electric dipole-dipole interactions near a planar metal film

Science.gov (United States)

Zhou, Lei-Ming; Yao, Pei-Jun; Zhao, Nan; Sun, Fang-Wen

2017-08-01

We investigate the enhanced electric dipole-dipole interaction of surface plasmon polaritons (SPPs) supported by a planar metal film waveguide. By taking two nitrogen-vacancy (NV) center electric dipoles in diamond as an example, both the coupling strength and collective relaxation of two dipoles are studied with the numerical Green Function method. Compared to two-dipole coupling on a planar surface, metal film provides stronger and tunable coupling coefficients. Enhancement of the interaction between coupled NV center dipoles could have applications in both quantum information and energy transfer investigation. Our investigation provides systematic results for experimental applications based on a dipole-dipole interaction mediated with SPPs on a planar metal film.

Electric-field-induced monoclinic phase in (Ba,Sr)TiO3 thin film

International Nuclear Information System (INIS)

Anokhin, A. S.; Yuzyuk, Yu. I.; Golovko, Yu. I.; Mukhortov, V. M.; El Marssi, M.

2011-01-01

We have studied electric-field-induced symmetry lowering in the tetragonal (001)-oriented heteroepitaxial (Ba 0.8 Sr 0.2 )TiO 3 thin film deposited on (001)MgO substrate. Polarized micro-Raman spectra were recorded from the film area in between two planar electrodes deposited on the film surface. Presence of c domains with polarization normal to the substrate was confirmed from polarized Raman study under zero field, while splitting and hardening of the E(TO) soft mode and polarization changes in the Raman spectra suggest monoclinic symmetry under external electric field.

Optical Absorption and Electric Resistivity of an l-Cysteine Film

Science.gov (United States)

Kamada, Masao; Hideshima, Takuya; Azuma, Junpei; Yamamoto, Isamu; Imamura, Masaki; Takahashi, Kazutoshi

2016-12-01

The optical and electric properties of an l-cysteine film have been investigated to understand its applicability to bioelectronics. The fundamental absorption is the allowed transition having the threshold at 5.8 eV and the absorption is due to the charge-transfer type transition from sulfur-3sp to oxygen-2p and/or carbon-2p states, while absorptions more than 9 eV can be explained with intra-atomic transitions in the functional groups. The electric resistivity is 2.0 × 104 Ω m at room temperature and increases as the sample temperature decreases. The results indicate that the l-cysteine film is a p-type semiconductor showing the hole conduction caused by the sulfur-3sp occupied states and unknown impurity or defect states as acceptors. The electron affinity of the l-cysteine film is derived as ≦-0.3 eV.

Electrical resistivity due to electron-phonon scattering in thin gadolinium films

International Nuclear Information System (INIS)

Urbaniak-Kucharczyk, A.

1988-01-01

The contribution to the electrical resistivity due to the electron-phonon scattering for the special case of h.c.p. structure is derived. The numerical results obtained for the case of polycrystalline gadolinum films show the resistivity dependence on the film thickness and the surface properties. (author)

Electrical and optical properties of Zn–In–Sn–O transparent conducting thin films

International Nuclear Information System (INIS)

Carreras, Paz; Antony, Aldrin; Rojas, Fredy; Bertomeu, Joan

2011-01-01

Indium tin oxide (ITO) is one of the widely used transparent conductive oxides (TCO) for application as transparent electrode in thin film silicon solar cells or thin film transistors owing to its low resistivity and high transparency. Nevertheless, indium is a scarce and expensive element and ITO films require high deposition temperature to achieve good electrical and optical properties. On the other hand, although not competing as ITO, doped Zinc Oxide (ZnO) is a promising and cheaper alternative. Therefore, our strategy has been to deposit ITO and ZnO multicomponent thin films at room temperature by radiofrequency (RF) magnetron co-sputtering in order to achieve TCOs with reduced indium content. Thin films of the quaternary system Zn–In–Sn–O (ZITO) with improved electrical and optical properties have been achieved. The samples were deposited by applying different RF powers to ZnO target while keeping a constant RF power to ITO target. This led to ZITO films with zinc content ratio varying between 0 and 67%. The optical, electrical and morphological properties have been thoroughly studied. The film composition was analysed by X-ray Photoelectron Spectroscopy. The films with 17% zinc content ratio showed the lowest resistivity (6.6 × 10 −4 Ω cm) and the highest transmittance (above 80% in the visible range). Though X-ray Diffraction studies showed amorphous nature for the films, using High Resolution Transmission Electron Microscopy we found that the microstructure of the films consisted of nanometric crystals embedded in a compact amorphous matrix. The effect of post deposition annealing on the films in both reducing and oxidizing atmospheres were studied. The changes were found to strongly depend on the zinc content ratio in the films.

Structural, optical and electrical characterization of vacuum-evaporated nanocrystalline CdSe thin films for photosensor applications

Energy Technology Data Exchange (ETDEWEB)

Kumar, Vipin; Sharma, D.K.; Sharma, Kapil [Krishna Institute of Engineering and Technology, Department of Physics, Ghaziabad (India); Dwivedi, D.K. [M.M.M University of Technology, Department of Physics, Gorakhpur (India)

2016-11-15

II-VI nanocrystalline semiconductors offer a wide range of applications in electronics, optoelectronics and photonics. Thin films of CdSe were deposited onto ultra-clean glass substrates by vacuum evaporation method. The as-deposited films were annealed in vacuum at 350 K. The structural, elemental, morphological, optical and electrical investigations of annealed films were carried out. The X-ray diffraction pattern of the films shows that films were polycrystalline in nature having hexagonal structure with preferential orientation of grains along (002) plane. SEM image indicates that the films were uniform and well covered to the glass substrate. EDAX analysis confirms the stoichiometric composition of the film. Raman spectra were used to observe the characteristic vibrational modes of CdSe. The energy band gap of these films was obtained by absorption spectra. The films were found to have a direct type of transition of band gap occurring at 1.75 eV. The dark electrical conductivity and photoconductivity reveals that the films were semiconducting in nature indicating the suitability of these films for photosensor applications. The Hall effect measurement reveals that the films have n-type electrical conductivity. (orig.)

Influence of the electric polarization on carrier transport and recombinaton dynamics in ZnO-based heterostructures

Energy Technology Data Exchange (ETDEWEB)

Brandt, Matthias

2010-08-16

The present thesis deals with the influence of the electric polarization on properties of free carriers in ZnO-based semiconductor heterostructures. Thereby especially transport properties of free carriers as well as their recombination dynamics are studied. The thesis treats four main topics. The first main topic lies on the phsical properties of the applied materials, here the connection of the band gap and the lattice constant of thin Mg{sub x}Zn{sub 1-x}O films and their magnesium content is described. Furthermore the morphology of such films is discussed. Different substrates and deposition conditions are thereby detailedly considered. The second main topic treats the properties of undoped and phosphorus doped thin ZnO and Mg{sub x}Zn{sub 1-x}O films. The structural, transport, and luminescence properties are here compared and conclusions drawn on the growth conditions. In the third main topic quantum effects on ZnO/Mg{sub x}Zn{sub 1-x}O interfaces are treated. Hereby especially the influence of the electric polarization is considered. The presence of a two-dimensional electron gas is proved, and the necessary conditions for the generation of the so-called confined Stark effect are explained. Especially the growth-relevant parameters are considered. The fourth main topic represent coupling phenomena in ZnO/BaTiO{sub 3} heterostructures. Thereby first the experimentally observed properties of different heterostructures are shown, which were grown on different substrates. Here structural and transport properties hold the spotlight. A model for the description of the formation of space-charge zones in such heterostructures is introduced and applied for the description of the experimental results. The usefulness of the ferroelectric properties of the material BaTiO{sub 3} in combination with semiconducting ZnO were studied. For this ferroelectric field effect transistors were fabricated under application of both materials. The principle suitedness of the

Electrically insulating films deposited on V-4%Cr-4%Ti by reactive CVD

International Nuclear Information System (INIS)

Park, J.H.

1998-04-01

In the design of liquid-metal blankets for magnetic fusion reactors, corrosion resistance of structural materials and the magnetohydrodynamic forces and their influence on thermal hydraulics and corrosion are major concerns. Electrically insulating CaO films deposited on V-4%Cr-4%Ti exhibit high-ohmic insulator behavior even though a small amount of vanadium from the alloy become incorporated into the film. However, when vanadium concentration in the film is > 15 wt.%, the film becomes conductive. When the vanadium concentration is high in localized areas, a calcium vanadate phase that exhibits semiconductor behavior can form. The objective of this study is to evaluate electrically insulating films that were deposited on V-4%Cr-4%Ti by a reactive chemical vapor deposition (CVD) method. To this end, CaO and Ca-V-O coatings were produced on vanadium alloys by CVD and by a metallic-vapor process to investigate the electrical resistance of the coatings. The authors found that the Ca-V-O films exhibited insulator behavior when the ratio of calcium concentration to vanadium concentration R in the film > 0.9, and semiconductor or conductor behavior when R 0.98 were exposed in liquid lithium. Based on these studies, they conclude that semiconductor behavior occurs if a conductive calcium vanadate phase is present in localized regions in the CaO coating

Thermoelectric Transport by Surface States in Bi2Se3-Based Topological Insulator Thin Films

International Nuclear Information System (INIS)

Li Long-Long; Xu Wen

2015-01-01

We develop a tractable theoretical model to investigate the thermoelectric (TE) transport properties of surface states in topological insulator thin films (TITFs) of Bi 2 Se 3 at room temperature. The hybridization between top and bottom surface states in the TITF plays a significant role. With the increasing hybridization-induced surface gap, the electrical conductivity and electron thermal conductivity decrease while the Seebeck coefficient increases. This is due to the metal-semiconductor transition induced by the surface-state hybridization. Based on these TE transport coefficients, the TE figure-of-merit ZT is evaluated. It is shown that ZT can be greatly improved by the surface-state hybridization. Our theoretical results are pertinent to the exploration of the TE transport properties of surface states in TITFs and to the potential application of Bi 2 Se 3 -based TITFs as high-performance TE materials and devices. (paper)

Structure, electrical characteristics, and high-temperature stability of aerosol jet printed silver nanoparticle films

Energy Technology Data Exchange (ETDEWEB)

Rahman, Md Taibur; McCloy, John; Panat, Rahul, E-mail: rahul.panat@wsu.edu, E-mail: rvchintalapalle@utep.edu [School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99163 (United States); Ramana, C. V., E-mail: rahul.panat@wsu.edu, E-mail: rvchintalapalle@utep.edu [Department of Mechanical Engineering, University of Texas at El Paso, El Paso, Texas 79968 (United States)

2016-08-21

Printed electronics has emerged as a versatile eco-friendly fabrication technique to create sintered nanoparticle (NP) films on arbitrary surfaces with an excellent control over the film microstructure. While applicability of such films for high-temperature applications is not explored previously, herein we report the high-temperature electrical stability of silver (Ag) metal NP films fabricated using an Aerosol Jet based printing technique and demonstrate that this behavior is dictated by changes in the film microstructure. In-situ high temperature (24–500 °C) impedance spectroscopy measurements show that the real part of the impedance increases with increasing temperature up to 150 °C, at which point a decreasing trend prevails until 300 °C, followed again by an increase in impedance. The electrical behavior is correlated with the in-situ grain growth of the Ag NP films, as observed afterwards by scanning electron microscopy and X-ray diffraction (XRD), and could be tailored by controlling the initial microstructure through sintering conditions. Using combined diffraction and spectroscopic analytical methods, it is demonstrated the Aerosol Jet printed Ag NP films exhibit enhanced thermal stability and oxidation resistance. In addition to establishing the conditions for stability of Ag NP films, the results provide a fundamental understanding of the effect of grain growth and reduction in grain boundary area on the electrical stability of sintered NP films.

Structure, electrical characteristics, and high-temperature stability of aerosol jet printed silver nanoparticle films

International Nuclear Information System (INIS)

Rahman, Md Taibur; McCloy, John; Panat, Rahul; Ramana, C. V.

2016-01-01

Printed electronics has emerged as a versatile eco-friendly fabrication technique to create sintered nanoparticle (NP) films on arbitrary surfaces with an excellent control over the film microstructure. While applicability of such films for high-temperature applications is not explored previously, herein we report the high-temperature electrical stability of silver (Ag) metal NP films fabricated using an Aerosol Jet based printing technique and demonstrate that this behavior is dictated by changes in the film microstructure. In-situ high temperature (24–500 °C) impedance spectroscopy measurements show that the real part of the impedance increases with increasing temperature up to 150 °C, at which point a decreasing trend prevails until 300 °C, followed again by an increase in impedance. The electrical behavior is correlated with the in-situ grain growth of the Ag NP films, as observed afterwards by scanning electron microscopy and X-ray diffraction (XRD), and could be tailored by controlling the initial microstructure through sintering conditions. Using combined diffraction and spectroscopic analytical methods, it is demonstrated the Aerosol Jet printed Ag NP films exhibit enhanced thermal stability and oxidation resistance. In addition to establishing the conditions for stability of Ag NP films, the results provide a fundamental understanding of the effect of grain growth and reduction in grain boundary area on the electrical stability of sintered NP films.

Structure, electrical characteristics, and high-temperature stability of aerosol jet printed silver nanoparticle films

Science.gov (United States)

Rahman, Md Taibur; McCloy, John; Ramana, C. V.; Panat, Rahul

2016-08-01

Printed electronics has emerged as a versatile eco-friendly fabrication technique to create sintered nanoparticle (NP) films on arbitrary surfaces with an excellent control over the film microstructure. While applicability of such films for high-temperature applications is not explored previously, herein we report the high-temperature electrical stability of silver (Ag) metal NP films fabricated using an Aerosol Jet based printing technique and demonstrate that this behavior is dictated by changes in the film microstructure. In-situ high temperature (24-500 °C) impedance spectroscopy measurements show that the real part of the impedance increases with increasing temperature up to 150 °C, at which point a decreasing trend prevails until 300 °C, followed again by an increase in impedance. The electrical behavior is correlated with the in-situ grain growth of the Ag NP films, as observed afterwards by scanning electron microscopy and X-ray diffraction (XRD), and could be tailored by controlling the initial microstructure through sintering conditions. Using combined diffraction and spectroscopic analytical methods, it is demonstrated the Aerosol Jet printed Ag NP films exhibit enhanced thermal stability and oxidation resistance. In addition to establishing the conditions for stability of Ag NP films, the results provide a fundamental understanding of the effect of grain growth and reduction in grain boundary area on the electrical stability of sintered NP films.

Electrical and optical properties of CZTS thin films prepared by SILAR method

Directory of Open Access Journals (Sweden)

J. Henry

2016-03-01

Full Text Available In the present work, Cu2ZnSnS4 (CZTS thin film was deposited onto the glass substrate by simple and economic SILAR method and its structural, morphological, optical and electrical properties were analyzed. X-ray diffraction (XRD analysis confirms the formation of CZTS with kesterite structure and the average crystallite size is found to be 142 nm. Scanning electron microscope (SEM image shows that the film has homogeneous, agglomerated surface without any cracks. The prepared CZTS film shows good optical absorption (104 cm−1 in the visible region and the optical band gap energy is found to be quite close to the optimum value of about 1.54 eV for solar cell application. The refractive index of the prepared film is found to be 2.85. The electrical resistivity of the film is found to be ∼10−2 Ω cm at room temperature.

Mechanical and electrical properties of diamond-like carbon films deposited by plasma source ion implantation

International Nuclear Information System (INIS)

Baba, K.; Hatada, R.; Flege, S.; Ensinger, W.

2009-01-01

Diamond-like carbon (DLC) films were prepared by a plasma source ion implantation method with superposed negative pulse and negative DC voltage. Acetylene gas was used as working gas for plasma formation. A negative DC voltage and a negative pulse voltage were superposed and applied to the substrate holder. The DC voltage was changed in the range from 0 to -4.8 kV and the pulse voltage was changed from -18 to -13.2 kV. The films were annealed in the range of 200-450 deg. C for 1 h. The surface morphology of the films and the film thickness were observed by atomic force microscopy and scanning electron microscopy. The film structure was characterized by Raman spectroscopy. The hardness of DLC films was evaluated by an indentation method. Measurement of the electrical resistivity was performed using a four-point probe station. Furthermore, a ball-on-disc test with 2 N load was employed to obtain information about the friction properties and sliding wear resistance of the films. The surface of the DLC films was very smooth and featureless. The deposition rate was changed with the DC voltage and pulse conditions. Integrated intensity ratios I D /I G of Raman spectroscopy and electrical resistivity of the DLC films changed with DC voltage. The electrical resistivity decreased with increasing I D /I G ratio. The I D /I G ratio was increased and the electrical resistivity was decreased with annealing temperature owing to graphitization. Very low friction coefficients around 0.05 were obtained for as-deposited films.

Graphene derivatives/Fe_3O_4/polymer nanocomposite films: Optical and electrical properties

International Nuclear Information System (INIS)

Hatel, Rhizlane; Goumri, Meryem; Ratier, Bernard; Baitoul, Mimouna

2017-01-01

This paper reports a simple solution casting method for the preparation of nanocomposite films in which graphene oxide (GO)/Fe_3O_4 nanocomposites are incorporated into poly (vinyl alcohol) (PVA) matrix. The films obtained with different weight percent of GO/Fe_3O_4 (0.5, 0.7 and 1 wt%) are subjected an in situ chemical and thermal reduction in order to explore the evolution and interactions between these components under different treatments and get an insight into on how this can affects the optical and electrical properties of these nanocomposites. Characterization was carried out using, UV–Vis absorption, Photoluminescence, electrical conductivity measurements, Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy. Strong covalent functionalization occurs between the polymer and graphene derivatives (GD)/Fe_3O_4 hybrids. The experimental results obtained for our nanocomposites films exhibit significant enhancement in properties highlighted the efficiency of the in situ thermal reduction. The high absorption with strong photoluminescence and electrical conductivity achieved might promote these nanocomposites for opto-electronic devices in near future. - Highlights: • Novel inorganic-organic hybrid flexible films were successfully prepared. • Good interfacial interaction between the graphene/Fe_3O_4 and the hydroxyl-rich PVA. • Optical and electrical properties of Graphene Derivatives/Fe_3O_4/PVA were investigated. • Thermally reduced GO/Fe_3O_4/PVA films show high absorption and strong photoluminescence.

Electroresistance effect in gold thin film induced by ionic-liquid-gated electric double layer

International Nuclear Information System (INIS)

Nakayama, Hiroyasu; Ohtani, Takashi; Fujikawa, Yasunori; Ando, Kazuya; Saitoh, Eiji; Ye, Jianting; Iwasa, Yoshihiro

2012-01-01

Electroresistance effect was detected in a metallic thin film using ionic-liquid-gated electric-double-layer transistors (EDLTs). We observed reversible modulation of the electric resistance of a Au thin film. In this system, we found that an electric double layer works as a nanogap capacitor with 27 (-25) MV cm -1 of electric field by applying only 1.7 V of positive (negative) gate voltage. The experimental results indicate that the ionic-liquid-gated EDLT technique can be used for controlling the surface electronic states on metallic systems. (author)

Electrical and optical performance of transparent conducting oxide films deposited by electrostatic spray assisted vapour deposition.

Science.gov (United States)

Hou, Xianghui; Choy, Kwang-Leong; Liu, Jun-Peng

2011-09-01

Transparent conducting oxide (TCO) films have the remarkable combination of high electrical conductivity and optical transparency. There is always a strong motivation to produce TCO films with good performance at low cost. Electrostatic Spray Assisted Vapor Deposition (ESAVD), as a variant of chemical vapour deposition (CVD), is a non-vacuum and low-cost deposition method. Several types of TCO films have been deposited using ESAVD process, including indium tin oxide (ITO), antimony-doped tin oxide (ATO), and fluorine doped tin oxide (FTO). This paper reports the electrical and optical properties of TCO films produced by ESAVD methods, as well as the effects of post treatment by plasma hydrogenation on these TCO films. The possible mechanisms involved during plasma hydrogenation of TCO films are also discussed. Reduction and etching effect during plasma hydrogenation are the most important factors which determine the optical and electrical performance of TCO films.

Influence of Gas Adsorption and Gold Nanoparticles on the Electrical Properties of CVD-Grown MoS2 Thin Films.

Science.gov (United States)

Cho, Yunae; Sohn, Ahrum; Kim, Sujung; Hahm, Myung Gwan; Kim, Dong-Ho; Cho, Byungjin; Kim, Dong-Wook

2016-08-24

Molybdenum disulfide (MoS2) has increasingly attracted attention from researchers and is now one of the most intensively explored atomic-layered two-dimensional semiconductors. Control of the carrier concentration and doping type of MoS2 is crucial for its application in electronic and optoelectronic devices. Because the MoS2 layers are atomically thin, their transport characteristics may be very sensitive to ambient gas adsorption and the resulting charge transfer. We investigated the influence of the ambient gas (N2, H2/N2, and O2) choice on the resistance (R) and surface work function (WF) of trilayer MoS2 thin films grown via chemical vapor deposition. We also studied the electrical properties of gold (Au)-nanoparticle (NP)-coated MoS2 thin films; their R value was found to be 2 orders of magnitude smaller than that for bare samples. While the WF largely varied for each gas, R was almost invariant for both the bare and Au-NP-coated samples regardless of which gas was used. Temperature-dependent transport suggests that variable range hopping is the dominant mechanism for electrical conduction for bare and Au-NP-coated MoS2 thin films. The charges transferred from the gas adsorbates might be insufficient to induce measurable R change and/or be trapped in the defect states. The smaller WF and larger localization length of the Au-NP-coated sample, compared with the bare sample, suggest that more carriers and less defects enhanced conduction in MoS2.

The Optical and Electrical Properties of ZnO/Ag/ZnO Films on Flexible Substrate

Science.gov (United States)

Yu, Xiaojing; Zhang, Dongyan; Wang, Pangpang; Murakami, Ri-Ichi; Ding, Bingjun; Song, Xiaoping

The deposition of ZnO/Ag/ZnO film on polyethylene terephthalate (PET) substrate was fabricated by DC magnetron sputtering method. The thicknesses of ZnO layers were 30 nm and Ag films' thicknesses were changed from 1 nm to 6 nm by controlled the sputtering time. This kind of film can be used as transparent conductive oxide (TCO) materials. The electrical and optical properties of composite layers were determined by Ag films. The optimum sputtering time of Ag thin films was found to be 20 s for the high optical transmittance with good electrical conductivity. The ZnO/Ag(20 s)/ZnO layer, which has high optical transmittance of 73% at 550 nm, shows sheet resistance as low as 6.7 ohm/sq. These multilayer transparent films had low electrical resistance as the widely used transparent conductive oxide electrodes. SEM, XRD, the UV-Vis-NIR and Hall Effect measurement system were used to characterize properties of fabricated films. The reasons for the change of transmittance and resistance will also be interpreted.

Pulsed laser deposition of semiconductor-ITO composite films on electric-field-applied substrates

International Nuclear Information System (INIS)

Narazaki, Aiko; Sato, Tadatake; Kawaguchi, Yoshizo; Niino, Hiroyuki; Yabe, Akira; Sasaki, Takeshi; Koshizaki, Naoto

2002-01-01

The DC electric-field effect on the crystallinity of II-VI semiconductor in composite systems has been investigated for CdS-ITO films fabricated via alternative pulsed laser deposition (PLD) of CdS and indium tin oxide (ITO) on electric-field-applied substrates. The alternative laser ablation was performed under irradiation of ArF excimer laser in mixture gas of helium and oxygen. The application of electric-field facilitated the preferential crystal-growth of CdS in nanometer scale at low pressure, whereas all the films grown without the field were amorphous. There is a large difference in the crystallization between the films grown on field-applied and heated substrates; the latter showed the crystal-growth with random orientations. This difference indicates that the existence of electric-field has an influence on the transformation from amorphous to crystalline phase of CdS. The driving force for the field-induced crystallization is also discussed in the light of the Joule heat

A new contact electric resistance technique for in-situ measurement of the electric resistance of surface films on metals in electrolytes at high temperatures and pressures

International Nuclear Information System (INIS)

Saario, T.; Marichev, V.A.

1993-01-01

Surface films play a major role in corrosion assisted cracking. A new Contact Electric Resistance (CER) method has been recently developed for in situ measurement of the electric resistance of surface films. The method has been upgraded for high temperature high pressure application. The technique can be used for any electrically conductive material in any environment including liquid, gas or vacuum. The technique has been used to determine in situ the electric resistance of films on metals during adsorption of water and anions, formation and destruction of oxides and hydrides, electroplating of metals and to study the electric resistance of films on semiconductors. The resolution of the CER technique is 10 -9 Ω, which corresponds to about 0.03 monolayers of deposited copper during electrochemical deposition Cu/Cu 2+ . Electric resistance data can be measured with a frequency of the order of one hertz, which enables one to follow in situ the kinetics of surface film related processes. The kinetics of these processes and their dependence on the environment, temperature, pH and electrochemical potential can be investigated

Electrical resistivity of CuAlMo thin films grown at room temperature by dc magnetron sputtering

OpenAIRE

Birkett, Martin; Penlington, Roger

2016-01-01

We report on the thickness dependence of electrical resistivity of CuAlMo films grown by dc magnetron sputtering on glass substrates at room temperature. The electrical resistance of the films was monitored in situ during their growth in the thickness range 10–1000 nm. By theoretically modelling the evolution of resistivity during growth we were able to gain an insight into the dominant electrical conduction mechanisms with increasing film thickness. For thicknesses in the range 10–25 nm the ...

Electrical Power Systems for NASA's Space Transportation Program

Science.gov (United States)

Lollar, Louis F.; Maus, Louis C.

1998-01-01

Marshall Space Flight Center (MSFC) is the National Aeronautics and Space Administration's (NASA) lead center for space transportation systems development. These systems include earth to orbit launch vehicles, as well as vehicles for orbital transfer and deep space missions. The tasks for these systems include research, technology maturation, design, development, and integration of space transportation and propulsion systems. One of the key elements in any transportation system is the electrical power system (EPS). Every transportation system has to have some form of electrical power and the EPS for each of these systems tends to be as varied and unique as the missions they are supporting. The Preliminary Design Office (PD) at MSFC is tasked to perform feasibility analyses and preliminary design studies for new projects, particularly in the space transportation systems area. All major subsystems, including electrical power, are included in each of these studies. Three example systems being evaluated in PD at this time are the Liquid Fly Back Booster (LFBB) system, the Human Mission to Mars (HMM) study, and a tether based flight experiment called the Propulsive Small Expendable Deployer System (ProSEDS). These three systems are in various stages of definition in the study phase.

Electronic transport properties of nano-scale Si films: an ab initio study

Science.gov (United States)

Maassen, Jesse; Ke, Youqi; Zahid, Ferdows; Guo, Hong

2010-03-01

Using a recently developed first principles transport package, we study the electronic transport properties of Si films contacted to heavily doped n-type Si leads. The quantum transport analysis is carried out using density functional theory (DFT) combined with nonequilibrium Green's functions (NEGF). This particular combination of NEGF-DFT allows the investigation of Si films with thicknesses in the range of a few nanometers and lengths up to tens of nanometers. We calculate the conductance, the momentum resolved transmission, the potential profile and the screening length as a function of length, thickness, orientation and surface structure. Moreover, we compare the properties of Si films with and without a top surface passivation by hydrogen.

The influence of Ga{sup +} irradiation on the transport properties of mesoscopic conducting thin films

Energy Technology Data Exchange (ETDEWEB)

Barzola-Quiquia, J; Dusari, S; Bridoux, G; Bern, F; Molle, A; Esquinazi, P, E-mail: j.barzola@physik.uni-leipzig.de, E-mail: esquin@physik.uni-leipzig.de [Division of Superconductivity and Magnetism, Universitaet Leipzig, Linnestrasse 5, D-04103 Leipzig (Germany)

2010-04-09

We studied the influence of 30 keV Ga{sup +}-ions-commonly used in focused-ion-beam (FIB) devices-on the transport properties of thin crystalline graphite flakes, and La{sub 0.7}Ca{sub 0.3}MnO{sub 3} and Co thin films. The changes in electrical resistance were measured in situ during irradiation and also the temperature and magnetic field dependence before and after irradiation. Our results show that the transport properties of these materials strongly change at Ga{sup +} fluences much below those used for patterning and ion-beam-induced deposition (IBID), seriously limiting the use of FIB when the intrinsic properties of the materials of interest are of importance. We present a method that can be used to protect the sample as well as to produce selectively irradiation-induced changes.

Role of low O 2 pressure and growth temperature on electrical transport of PLD grown ZnO thin films on Si substrates

Science.gov (United States)

Pandis, Ch.; Brilis, N.; Tsamakis, D.; Ali, H. A.; Krishnamoorthy, S.; Iliadis, A. A.

2006-06-01

Undoped ZnO thin films have been grown on (100) Si substrates by pulsed laser deposition. The effect of growth parameters such as temperature, O 2 partial pressure and laser fluence on the structural and electrical properties of the films has been investigated. It is shown that the well-known native n-type conductivity, attributed to the activation of hydrogenic donor states, exhibits a conversion from n-type to p-type when the O 2 partial pressure is reduced from 10 -4 to 10 -7 Torr at growth temperatures lower than 400 °C. The p-type conductivity could be attributed to the dominant role of the acceptor Zn vacancies for ZnO films grown at very low O 2 pressures.

The effect of ZnS thin film's electrical conductivity on electromagnetic ...

African Journals Online (AJOL)

The effect of electrical conductivity on an electromagnetic wave propagating through ZnS thin film is analyzed using electromagnetic wave equation with relevant boundary condition. The solution of this equation enabled us to obtain a parameter known as the skin depth that relates to the conductivity of the thin film. This was ...

Electricity for Road Transport, Flexible Power Systems and Wind Power

DEFF Research Database (Denmark)

Nielsen, Lars Henrik; Ravn, Hans; Meibom, Peter

The aim of the project is to analyse the potential synergistic interplay that may arise between the power sector and the transport sector, if parts of the road transport energy needs are based on electricity via the utilisation of plug-in hybrid electric vehicles and pure electric vehicles....... The project focuses on the technical elements in the chain that comprises: 1: The electric vehicle status, potentials and expected development. Electric batteries are in focus in this part of the analysis. 2: Analysis of plug-in hybrid electric vehicle interacting with a local grid. 3: Analysis of grid-vehicle...

High electrical conductivity in out of plane direction of electrodeposited Bi2Te3 films

Directory of Open Access Journals (Sweden)

Miguel Muñoz Rojo

2015-08-01

Full Text Available The out of plane electrical conductivity of highly anisotropic Bi2Te3 films grown via electro-deposition process was determined using four probe current-voltage measurements performed on 4.6 - 7.2 μm thickness Bi2Te3 mesa structures with 80 - 120 μm diameters sandwiched between metallic film electrodes. A three-dimensional finite element model was used to predict the electric field distribution in the measured structures and take into account the non-uniform distribution of the current in the electrodes in the vicinity of the probes. The finite-element modeling shows that significant errors could arise in the measured film electrical conductivity if simpler one-dimensional models are employed. A high electrical conductivity of (3.2 ± 0.4 ⋅ 105 S/m is reported along the out of plane direction for Bi2Te3 films highly oriented in the [1 1 0] direction.

Electrical properties of single crystal Yttrium Iron Garnet ultra-thin films at high temperatures

OpenAIRE

Thiery, Nicolas; Naletov, Vladimir V.; Vila, Laurent; Marty, Alain; Brenac, Ariel; Jacquot, Jean-François; de Loubens, Grégoire; Viret, Michel; Anane, Abdelmadjid; Cros, Vincent; Youssef, Jamal Ben; Demidov, Vladislav E.; Demokritov, Sergej O.; Klein, Olivier

2017-01-01

We report a study on the electrical properties of 19 nm thick Yttrium Iron Garnet (YIG) films grown by liquid phase epitaxy. The electrical conductivity and Hall coefficient are measured in the high temperature range [300,400]~K using a Van der Pauw four-point probe technique. We find that the electrical resistivity decreases exponentially with increasing temperature following an activated behavior corresponding to a band-gap of $E_g\\approx 2$ eV, indicating that epitaxial YIG ultra-thin film...

Quantum transport in new two-dimensional heterostructures: Thin films of topological insulators, phosphorene

Science.gov (United States)

Majidi, Leyla; Zare, Moslem; Asgari, Reza

2018-06-01

The unusual features of the charge and spin transport characteristics are investigated in new two-dimensional heterostructures. Intraband specular Andreev reflection is realized in a topological insulator thin film normal/superconducting junction in the presence of a gate electric field. Perfect specular electron-hole conversion is shown for different excitation energy values in a wide experimentally available range of the electric field and also for all angles of incidence when the excitation energy has a particular value. It is further demonstrated that the transmission probabilities of the incoming electrons from different spin subbands to the monolayer phosphorene ferromagnetic/normal/ferromagnetic (F/N/F) hybrid structure have different behavior with the angle of incidence and perfect transmission occurs at defined angles of incidence to the proposed structure with different length of the N region, and different alignments of magnetization vectors. Moreover, the sign change of the spin-current density is demonstrated by tuning the chemical potential and exchange field of the F region.

Increase of the electrical resistance of thin aluminium film due to 14 MeV neutron irradiation

Energy Technology Data Exchange (ETDEWEB)

Agrawal, S K; Kumar, U; Singh, S P; Bhattacharya, S; Nigam, A K [Banaras Hindu Univ. (India). Dept. of Physics

1978-01-01

The effect of 14 MeV neutron bombardment on the electrical resistance of 500 A thick vacuum-coated Al film is investigated. In the beginning, a slow, then sharp and finally again slow increase is observed in the electrical resistance of the film. Transmission electron micrographs of the film after the same dose of neutron irradiation show a large number of defects produced in the film due to neutron irradiation, which seems to be the cause of this increase.

Tunability of the Quantum Spin Hall Effect in Bi(110) Films: Effects of Electric Field and Strain Engineering.

Science.gov (United States)

Li, Sheng-Shi; Ji, Wei-Xiao; Li, Ping; Hu, Shu-Jun; Cai, Li; Zhang, Chang-Wen; Yan, Shi-Shen

2017-06-28

The quantum spin Hall (QSH) effect is promising for achieving dissipationless transport devices due to their robust gapless edge states inside insulating bulk gap. However, the currently discussed QSH insulators usually suffer from ultrahigh vacuum or low temperature due to the small bulk gap, which limits their practical applications. Searching for large-gap QSH insulators is highly desirable. Here, the tunable QSH state of a Bi(110) films with a black phosphorus (BP) structure, which is robust against structural deformation and electric field, is explored by first-principles calculations. It is found that the two-monolayer BP-Bi(110) film obtains a tunable large bulk gap by strain engineering and its QSH effect shows a favorable robustness within a wide range of combinations of in-plane and out-of-plane strains, although a single in-plane compression or out-of-plane extension may restrict the topological phase due to the self-doping effect. More interestingly, in view of biaxial strain, two competing physics on band topology induced by bonding-antibonding and p x,y -p z band inversions are obtained. Meanwhile, the QSH effect can be persevered under an electric field of up to 0.9 V/Å. Moreover, with appropriate in-plane strain engineering, a nontrivial topological phase in a four-monolayer BP-Bi(110) film is identified. Our findings suggest that these two-dimensional BP-Bi(110) films are ideal platforms of the QSH effect for low-power dissipation devices.

Low temperature electrical transport in modified carbon nanotube fibres

International Nuclear Information System (INIS)

Lekawa-Raus, Agnieszka; Walczak, Kamil; Kozlowski, Gregory; Hopkins, Simon C.; Wozniak, Mariusz; Glowacki, Bartek A.; Koziol, Krzysztof

2015-01-01

Carbon nanotube fibres are a new class of materials highly promising for many electrical/electronic applications. The range of applications could be extended through the modification of their electrical transport properties by inclusions of foreign materials. However, the changes in electrical transport are often difficult to assess. Here, we propose that the analysis of resistance–temperature dependencies of modified fibres supported by a recently developed theoretical model may aid research in this area and accelerate real life applications of the fibres

Improved lifetime of chitosan film in converting water vapor to electrical power by adding carboxymethyl cellulose

Science.gov (United States)

Nasution, T. I.; Balyan, M.; Nainggolan, I.

2018-02-01

A Water vapor cell based on chitosan film has been successfully fabricated in film form to convert water vapor to electrical power. In order to improve the lifetime of water vapor cell, Carboxymethyl Cellulose (CMC) was added into 1% chitosan solution within concentration variations of 0.01, 0.05, 0.1 and 0.5%. The result showed that the lifetime of water vapor cell increased higher by adding the higher concentration of Carboxymethyl cellulose. The highest lifetime was evidenced by adding 0.5%CMC which maintained for 48 weeks. However, the average electrical power became lower to 4.621 µW. This electrical power lower than the addition of 0.1%CMC which maintained for 5.167 µW. While, the lifetime of chitosan-0.1%CMC film of 44 weeks is shorter compared to chitosan-0.5%CMC film. Based on FTIR characterization, it was founded that the chitosan structure did not change until the addition of 0.1%CMC. This caused the electrical power of water vapor cell degenerated. Therefore, chitosan-0.5%CMC film has excellent lifetime in converting water vapor to electrical power.

Effect of annealing on structural, optical and electrical properties of SILAR synthesized CuO thin film

Science.gov (United States)

Das, M. R.; Mukherjee, A.; Mitra, P.

2017-05-01

Nano crystalline CuO thin films were synthesize on glass substrate using SILAR technique. The structural, optical and electrical properties of the films were carried out for as deposited as well as for films post annealed in the temperature range 300 - 500° C. The X-ray diffraction pattern shows all the films are polycrystalline in nature with monoclinic phase. The crystallite size increase and lattice strain decreases with increase of annealing temperature indicating high quality of the films for annealed films. The value of band gap decreases with increases of annealing temperature of the film. The effect of annealing temperature on ionic conductivity and activation energy to electrical conduction process are discussed.

Electric and ferroelectric properties of PZT/BLT multilayer films prepared by photochemical metal-organic deposition

Science.gov (United States)

Park, Hyeong-Ho; Lee, Hong-Sub; Park, Hyung-Ho; Hill, Ross H.; Hwang, Yun Taek

2009-01-01

The electric and ferroelectric properties of lead zirconate titanate (PZT) and lanthanum-substituted bismuth titanate (BLT) multilayer films prepared using photosensitive precursors were characterized. The electric and ferroelectric properties were investigated by studying the effect of the stacking order of four ferroelectric layers of PZT or BLT in 4-PZT, PZT/2-BLT/PZT, BLT/2-PZT/BLT, and 4-BLT multilayer films. The remnant polarization values of the 4-BLT and BLT/2-PZT/BLT multilayer films were 12 and 17 μC/cm 2, respectively. Improved ferroelectric properties of the PZT/BLT multilayer films were obtained by using a PZT intermediate layer. The films which contained a BLT layer on the Pt substrate had improved leakage currents of approximately two orders of magnitude and enhanced fatigue resistances compared to the films with a PZT layer on the Pt substrate. These improvements are due to the reduced number of defects and space charges near the Pt electrodes. The PZT/BLT multilayer films prepared by photochemical metal-organic deposition (PMOD) possessed enhanced electric and ferroelectric properties, and allow direct patterning to fabricate micro-patterned systems without dry etching.

Electric and ferroelectric properties of PZT/BLT multilayer films prepared by photochemical metal-organic deposition

International Nuclear Information System (INIS)

Park, Hyeong-Ho; Lee, Hong-Sub; Park, Hyung-Ho; Hill, Ross H.; Hwang, Yun Taek

2009-01-01

The electric and ferroelectric properties of lead zirconate titanate (PZT) and lanthanum-substituted bismuth titanate (BLT) multilayer films prepared using photosensitive precursors were characterized. The electric and ferroelectric properties were investigated by studying the effect of the stacking order of four ferroelectric layers of PZT or BLT in 4-PZT, PZT/2-BLT/PZT, BLT/2-PZT/BLT, and 4-BLT multilayer films. The remnant polarization values of the 4-BLT and BLT/2-PZT/BLT multilayer films were 12 and 17 μC/cm 2 , respectively. Improved ferroelectric properties of the PZT/BLT multilayer films were obtained by using a PZT intermediate layer. The films which contained a BLT layer on the Pt substrate had improved leakage currents of approximately two orders of magnitude and enhanced fatigue resistances compared to the films with a PZT layer on the Pt substrate. These improvements are due to the reduced number of defects and space charges near the Pt electrodes. The PZT/BLT multilayer films prepared by photochemical metal-organic deposition (PMOD) possessed enhanced electric and ferroelectric properties, and allow direct patterning to fabricate micro-patterned systems without dry etching.

Structural, optical and electrical peculiarities of r.f. plasma sputtered indium tin oxide films

International Nuclear Information System (INIS)

Boycheva, Sylvia; Sytchkova, Anna Krasilnikova; Grilli, Maria Luisa; Piegari, Angela

2007-01-01

In this work the influence of the deposition conditions on the structural, electrical and optical properties of the ITO films was studied. Films were deposited by r.f. plasma sputtering technique in Ar and varying Ar + O 2 gas mixtures, with and without substrate heating. Transmittance and reflectance of the films were measured in the range 350-2500 nm; the refractive index (n) and the extinction coefficient (k) were calculated by the spectral data simulation. The sheet resistance of the films was measured by four-point probe method. X-ray diffraction analysis was performed to study the texture of the films. Threshold behaviour was observed in the optical and electrical properties of ITO films deposited in Ar + O 2 atmosphere at a certain oxygen concentration determined by a fix combination of all other deposition conditions. A schematic diagram for the change of the film properties versus composition was suggested, which explains the obtained results

Optical and Electrical Performance of ZnO Films Textured by Chemical Etching

Directory of Open Access Journals (Sweden)

Shiuh-Chuan HER

2015-11-01

Full Text Available Zinc oxide (ZnO films were prepared by radio frequency (RF magnetron sputtering on the glass substrate as transparent conductive oxide films. For silicon solar cells, a proper surface texture is essential to introduce light scattering and subsequent light trapping to enhance the current generation. In this study, the magnetron-sputtered ZnO films were textured by wet-chemical etching in diluted hydrochloric acid (HCl for better light scattering. The diffuse transmittance of the surface textured ZnO films was measured to evaluate the light scattering. The influence of hydrochloric acid concentration on the morphology, optical and electrical properties of the surface-textured ZnO film was investigated. The ZnO film etched in 0.05M HCl solution for 30 s exhibited average diffuse transmittance in the visible wavelength range of 9.52 % and good resistivity of 1.10 x 10-3 W×cm while the as-deposited ZnO film had average diffuse transmittance of 0.51 % and relatively high resistivity of 5.84 x 10-2 W×cm. Experimental results illustrated that the optical and electrical performance of ZnO films can be significantly improved by introducing the surface texture through the wet-chemical etching process.DOI: http://dx.doi.org/10.5755/j01.ms.21.4.9624

In situ study of electric field controlled ion transport in the Fe/BaTiO3 interface

DEFF Research Database (Denmark)

Merkel, D. G.; Bessas, D.; Bazso, G.

2018-01-01

Electric field controlled ion transport and interface formation of iron thin films on a BaTiO3 substrate have been investigated by in situ nuclear resonance scattering and x-ray reflectometry techniques. At early stage of deposition, an iron-II oxide interface layer was observed. The hyperfine...... parameters of the interface layer were found insensitive to the evaporated layer thickness. When an electric field was applied during growth, a 10 angstrom increase of the nonmagnetic/magnetic thickness threshold and an extended magnetic transition region was measured compared to the case where no field...... was applied. The interface layer was found stable under this threshold when further evaporation occurred, contrary to the magnetic layer where the magnitude and orientation of the hyperfine magnetic field vary continuously. The obtained results of the growth mechanism and of the electric field effect...

Influence of substrate temperature on the optical and electrical properties magnetron sputtering ITO films

International Nuclear Information System (INIS)

Khripunov, G.S.; Yurchenko, G.V.

1999-01-01

Electrical and optical properties of ITO films obtained at substrate temperature from 200 degree C to 500 degree C by magnetron sputtering of target 95% In 2 O 3 - 5% SnO 2 were studied. It was shown that the ITO film obtained at the substrate temperature 300 i N have optimum combination of the optical and electrical characteristics: resistivity 2.1 centre dot 10 -4 Ω cm, transmittance in visible spectral range about 88% at the thickness film 0.61 μ, factor of quality reaches 8.2 centre dot 10 -2 Ω 1

Title: Using Alignment and 2D Network Simulations to Study Charge Transport Through Doped ZnO Nanowire Thin Film Electrodes

KAUST Repository

Phadke, Sujay

2011-09-30

Factors affecting charge transport through ZnO nanowire mat films were studied by aligning ZnO nanowires on substrates and coupling experimental measurements with 2D nanowire network simulations. Gallium doped ZnO nanowires were aligned on thermally oxidized silicon wafer by shearing a nanowire dispersion in ethanol. Sheet resistances of nanowire thin films that had current flowing parallel to nanowire alignment direction were compared to thin films that had current flowing perpendicular to nanowire alignment direction. Perpendicular devices showed ∼5 fold greater sheet resistance than parallel devices supporting the hypothesis that aligning nanowires would increase conductivity of ZnO nanowire electrodes. 2-D nanowire network simulations of thin films showed that the device sheet resistance was dominated by inter-wire contact resistance. For a given resistivity of ZnO nanowires, the thin film electrodes would have the lowest possible sheet resistance if the inter-wire contact resistance was one order of magnitude lower than the single nanowire resistance. Simulations suggest that the conductivity of such thin film devices could be further enhanced by using longer nanowires. Solution processed Gallium doped ZnO nanowires are aligned on substrates using an innovative shear coating technique. Nanowire alignment has shown improvement in ZnO nanowire transparent electrode conductivity. 2D network simulations in conjunction with electrical measurements have revealed different regimes of operation of nanowire thin films and provided a guideline for improving electrical performance of nanowire electrodes. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Effect of Deposition Rate on Electrical, Optical and Structural Properties of ITO Thin Films

Directory of Open Access Journals (Sweden)

P. S. Raghupathi

2005-01-01

Full Text Available Indium tin oxide (ITO thin films have been prepared using the reactive evaporation technique on glass substrates in an oxygen atmosphere. It is found that the deposition rate plays prominent role in controlling the electrical and optical properties of the ITO thin films. Resistivity, electrical conductivity, activation energy, optical transmission and band gap energy were investigated. A transmittance value of more than 90% in the visible region of the spectrum and an electrical conductivity of 3x10–6 Ωm has been obtained with a deposition rate of 2 nm/min. XRD studies showed that the films are polycrystalline.

Electrical energy conversion and transport an interactive computer-based approach

CERN Document Server

Karady, George G

2013-01-01

Provides relevant material for engineering students and practicing engineers who want to learn the basics of electrical power transmission, generation, and usage This Second Edition of Electrical Energy Conversion and Transport is thoroughly updated to address the recent environmental effects of electric power generation and transmission, which have become more important in conjunction with the deregulation of the industry. The maintenance and development of the electrical energy generation and transport industry requires well-trained engineers who are able to use mode

In situ characterization of the film coverage and the charge transport in the alkylated-organic thin film transistor

Science.gov (United States)

Watanabe, Takeshi; Koganezawa, Tomoyuki; Kikuchi, Mamoru; Muraoka, Hiroki; Ogawa, Satoshi; Yoshimoto, Noriyuki; Hirosawa, Ichiro

2018-03-01

We propose an in situ experimental method of investigating the correlations of the film coverage of the organic semiconductor layers and charge transport properties of organic thin film transistors during vacuum deposition. The coverage of each monolayer was estimated using the intensity of off-specular diffuse scattering and diffraction. Experimental data were obtained from the in situ measurements of two-dimensional grazing incidence X-ray scattering and charge transport. The source-drain current increased over the film coverage of the first monolayer (= 0.48). This is in agreement with the critical percolation coverage, indicating that the conductivities of the first and second monolayers are different.

Effects of germane flow rate in electrical properties of a-SiGe:H films for ambipolar thin-film transistors

Energy Technology Data Exchange (ETDEWEB)

Dominguez, Miguel, E-mail: madominguezj@gmail.com [Centro de Investigaciones en Dispositivos Semiconductores, Instituto de Ciencias, Benemerita Universidad Autonoma de Puebla (BUAP), Puebla 72570 (Mexico); Rosales, Pedro, E-mail: prosales@inaoep.mx [National Institute for Astrophysics, Optics and Electronics (INAOE), Electronics Department, Luis Enrique Erro No. 1, Puebla 72840 (Mexico); Torres, Alfonso [National Institute for Astrophysics, Optics and Electronics (INAOE), Electronics Department, Luis Enrique Erro No. 1, Puebla 72840 (Mexico); Flores, Francisco [Centro de Investigaciones en Dispositivos Semiconductores, Instituto de Ciencias, Benemerita Universidad Autonoma de Puebla (BUAP), Puebla 72570 (Mexico); Molina, Joel; Moreno, Mario [National Institute for Astrophysics, Optics and Electronics (INAOE), Electronics Department, Luis Enrique Erro No. 1, Puebla 72840 (Mexico); Luna, Jose [Centro de Investigaciones en Dispositivos Semiconductores, Instituto de Ciencias, Benemerita Universidad Autonoma de Puebla (BUAP), Puebla 72570 (Mexico); Orduña, Abdu [Centro de Investigación en Biotecnología Aplicada (CIBA), IPN, Tlaxcala, Tlaxcala 72197 (Mexico)

2014-07-01

In this work, the study of germane flow rate in electrical properties of a-SiGe:H films is presented. The a-SiGe:H films deposited by low frequency plasma-enhanced chemical vapor deposition at 300 °C were characterized by Fourier transform infrared spectroscopy, measurements of temperature dependence of conductivity and UV–visible spectroscopic ellipsometry. After finding the optimum germane flow rate conditions, a-SiGe:H films were deposited at 200 °C and analyzed. The use of a-SiGe:H films at 200 °C as active layer of low-temperature ambipolar thin-film transistors (TFTs) was demonstrated. The inverted staggered a-SiGe:H TFTs with Spin-On Glass as gate insulator were fabricated. These results suggest that there is an optimal Ge content in the a-SiGe:H films that improves its electrical properties. - Highlights: • As the GeH{sub 4} flow rate increases the content of oxygen decreases. • Ge-H bonds show the highest value in a-SiGe:H films with GeH{sub 4} flow of 105 sccm. • Films with GeH{sub 4} flow of 105 sccm show the highest activation energy. • An optimum incorporation of germanium is obtained with GeH{sub 4} flow rate of 105 sccm. • At 200 °C the optimum condition of the a-SiGe:H films remain with no changes.

In situ study of electric field controlled ion transport in the Fe/BaTiO3 interface

Science.gov (United States)

Merkel, D. G.; Bessas, D.; Bazsó, G.; Jafari, A.; Rüffer, R.; Chumakov, A. I.; Khanh, N. Q.; Sajti, Sz; Celse, J.-P.; Nagy, D. L.

2018-01-01

Electric field controlled ion transport and interface formation of iron thin films on a BaTiO3 substrate have been investigated by in situ nuclear resonance scattering and x-ray reflectometry techniques. At early stage of deposition, an iron-II oxide interface layer was observed. The hyperfine parameters of the interface layer were found insensitive to the evaporated layer thickness. When an electric field was applied during growth, a 10 Å increase of the nonmagnetic/magnetic thickness threshold and an extended magnetic transition region was measured compared to the case where no field was applied. The interface layer was found stable under this threshold when further evaporation occurred, contrary to the magnetic layer where the magnitude and orientation of the hyperfine magnetic field vary continuously. The obtained results of the growth mechanism and of the electric field effect of the Fe/BTO system will allow the design of novel applications by creating custom oxide/metallic nanopatterns using laterally inhomogeneous electric fields during sample preparation.

Microstructural and electrical characteristics of rare earth oxides doped ZnO varistor films

Science.gov (United States)

Jiao, Lei; Mei, Yunzhu; Xu, Dong; Zhong, Sujuan; Ma, Jia; Zhang, Lei; Bao, Li

2018-02-01

ZnO-Bi2O3 varistor films doped with two kinds of rare earth element oxides (Lu2O3 and Yb2O3) were prepared by the sol-gel method. The effects of Lu2O3/Yb2O3 doping on the microstructure and electrical characteristics of ZnO-Bi2O3 varistor films were investigated. All samples show a homogenized morphology and an improved nonlinear relationship between the electric field (E) and current density (I). Both Yb2O3 and Lu2O3 doping can decrease the grain size of ZnO-Bi2O3 varistor films and improve the electrical properties, which have a positive effect on the development of ZnO varistor ceramics. Yb2O3 doping significantly increases the dielectric constant at low frequency. 0.2 mol. % Yb2O3 doped ZnO-Bi2O3 varistor films exhibit the highest nonlinear coefficient (2.5) and the lowest leakage current (328 μA) among Lu2O3/Yb2O3 doped ZnO-Bi2O3 varistor films. Similarly, 0.1 mol. % Lu2O3 doping increases the nonlinear coefficient to 1.9 and decrease the leakage current to 462 μA.

Structural, electrical and optical studies of SILAR deposited cadmium oxide thin films: Annealing effect

International Nuclear Information System (INIS)

Salunkhe, R.R.; Dhawale, D.S.; Gujar, T.P.; Lokhande, C.D.

2009-01-01

Successive ionic layer adsorption and reaction (SILAR) method has been successfully employed for the deposition of cadmium oxide (CdO) thin films. The films were annealed at 623 K for 2 h in an air and changes in the structural, electrical and optical properties were studied. From the X-ray diffraction patterns, it was found that after annealing, H 2 O vapors from as-deposited Cd(O 2 ) 0.88 (OH) 0.24 were removed and pure cubic cadmium oxide was obtained. The as-deposited film consists of nanocrystalline grains of average diameter about 20-30 nm with uniform coverage of the substrate surface, whereas for the annealed film randomly oriented morphology with slight increase in the crystallite size has been observed. The electrical resistivity showed the semiconducting nature with room temperature electrical resistivity decreased from 10 -2 to 10 -3 Ω cm after annealing. The decrease in the band gap energy from 3.3 to 2.7 eV was observed after the annealing

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.

Optical and electrical properties of nickel xanthate thin films

Indian Academy of Sciences (India)

Administrator

metal-xanthate thin films' production, nor their optical, electrical properties and .... vibration of –CH3 at 894 cm–1, (vii) the symmetric bend- ing vibration of C–O–C at 458 .... vity values are the two most important factors, affecting band width.

Electrical transport properties and laser-induced voltage effect in La{sub 0.8}Ca{sub 0.2}MnO{sub 3} epitaxial thin films

Energy Technology Data Exchange (ETDEWEB)

Theingi, Mya [Kunming University of Science and Technology, Faculty of Materials Science and Engineering, Kunming (China); University of Yangon, Department of Chemistry, Yangon (Myanmar); Ma, Ji; Zhang, Hui; Cui, Qi; Yi, Jianhong; Chen, Qingming [Kunming University of Science and Technology, Faculty of Materials Science and Engineering, Kunming (China)

2014-03-15

La{sub 0.8}Ca{sub 0.2}MnO{sub 3} (LCMO) thin films about 200 nm thickness were grown on untilted and tilted (5 , 10 and 15 ) LaAlO{sub 3} (100) single crystal substrates by pulsed laser deposition technique. Electrical properties of the epitaxial thin films were studied by conventional four-probe technique and the anisotropic thermoelectric properties of the films grown on the tilted substrates have been investigated by laser-induced voltage (LIV) measurements. X-ray diffraction analysis and atomic force microscopy results show that the prepared LCMO thin films have a single phase and high crystalline quality. The remarkably large temperature coefficient of resistance (TCR) values (above 11 %/K) are observed in the all films. TCR value reaches 18 %/K on the film grown on 10 tilted substrate. The intensity of LIV signals monotonously increases with the tilting angles, and the largest signal is 148 mV with the fast time response 229 ns for the film grown on 15 tilted substrate. (orig.)

Synthesis and electrical transport properties of the LaVO{sub 3}/SrTiO{sub 3} interface

Energy Technology Data Exchange (ETDEWEB)

Hentrich, Richard; Schultz, Ludwig; Huehne, Ruben [IFW Dresden (Germany); Haenisch, Jens [IFW Dresden (Germany); ITEP, Karlsruhe Institute of Technology (KIT) (Germany)

2015-07-01

We have investigated the two dimensional electron gas at the interface of band gap insulator SrTiO{sub 3} and mott insulator LaVO{sub 3} in comparison to the well-known, purely band insulating LaAlO{sub 3}/SrTiO{sub 3} system. Thin films of LaVO{sub 3} were grown epitaxially on TiO{sub 2} terminated SrTiO{sub 3} single crystal substrates using RHEED-monitored pulsed laser deposition. Optimal process parameters for layer-by-layer growth were found resulting in the growth of atomically smooth films of well-defined thickness. Electrical transport measurements revealed an insulator-metal transition at a film thickness of six unit cells, which is different to previously reported values. Conducting samples showed metallic behavior in a wide temperature range, with their conductivity showing little to no dependence on layer thickness. This led to the conclusion of the metallic behavior being a merely interface driven effect.

Neoclassical transport and radial electric fields in TJ-K

International Nuclear Information System (INIS)

Rahbarnia, K.; Greiner, F.; Ramisch, M.; Stroth, U.; Greiner, F.

2003-01-01

The neoclassical transport is investigated in the torsatron TJ-K, which is operated with a low-temperature plasma. In the low-collisionality regime neoclassical losses are not intrinsically ambipolar, leading to the formation of a radial electric field which acts on both neoclassical and turbulent transport. This electric field is measured with a combination of Langmuir and emissive probes. The data are compared with the ambipolar electric field calculated with an analytic model. The experimental fields are positive and larger than the calculated ones. Direct losses of the fast electrons might explain this discrepancy. (orig.)

Electrical conduction of polyimide films prepared from polyamic acid (PAA and pre-imidized polyimide (PI solution

Directory of Open Access Journals (Sweden)

2007-07-01

Full Text Available Electrical conduction characteristics in two different polyimide films prepared by the imidization of polyamic acid (PAA and pre-imidized polyimide (PI solution were investigated. It is found that the current density of the polyimide film from PAA was higher than that of the polyimide film from PI at the same electric field, even though the conduction mechanism in both polyimide films follows the ionic hopping model. The hopping distance was calculated to be 2.8 nm for PAA type and 3.2 nm for PI type polyimide film. It is also found that the decay rate of the residual electrostatic charges on the polyimide films becomes faster in the PAA type than in the PI type polyimide film.

Observation of dopant-profile independent electron transport in sub-monolayer TiO{sub x} stacked ZnO thin films grown by atomic layer deposition

Energy Technology Data Exchange (ETDEWEB)

Saha, D., E-mail: sahaphys@gmail.com, E-mail: pmisra@rrcat.gov.in; Misra, P., E-mail: sahaphys@gmail.com, E-mail: pmisra@rrcat.gov.in; Joshi, M. P.; Kukreja, L. M. [Laser Materials Processing Division, Raja Ramanna Centre for Advanced Technology, Indore 452 013 (India); Das, Gangadhar [Indus Synchrotrons Utilisation Division, Raja Ramanna Centre for Advanced Technology, Indore 452 013 (India)

2016-01-18

Dopant-profile independent electron transport has been observed through a combined study of temperature dependent electrical resistivity and magnetoresistance measurements on a series of Ti incorporated ZnO thin films with varying degree of static-disorder. These films were grown by atomic layer deposition through in-situ vertical stacking of multiple sub-monolayers of TiO{sub x} in ZnO. Upon decreasing ZnO spacer layer thickness, electron transport smoothly evolved from a good metallic to an incipient non-metallic regime due to the intricate interplay of screening of spatial potential fluctuations and strength of static-disorder in the films. Temperature dependent phase-coherence length as extracted from the magnetotransport measurement revealed insignificant role of inter sub-monolayer scattering as an additional channel for electron dephasing, indicating that films were homogeneously disordered three-dimensional electronic systems irrespective of their dopant-profiles. Results of this study are worthy enough for both fundamental physics perspective and efficient applications of multi-stacked ZnO/TiO{sub x} structures in the emerging field of transparent oxide electronics.

The influence of Ac parameters in the process of micro-arc oxidation film electric breakdown

Directory of Open Access Journals (Sweden)

Ma Jin

2016-01-01

Full Text Available This paper studies the electric breakdown discharge process of micro-arc oxidation film on the surface of aluminum alloy. Based on the analysis of the AC parameters variation in the micro-arc oxidation process, the following conclusions can be drawn: The growth of oxide film can be divided into three stages, and Oxide film breakdown discharge occurs twice in the micro-arc oxidation process. The first stage is the formation and disruptive discharge of amorphous oxide film, producing the ceramic oxide granules, which belong to solid dielectric breakdown. In this stage the membrane voltage of the oxide film plays a key role; the second stage is the formation of ceramic oxide film, the ceramic oxide granules turns into porous structure oxide film in this stage; the third stage is the growth of ceramic oxide film, the gas film that forms in the oxide film’s porous structure is electric broken-down, which is the second breakdown discharge process, the current density on the oxide film surface could affect the breakdown process significantly.

Crystalline, Optical and Electrical Properties of NiZnO Thin Films Fabricated by MOCVD

International Nuclear Information System (INIS)

Wang Jin; Wang Hui; Zhao Wang; Ma Yan; Li Wan-Cheng; Shi Zhi-Feng; Zhao Long; Zhang Bao-Lin; Dong Xin; Du Guo-Tong; Xia Xiao-Chuan

2011-01-01

NiZnO thin films are grown on c-plane sapphire substrates by using a photo-assisted metal organic chemical vapor deposition (MOCVD) system. The effect of the Ni content on the crystalline, optical and electrical properties of the films are researched in detail. The NiZnO films could retain a basic wurtzite structure when the Ni content is less than 0.18. As Ni content increases, crystal quality degradation could be observed in the x-ray diffraction patterns and a clear red shift of the absorption edge can be observed in the transmittance spectrum. Furthermore, the donor defects in the NiZnO film can be compensated for effectively by increasing the Ni content. The change of Ni content has an important effect on the properties of NiZnO films. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

The effect of laser irradiation on electrical and structural properties of ZnO thin films

Directory of Open Access Journals (Sweden)

P Kameli

2013-03-01

Full Text Available  In this paper, ZnO thin film was prepared by sol-gel process on glass substrates. The deposited films were dried at 100 and 240 ˚C and then annealed at 300, 400 and 500 ˚C. The two-probe measurement showed that resistance of as-prepared films is very high. The KrF excimer (λ=248 nm laser irradiation with 1000 pulses, frequency of 1 Hz and 90 mJ/cm2 energy on surface of film resulted in the reduction of the films electrical resistance. X-ray diffraction (XRD patterns confirmed the improved hexagonal wurtzite structure of film, and AFM and FE-SEM analyses showed regular and spherical grain was formed on the surface. The particle size was increased from ~10 to ~30 nm after leaser irradiation. Generally, it was showed that electrical, structural and morphological properties of films improve considerably by laser irradiation.

Structural and electrical properties of sputter deposited ZnO thin films

Science.gov (United States)

Muhammed Shameem P., V.; Mekala, Laxman; Kumar, M. Senthil

2018-05-01

The growth of zinc oxide thin films having different oxygen content was achieved at ambient temperature by reactive dc magnetron sputtering technique and their structural and electrical properties are studied. The structural studies show that the films are polycrystalline with a preferential orientation of the grains along the c-axis [002], which increases with increase in oxygen partial pressure. The grain size and the surface roughness of the zinc oxide films are found to decrease with increasing oxygen partial pressure. It is observed that the resistivity of the zinc oxide films can be tuned from semiconducting to insulating regime by varying the oxygen content.

Electrokinetic transport of aerobic microorganisms under low-strength electric fields.

Science.gov (United States)

Maillacheruvu, Krishnanand Y; Chinchoud, Preethi R

2011-01-01

To investigate the feasibility of utilizing low strength electric fields to transport commonly available mixed cultures such as those from an activated sludge process, bench scale batch reactor studies were conducted in sand and sandy loam soils. A readily biodegradable substrate, dextrose, was used to test the activity of the transported microorganisms. Electric field strengths of 7V, 10.5V, and 14V were used. Results from this investigation showed that an electric field strength of 0.46 Volts per cm was sufficient to transport activated sludge microorganisms across a sandy loam soil across a distance of about 8 cm in 72 h. More importantly, the electrokinetically transported microbial culture remained active and viable after the transport process and was biodegrade 44% of the dextrose in the soil medium. Electrokinetic treatment without microorganisms resulted in removal of 37% and the absence of any treatment yielded a removal of about 15%.

Beyond sustainable transport. Electric car features and services

Energy Technology Data Exchange (ETDEWEB)

Malinen, P.; Pirhonen, V.; Giesecke, R. [Aalto Univ. School of Science, Espoo (Finland). BIT Research Centre

2011-07-01

The overall aim of the Finnish SIMBe project (www.SIMBe.fi) is to significantly accelerate the introduction of sustainable electric mobility in Finland. SIMBe stands for Smart Infrastructures for Electric Mobility in Built Environments. The fundamental assumption of the project is that electric (e-) mobility is inherently more sustainable than mobility based on fossil fuels. However, as has been widely recognized in the e-mobility field, the currently used batteries are expensive, often more expensive than the rest of the particular electric vehicle (EV) that they propel. There are two opposite schools of thought how to address this problem, which can be summarized as follows: a) Leave the battery in peace, as it is precious. Use it only to propel the EV of which it is an integral part. Use it instead of fuel, and do not use it for any other applications. The EV's sole purpose is that of a transportation device. b) Make as much use of the battery as possible, as it is precious. Involve vehicle to grid (V2G) or vehicle to house charging. Additionally, invent new features, meanings and services for the battery driven EV, which go distinctively beyond transport. The SIMBe project decided to opt for school (b), based on the smart energy production and distribution scenario, in which electric and hybrid vehicles' batteries will deliver energy on demand to the grid. SIMBe aims to prepare key Finnish industrial players and consumers for the transition to this new energy-transportation paradigm. But how can we replace the conservative understanding of the 'transport only' school by a holistic view of what features, meanings and services are actually possible by using a large scale fleet of 'batteries on wheels'? The Nordic Climate Festival (at) Aalto provided the unique opportunity to tap into the knowledge and creativity of students within the Nordic countries. Being properly prepared and facilitated, a workshop may provide some insights and

Beyond sustainable transport. Electric car features and services

Energy Technology Data Exchange (ETDEWEB)

Malinen, P; Pirhonen, V; Giesecke, R [Aalto Univ. School of Science, Espoo (Finland). BIT Research Centre

2011-07-01

The overall aim of the Finnish SIMBe project (www.SIMBe.fi) is to significantly accelerate the introduction of sustainable electric mobility in Finland. SIMBe stands for Smart Infrastructures for Electric Mobility in Built Environments. The fundamental assumption of the project is that electric (e-) mobility is inherently more sustainable than mobility based on fossil fuels. However, as has been widely recognized in the e-mobility field, the currently used batteries are expensive, often more expensive than the rest of the particular electric vehicle (EV) that they propel. There are two opposite schools of thought how to address this problem, which can be summarized as follows: a) Leave the battery in peace, as it is precious. Use it only to propel the EV of which it is an integral part. Use it instead of fuel, and do not use it for any other applications. The EV's sole purpose is that of a transportation device. b) Make as much use of the battery as possible, as it is precious. Involve vehicle to grid (V2G) or vehicle to house charging. Additionally, invent new features, meanings and services for the battery driven EV, which go distinctively beyond transport. The SIMBe project decided to opt for school (b), based on the smart energy production and distribution scenario, in which electric and hybrid vehicles' batteries will deliver energy on demand to the grid. SIMBe aims to prepare key Finnish industrial players and consumers for the transition to this new energy-transportation paradigm. But how can we replace the conservative understanding of the 'transport only' school by a holistic view of what features, meanings and services are actually possible by using a large scale fleet of 'batteries on wheels'? The Nordic Climate Festival (at) Aalto provided the unique opportunity to tap into the knowledge and creativity of students within the Nordic countries. Being properly prepared and facilitated, a workshop may provide some insights and ideas. In scope of the

TiFeCoNi oxide thin film - A new composition with extremely low electrical resistivity at room temperature

International Nuclear Information System (INIS)

Yang, Ya-Chu; Tsau, Chun-Huei; Yeh, Jien-Wei

2011-01-01

We show the electrical resistivity of a TiFeCoNi oxide thin film. The electrical resistivity of the TiFeCoNi thin film decreased sharply after a suitable period of oxidation at high temperature. The lowest resistivity of the TiFeCoNi oxide film was 35 ± 3 μΩ-cm. The low electrical resistivity of the TiFeCoNi oxide thin film was attributed to Ti, which is more reactive than the other elements, reacting with oxygen at the initial stage of annealing. The low resistivity is caused by the remaining electrons.

Effect of Se addition on optical and electrical properties of chalcogenide CdSSe thin films

Science.gov (United States)

Hassanien, A. S.; Akl, Alaa A.

2016-01-01

Compositional dependence of optical and electrical properties of chalcogenide CdSxSe1-x (0.4 ≥ x ≥ 0.0 at. %) thin films was studied. Cadmium sulphoselenide films were deposited by thermal evaporation technique at vacuum (8.2 × 10-4 Pa) onto preheated glass substrates (523 K). The evaporation rate and film thickness were kept constant at 2.50 nm/s and 375 ± 5 nm, respectively. X-ray diffractograms showed that, the deposited films have the low crystalline nature. Energy dispersive analysis by X-ray (EDAX) was used to check the compositional elements of deposited films. The absorption coefficient was determined from transmission and reflection measurements at room temperature in the wavelength range 300-2500 nm. Optical density, skin depth, optical energy gap and Urbach's parameters of CdSSe thin films have also been estimated. The direct optical energy gap decreased from 2.248 eV to 1.749 eV when the ratio of Se-content was increased from 0.60 to 1.00 . Conduction band and valance band positions were evaluated. The temperature dependence of dc-electrical resistivity in the temperature range (293-450 K) has been reported. Three conduction regions due to different conduction mechanisms were detected. Electrical sheet resistance, activation energy and pre-exponential parameters were discussed. The estimated values of optical and electrical parameters were strongly dependent upon the Se-content in CdSSe matrix.

Structural and electrical studies on nanostructured InSe thin films

Energy Technology Data Exchange (ETDEWEB)

Darwish, A.A.A., E-mail: aaadarwish@gmail.com [Physics Department, Faculty of Science, University of Tabuk, Tabuk (Saudi Arabia); Physics Department, Faculty of Education at Al-Mahweet, Sana’a University, Al-Mahweet (Yemen); El-Nahass, M.M. [Physics Department, Faculty of Education, Ain Shams University, Rorxy, Cairo 11757 (Egypt); Bahlol, M.H. [Physics Department, Faculty of Education, Science and Arts at Sada’a, Amran University, Sada’a (Yemen)

2013-07-01

InSe powder was found to be polycrystalline with hexagonal system. X-ray diffraction and scanning electron microscopy results confirmed that the InSe films have nanostructure nature. The heat treatment enhance the crystallite size. The dark electrical conductivity of InSe films showed that the dominant conduction is through the extended states in the temperature range 293–473 K. Thermoelectric properties show a negative sign exhibiting n-type semiconductig nature of films. Current density–voltage characteristics of InSe films showed Ohmic conduction in the lower voltage range, and space charge limited conductivity (SCLC) in the relatively high-voltage range. The SCLC was controlled by an exponential distribution of traps below the conduction band. The temperature dependence of the current density allowed the calculation of some essential parameters.

Influence of iodine on the electrical and photoelectrical properties of zinc phthalocyanine thin film devices

Energy Technology Data Exchange (ETDEWEB)

Sharma, G.D. [Jodhpur Univ. (India). Dept. of Physics; Sangodkar, S.G. [Jodhpur Univ. (India). Dept. of Physics; Roy, M.S. [Camouflage Division, Defence Laboratory, Jodhpur (Raj.) (India)

1996-11-01

The electrical and photovoltaic properties of the zinc phthalocyanine (ZnPc) and I{sub 2} doped ZnPc thin films, sandwiched between indium tin oxide (ITO) and Al electrodes, were investigated. Doping with iodine brings adequate changes in the characteristics of the device. The devices constitute a metal-insulator-semiconductor (MIS) structure, in which depletion layer is formed in ZnPc, near Al-Al{sub 2}O{sub 3}/ZnPc. The depletion layer width and potential barrier height decrease with I{sub 2} doping. The charge transport phenomenon at higher voltage range appears to be space charge limited conduction (SCLC), in the presence of the discrete trapping level. The position of Fermi level shifts toward the valence band edge, which indicates that I{sub 2} doping increases the P-type conductivity. Various electrical and photovoltaic parameters were determined from the J-V and C-V analysis. The influence of the I{sub 2} doping has been discussed in detail. (orig.)

Optical and electrical properties of polycrystalline and amorphous Al-Ti thin films

DEFF Research Database (Denmark)

Canulescu, Stela; Borca, C. N.; Rechendorff, Kristian

2016-01-01

The structural, optical, and transport properties of sputter-deposited Al-Ti thin films have been investigated as a function of Ti alloying with a concentration ranging from 2% to 46%. The optical reflectivity of Al-Ti films at visible and near-infrared wavelengths decreases with increasing Ti...... content. Xray absorption fine structure measurements reveal that the atomic ordering around Ti atoms increases with increasing Ti content up to 20% and then decreases as a result of a transition from a polycrystalline to amorphous structure. The transport properties of the Al-Ti films are influenced...... by electron scattering at the grain boundaries in the case of polycrystalline films and static defects, such as antisite effects and vacancies in the case of the amorphous alloys. The combination of Ti having a real refractive index (n) comparable with the extinction coefficient (k) and Al with n much smaller...

Preparation and Characterization of Sb2Te3 Thin Films by Coevaporation

Directory of Open Access Journals (Sweden)

Bin Lv

2010-01-01

Full Text Available Deposition of Sb2Te3 thin films on soda-lime glass substrates by coevaporation of Sb and Te is described in this paper. Sb2Te3 thin films were characterized by x-ray diffraction (XRD, x-ray fluorescence (XRF, atomic force microscopy (AFM, x-ray photoelectron spectroscopy (XPS, electrical conductivity measurements, and Hall measurements. The abnormal electrical transport behavior occurred from in situ electrical conductivity measurements. The results indicate that as-grown Sb2Te3 thin films are amorphous and undergo an amorphous-crystalline transition after annealing, and the posttreatment can effectively promote the formation of Sb-Te bond and prevent oxidation of thin film surface.

Spectroelectrochemical properties of ultra-thin indium tin oxide films under electric potential modulation

Energy Technology Data Exchange (ETDEWEB)

Han, Xue, E-mail: x0han004@louisville.edu; Mendes, Sergio B., E-mail: sbmend01@louisville.edu

2016-03-31

In this work, the spectroscopic properties of ultra-thin ITO films are characterized under an applied electric potential modulation. To detect minute spectroscopic features, the ultra-thin ITO film was coated over an extremely sensitive single-mode integrated optical waveguide, which provided a long pathlength with more than adequate sensitivity for optical interrogation of the ultra-thin film. Experimental configurations with broadband light and several laser lines at different modulation schemes of an applied electric potential were utilized to elucidate the nature of intrinsic changes. The imaginary component of the refractive index (absorption coefficient) of the ultra-thin ITO film is unequivocally shown to have a dependence on the applied potential and the profile of this dependence changes substantially even for wavelengths inside a small spectral window (500–600 nm). The characterization technique and the data reported here can be crucial to several applications of the ITO material as a transparent conductive electrode, as for example in spectroelectrochemical investigations of surface-confined redox species. - Highlights: • Optical waveguides are applied for spectroscopic investigations of ultra-thin films. • Ultra-thin ITO films in aqueous environment are studied under potential modulation. • Unique spectroscopic features of ultra-thin ITO films are unambiguously observed.

Electrical resistivity of CuAlMo thin films grown at room temperature by dc magnetron sputtering

Science.gov (United States)

Birkett, Martin; Penlington, Roger

2016-07-01

We report on the thickness dependence of electrical resistivity of CuAlMo films grown by dc magnetron sputtering on glass substrates at room temperature. The electrical resistance of the films was monitored in situ during their growth in the thickness range 10-1000 nm. By theoretically modelling the evolution of resistivity during growth we were able to gain an insight into the dominant electrical conduction mechanisms with increasing film thickness. For thicknesses in the range 10-25 nm the electrical resistivity is found to be a function of the film surface roughness and is well described by Namba’s model. For thicknesses of 25-40 nm the experimental data was most accurately fitted using the Mayadas and Shatkes model which accounts for grain boundary scattering of the conduction electrons. Beyond 40 nm, the thickness of the film was found to be the controlling factor and the Fuchs-Sonheimer (FS) model was used to fit the experimental data, with diffuse scattering of the conduction electrons at the two film surfaces. By combining the Fuchs and Namba (FN) models a suitable correlation between theoretical and experimental resistivity can be achieved across the full CuAlMo film thickness range of 10-1000 nm. The irreversibility of resistance for films of thickness >200 nm, which demonstrated bulk conductivity, was measured to be less than 0.03% following subjection to temperature cycles of -55 and +125 °C and the temperature co-efficient of resistance was less than ±15 ppm °C-1.

Spin Seebeck effect and ballistic transport of quasi-acoustic magnons in room-temperature yttrium iron garnet films

Science.gov (United States)

Noack, Timo B.; Musiienko-Shmarova, Halyna Yu; Langner, Thomas; Heussner, Frank; Lauer, Viktor; Heinz, Björn; Bozhko, Dmytro A.; Vasyuchka, Vitaliy I.; Pomyalov, Anna; L’vov, Victor S.; Hillebrands, Burkard; Serga, Alexander A.

2018-06-01

We studied the transient behavior of the spin current generated by the longitudinal spin Seebeck effect (LSSE) in a set of platinum-coated yttrium iron garnet (YIG) films of different thicknesses. The LSSE was induced by means of pulsed microwave heating of the Pt layer and the spin currents were measured electrically using the inverse spin Hall effect in the same layer. We demonstrate that the time evolution of the LSSE is determined by the evolution of the thermal gradient triggering the flux of thermal magnons in the vicinity of the YIG/Pt interface. These magnons move ballistically within the YIG film with a constant group velocity, while their number decays exponentially within an effective propagation length. The ballistic flight of the magnons with energies above 20 K is a result of their almost linear dispersion law, similar to that of acoustic phonons. By fitting the time-dependent LSSE signal for different film thicknesses varying by almost an order of magnitude, we found that the effective propagation length is practically independent of the YIG film thickness. We consider this fact as strong support of a ballistic transport scenario—the ballistic propagation of quasi-acoustic magnons in room temperature YIG.

Electrical and structural characterization of Nb-Si thin alloy film

International Nuclear Information System (INIS)

Nava, F.; Psaras, P.A.; Takai, H.; Tu, K.N.; Valeri, S.; Bisi, O.

1986-01-01

The structural and electrical properties of a Nb-Si thin alloy film as a function of temperature have been studied by Auger electron spectrometry, Rutherford backscattering spectroscopy, transmission electron microscopies, and in situ electrical resistivity and Hall coefficient measurements. The NbSi/sub 2.8/ films were deposited by double electron-gun coevaporation onto oxidized silicon. For electrical measurements samples of a van der Pauw pattern were made through metallic masks. In the as-deposited state the coevaporated alloy film was amorphous. Upon annealing a precipitous drop in resistivity near 270 0 C has been determined to be the amorphous to crystalline phase transformation. The kinetics of the transformation has been determined by isothermal heat treatment over the temperature range of 224 0 to 252 0 C. An apparent activation energy of 1.90 eV has been measured. The nucleation and growth kinetics in the crystallization process show a change in the power of time dependence from 5.5 to 2.4. The microstructures of films at various states of annealing have been correlated to the resistivity change. The crystalline NbSi 2 shows an anomalous metallic behavior. The resistivity (rho) versus temperature curve has a large negative deviation from linearity (dfl) and it approaches a saturation value (rho/sub sat/) as temperature increases. The resistivity data are fitted by two empirical expressions put forth to explain the resistivity behavior in A15 superconductors at low and high temperatures. One is based on the idea that ideal resistivity must approach some limiting value in the regime where the mean free path becomes comparable to the interatomic spacing and the other is based on a selective electron--phonon assisted scattering

Structural, optical and electrical characteristics of nickel oxide thin films synthesised through chemical processing method

Science.gov (United States)

Akinkuade, Shadrach; Mwankemwa, Benanrd; Nel, Jacqueline; Meyer, Walter

2018-04-01

A simple and cheap chemical deposition method was used to produce a nickel oxide (NiO) thin film on glass substrates from a solution that contained Ni2+ and monoethanolamine. Thermal treatment of the film at temperatures above 350 °C for 1 h caused decomposition of the nickel hydroxide into nickel oxide. Structural, optical and electrical properties of the film were studied using X-ray diffraction (XRD), spectrophotometry, current-voltage measurements and scanning electron microscopy (SEM). The film was found to be polycrystalline with interplanar spacing of 0.241 nm, 0.208 nm and 0.148 nm for (111), (200) and (220) planes respectively, the lattice constant a was found to be 0.417 nm. The film had a porous surface morphology, formed from a network of nanowalls of average thickness of 66.67 nm and 52.00 nm for as-deposited and annealed films respectively. Transmittance of visible light by the as-deposited film was higher and the absorption edge of the film blue-shifted after annealing. The optical band gap of the annealed film was 3.8 eV. Electrical resistivity of the film was 378 Ωm.

Electrical and optical properties of Cu–Cr–O thin films fabricated by chemical vapour deposition

Energy Technology Data Exchange (ETDEWEB)

Lunca Popa, P., E-mail: petru.luncapopa@list.lu; Crêpellière, J.; Leturcq, R.; Lenoble, D.

2016-08-01

We present electrical and optical properties of CuCrO{sub 2} thin films deposited by chemical vapour deposition, as well as the influence of depositions' parameters on these properties. Oxygen partial pressure and precursor's concentrations have the greatest influence on optical and electrical properties of the films. Values of conductivities ranging from 10{sup −4} to 10 S/cm were obtained using different deposition conditions. The conductivity is thermally activated with an activation energy ranging from 57 to 283 meV. Thermoelectric measurements confirm the p-type conduction, and demonstrate high carrier concentration typical for a degenerate semiconductor. The as-deposited films show a medium degree of crystallinity, a maximum optical transmission up to 80% in the visible range with a corresponding band gap around 3.2 eV. - Highlights: • CuCrO{sub 2} thin films deposited via a new innovative method - DLICVD. • Band gap and electrical conductivity can be tuned by controlling deposition parameters • Key process parameter is the metallic/oxygen atomic ratio involved in the process • Electrical conductivities values spanning 5 orders of magnitudes were obtained using different deposition parameters.

Electrical, optical and etching properties of Zn-Sn-O thin films deposited by combinatorial sputtering

International Nuclear Information System (INIS)

Kim, J. S.; Park, J. K.; Baik, Y. J.; Kim, W. M.; Jeong, J.; Seong, T. Y.

2012-01-01

Zn-Sn-O (ZTO) films are known to be able to form an amorphous phase, which provides a smooth surface morphology as well as etched side wall, when deposited by using the conventional sputtering technique and, therefore, to have a potential to be applied as transparent thin film transistors. In this study, ZTO thin films were prepared by using combined sputtering of ZnO and SnO 2 targets, and the dependences of their electrical and optical properties on the composition and the deposition parameters were examined. The Sn content in the films was varied in the range of 35 ∼ 85 at .%. The deposition was carried out at room temperature, 150 and 300 .deg. C, and the oxygen content in sputtering gas was varied from 0 to 1 vol.%. Sn-rich films had better electrical properties, but showed large oxygen deficiency when deposited at low oxygen partial pressures. ZTO films with Sn contents lower than 55 at.% had good optical transmission, but the electrical properties were poor due to very low carrier concentrations. A high Hall mobility of larger than 10 cm 2 /Vs could be obtained in the carrier density range 10 17 ∼ 10 20 cm -3 , and the etching rate was measurable for films with Sn content up to 70 at.% when using a dilute HCl solution, indicating a good possibility of utilizing ZTO films for device applications.

Kinetic phenomena in Sc films

International Nuclear Information System (INIS)

Stasyuk, Z.V.

1992-01-01

Size effects in electrical conductivity, thermoelectric power and Hall coefficient of thin scandium films have been investigated. An analysis of experimental data was made within the framework of Mayadas-Shatzkes and Tellier-Tosser-Pichard models. The transport parameters of scandium have been found. (author)

URBAN PUBLIC TRANSPORT WITH THE USE OF ELECTRIC BUSES – DEVELOPMENT TENDENCIES

Directory of Open Access Journals (Sweden)

Stanisław KRAWIEC

2016-12-01

Full Text Available The programing documents of the European Union determine the direction of transport systems development, including large cities and agglomerations. The context of these actions which aim to transform into ecologically clean and sustainable transport system is a significant reduction of greenhouse gas emissions. Assuming that public transport will significantly reduce the use of combustion-powered buses, studies on urban logistic enabling the use of electric buses for public transport are needed. The article presents the variants and scenarios for electric buses implementation in urban public transport, as well as the decision algorithm to support electric bus implementation based on technological, organisational, economic and ecological variables.

Electricity transport regimes: their impact on cogeneration

Energy Technology Data Exchange (ETDEWEB)

Cotard, Erwan [COGEN, Europe (Belgium)

2000-12-01

In many cases the main product of cogeneration is heat and the surplus electricity is sold to the grid. However, the economics of cogeneration can be influenced by transport networks (transmission and distribution): the structure of network pricing is relatively new. In a recent note from COGEN Europe it was recommended that cogenerators who use only the local distribution system should not pay for the transmission system and that tariffs should be structured in sufficient detail for the advantages of decentralisation to be realised. The article is presented under the sub-headings of (i) why is this important? (the omission of the transmission element reduces the overall price of cogeneration); (ii) the advantages of decentralised cogeneration; (iv) the theory - the different systems (the European Directive on electricity market liberalization); (v) the options for transport fees; (vi) current regimes in some EU states (vii) the case of transborder transport; impact of each system on cogeneration; recommendations to policymakers; (viii) the Netherlands and (ix) the UK.

Implanted ZnO thin films: Microstructure, electrical and electronic properties

International Nuclear Information System (INIS)

Lee, J.; Metson, J.; Evans, P.J.; Kinsey, R.; Bhattacharyya, D.

2007-01-01

Magnetron sputtered polycrystalline ZnO thin films were implanted using Al, Ag, Sn, Sb and codoped with TiN in order to improve the conductivity and to attempt to achieve p-type behaviour. Structural and electrical properties of the implanted ZnO thin films were examined with X-ray diffractometry (XRD), scanning electron microscopy (SEM), secondary ion mass spectrometry (SIMS), atomic force microscopy (AFM) and conductivity measurements. Depth profiles of the implanted elements varied with the implant species. Implantation causes a partial amorphisation of the crystalline structure and decreases the effective grain size of the films. One of the findings is the improvement, as a consequence of implantation, in the conductivity of initially poorly conductive samples. Heavy doping may help for the conversion of conduction type of ZnO thin films. Annealing in vacuum mitigated structural damage and stress caused by implantation, and improved the conductivity of the implanted ZnO thin films

Graphene-based LbL deposited films: further study of electrical and gas sensing properties

Directory of Open Access Journals (Sweden)

Nabok A.

2017-01-01

Full Text Available Graphene-surfactant composite materials obtained by the ultrasonic exfoliation of graphite powder in the presence of ionic surfactants (either CTAB or SDS were utilised to construct thin films using layer-by-layer (LbL electrostatic deposition technique. A series of graphene-based thin films were made by alternating layers of either graphene-SDS with polycations (PEI or PAH or graphene-CTAB with polyanions (PSS. Also, graphene-phthalocyanine composite films were produced by alternating layers of graphene-CTAB with tetrasulfonated nickel phthalocyanine. Graphene-surfactant LbL films exhibited good electric conductivity (about 0.1 S/cm of semiconductor type with a band gap of about 20 meV. Judging from UV-vis spectra measurements, graphene-phthalocyanine LbL films appeared to form joint π-electron system. Gas sensing testing of such composite films combining high conductivity of graphene with the gas sensing abilities of phthalocyanines showed substantial changes (up to 10% in electrical conductivity upon exposure to electro-active gases such as HCl and NH3.

ITO films with enhanced electrical properties deposited on unheated ZnO-coated polymer substrates

International Nuclear Information System (INIS)

Nunes de Carvalho, C.; Lavareda, G.; Fortunato, E.; Alves, H.; Goncalves, A.; Varela, J.; Nascimento, R.; Amaral, A.

2005-01-01

Indium tin oxide (ITO) films were deposited by radio frequency (rf)-plasma enhanced reactive thermal evaporation (rf-PERTE) at room temperature on intrinsic ZnO/polymer substrates to enhance their electrical and structural properties. The polymer substrate used is polyethylene terephthalate (PET). The thickness of the ZnO films varied in the range 50-150 nm. The average thickness of the ITO films is of about 170 nm. Results show that ITO deposited on bare PET substrates exhibit: an average visible transmittance of about 85% and an electrical resistivity of 5.6 x 10 -2 Ω cm. ITO on ZnO/PET substrates show the optical quality practically preserved and the resistivity decreased to a minimum value of 1.9x10 -3 Ω cm for ZnO layers 125 nm thick. The electrical properties of ITO on ZnO/PET are largely improved by the increase in carrier mobility

Electrical characteristics of SrTiO{sub 3}/Al{sub 2}O{sub 3} laminated film capacitors

Energy Technology Data Exchange (ETDEWEB)

Peng, Yong; Yao, Manwen, E-mail: yaomw@tongji.edu.cn; Chen, Jianwen; Xu, Kaien; Yao, Xi [Functional Materials Research Laboratory, School of Materials Science and Engineering, Tongji University, Shanghai 200092 (China)

2016-07-07

The electrical characteristics of SrTiO{sub 3}/Al{sub 2}O{sub 3} (160 nm up/90 nm down) laminated film capacitors using the sol-gel process have been investigated. SrTiO{sub 3} is a promising and extensively studied high-K dielectric material, but its leakage current property is poor. SrTiO{sub 3}/Al{sub 2}O{sub 3} laminated films can effectively suppress the demerits of pure SrTiO{sub 3} films under low electric field, but the leakage current value reaches to 0.1 A/cm{sup 2} at higher electric field (>160 MV/m). In this study, a new approach was applied to reduce the leakage current and improve the dielectric strength of SrTiO{sub 3}/Al{sub 2}O{sub 3} laminated films. Compared to laminated films with Au top electrodes, dielectric strength of laminated films with Al top electrodes improves from 205 MV/m to 322 MV/m, simultaneously the leakage current maintains the same order of magnitude (10{sup −4} A/cm{sup 2}) until the breakdown occurs. The above electrical characteristics are attributed to the anodic oxidation reaction in origin, which can repair the defects of laminated films at higher electric field. The anodic oxidation reactions have been confirmed by the corresponding XPS measurement and the cross sectional HRTEM analysis. This work provides a new approach to fabricate dielectrics with high dielectric strength and low leakage current.

Controlling In–Ga–Zn–O thin films transport properties through density changes

Energy Technology Data Exchange (ETDEWEB)

Kaczmarski, Jakub, E-mail: kaczmarski@ite.waw.pl [Institute of Electron Technology, al. Lotników 32/46, 02-668 Warsaw (Poland); Boll, Torben [Department of Applied Physics, Chalmers University of Technology, Fysikgränd 3, SE-412 96 Gothenburg (Sweden); Borysiewicz, Michał A. [Institute of Electron Technology, al. Lotników 32/46, 02-668 Warsaw (Poland); Taube, Andrzej [Institute of Electron Technology, al. Lotników 32/46, 02-668 Warsaw (Poland); Institute of Microelectronics & Optoelectronics, Warsaw University of Technology, ul. Koszykowa 75, 00-662 Warsaw (Poland); Thuvander, Mattias; Law, Jia Yan [Department of Applied Physics, Chalmers University of Technology, Fysikgränd 3, SE-412 96 Gothenburg (Sweden); Kamińska, Eliana [Institute of Electron Technology, al. Lotników 32/46, 02-668 Warsaw (Poland); Stiller, Krystyna [Department of Applied Physics, Chalmers University of Technology, Fysikgränd 3, SE-412 96 Gothenburg (Sweden)

2016-06-01

In the following study we investigate the effect of the magnetron cathode current (I{sub c}) during reactive sputtering of In–Ga–Zn–O (a-IGZO) on thin-films nanostructure and transport properties. All fabricated films are amorphous, according to X-ray diffraction measurements. However, High Resolution Transmission Electron Microscopy revealed the a-IGZO fabricated at I{sub C} = 70 mA to contain randomly-oriented nanocrystals dispersed in amorphous matrix, which disappear in films deposited at higher cathode current. These nanocrystals have the same composition as the amorphous matrix. One can observe that, while I{sub C} is increased from 70 to 150 mA, the carrier mobility improves from μ{sub Hall} = 6.9 cm{sup 2}/Vs to μ{sub Hall} = 9.1 cm{sup 2}/Vs. Additionally, the increase of I{sub C} caused a reduction of the depletion region trap states density of the Ru–Si–O/In–Ga–Zn–O Schottky barrier. This enhancement in transport properties is attributed to the greater overlapping of s-orbitals of the film-forming cations caused by increased density, evidenced by X-ray reflectivity, at a fixed chemical composition, regardless nanostructure of thin films. - Highlights: • Magnetron cathode current (I{sub C}) controls the transport properties of In–Ga–Zn–O (IGZO). • Low I{sub C} results in IGZO films with nanocrystalline inclusions in amorphous matrix. • High I{sub C} reduces the number of trap states in depletion region of Schottky contacts.

Strain and Defect Engineering for Tailored Electrical Properties in Perovskite Oxide Thin Films and Superlattices

Science.gov (United States)

Hsing, Greg Hsiang-Chun

Functional complex-oxides display a wide spectrum of physical properties, including ferromagnetism, piezoelectricity, ferroelectricity, photocatalytic and metal-insulating transition (MIT) behavior. Within this family, oxides with a perovskite structure have been widely studied, especially in the form of thin films and superlattices (heterostructures), which are strategically and industrially important because they offer a wide range of opportunities for electronic, piezoelectric and sensor applications. The first part of my thesis focuses on understanding and tuning of the built-in electric field found in PbTiO3/SrTiO3 (PTO/STO) ferroelectric superlattices and other ferroelectric films. The artificial layering in ferroelectric superlattices is a potential source of polarization asymmetry, where one polarization state is preferred over another. One manifestation of this asymmetry is a built-in electric field associated with shifted polarization hysteresis. Using off-axis RF-magnetron sputtering, we prepared several compositions of PTO/STO superlattice thin films; and for comparison PbTiO3/SrRuO 3 (PTO/SRO) superlattices, which have an additional intrinsic compositional asymmetry at the interface. Both theoretical modeling and experiments indicate that the layer-by-layer superlattice structure aligns the Pb-O vacancy defect dipoles in the c direction which contributes significantly to the built-in electric field; however the preferred polarization direction is different between the PTO/STO and PTO/SRO interface. By designing a hybrid superlattice that combines PTO/STO and PTO/SRO superlattices, we show the built-in electric field can be tuned to zero by changing the composition of the combo-superlattice. The second part of my thesis focuses on the epitaxial growth of SrCrO 3 (SCO) films. The inconsistent reports regarding its electrical and magnetic properties through the years stem from the compositionally and structurally ill-defined polycrystalline samples, but

Raman scattering, electrical and optical properties of fluorine-doped tin oxide thin films with (200) and (301) preferred orientation

Energy Technology Data Exchange (ETDEWEB)

Kim, Chang-Yeoul, E-mail: cykim15@kicet.re.kr [Nano-Convergence Intelligence Material Team, Korea Institute of Ceramic Eng. and Tech., Gasan-digtial-ro 10 Gil 77 Geumcheon-gu, 153-801 Seoul (Korea, Republic of); Riu, Doh-Hyung [Dept. of New Material Sci. and Eng., Seoul National University of Technology, Seoul (Korea, Republic of)

2014-12-15

(200) and (301) preferred oriented fluorine-doped tin oxide (FTO) thin films were fabricated by spray pyrolysis of ethanol-added and water-based FTO precursor solutions, respectively. (200) oriented FTO thin film from ethanol-added solution shows the lower electrical resistivity and visible light transmission than (301) preferred thin film from water-based solution. It is due to the higher carrier concentration and electron mobility in (200) oriented crystals, that is, the lower ionized impurity scattering. The higher electron concentration is related to the higher optical band gap energy, the lower visible light transmission, and the higher IR reflection. For (301) preferred FTO thin films from water-based solution, the lower carrier concentration and electron mobility make the higher electrical resistivity and visible light transmission. Raman scattering analysis shows that IR active modes prominent in (200) oriented FTO thin film are related with the lower electrical resistivity. - Highlights: • We coated fluorine-doped tin oxide thin films with preferred orientation of (200) and (301). • We examine changes in the level of electrical and optical properties with the orientation. • (200) preferred orientation showed lower electrical resistivity and optical transmittance. • (200) oriented thin films have higher electron concentrations that are related with IR active modes.

Study of post annealing influence on structural, chemical and electrical properties of ZTO thin films

International Nuclear Information System (INIS)

Jain, Vipin Kumar; Kumar, Praveen; Kumar, Mahesh; Jain, Praveen; Bhandari, Deepika; Vijay, Y.K.

2011-01-01

Research highlights: → Structural, chemical and electrical properties of cost effective ZTO thin films with varying concentrations. → Effect of annealing of ZTO films. - Abstract: Zinc-Tin-Oxide (ZTO) thin films were deposited on glass substrate with varying concentrations (ZnO:SnO 2 ; 100:0, 90:10, 70:30 and 50:50 wt.%) at room temperature by flash evaporation technique. These deposited ZTO films were annealed at 450 deg. C in vacuum. These films were characterized to study the effect of annealing and addition of SnO 2 concentration on the structural, chemical and electrical properties. The XRD analysis indicates that crystallization of the ZTO films strongly depends on the concentration of SnO 2 and post annealing where annealed films showed polycrystalline nature. Atomic force microscopy (AFM) images manifest the surface morphology of these ZTO thin films. The XPS core level spectra of Zn(2p), O(1s) and Sn(3d) have been deconvoluted into their Gaussian component to evaluate the chemical changes, while valence band spectra reveal the electronic structures of these films. A small shift in Zn(2p) and Sn(3d) core level towards higher binding energy and O(1s) core level towards lower binding energy have been observed. The minimum electrical resistivity (ρ ∼ 3.69 x 10 -2 Ω-cm), maximum carrier concentration (n ∼ 3.26 x 10 19 cm -3 ) and Hall mobility (μ ∼ 5.2 cm 2 v -1 s -1 ) were obtained for as-prepared ZTO (50:50) film thereafter move towards lowest resistivity (ρ ∼ 1.12 x 10 -3 Ω-cm), highest carrier concentration (n ∼ 2.96 x 10 20 cm -3 ) and mobility (μ ∼ 18.8 cm 2 v -1 s -1 ) for annealed ZTO (50:50) thin film.

Electric conduction mechanism of some heterocyclic compounds, 4,4′-bipyridine and indolizine derivatives in thin films

Energy Technology Data Exchange (ETDEWEB)

Danac, Ramona, E-mail: rdanac@uaic.ro [Faculty of Chemistry, Alexandru Ioan Cuza University of Iasi, Bulevardul Carol I, Nr. 11, 700506 Iasi (Romania); Leontie, Liviu, E-mail: lleontie@uaic.ro [Faculty of Physics, Alexandru Ioan Cuza University of Iasi, Bulevardul Carol I, Nr. 11, 700506 Iasi (Romania); Carlescu, Aurelian, E-mail: carlescu_aurelian@yahoo.com [Faculty of Physics, Alexandru Ioan Cuza University of Iasi, Bulevardul Carol I, Nr. 11, 700506 Iasi (Romania); Shova, Sergiu, E-mail: shova@icmpp.ro [Petru Poni Institute of Macromolecular Chemistry, Aleea Grigore Ghica Voda, Nr. 41A, 700487 Iasi (Romania); Tiron, Vasile, E-mail: vasile.tiron@uaic.ro [Faculty of Physics, Alexandru Ioan Cuza University of Iasi, Bulevardul Carol I, Nr. 11, 700506 Iasi (Romania); Rusu, George G., E-mail: rusugxg@uaic.ro [Faculty of Physics, Alexandru Ioan Cuza University of Iasi, Bulevardul Carol I, Nr. 11, 700506 Iasi (Romania); Iacomi, Felicia, E-mail: iacomi@uaic.ro [Faculty of Physics, Alexandru Ioan Cuza University of Iasi, Bulevardul Carol I, Nr. 11, 700506 Iasi (Romania); Gurlui, Silviu, E-mail: sgurlui@uaic.ro [Faculty of Physics, Alexandru Ioan Cuza University of Iasi, Bulevardul Carol I, Nr. 11, 700506 Iasi (Romania); Șușu, Oana, E-mail: oasusu@gmail.com [Faculty of Physics, Alexandru Ioan Cuza University of Iasi, Bulevardul Carol I, Nr. 11, 700506 Iasi (Romania); Rusu, Gheorghe I., E-mail: girusu@uaic.ro [Faculty of Physics, Alexandru Ioan Cuza University of Iasi, Bulevardul Carol I, Nr. 11, 700506 Iasi (Romania)

2016-08-01

Temperature dependence of d. c. electric conductivity of some recently synthesized heterocyclic compounds, 4,4′-bipyridine and indolizine derivatives, in thin films (d = 0.27–0.51 μm) spin-coated from chloroform solutions onto glass, is studied. The investigated compounds are polycrystalline (as shown by X-ray Diffraction analysis) and show typical n-type semiconductor behavior. The activation energy of d. c. electric conduction ranges between 1.55 and 2.33 eV. Some correlations between semiconducting characteristics and essential features of molecular structure of organic compounds have been established. In the higher temperature range (400–520 K), the electronic transport properties in present compounds can be explained in the frame of band gap representation model, while in the lower temperature range (300–350 K), the Mott's variable-range hopping conduction model can be conveniently used. - Highlights: • 4,4′-bipyridine and indolizine derivatives in thin films behave as n-type semiconductors. • The electron transfer is favored by extended conjugation and packing capacity. • The band gap representation is suitable in the higher temperature range. • The Mott's VRH conduction model may be used in the lower temperature range.

Vanadium Oxide Thin Films Alloyed with Ti, Zr, Nb, and Mo for Uncooled Infrared Imaging Applications

Science.gov (United States)

Ozcelik, Adem; Cabarcos, Orlando; Allara, David L.; Horn, Mark W.

2013-05-01

Microbolometer-grade vanadium oxide (VO x ) thin films with 1.3 Nb, Mo, and Zr using a second gun and radiofrequency (RF) reactive co-sputtering to probe the effects of the transition metals on the film charge transport characteristics. The results reveal that the temperature coefficient of resistance (TCR) and resistivity are unexpectedly similar for alloyed and unalloyed films up to alloy compositions in the ˜20 at.% range. Analysis of the film structures for the case of the 17% Nb-alloyed film by glancing-angle x-ray diffraction and transmission electron microscopy shows that the microstructure remains even with the addition of high concentrations of alloy metal, demonstrating the robust character of the VO x films to maintain favorable electrical transport properties for bolometer applications. Postdeposition thermal annealing of the alloyed VO x films further reveals improvement of electrical properties compared with unalloyed films, indicating a direction for further improvements in the materials.

Asymmetry of neoclassical transport by dipole electric field

International Nuclear Information System (INIS)

Wang Zhongtian; Wang Long

2004-01-01

Effects of dipole electric fields on neoclassical transport are studied. Large asymmetry in transport is created. The dipole fields, which are in a negative R-direction, reduce the ion drift, increase electron drift, and change the steps of excursion due to collisions. It is found that different levels of dipole field intensities have different types of transport. For the lowest level of the dipole field, the transport returns to the neoclassical one. For the highest level of the dipole field, the transport is turned to be the turbulence transport similar to the pseudo-classical transport. Experimental data may be corresponded to a large level of the dipole field intensity. (authors)

Thermal transport properties of polycrystalline tin-doped indium oxide films

International Nuclear Information System (INIS)

Ashida, Toru; Miyamura, Amica; Oka, Nobuto; Sato, Yasushi; Shigesato, Yuzo; Yagi, Takashi; Taketoshi, Naoyuki; Baba, Tetsuya

2009-01-01

Thermal diffusivity of polycrystalline tin-doped indium oxide (ITO) films with a thickness of 200 nm has been characterized quantitatively by subnanosecond laser pulse irradiation and thermoreflectance measurement. ITO films sandwiched by molybdenum (Mo) films were prepared on a fused silica substrate by dc magnetron sputtering using an oxide ceramic ITO target (90 wt %In 2 O 3 and 10 wt %SnO 2 ). The resistivity and carrier density of the ITO films ranged from 2.9x10 -4 to 3.2x10 -3 Ω cm and from 1.9x10 20 to 1.2x10 21 cm -3 , respectively. The thermal diffusivity of the ITO films was (1.5-2.2)x10 -6 m 2 /s, depending on the electrical conductivity. The thermal conductivity carried by free electrons was estimated using the Wiedemann-Franz law. The phonon contribution to the heat transfer in ITO films with various resistivities was found to be almost constant (λ ph =3.95 W/m K), which was about twice that for amorphous indium zinc oxide films

Formation of electrically conducting, transparent films using silver nanoparticles connected by carbon nanotubes

International Nuclear Information System (INIS)

Hwang, Sunna; Noh, Sun Young; Kim, Heesuk; Park, Min; Lee, Hyunjung

2014-01-01

To achieve both optical transparency and electrical conductivity simultaneously, we fabricated a single-walled carbon nanotube (SWNT)/silver fiber-based transparent conductive film using silver fibers produced by the electrospinning method. Electrospun silver fibers provided a segregated structure with the silver nanoparticles within the fibrous microstructures as a framework. Additional deposition of SWNT/poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate) (PEDOT:PSS) layers resulted in a remarkable decrease in the surface resistance from very high value (> 3000 kΩ/sq) for the films of electrospun silver fibers, without affecting the optical transmittance at 550 nm. The surface resistance of the SWNT/silver film after the deposition of three layers decreased to 17 Ω/sq with 80% transmittance. Successive depositions of SWNT/PEDOT:PSS layers reduced the surface resistance to 2 Ω/sq without severe loss in optical transmittance (ca. 65%). The transparent conductive films exhibited a performance comparable to that of commercial indium tin oxide films. The individual silver nanoparticles within the electrospun fibers on the substrate were interconnected with SWNTs, which resulted in the efficient activation of a conductive network by bridging the gaps among separate silver nanoparticles. Such a construction of microscopically conductive networks with the minimum use of electrically conductive nanomaterials produced superior electrical conductivity, while maintaining the optical transparency. - Highlights: • Silver fibrous structures were produced by electrospinning method. • SWNTs/PEDOT:PSS was deposited on silver fibrous structures. • These films exhibited a low sheet resistance (∼ 17 Ω/sq) at ∼ 80% optical transparency. • Successive depositions of SWNT/PEDOT:PSS layers reduced the surface resistance to 2 Ω/sq

Research and development of electric vehicles for clean transportation.

Science.gov (United States)

Wada, Masayoshi

2009-01-01

This article presents the research and development of an electric vehicle (EV) in Department of Human-Robotics Saitama Institute of Technology, Japan. Electric mobile systems developed in our laboratory include a converted electric automobile, electric wheelchair and personal mobile robot. These mobile systems contribute to realize clean transportation since energy sources and devices from all vehicles, i.e., batteries and electric motors, does not deteriorate the environment. To drive motors for vehicle traveling, robotic technologies were applied.

Electrical properties of thermally evaporated nickel-dimethylglyoxime thin films

Science.gov (United States)

Dakhel, A. A.; Ali-Mohamed Ahmed, Y.

2005-06-01

Thin Bis-(dimethylglyoximato)nickel(II) [Ni(DMG)2] films of amorphous and crystalline structures were prepared by vacuum deposition on Si (P) substrates. The films were characterised by X-ray fluorescence and X-ray diffraction. The constructed Al/Ni(DMG)2/Si(P) metal-insulator-semiconductor devices were characterised by the measurement of the gate-voltage dependence of their capacitance and ac conductance, from which the surface states density Dit of insulator/semiconductor interface and the density of the fixed charges in the oxide were determined. The ac electrical conduction and dielectric properties of the Ni(DMG)2-Silicon structure were studied at room temperature. The data of the ac measurements of the annealed films follow the correlated barrier-hopping CBH mode, from which the fundamental absorption bandgap, the minimum hopping distance, and other parameters of the model were determined.

Related electrical, superconducting and structural characteristics of low temperature indium films

International Nuclear Information System (INIS)

Belevtsev, B.I.; Pilipenko, V.V.; Yatsuk, L.Ya.

1981-01-01

Reported are results of a complex study of electrical, superconducting and structural properties of indium films vacuum evaporated onto a liquid helium-cooled substrate. Structural electron diffraction investigations gave a better insight into the general features of the annealing during the warming-up of cold-deposited films. It is found that the annealing of indium films to about 80 to 100 K entails an irreversible growth of interplanar separations due to decreasing inhomogeneous microstresses. As the films are warmed from 100 to 300 K, the principal annealing processes are determined by crystallite growth and development of dominating orientation. The changes in the residual resistance and in Tsub(c) with warming the cold-deported films are explained on the base of structural data obtained. In particular, a direct relationship is revealed between the crystallite size and Tsub(c) [ru

Remote PECVD silicon nitride films with improved electrical properties for GaAs P-HEMT passivation

CERN Document Server

Sohn, M K; Kim, K H; Yang, S G; Seo, K S

1998-01-01

In order to obtain thin silicon nitride films with excellent electrical and mechanical properties, we employed RPECVD (Remote Plasma Enhanced Chemical Vapor Deposition) process which produces less plasma-induced damage than the conventional PECVD. Through the optical and electrical measurements of the deposited films, we optimized the various RPECVD process parameters. The optimized silicon nitride films showed excellent characteristics such as small etch rate (approx 33 A/min by 7:1 BHF), high breakdown field (>9 MV/cm), and low compressive stress (approx 3.3x10 sup 9 dyne/cm sup 2). We successfully applied thin RPECVD silicon nitride films to the surface passivation of GaAs pseudomorphic high electron mobility transistors (P-HEMTs) with negligible degradations in DC and RF characteristics.

Thin films of molecular materials synthesized from fisher's carbene ferrocenyl: Film formation and electrical properties

International Nuclear Information System (INIS)

Sanchez-Vergara, M.E.; Ortiz, A.; Alvarez-Toledano, C.; Moreno, A.; Alvarez, J.R.

2008-01-01

The synthesis of materials from Fisher's carbene ferrocenyl of the elements chromium, molybdenum and tungsten was carried out. The Fisher's compounds that were synthesized included the following combinations of two different metallic atoms: iron with chromium, iron with molybdenum and iron with tungsten. The molecular solids' preparation was done in electro-synthesis cells with platinum electrodes. Thin films were prepared by vacuum thermal evaporation on quartz substrates and crystalline silicon wafers. Pellets and thin films from these compounds were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive spectroscopy, atomic force microscopy and ellipsometry. The powder and thin films synthesized from these materials show the same intra-molecular bonds shown by infrared spectroscopy results, suggesting that thermal evaporation does not alter these bonds in spite of the thin films being amorphous, in contrast with other bimetallic complexes where material decomposition occurs. The differences in the conductivity values of the prepared films are very small, so they may be attributed to the different metallic ions employed in each case. The tungsten complex exhibits a higher conductivity than the molybdenum and chromium complexes at room temperature. Electrical conductivity values found for thin films are higher than for pellets made of the same molecular materials

Control of electrical resistivity of TaN thin films by reactive sputtering for embedded passive resistors

International Nuclear Information System (INIS)

Kang, S.M.; Yoon, S.G.; Suh, S.J.; Yoon, D.H.

2008-01-01

Tantalum nitride thin films were deposited by radio frequency (RF) reactive sputtering at various N 2 /Ar gas flow ratios and working pressures to examine the change of their electrical resistivity. From the X-ray diffraction (XRD) and four-point probe sheet resistance measurements of the TaN x films, it was found that the change of the crystalline structures of the TaN x films as a function of the N 2 partial pressure caused an abrupt change of the electrical resistivity. When the hexagonal structure TaN thin films changed to an f.c.c. structure, the sheet resistance increased from 16 Ω/sq to 1396 Ω/sq. However, we were able to control the electrical resistivity of the TaN thin film in the range from 69 Ω/sq to 875 Ω/sq, with no change in crystalline structure, within a certain range of working pressures. The size of the grains in the scanning electron microscopy (SEM) images seemed to decrease with the increase of working pressure

Electrical and optical properties of spray - deposited CdSe thin films

International Nuclear Information System (INIS)

Bedir, M.; Oeztas, M.; Bakkaloglu, O. F.

2002-01-01

The CdSe thin films were developed by using spray-deposition technique at different substrate temperatures of 380C, 400C and, 420C on the glass substrate. All spraying processes involved CdCI 2 (0.05 moles/liter) and SeO 2 (0.05 moles/liter ) and were carried out in atmospheric condition. The CdSe thin film samples were characterized using x-ray diffractometer and optical absorption measurements. The electrical properties of the thin film samples were investigated via Wander Pauw method. XRD patterns indicated that the CdSe thin film samples have a hexagonal structure. The direct band gap of the CdSe thin film samples were determined from optical absorption and spectral response measurements of 1.76 eV. The resistivity of the CdSe thin film samples were found to vary in the range from 5.8x10''5 to 7.32x10''5 Ωcm depending to the substrate temperature

Influence of a ZnO Buffer Layer on the Structural, Optical, and Electrical Properties of ITO/ZnO Bi-Layered Films

International Nuclear Information System (INIS)

Heo, Sung-Bo; Moon, Hyun-Joo; Kim, Daeil; Kim, Jun-Ho

2016-01-01

Sn-doped indium oxide (ITO) films and ITO/ZnO bi-layered films were prepared on polycarbonate substrates by RF magnetron sputtering without intentional substrate heating. In order to consider the influence of the ZnO thickness on the structural, optical, and electrical properties of ITO/ZnO films, the thickness of the ZnO buffer layer was varied from 5 to 20 nm. As-deposited ITO films show an average optical transmittance of 79.2% in the visible range and an electrical resistivity of 3.0×10"-"4 Ωcm, while films with a 5-nm thick ZnO buffer layer film show an electrical resistivity of 2.6×10"-"4 Ωcm and films with a 20-nm thick ZnO buffer layer show an optical transmittance of 82.0%. Based on the figure of merit, it is concluded that the ZnO buffer layer enhances the optical and electrical performance of ITO films used as transparent conducting oxides in flexible display applications.

Workshop on diamond and diamond-like-carbon films for the transportation industry

Energy Technology Data Exchange (ETDEWEB)

Nichols, F.A.; Moores, D.K. [eds.

1993-01-01

Applications exist in advanced transportation systems as well as in manufacturing processes that would benefit from superior tribological properties of diamond, diamond-like-carbon and cubic boron nitride coatings. Their superior hardness make them ideal candidates as protective coatings to reduce adhesive, abrasive and erosive wear in advanced diesel engines, gas turbines and spark-ignited engines and in machining and manufacturing tools as well. The high thermal conductivity of diamond also makes it desirable for thermal management not only in tribological applications but also in high-power electronic devices and possibly large braking systems. A workshop has been recently held at Argonne National Laboratory entitled ``Diamond and Diamond-Like-Carbon Films for Transportation Applications`` which was attended by 85 scientists and engineers including top people involved in the basic technology of these films and also representatives from many US industrial companies. A working group on applications endorsed 18 different applications for these films in the transportation area alone. Separate abstracts have been prepared.

Effects of γ-rays on electrical conductivity of polyvinyl alcohol-polypyrrole composite polymer films

International Nuclear Information System (INIS)

Mohd Hamzah Harun; Elias Saion; Noorhana Yahya; Anuar Kassim; Ekramul Mahmud; Muhammad Yousuf Hussain; Iskandar Shahrim Mustafa; Azian Othman; Norazimah Mohd Yusof; Mohd Ahmad Ali Omer

2007-01-01

The composite polymer films of polyvinyl alcohol/polypyrrole/chloral hydrate (PVA-PPy-CH) had been prepared. Effects of γ-rays on the electrical conductivity of the composite polymer films had been investigated by using Inductance Resistance meter (LCR) meter at a frequency ranging from 20 Hz to 1 MHz. With the incorporation of choloral hydrate in the polymer sample, the conductivity increased indicates that it is capable to be used as dopant for polymerizing conjugated polymer. The electrical conductivity obtained increased as the dose increased, which is in the order of 10 -5 Scm -1 indicates that γ-ray is capable to enhance the electrical conductivity of the composite polymer films. The parameter of s is in the range of 0.31 ≤ S ≤ 0.49 and obeyed simple power law dispersion ω S . The Scanning Electron Microscopy (SEM) micrographs reveal the formation of polypyrrole globules in polyvinyl alcohol matrix which increased as the irradiation dose was increased. (Author)

Enhancement of charge-transport characteristics in polymeric films using polymer brushes

DEFF Research Database (Denmark)

Whiting, G.L.; Snaith, H.J.; Khodabakhsh, S.

2006-01-01

We show that charge-transporting polymer chains in the brush conformation can be synthesized from a variety of substrates of interest, displaying a high degree of stretching and showing up to a 3 orders of magnitude increase in current density normal to the substrate as compared with a spin......-coated film. These nanostructured polymeric films may prove to be suitable for electronic devices based on molecular semiconductors as current fabrication techniques often provide little control over film structure....

Graphene derivatives/Fe{sub 3}O{sub 4}/polymer nanocomposite films: Optical and electrical properties

Energy Technology Data Exchange (ETDEWEB)

Hatel, Rhizlane [University Sidi Mohammed Ben Abdellah, Faculty of Sciences Dhar El Mahraz, Laboratory of Solid State Physics, Group of Polymers and Nanomaterials, PO Box 1796, Atlas, Fez 30000 (Morocco); Goumri, Meryem [University Sidi Mohammed Ben Abdellah, Faculty of Sciences Dhar El Mahraz, Laboratory of Solid State Physics, Group of Polymers and Nanomaterials, PO Box 1796, Atlas, Fez 30000 (Morocco); XLIM UMR 7252- University of Limoges/CNRS, 123 Avenue Albert Thomas, 87060 Limoges Cedex (France); Ratier, Bernard [XLIM UMR 7252- University of Limoges/CNRS, 123 Avenue Albert Thomas, 87060 Limoges Cedex (France); Baitoul, Mimouna, E-mail: baitoul@yahoo.fr [University Sidi Mohammed Ben Abdellah, Faculty of Sciences Dhar El Mahraz, Laboratory of Solid State Physics, Group of Polymers and Nanomaterials, PO Box 1796, Atlas, Fez 30000 (Morocco)

2017-06-01

This paper reports a simple solution casting method for the preparation of nanocomposite films in which graphene oxide (GO)/Fe{sub 3}O{sub 4} nanocomposites are incorporated into poly (vinyl alcohol) (PVA) matrix. The films obtained with different weight percent of GO/Fe{sub 3}O{sub 4} (0.5, 0.7 and 1 wt%) are subjected an in situ chemical and thermal reduction in order to explore the evolution and interactions between these components under different treatments and get an insight into on how this can affects the optical and electrical properties of these nanocomposites. Characterization was carried out using, UV–Vis absorption, Photoluminescence, electrical conductivity measurements, Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy. Strong covalent functionalization occurs between the polymer and graphene derivatives (GD)/Fe{sub 3}O{sub 4} hybrids. The experimental results obtained for our nanocomposites films exhibit significant enhancement in properties highlighted the efficiency of the in situ thermal reduction. The high absorption with strong photoluminescence and electrical conductivity achieved might promote these nanocomposites for opto-electronic devices in near future. - Highlights: • Novel inorganic-organic hybrid flexible films were successfully prepared. • Good interfacial interaction between the graphene/Fe{sub 3}O{sub 4} and the hydroxyl-rich PVA. • Optical and electrical properties of Graphene Derivatives/Fe{sub 3}O{sub 4}/PVA were investigated. • Thermally reduced GO/Fe{sub 3}O{sub 4}/PVA films show high absorption and strong photoluminescence.

Correlation of Critical Temperatures and Electrical Properties in Titanium Films

Science.gov (United States)

Gandini, C.; Lacquaniti, V.; Monticone, E.; Portesi, C.; Rajteri, M.; Rastello, M. L.; Pasca, E.; Ventura, G.

Recently transition-edge sensors (TES) have obtained an increasing interest as light detectors due to their high energy resolution and broadband response. Titanium (Ti), with transition temperature up to 0.5 K, is among the suitable materials for TES application. In this work we investigate Ti films obtained from two materials of different purity deposited by e-gun on silicon nitride. Films with different thickness and deposition substrate temperature have been measured. Critical temperatures, electrical resistivities and structural properties obtained from x-ray are related to each other.

Development of Nanoscale Graphitic Devices and The Transport Characterization

International Nuclear Information System (INIS)

Gunasekaran, Venugopal

2011-02-01

This dissertation describes the development of graphitic based nanoscale devices with its fabrication and transport characterization results. It covers graphite nano-scale stacked-junctions fabricated using focused ion beam (FIB) 3-D etching technique, a single layer graphite layer (graphene) preparation and its electrical transport characterization results and the synthesis and investigation of electrical transport behavior of graphene oxide based thin film devices. The first chapter describes the basic information about the carbon family in detail in which the electronic properties and structure of graphite, graphene and graphene oxide are discussed. In addition, the necessity of developing nanoscale graphitic devices is given. The second chapter explains the experimental techniques used in this research for fabricating nanoscale devices which includes focused ion beam 3-D fabrication procedures, mechanical exfoliation technique and photolithographic methods. In third chapter, we have reported the results on temperature dependence of graphite planar-type structures fabricated along ab-plane. In the fourth and fifth chapters, the fabrication and electrical transport characteristics of large in-plane area graphite planar-type structures (fabricated along ab-plane and c-axis) were discussed and their transport anisotropy properties were investigated briefly. In the sixth chapter, we focused the fabrication of the submicron sized graphite stacked junctions and their electrical transport characterization studies. In which, FIB was used to fabricated the submicron junctions with various in-plane area (with same stack height) are and their transport characteristics were compared. The seventh chapter reports investigation of electrical transport results of nanoscale graphite stacked-junctions in which the temperature dependent transport (R-T) studies, current-voltage measurements for the various in-plane areas and for various stack height samples were analyzed. The

Environmental effects on electrical properties of Cr-Si-Ni resistive films deposited by magnetron sputtering

International Nuclear Information System (INIS)

Zhang Yuqin; Dong Xianping; Wu Jiansheng

2005-01-01

The present paper investigated the environmental effects on electrical properties stability and long-term reliability of magnetron sputtered Cr-Si-Ni resistive films in 3.5% NaCl, 0.5 M Na 2 SO 4 and 0.5 M HCl solutions at 25 deg. C, which simulated marine, industrial and acidic environments. The relative resistance change (ΔR/R) for the annealed films revealed that the films had the best electrical properties stability and long-term reliability in industrial environments at 25 deg. C. After immersion in corrosion solutions for 480 h, the value of ΔR/R for the films was only 0.41% in industrial environments, and the values were 0.56 and 1.96% in marine and acidic environments, respectively. The polarization measurements and AES results indicated that the films presented a spontaneous trend to passivation, and could form a dense and stable protective oxide layer (Si oxide) on its surface rapidly that protected the films from further corrosion in three different environments. Furthermore, the formed passive film in industrial environments exhibited much more protective effects on the films than in marine and acidic environments

Photoconductivity of oxidized nanostructured PbTe(In) films

International Nuclear Information System (INIS)

Dobrovolsky, A A; Ryabova, L I; Khokhlov, D R; Dashevsky, Z M; Kasiyan, V A

2009-01-01

Photoconductivity of as-grown and oxidized nanocrystalline PbTe(In) films has been studied in the dc and ac modes at temperatures 4.2–300 K. The electric transport in the films is defined by two mechanisms: conductivity through barriers at grain boundaries and transport along inversion channels at the grain surface. Modification of the transport mechanisms induced by oxidation is considered. Relatively weak oxidation results in an increase in the contribution of grain barriers to conductivity followed by an enhancement of the photoconductivity amplitude. Instead, this contribution drops in the case of deep oxidation resulting in a photoresponse reduction. It is shown that the main mechanism of charge transport in deeply oxidized films at low temperatures is hopping along inversion channels at the grain surface. It is demonstrated that the photoconductive response of nanocrystalline materials may be optimized by variation of the oxidation level, measurement frequency and temperature

Electrical and optical properties of ITO and ITO/Cr-doped ITO films

International Nuclear Information System (INIS)

Caricato, A.P.; Cesaria, M.; Luches, A.; Martino, M.; Valerini, D.; Maruccio, G.; Catalano, M.; Cola, A.; Manera, M.G.; Lomascolo, M.; Taurino, A.; Rella, R.

2010-01-01

In this paper we report on the effects of the insertion of Cr atoms on the electrical and optical properties of indium tin oxide (ITO) films to be used as electrodes in spin-polarized light-emitting devices. ITO films and ITO(80 nm)/Cr-doped ITO(20 nm) bilayers and Cr-doped ITO films with a thickness of 20 nm were grown by pulsed ArF excimer laser deposition. The optical, structural, morphological and electrical properties of ITO films and ITO/Cr-doped structures were characterized by UV-Visible transmission and reflection spectroscopy, transmission electron microscopy (TEM), atomic force microscopy (AFM) and Hall-effect analysis. For the different investigations, the samples were deposited on different substrates like silica and carbon coated Cu grids. ITO films with a thickness of 100 nm, a resistivity as low as ∝4 x 10 -4 Ω cm, an energy gap of ∝4.3 eV and an atomic scale roughness were deposited at room temperature without any post-deposition process. The insertion of Cr into the ITO matrix in the upper 20 nm of the ITO matrix induced variations in the physical properties of the structure like an increase of average roughness (∝0.4-0.5 nm) and resistivity (up to ∝8 x 10 -4 Ω cm). These variations were correlated to the microstructure of the Cr-doped ITO films with particular attention to the upper 20 nm. (orig.)

Electrical and optical properties of ITO and ITO/Cr-doped ITO films

Science.gov (United States)

Caricato, A. P.; Cesaria, M.; Luches, A.; Martino, M.; Maruccio, G.; Valerini, D.; Catalano, M.; Cola, A.; Manera, M. G.; Lomascolo, M.; Taurino, A.; Rella, R.

2010-12-01

In this paper we report on the effects of the insertion of Cr atoms on the electrical and optical properties of indium tin oxide (ITO) films to be used as electrodes in spin-polarized light-emitting devices. ITO films and ITO(80 nm)/Cr-doped ITO(20 nm) bilayers and Cr-doped ITO films with a thickness of 20 nm were grown by pulsed ArF excimer laser deposition. The optical, structural, morphological and electrical properties of ITO films and ITO/Cr-doped structures were characterized by UV-Visible transmission and reflection spectroscopy, transmission electron microscopy (TEM), atomic force microscopy (AFM) and Hall-effect analysis. For the different investigations, the samples were deposited on different substrates like silica and carbon coated Cu grids. ITO films with a thickness of 100 nm, a resistivity as low as ˜4×10-4 Ω cm, an energy gap of ˜4.3 eV and an atomic scale roughness were deposited at room temperature without any post-deposition process. The insertion of Cr into the ITO matrix in the upper 20 nm of the ITO matrix induced variations in the physical properties of the structure like an increase of average roughness (˜0.4-0.5 nm) and resistivity (up to ˜8×10-4 Ω cm). These variations were correlated to the microstructure of the Cr-doped ITO films with particular attention to the upper 20 nm.

Electrical and optical properties of ITO and ITO/Cr-doped ITO films

Energy Technology Data Exchange (ETDEWEB)

Caricato, A.P.; Cesaria, M.; Luches, A.; Martino, M.; Valerini, D. [University of Salento, Physics Department, Lecce (Italy); Maruccio, G. [University of Salento, Scuola Superiore Isufi, Lecce (Italy); Catalano, M.; Cola, A.; Manera, M.G.; Lomascolo, M.; Taurino, A.; Rella, R. [IMM-CNR, Institute for Microelectronics and Microsystems, Lecce (Italy)

2010-12-15

In this paper we report on the effects of the insertion of Cr atoms on the electrical and optical properties of indium tin oxide (ITO) films to be used as electrodes in spin-polarized light-emitting devices. ITO films and ITO(80 nm)/Cr-doped ITO(20 nm) bilayers and Cr-doped ITO films with a thickness of 20 nm were grown by pulsed ArF excimer laser deposition. The optical, structural, morphological and electrical properties of ITO films and ITO/Cr-doped structures were characterized by UV-Visible transmission and reflection spectroscopy, transmission electron microscopy (TEM), atomic force microscopy (AFM) and Hall-effect analysis. For the different investigations, the samples were deposited on different substrates like silica and carbon coated Cu grids. ITO films with a thickness of 100 nm, a resistivity as low as {proportional_to}4 x 10{sup -4} {omega} cm, an energy gap of {proportional_to}4.3 eV and an atomic scale roughness were deposited at room temperature without any post-deposition process. The insertion of Cr into the ITO matrix in the upper 20 nm of the ITO matrix induced variations in the physical properties of the structure like an increase of average roughness ({proportional_to}0.4-0.5 nm) and resistivity (up to {proportional_to}8 x 10{sup -4}{omega} cm). These variations were correlated to the microstructure of the Cr-doped ITO films with particular attention to the upper 20 nm. (orig.)

Electrical current at micro-/macro-scale of undoped and nitrogen-doped MWPECVD diamond films

Science.gov (United States)

Cicala, G.; Velardi, L.; Senesi, G. S.; Picca, R. A.; Cioffi, N.

2017-12-01

Chemical, structural, morphological and micro-/macro-electrical properties of undoped and nitrogen-(N-)doped diamond films are determined by X-ray photoelectron spectroscopy, Raman and photoluminescence spectroscopies, field emission scanning electron microscopy, atomic force microscopy, scanning capacitance microscopy (SCM) and two points technique for I-V characteristics, respectively. The characterization results are very useful to examine and understand the relationship among these properties. The effect of the nitrogen incorporation in diamond films is investigated through the evolution of the chemical, structural, morphological and topographical features and of the electrical behavior. The distribution of the electrical current is first assessed at millimeter scale on the surface of diamond films and then at micrometer scale on small regions in order to establish the sites where the carriers preferentially move. Specifically, the SCM images indicate a non-uniform distribution of carriers on the morphological structures mainly located along the grain boundaries. A good agreement is found by comparing the electrical currents at the micro- and macro-scale. This work aims to highlight phenomena such as photo- and thermionic emission from N-doped diamond useful for microelectronic engineering.

Correlation of electrical transport and magnetism in amorphous Mn-B alloys

Science.gov (United States)

Bryden, W. A.; Morgan, J. S.; Kistenmacher, T. J.; Moorjani, K.

1987-04-01

X-ray scattering, magnetism, and electrical transport studies on amorphous thin films of MnxB100-x alloys with x=52 and 48 are reported. Each alloy exhibits a low-field (5 G) static susceptibility peak (10 K, x=52; 16 K, x=48) associated with a spin-glass transition. Isothermal magnetization data (6 K) are analyzed within the random anisotropy model of Chudnovsky, Saslow, and Serota. The magnetization isotherm for the x=52 alloy is dominated at high fields (>24 kG) by field-induced moments, while for x=48 a term (αH-1/2) arising from a ferromagnet with a wandering axis prevails to the highest field strength (44 kG). Initially the electrical resistance for these Mn-B alloys decreases monotonically with decreasing temperature, reaching a minimum (Tm) at 22 K (x=52) and 45 K (x=48). For T>Tm, a quadratic form can be effectively employed, with a negative T2 coefficient and a positive linear coefficient. The rise in resistivity for T

The local structure, magnetic, and transport properties of Cr-doped In2O3 films

International Nuclear Information System (INIS)

Wang Shiqi; An Yukai; Feng Deqiang; Liu Jiwen; Wu Zhonghua

2013-01-01

Cr-doped In 2 O 3 films were deposited on Si (100) substrates by RF-magnetron sputtering technique. The local structure, magnetic, and transport properties of films are investigated by X-ray diffraction, X-ray photoelectron spectroscopy, X-ray absorption fine structure, Hall effect, R-T, and magnetic measurements. Structural analysis clearly indicates that Cr ions substitute for In 3+ sites of the In 2 O 3 lattice in the valence of +2 states and Cr-related secondary phases or clusters as the source of ferromagnetism is safely ruled out. The films with low Cr concentration show a crossover from semiconducting to metallic transport behavior, whereas only semiconducting behavior is observed in high Cr concentration films. The transport property of all films is governed by Mott variable range hopping behavior, suggesting that the carriers are strongly localized. Magnetic characterizations show that the saturated magnetization of films increases first, and then decreases with Cr doping, while carrier concentration n c decreases monotonically, implying that the ferromagnetism is not directly induced by the mediated carriers. It can be concluded the ferromagnetism of films is intrinsic and originates from electrons bound in defect states associated with oxygen vacancies.

Structural and electrical properties of CZTS thin films by electrodeposition

Science.gov (United States)

Rao, M. C.; Basha, Sk. Shahenoor

2018-06-01

CZTS (Cu2ZnSnS4) thin films were coated on ITO glass substrates by single bath electrodeposition technique. The prepared films were subsequently characterized by XRD, SEM, FTIR, UV-visible spectroscopy and Raman studies. The thickness of the thin films was measured by wedge method. X-ray diffraction studies revealed the formation of polycrystalline phase. The morphological surface of the prepared thin films was examined by SEM and AFM and showed the presence of microcrystals on the surface of the samples. The elemental analysis and their compositional ratios present in the samples were confirmed by the energy dispersive X-ray analysis. Functional groups and the position of band structure involved in the materials were confirmed by FTIR. Optical absorption studies were performed on the prepared thin films in the wavelength ranging from 300 to 1000 nm and the energy bandgap values were found to be in the range from 1.39 to 1.60 eV. Raman spectral peak which was observed at 360 cm-1 correspond to kesterite phase, was formed due to the vibration of the molecules. Electrical measurements confirmed the nature of the thin film depending on the charge concentration present in the samples.

Optical, electrical, structural and microstructural characteristics of rf sputtered ITO films developed for art protection coatings

International Nuclear Information System (INIS)

Krasilnikova Sytchkova, A.; Grilli, M.L.; Piegari, A.; Boycheva, S.

2007-01-01

Transparent and conductive tin-doped indium oxide (ITO) films have been prepared by rf sputtering in an Ar and Ar+O 2 gas mixture, both with and without additional substrate heating. The influence of both deposition conditions and post-annealing treatment on optical, electrical, structural and microstructural properties of the ITO films has been investigated. The optical constants have been calculated in the range 320-2500 nm using a combination of several theoretical models. A schematic diagram for the film properties change versus composition has been proposed in terms of a generalized parameter characterising the energy efficiency of the film formation. The deposition conditions and the optical and electrical properties of the films have been optimized with respect to the requirements for their application in art protection coatings. (orig.)

Optical and electrical characteristics of zirconium oxide thin films deposited on silicon substrates by spray pyrolysis

International Nuclear Information System (INIS)

Aguilar-Frutis, M.; Araiza, J.J.; Falcony, C.; Garcia, M.

2002-01-01

The optical and electrical characteristics of zirconium oxide thin films deposited by spray pyrolysis on silicon substrates are reported. The films were deposited from a spraying solution of zirconium acetylacetonate in N,N-dimethylformamide using an ultrasonic mist generator on (100) Si substrates. The substrate temperature during deposition was in the range of 400 to 600 grad C. Deposition rates up to 16 A/sec were obtained depending on the spraying solution concentration and on the substrate temperature. A refraction index of the order of 2.0 was measured on these films by ellipsometry. The electrical characteristics of the films were determined from the capacitance and current versus voltage measurements. The addition of water mist during the spraying deposition process was also studied in the characteristics of the films. (Authors)

Electrical and thermoelectric properties of different compositions of Ge–Se–In thin films

Energy Technology Data Exchange (ETDEWEB)

Aly, K.A., E-mail: kamalaly2001@gmail.com [Physics Department, Faculty of Science and Arts Khulais, University of Jeddah (Saudi Arabia); Physics Department, Faculty of Science, Al-Azhar University, Assiut Branch, Assiut (Egypt); Dahshan, A., E-mail: adahshan73@gmail.com [Department of Physics, Faculty of Science, Port Said University, Port Said (Egypt); Department of Physics, Faculty of Science for Girls, King Khalid University, Abha (Saudi Arabia); Abbady, Gh. [Department of Physics, Faculty of Science, Assuit University, Assuit (Egypt); Saddeek, Y. [Physics Department, Faculty of Science, Al-Azhar University, Assiut Branch, Assiut (Egypt)

2016-09-15

The effect of temperature in the range of 300–450 K and the indium content on the electrical and thermoelectric properties of Ge{sub 20}Se{sub 80−x}In{sub x} (0.0≤x≤24 at%) chalcogenide glassy thin films have been studied. From dc electrical and thermoelectric measurements, it was observed that the activation energies for electrical conductivity (ΔE) and for thermoelectric (ΔE{sub s}) decrease while the conductivity (σ) and Seebeck coefficient (S) increase upon introducing In into the Ge–Se glasses. In contrast to the behavior obtained with Bi or Pb doping, In incorporated in Ge–Se does not lead to a p-to n-type conduction inversion. The power factor (P) which is strongly depends on both of the Seebeck coefficient and the electrical conductivity. According to the obtained results, the Ge{sub 20}Se{sub 80−x}In{sub x} films can be considered potential candidates for incurring high action thermoelectric materials.

Optical and Electrical Properties of Copper Oxide Thin Films Synthesized by Spray Pyrolysis Technique

Directory of Open Access Journals (Sweden)

S. S. Roy

2015-08-01

Full Text Available Copper oxide (CuO thin films have been synthesized on to glass substrates at different temperatures in the range 250-450 °C by spray pyrolysis technique from aqueous solution using cupric acetate Cu(CH3COO2·H2O as a precursor. The structure of the deposited CuO thin films characterized by X-ray diffraction, the surface morphology was observed by a scanning electron microscope, the presence of elements was detected by energy dispersive X-ray analysis, the optical transmission spectra was recorded by ultraviolet-visible spectroscopy and electrical resistivity was studied by Van-der Pauw method. All the CuO thin films, irrespective of growth temperature, showed a monoclinic structure with the main CuO (111 orientation, and the crystallite size was about 8.4784 Å for the thin film synthesized at 350 °C. The optical transmission of the as-deposited film is found to decrease with the increase of substrate temperature, the optical band gap of the thin films varies from 1.90 to 1.60 eV and the room temperature electrical resistivity varies from 30 to18 Ohm·cm for the films grown at different substrate temperatures.

Electrical investigations of layer-by-layer films of carbon nanotubes

International Nuclear Information System (INIS)

Palumbo, M; Lee, K U; Ahn, B T; Suri, A; Coleman, K S; Zeze, D; Wood, D; Pearson, C; Petty, M C

2006-01-01

Single-wall carbon nanotubes (SWNTs) with anionic or cationic coatings have been prepared by exploiting the ability of certain surfactants to form a monolayer shell around the nanotube. The presence of electrically charged functional groups on the surface of the SWNT allows thin film deposition to proceed via the electrostatic layer-by-layer method. This self-assembly process was monitored using the quartz microbalance technique and Raman spectroscopy, while the morphology of the resulting thin layers was studied with atomic force microscopy. A variety of different architectures has been built up. In one arrangement, a single species of a modified SWNT (anionic or cationic) was alternated with a passive polymer to form a composite structure. A 'superlattice' architecture comprising alternating anionic and cationic modified nanotubes was also fabricated. The in-plane and out-of-plane dc conductivities of the films were measured at room temperature and contrasted with reference architectures (i.e. those containing no nanotubes). The results showed clearly that the incorporation of SWNTs into the multilayer assemblies provided electrically conductive thin films. It is suggested that the current versus voltage behaviour, particularly in the out-of-plane direction, is controlled by quantum mechanical tunnelling of carriers between the nanotubes

Study on the electrical properties of ITO films deposited by facing target sputter deposition

International Nuclear Information System (INIS)

Kim, Youn J; Jin, Su B; Kim, Sung I; Choi, Yoon S; Choi, In S; Han, Jeon G

2009-01-01

This study examined the mechanism for the change in the electrical properties (carrier concentration (n) and mobility (μ)) of tin-doped indium oxide (ITO) films deposited by magnetron sputtering in a confined facing magnetic field. The relationship between the carrier concentration and the mobility was significantly different from the results reported for ITO films deposited by other magnetron sputtering processes. The lowest resistivity obtained for ITO films deposited in a confined facing magnetic field at low substrate temperatures (approximately 120 0 C) was 4.26 x 10 -4 Ω cm at a power density of 3 W cm -2 . Crystalline ITO films were obtained at a low power density range from 3 to 5 W cm -2 due to the increase in the substrate temperature from 120 to 162 0 C. This contributed to the increased carrier concentration and decreased electrical resistivity. X-ray photoelectron spectroscopy revealed an increase in the concentration of the Sn 4+ states. This was attributed to the formation of a crystalline ITO film, which effectively enhanced the carrier concentration and reduced the carrier mobility.

Transport, mechanical and global migration data of multilayer copolyamide nanocomposite films with different layouts.

Science.gov (United States)

Scarfato, P; Garofalo, E; Di Maio, L; Incarnato, L

2017-06-01

Transport, mechanical and global migration data concern multilayer food packaging films with different layouts, all incorporating a layered silicate/polyamide nanocomposite as oxygen barrier layer, and a low-density polyethylene (LDPE) as moisture resistant layer in direct contact with food. The data are related to "Tuning of co-extrusion processing conditions and film layout to optimize the performances of PA/PE multilayer nanocomposite films for food packaging" by Garofalo et al. (2017) [1]. Nanocomposite multilayer films, with different relative layer thicknesses and clay types, were produced using a laboratory scale co-extrusion blown-film equipment and were analyzed in terms of transport to oxygen and water vapor, mechanical properties and overall migration. The results have shown that all the multilayer hybrid films, based on the copolyamide layer filled with Cloisite 30B, displayed the most significant oxygen barrier improvements and the best mechanical properties compared to the unfilled films. No significant alteration of the overall migration values was observed, as expectable [2], [3], [4]. The performance improvement was more relevant in the case of the film with the thinner nanocomposite layer.

Optical and electrical characterization of AgInS2 thin films deposited by spray pyrolysis

International Nuclear Information System (INIS)

Calixto-Rodriguez, M.; Martinez, H.; Calixto, M.E.; Pena, Y.; Martinez-Escobar, Dalia; Tiburcio-Silver, A.; Sanchez-Juarez, A.

2010-01-01

Silver indium sulfide (AgInS 2 ) thin films have been prepared by spray pyrolysis (SP) technique using silver acetate, indium acetate, and N, N-dimethylthiourea as precursor compounds. Films were deposited onto glass substrates at different substrate temperatures (T s ) and Ag:In:S ratios in the starting solutions. Optical transmission and reflection as well as electrical measurements were performed in order to study the effect of deposition parameters on the optical and electrical properties of AgInS 2 thin films. X-ray diffraction measurements were used to identify the deposited compounds. It was found that different compounds such as AgInS 2 , Ag 2 S, In 2 O 3 , and In 2 S 3 can be grown only by changing the Ag:In:S ratio in the starting solution and T s . So that, by carefully selecting the deposition parameters, single phase AgInS 2 thin films can be easily grown. Thin films obtained using a molar ratio of Ag:In:S = 1:1:2 and T s = 400 o C, have an optical band gap of 1.9 eV and n-type electrical conductivity with a value of 0.3 Ω -1 cm -1 in the dark.

Effect of annealing on electrical properties of plasmatron deposited ZnO films

International Nuclear Information System (INIS)

Joa, Sang Beom; Penkov, Oteksiy V.; Plaksin, Vadim Yu; Mansur, Rakib; Kim, Ji Hun; Lee, Heon Ju

2009-01-01

Transparent conductive zinc oxide (ZnO) has been extensively studied in recent several years because they have very interesting properties. Besides this, zinc oxide is non-poisonous, abundant and cheap material. ZnO films are employed in different applications like transparent conductive layers in solar cells, protective coatings and so on. Wide industrial application of the ZnO films requires of development of cheap, effective and scalable technology. Typically used technology like RF sputtering, pyrolysis and metal-organic CVD don't completely satisfy the industrial requirements. In our previous publications the new perspective ZnO deposition technology based DC Arc Plasmatron was described. This technology has several advantages (low cost, high deposition rate, low substrate temperature). Currently, films deposited using this technology has can be used only as protective or insulation coatings because of very high resistance. Applying of plasmatron technology in the microelectronics or solar cell production requires the improvement of electrical properties of the films. This can be achieved by optimization of deposition parameters, using of doping, or by post-deposition treatment such as annealing, or by combination of mentioned. It was shown that proposed technology can be used for the deposition of pure ZnO film with good electrical and optical properties. Proposed technology has several disadvantages which can be overcome in the near-term outlook

The effects of film thickness on the electrical, optical, and structural properties of cylindrical, rotating, magnetron-sputtered ITO films

Science.gov (United States)

Kim, Jae-Ho; Seong, Tae-Yeon; Ahn, Kyung-Jun; Chung, Kwun-Bum; Seok, Hae-Jun; Seo, Hyeong-Jin; Kim, Han-Ki

2018-05-01

We report the characteristics of Sn-doped In2O3 (ITO) films intended for use as transparent conducting electrodes; the films were prepared via a five-generation, in-line type, cylindrical, rotating magnetron sputtering (CRMS) system as a function of film thickness. By using a rotating cylindrical ITO target with high usage (∼80%), we prepared high conductivity, transparent ITO films on five-generation size glass. The effects of film thickness on the electrical, optical, morphological, and structural properties of CRMS-grown ITO films are investigated in detail to correlate the thickness and performance of ITO films. The preferred orientation changed from the (2 2 2) to the (4 0 0) plane with increasing thickness of ITO is attributed to the stability of the (4 0 0) plane against resputtering during the CRMS process. Based on X-ray diffraction, surface field emission scanning electron microscopy, and cross-sectional transmission electron microscopy, we suggest a possible mechanism to explain the preferred orientation and effects of film thickness on the performance of CRMS-grown ITO films.

Film growth kinetics and electric field patterning during electrospray deposition of block copolymer thin films

Science.gov (United States)

Toth, Kristof; Hu, Hanqiong; Choo, Youngwoo; Loewenberg, Michael; Osuji, Chinedum

The delivery of sub-micron droplets of dilute polymer solutions to a heated substrate by electrospray deposition (ESD) enables precisely controlled and continuous growth of block copolymer (BCP) thin films. Here we explore patterned deposition of BCP films by spatially varying the electric field at the substrate using an underlying charged grid, as well as film growth kinetics. Numerical analysis was performed to examine pattern fidelity by considering the trajectories of charged droplets during flight through imposed periodic field variations in the vicinity of the substrate. Our work uncovered an unexpected modality for improving the resolution of the patterning process via stronger field focusing through the use of a second oppositely charged grid beneath a primary focusing array, with an increase in highly localized droplet deposition on the intersecting nodes of the grid. Substrate coverage kinetics are considered for homopolymer deposition in the context of simple kinetic models incorporating temperature and molecular weight dependence of diffusivity. By contrast, film coverage kinetics for block copolymer depositions are additionally convoluted with preferential wetting and thickness-periodicity commensurability effects. NSF GRFP.

Reversible and nonvolatile ferroelectric control of two-dimensional electronic transport properties of ZrCuSiAs-type copper oxyselenide thin films with a layered structure

Science.gov (United States)

Zhao, Xu-Wen; Gao, Guan-Yin; Yan, Jian-Min; Chen, Lei; Xu, Meng; Zhao, Wei-Yao; Xu, Zhi-Xue; Guo, Lei; Liu, Yu-Kuai; Li, Xiao-Guang; Wang, Yu; Zheng, Ren-Kui

2018-05-01

Copper-based ZrCuSiAs-type compounds of LnCuChO (Ln =Bi and lanthanides, Ch =S , Se, Te) with a layered crystal structure continuously attract worldwide attention in recent years. Although their high-temperature (T ≥ 300 K) electrical properties have been intensively studied, their low-temperature electronic transport properties are little known. In this paper, we report the integration of ZrCuSiAs-type copper oxyselenide thin films of B i0.94P b0.06CuSeO (BPCSO) with perovskite-type ferroelectric Pb (M g1 /3N b2 /3 ) O3-PbTi O3 (PMN-PT) single crystals in the form of ferroelectric field effect devices that allow us to control the electronic properties (e.g., carrier density, magnetoconductance, dephasing length, etc.) of BPCSO films in a reversible and nonvolatile manner by polarization switching at room temperature. Combining ferroelectric gating and magnetotransport measurements with the Hikami-Larkin-Nagaoka theory, we demonstrate two-dimensional (2D) electronic transport characteristics and weak antilocalization effect as well as strong carrier-density-mediated competition between weak antilocalization and weak localization in BPCSO films. Our results show that ferroelectric gating using PMN-PT provides an effective and convenient approach to probe the carrier-density-related 2D electronic transport properties of ZrCuSiAs-type copper oxyselenide thin films.

Research on structure and electrical parameters of indium antimonide films

International Nuclear Information System (INIS)

Mukhametniyazova, A.; Konyaeva, V.F.; Sukhanov, S.; Ashirov, A.; Aleksanyan, S.N.

1980-01-01

Results of investigations into the effect of conditions of formation of indium antimonide films prepared by thermal vacuum spraying on their structure, phase composition and electric parameters, are presented. The method of studying the synthesized semiconductor layers on the DRON-0.5 X-ray device with CoKsub(α)-radiation is tested. The dependence of structure, phase composition and electric properties of InSb layers 1+3 μm thick sprayed on ferrite substrates on condensation temperature, is established. Hexagonal InSb modification is found

Research on structure and electrical parameters of indium antimonide films

Energy Technology Data Exchange (ETDEWEB)

Mukhametniyazova, A; Konyaeva, V F; Sukhanov, S; Ashirov, A; Aleksanyan, S N [AN Turkmenskoj SSR, Ashkhabad. Fiziko-Tekhnicheskii Inst.

1980-01-01

Results of investigations into the effect of conditions of formation of indium antimonide films prepared by thermal vacuum spraying on their structure, phase composition and electric parameters, are presented. The method of studying the synthesized semiconductor layers on the DRON-0.5 X-ray device with CoKsub(..cap alpha..)-radiation is tested. The dependence of structure, phase composition and electric properties of InSb layers 1+3 ..mu..m thick sprayed on ferrite substrates on condensation temperature, is established. Hexagonal InSb modification is found.

A Boltzmann-weighted hopping model of charge transport in organic semicrystalline films

KAUST Repository

Kwiatkowski, Joe J.; Jimison, Leslie H.; Salleo, Alberto; Spakowitz, Andrew J.

2011-01-01

We present a model of charge transport in polycrystalline electronic films, which considers details of the microscopic scale while simultaneously allowing realistically sized films to be simulated. We discuss the approximations and assumptions made by the model, and rationalize its application to thin films of directionally crystallized poly(3-hexylthiophene). In conjunction with experimental data, we use the model to characterize the effects of defects in these films. Our findings support the hypothesis that it is the directional crystallization of these films, rather than their defects, which causes anisotropic mobilities. © 2011 American Institute of Physics.

Growth and quantum transport properties of vertical Bi2Se3 nanoplate films on Si substrates.

Science.gov (United States)

Li, M Z; Wang, Z H; Yang, L; Pan, D S; Li, Da; Gao, Xuan; Zhang, Zhi-Dong

2018-05-14

Controlling the growth direction (planar vs. vertical) and surface-to-bulk ratio can lead to lots of unique properties for two-dimensional (2D) layered materials. We report a simple method to fabricate continuous films of vertical Bi2Se3 nanoplates on Si substrate and investigate the quantum transport properties of such films. In contrast to (001) oriented planar Bi2Se3 nanoplate film, vertical Bi2Se3 nanoplate films are enclosed by (015) facets, which possess high surface-to-bulk ratio that can enhance the quantum transport property of topological surface states. And by controlling the compactness of vertical Bi2Se3 nanoplates, we realized an effective tuning of the weak antilocalization (WAL) effect from topological surface states in Bi2Se3 films. Our work paves a way for exploring the unique transport properties of this unconventional structure topological insulator film. © 2018 IOP Publishing Ltd.

High-electric-field quantum transport theory for semiconductor superlattices

International Nuclear Information System (INIS)

Nguyen Hong Shon; Nazareno, H.N.

1995-12-01

Based on the Baym-Kadanoff-Keldysh nonequilibrium Green's functions technique, a quantum transport theory for semiconductor superlattices under high-electric field is developed. This theory is capable of considering collisional broadening, intra-collisional field effects and band transport and hopping regimes simultaneously. Numerical calculations for narrow-miniband superlattices in high electric field, when the hopping regime dominates are in reasonable agreement with experimental results and show a significant deviation from the Boltzmann theory. A semiphenomenological formula for current density in hopping regime is proposed. (author). 60 refs, 4 figs

Opto-electrical properties of amorphous carbon thin film deposited from natural precursor camphor

Energy Technology Data Exchange (ETDEWEB)

Pradhan, Debabrata [Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400 076 (India)]. E-mail: dpradhan@sciborg.uwaterloo.ca; Sharon, Maheshwar [Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400 076 (India)

2007-06-30

A simple thermal chemical vapor deposition technique is employed for the pyrolysis of a natural precursor 'camphor' and deposition of carbon films on alumina substrate at higher temperatures (600-900 deg. C). X-ray diffraction measurement reveals the amorphous structure of these films. The carbon films properties are found to significantly vary with the deposition temperatures. At higher deposition temperature, films have shown predominately sp{sup 2}-bonded carbon and therefore, higher conductivity and lower optical band gap (Tauc gap). These amorphous carbon (a-C) films are also characterized with Raman and X-ray photoelectron spectroscopy. In addition, electrical and optical properties are measured. The thermoelectric measurement shows these as-grown a-C films are p-type in nature.

Electric Field-Controlled Ion Transport In TiO2 Nanochannel.

Science.gov (United States)

Li, Dan; Jing, Wenheng; Li, Shuaiqiang; Shen, Hao; Xing, Weihong

2015-06-03

On the basis of biological ion channels, we constructed TiO2 membranes with rigid channels of 2.3 nm to mimic biomembranes with flexible channels; an external electric field was employed to regulate ion transport in the confined channels at a high ionic strength in the absence of electrical double layer overlap. Results show that transport rates for both Na+ and Mg2+ were decreased irrespective of the direction of the electric field. Furthermore, a voltage-gated selective ion channel was formed, the Mg2+ channel closed at -2 V, and a reversed relative electric field gradient was at the same order of the concentration gradient, whereas the Na+ with smaller Stokes radius and lower valence was less sensitive to the electric field and thus preferentially occupied and passed the channel. Thus, when an external electric field is applied, membranes with larger nanochannels have promising applications in selective separation of mixture salts at a high concentration.

Efficient reduction of graphene oxide film by low temperature heat treatment and its effect on electrical conductivity

Energy Technology Data Exchange (ETDEWEB)

Hu, Xuebing; Chen, Zheng [Jingdezhen Ceramic Institute, Jingdezhen (China). Key Lab. of Inorganic Membrane; Yu, Yun [Shanghai Institute of Ceramics, Shanghai (China). Key Lab. of Inorganic Coating Materials; Zhang, Xiaozhen; Wang, Yongqing; Zhou, Jianer [Jingdezhen Ceramic Institute, Jingdezhen (China). Dept. of Materials Engineering

2018-03-01

Graphene-based conductive films have already attracted great attention due to their unique and outstanding physical properties. In this work, in order to develop a novel, effective method to produce these films with good electrical conductivity, a simple and green method is reported to rapidly and effectively reduce graphene oxide film using a low temperature heat treatment. The reduction of graphene oxide film is verified by XRD, FT-IR and Raman spectroscopy. Compared with graphene oxide film, the obtained reduced graphene oxide film has better electrical conductivity and its sheet resistance decreases from 25.3 kΩ x sq{sup -1} to 3.3 kΩ x sq{sup -1} after the heat treatment from 160 to 230 C. The mechanism of thermal reduction of the graphene oxide film mainly results from the removal of the oxygen-containing functional groups and the structural changes. All these results indicate that the low temperature heat treatment is a suitable and effective method for the reduction of graphene oxide film.

Challenges and Opportunities of Grid Modernization and Electric Transportation

Energy Technology Data Exchange (ETDEWEB)

Graham, Robert L. [Dept. of Energy (DOE), Washington DC (United States); Francis, Julieta [Allegheny Science and Technology, Bridgeport, WV (United States); Bogacz, Richard J. [Allegheny Science and Technology, Bridgeport, WV (United States)

2017-03-31

Grid investments that support electric vehicle deployments as a part of planned modernization efforts can enable a more efficient and cost-effective transition to electric transportation and allow investor-owned electric companies and public power companies to realize new revenue resources in times of flat or declining loads. This paper discusses the challenges and opportunities associated with an increase in plug-in electric vehicle (PEV) adoption and how working together both sectors stand to benefit from closer integration.

A study on electric properties for pulse laser annealing of ITO film after wet etching

International Nuclear Information System (INIS)

Lee, C.J.; Lin, H.K.; Li, C.H.; Chen, L.X.; Lee, C.C.; Wu, C.W.; Huang, J.C.

2012-01-01

The electric properties of ITO thin film after UV or IR laser annealing and wet etching was analyzed via grazing incidence in-plane X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectra and residual stress measurement. The laser annealing process readily induced microcracks or quasi-microcracks on the ITO thin film due to the residual tension stress of crystalline phase transformation between irradiated and non-irradiated areas, and these defects then became the preferred sites for a higher etching rate, resulting in discontinuities in the ITO thin film after the wet etching process. The discontinuities in the residual ITO thin film obstruct carrier transmission and further result in electric failure. - Highlights: ► The laser annealing process induces microcracks in InSnO 2 thin films. ► The defects result in higher local etching rate during wet etching. ► These process defects originate from residual tension stress. ► Decreasing the thermal shock is suggested in order to reduce these process defects.

Electrical transport properties of calcium and barium aluminates

NARCIS (Netherlands)

Metselaar, R.; Hoefsloot, A.M.

1987-01-01

Electrical conductivity and ionic transport numbers have been measured of barium and calcium aluminates with composition CaO·nAl2O3 (n=7/12, 1, 2, 6) and 0.82 BaO·6Al2O3. At room temperatures these compounds are insulators, but at high temperatures mixed conductivity is observed. Ionic transport

Electrical and optical properties of ultrasonically sprayed Al-doped zinc oxide thin films

Energy Technology Data Exchange (ETDEWEB)

Babu, B.J., E-mail: jbabu@cinvestav.mx [Department of Electrical Engineering-SEES, CINVESTAV-IPN, Zacatenco, D.F., C.P. 07360 (Mexico); Maldonado, A.; Velumani, S.; Asomoza, R. [Department of Electrical Engineering-SEES, CINVESTAV-IPN, Zacatenco, D.F., C.P. 07360 (Mexico)

2010-10-25

Aluminium-doped ZnO (AZO) films were deposited by ultrasonic spray pyrolysis (USP) technique to investigate its potential application as antireflection coating and top contact layer for copper indium gallium diselenide (CIGS) based photovoltaic cells. The solution used to prepare AZO thin films contained 0.2 M of zinc acetate and 0.2 M of aluminium pentanedionate solutions in the order of 2, 3 and 4 at.% of Al/Zn. AZO films were deposited onto glass substrates at different substrate temperatures starting from 450 deg. C to 500 deg. C. XRD and FESEM analysis revealed the structural properties of the films and almost all the films possessed crystalline structure with a preferred (0 0 2) orientation except for the 4 at.% of Al. Grain size of AZO films varied from 29.7 to 37 nm for different substrate temperatures and atomic percentage of aluminium. The average optical transmittance of all films with the variation of doping concentration and substrate temperature was 75-90% in the visible range of wavelength 600-700 nm. Optical direct band gap value of 2, 3 and 4 at.% Al-doped films sprayed at different temperatures varied from 3.32 to 3.46 eV. Hall studies were carried out to analyze resistivity, mobility and carrier concentration of the films. AZO films deposited at different substrate temperatures and at various Al/Zn ratios showed resistivity ranging from 0.12 to 1.0 x 10{sup -2} {Omega} cm. Mobility value was {approx}5 cm{sup 2}/V s and carrier concentration value was {approx}7.7 x 10{sup 19} cm{sup -3}. Minimum electrical resistivity was obtained for the 3 at.% Al-doped film sprayed at 475 deg. C and its value was 1.0 x 10{sup -2} {Omega} cm with film thickness of 602 nm. The electrical conductivity of ZnO films was improved by aluminium doping.

Effect of thickness on electrical properties of SILAR deposited SnS thin films

Science.gov (United States)

Akaltun, Yunus; Astam, Aykut; Cerhan, Asena; ćayir, Tuba

2016-03-01

Tin sulfide (SnS) thin films of different thickness were prepared on glass substrates by successive ionic layer adsorption and reaction (SILAR) method at room temperature using tin (II) chloride and sodium sulfide aqueous solutions. The thicknesses of the films were determined using spectroscopic ellipsometry measurements and found to be 47.2, 65.8, 111.0, and 128.7nm for 20, 25, 30 and 35 deposition cycles respectively. The electrical properties of the films were investigated using d.c. two-point probe method at room temperature and the results showed that the resistivity was found to decrease with increasing film thickness.

Spontaneous electric fields in solid films: spontelectrics

DEFF Research Database (Denmark)

Field, David; Plekan, Oksana; Cassidy, Andrew

2013-01-01

When dipolar gases are condensed at sufficiently low temperature onto a solid surface, they form films that may spontaneously exhibit electric fields in excess of 108V/m. This effect, called the ‘spontelectric effect’, was recently revealed using an instrument designed to measure scattering....... Heterolayers may also be laid down creating potential wells on the nanoscale. A model is put forward based upon competition between dipole alignment and thermal disorder, which is successful in reproducing the variation of the degree of dipole alignment and the spontelectric field with deposition temperature...

First-principles-based study of transport properties of Fe thin films on Cu surfaces

Energy Technology Data Exchange (ETDEWEB)

Kishi, Tomoya [Department of Applied Physics, Osaka University, Suita, Osaka 565-0871 (Japan); Kasai, Hideaki [Department of Applied Physics, Osaka University, Suita, Osaka 565-0871 (Japan); Nakanishi, Hiroshi [Department of Applied Physics, Osaka University, Suita, Osaka 565-0871 (Japan); Dino, Wilson Agerico [Department of Applied Physics, Osaka University, Suita, Osaka 565-0871 (Japan); Komori, Fumio [Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8587 (Japan)

2004-12-08

We investigate the transport properties of Fe thin films on Cu(111) based on first principles calculation. We calculate the electron current through these Fe thin films, which can be observed by using a double-tipped scanning tunnelling microscope. We find that the conductance is majority spin polarized. On the basis of the band structures for this system, we discuss the origin of these interesting transport properties.

First-principles-based study of transport properties of Fe thin films on Cu surfaces

International Nuclear Information System (INIS)

Kishi, Tomoya; Kasai, Hideaki; Nakanishi, Hiroshi; Dino, Wilson Agerico; Komori, Fumio

2004-01-01

We investigate the transport properties of Fe thin films on Cu(111) based on first principles calculation. We calculate the electron current through these Fe thin films, which can be observed by using a double-tipped scanning tunnelling microscope. We find that the conductance is majority spin polarized. On the basis of the band structures for this system, we discuss the origin of these interesting transport properties

Nanocomposite oxide thin films grown by pulsed energy beam deposition

International Nuclear Information System (INIS)

Nistor, M.; Petitmangin, A.; Hebert, C.; Seiler, W.

2011-01-01

Highly non-stoichiometric indium tin oxide (ITO) thin films were grown by pulsed energy beam deposition (pulsed laser deposition-PLD and pulsed electron beam deposition-PED) under low oxygen pressure. The analysis of the structure and electrical transport properties showed that ITO films with a large oxygen deficiency (more than 20%) are nanocomposite films with metallic (In, Sn) clusters embedded in a stoichiometric and crystalline oxide matrix. The presence of the metallic clusters induces specific transport properties, i.e. a metallic conductivity via percolation with a superconducting transition at low temperature (about 6 K) and the melting and freezing of the In-Sn clusters in the room temperature to 450 K range evidenced by large changes in resistivity and a hysteresis cycle. By controlling the oxygen deficiency and temperature during the growth, the transport and optical properties of the nanocomposite oxide films could be tuned from metallic-like to insulating and from transparent to absorbing films.

Electrical, optical, and electronic properties of Al:ZnO films in a wide doping range

International Nuclear Information System (INIS)

Valenti, Ilaria; Valeri, Sergio; Benedetti, Stefania; Bona, Alessandro di; Lollobrigida, Valerio; Perucchi, Andrea; Di Pietro, Paola; Lupi, Stefano; Torelli, Piero

2015-01-01

The combination of photoemission spectroscopies, infrared and UV-VIS absorption, and electric measurements has allowed to clarify the mechanisms governing the conductivity and the electronic properties of Al-doped ZnO (AZO) films in a wide doping range. The contribution of defect-related in-gap states to conduction has been excluded in optimally doped films (around 4 at. %). The appearance of gap states at high doping, the disappearance of occupied DOS at Fermi level, and the bands evolution complete the picture of electronic structure in AZO when doped above 4 at. %. In this situation, compensating defects deplete the conduction band and increase the electronic bandgap of the material. Electrical measurements and figure of merit determination confirm the high quality of the films obtained by magnetron sputtering, and thus allow to extend their properties to AZO films in general

Electrical, optical, and electronic properties of Al:ZnO films in a wide doping range

Energy Technology Data Exchange (ETDEWEB)

Valenti, Ilaria; Valeri, Sergio [CNR, Istituto Nanoscienze, S3, Via G. Campi 213/a, 41125 Modena (Italy); Dipartimento di Scienze Fisiche, Informatiche e Matematiche, Università di Modena e Reggio Emilia, Via G. Campi 213/a, 41125 Modena (Italy); Benedetti, Stefania, E-mail: stefania.benedetti@unimore.it; Bona, Alessandro di [CNR, Istituto Nanoscienze, S3, Via G. Campi 213/a, 41125 Modena (Italy); Lollobrigida, Valerio [Dipartimento di Scienze, Università Roma Tre, I-00146 Rome, Italy and Dipartimento di Matematica e Fisica, Università Roma Tre, I-00146 Rome (Italy); Perucchi, Andrea; Di Pietro, Paola [INSTM Udr Trieste-ST and Elettra-Sincrotrone Trieste S.C.p.A., Area Science Park, I-34012 Trieste (Italy); Lupi, Stefano [CNR-IOM and Dipartimento di Fisica, Università di Roma Sapienza, P.le Aldo Moro 2, I-00185 Roma (Italy); Torelli, Piero [Laboratorio TASC, IOM-CNR, S.S. 14 km 163.5, Basovizza, I-34149 Trieste (Italy)

2015-10-28

The combination of photoemission spectroscopies, infrared and UV-VIS absorption, and electric measurements has allowed to clarify the mechanisms governing the conductivity and the electronic properties of Al-doped ZnO (AZO) films in a wide doping range. The contribution of defect-related in-gap states to conduction has been excluded in optimally doped films (around 4 at. %). The appearance of gap states at high doping, the disappearance of occupied DOS at Fermi level, and the bands evolution complete the picture of electronic structure in AZO when doped above 4 at. %. In this situation, compensating defects deplete the conduction band and increase the electronic bandgap of the material. Electrical measurements and figure of merit determination confirm the high quality of the films obtained by magnetron sputtering, and thus allow to extend their properties to AZO films in general.

Measurement of full-field deformation induced by a dc electrical field in organic insulator films

Directory of Open Access Journals (Sweden)

Boudou L.

2010-06-01

Full Text Available Digital image correlation method (DIC using the correlation coefficient curve-fitting for full-field surface deformation measurements of organic insulator films is investigated in this work. First the validation of the technique was undertaken. The computer-generated speckle images and the measurement of coefficient of thermal expansion (CTE of aluminium are used to evaluate the measurement accuracy of the technique. In a second part the technique is applied to measure the mechanical deformation induced by electrical field application to organic insulators. For that Poly(ethylene naphthalene 2,6-dicarboxylate (PEN thin films were subjected to DC voltage stress and DIC provides the full-field induced deformations of the test films. The obtained results show that the DIC is a practical and robust tool for better comprehension of mechanical behaviour of the organic insulator films under electrical stress.

Electric transport in the Netherlands in an international perspective. Benchmark electric driving 2012

International Nuclear Information System (INIS)

Kroon, P.; Weeda, M.; Appels, D.

2012-07-01

This international benchmark on electric mobility has been conducted to compare the Dutch governmental efforts and developments in the field of electric road transport. The countries that have been considered in this benchmark are: Austria, Belgium, Denmark, France, Germany, the Netherlands, Norway, Portugal, Spain, UK, China, USA and South Korea. The Netherlands has a high ambition level with regard to the number of electric vehicles compared to other countries without a large car industry. As for the envisaged number of charging points, the Netherlands is one of the prominent leaders. In the field of R and D, Germany, South Korea and China take the lead, followed by France, the UK, the USA and Austria. However, the benchmark has only looked at specific funds for electric mobility, and has not looked at general R and D and innovation funds. The Netherlands has several electro-mobility field tests, but is not leading in number. However, regarding general market penetration, the Netherlands is one of the leading countries, next to Norway, based on the relative number of passenger cars and commercial vehicles on the road. Norway and Austria are leading countries when it comes to implementation of public charging infrastructure, but also in this field the Netherlands has a prominent position in the group of countries that follow. In the current pre-commercial phase, the introduction of electric transportation in the Netherlands is supported by a high-level advisory group, the so-called Formula E-Team. This group consists of representatives and experts from industry and (scientific) society, and acts as a figurehead for electric transport. The group advises on coordination of actions to stimulate not only electro- mobility, but also innovation which should lead to new economic activities. Currently, about two hundred companies are already active in the field of electro-mobility in the Netherlands, including some top players and many SMEs (Small Medium Enterprises). The

Impact of Argon gas on optical and electrical properties of Carbon thin films

Energy Technology Data Exchange (ETDEWEB)

Usman, Arslan, E-mail: arslan.usman@gmail.com [Department of Physics, COMSATS Institute of Information Technology, Lahore (Pakistan); Rafique, M.S. [Department of Physics, University of Engineering & Technology, Lahore 54890 (Pakistan); Shaukat, S.F. [Department of Physics, COMSATS Institute of Information Technology, Lahore (Pakistan); Siraj, Khurram [Department of Physics, University of Engineering & Technology, Lahore 54890 (Pakistan); Ashfaq, Afshan [Institute of Nuclear Medicine and Oncology Lahore (INMOL), 54000 Pakistan (Pakistan); Anjum, Safia [Department of Physics, Lahore College for Women University (Pakistan); Imran, Muhammad; Sattar, Abdul [Department of Physics, COMSATS Institute of Information Technology, Lahore (Pakistan)

2016-12-15

Nanostructured thin films of carbon were synthesized and investigated for their electrical, optical, structural and surface properties. Pulsed Laser Deposition (PLD) technique was used for the preparation of these films under Argon gas environment. A KrF Laser (λ=248 nm) was used as source of ablation and plasma formation. It was observed that the carbon ions and the background gas environment has deep impact on the morphology as well as on the microstructure of the films. Time of Flight (TOF) method was used to determine the energies of the ablated carbon ions. The morphology of film surfaces deposited at various argon pressure was analysed using an atomic force microscope. The Raman spectroscopic measurement reveal that there is shift in phase from sp{sup 3} to sp{sup 2} and a decrease in FWHM of G band, which is a clear indication of enhanced graphitic clusters. The electrical resistivity was also reduced from 85.3×10{sup −1} to 2.57×10{sup −1} Ω-cm. There is an exponential decrease in band gap E{sub g} of the deposited films from 1.99 to 1.37 eV as a function of argon gas pressure.

Chronological change of electrical resistance in GeCu2Te3 amorphous film induced by surface oxidation

International Nuclear Information System (INIS)

Saito, Yuta; Shindo, Satoshi; Sutou, Yuji; Koike, Junichi

2014-01-01

Unusual chronological electrical resistance change behavior was investigated for amorphous GeCu 2 Te 3 phase change material. More than a 1 order decrease of electrical resistance was observed in the air even at room temperature. The resistance of the amorphous film gradually increased with increasing temperature and then showed a drop upon crystallization. Such unusual behavior was attributed to the oxidation of the amorphous GeCu 2 Te 3 film. From the compositional depth profile measurement, the GeCu 2 Te 3 film without any capping layer was oxidized in air at room temperature and the formed oxide was mainly composed of germanium oxide. Consequently, a highly-conductive Cu-rich layer was formed in the vicinity of the surface of the film, which reduced the total resistance of the film. The present results could provide insight into the chronological change of electrical resistance in amorphous chalcogenide materials, indicating that not only relaxation of the amorphous, but also a large atomic diffusion contributes to the chronological resistance change. (paper)

The evolution of magneto-transport and magneto-optical properties of thin La{sub 0.8}Ag{sub 0.1}MnO{sub 3+{delta}} films possessing the in-plane variant structure as a function of the film thickness

Energy Technology Data Exchange (ETDEWEB)

Melnikov, O V [Lomonosov Moscow State University, 119992 Moscow (Russian Federation); Sukhorukov, Yu P [Institute of Metal Physics, Ural Division of RAN, 620219 Ekaterinburg (Russian Federation); Telegin, A V [Institute of Metal Physics, Ural Division of RAN, 620219 Ekaterinburg (Russian Federation); Gan' shina, E A [Lomonosov Moscow State University, 119992 Moscow (Russian Federation); Loshkareva, N N [Institute of Metal Physics, Ural Division of RAN, 620219 Ekaterinburg (Russian Federation); Kaul, A R [Lomonosov Moscow State University, 119992 Moscow (Russian Federation); Gorbenko, O Yu [Lomonosov Moscow State University, 119992 Moscow (Russian Federation); Vinogradov, A N [Lomonosov Moscow State University, 119992 Moscow (Russian Federation); Smoljak, I B [Institute of Metal Physics, Ural Division of RAN, 620219 Ekaterinburg (Russian Federation)

2006-04-19

Epitaxial La{sub 0.8}Ag{sub 0.1}MnO{sub 3+{delta}} films of different thicknesses (500-1000 nm) were grown on ZrO{sub 2}(Y{sub 2}O{sub 3}) substrates. Their optical, magneto-optical and transport properties were studied in order to clarify the effect of the epitaxial variant structure and Ag ion distribution on the conductivity, magnetoresistance and infrared magnetotransmission in these films. An original method was developed for separating MR contributions related to the colossal magnetoresistance near T{sub C} and the tunnelling magnetoresistance. It was established that in the La{sub 0.8}Ag{sub 0.1}MnO{sub 3+{delta}} films spin-polarization of electrons P reached {approx}0.5. The transverse Kerr effect revealed the irregular distribution of Ag ions through the film thickness. The comparison of optical and electrical data implies lower silver content near the film-substrate boundary in relation to that in the domain volume.

Electric-field induced spin accumulation in the Landau level states of topological insulator thin films

Science.gov (United States)

Siu, Zhuo Bin; Chowdhury, Debashree; Basu, Banasri; Jalil, Mansoor B. A.

2017-08-01

A topological insulator (TI) thin film differs from the more typically studied thick TI system in that the former has both a top and a bottom surface where the states localized at both surfaces can couple to one other across the finite thickness. An out-of-plane magnetic field leads to the formation of discrete Landau level states in the system, whereas an in-plane magnetization breaks the angular momentum symmetry of the system. In this work, we study the spin accumulation induced by the application of an in-plane electric field to the TI thin film system where the Landau level states and inter-surface coupling are simultaneously present. We show, via Kubo formula calculations, that the in-plane spin accumulation perpendicular to the magnetization due to the electric field vanishes for a TI thin film with symmetric top and bottom surfaces. A finite in-plane spin accumulation perpendicular to both the electric field and magnetization emerges upon applying either a differential magnetization coupling or a potential difference between the two film surfaces. This spin accumulation results from the breaking of the antisymmetry of the spin accumulation around the k-space equal-energy contours.

Emissions of greenhouse gases from the use of transportation fuels and electricity

International Nuclear Information System (INIS)

DeLuchi, M.A.

1991-11-01

This report presents estimates of full fuel-cycle emissions of greenhouse gases from using transportation fuels and electricity. The data cover emissions of carbon dioxide (CO 2 ), methane, carbon monoxide, nitrous oxide, nitrogen oxides, and nonmethane organic compounds resulting from the end use of fuels, compression or liquefaction of gaseous transportation fuels, fuel distribution, fuel production, feedstock transport, feedstock recovery, manufacture of motor vehicles, maintenance of transportation systems, manufacture of materials used in major energy facilities, and changes in land use that result from using biomass-derived fuels. The results for electricity use are in grams of CO 2 -equivalent emissions per kilowatt-hour of electricity delivered to end users and cover generating plants powered by coal, oil, natural gas, methanol, biomass, and nuclear energy. The transportation analysis compares CO 2 -equivalent emissions, in grams per mile, from base-case gasoline and diesel fuel cycles with emissions from these alternative- fuel cycles: methanol from coal, natural gas, or wood; compressed or liquefied natural gas; synthetic natural gas from wood; ethanol from corn or wood; liquefied petroleum gas from oil or natural gas; hydrogen from nuclear or solar power; electricity from coal, uranium, oil, natural gas, biomass, or solar energy, used in battery-powered electric vehicles; and hydrogen and methanol used in fuel-cell vehicles

Electrical and thermal transport in the quasiatomic limit of coupled Luttinger liquids

Science.gov (United States)

Szasz, Aaron; Ilan, Roni; Moore, Joel E.

2017-02-01

We introduce a new model for quasi-one-dimensional materials, motivated by intriguing but not yet well-understood experiments that have shown two-dimensional polymer films to be promising materials for thermoelectric devices. We consider a two-dimensional material consisting of many one-dimensional systems, each treated as a Luttinger liquid, with weak (incoherent) coupling between them. This approximation of strong interactions within each one-dimensional chain and weak coupling between them is the "quasiatomic limit." We find integral expressions for the (interchain) transport coefficients, including the electrical and thermal conductivities and the thermopower, and we extract their power law dependencies on temperature. Luttinger liquid physics is manifested in a violation of the Wiedemann-Franz law; the Lorenz number is larger than the Fermi liquid value by a factor between γ2 and γ4, where γ ≥1 is a measure of the electron-electron interaction strength in the system.

Using Mosaicity to Tune Thermal Transport in Polycrystalline AlN Thin Films

KAUST Repository

Singh, Shivkant

2018-05-17

The effect of controlling the c-axis alignment (mosaicity) to the cross-plane thermal transport in textured polycrystalline aluminum nitride (AlN) thin films is experimentally and theoretically investigated. We show that by controlling the sputtering conditions we are able to deposit AlN thin films with varying c-axis grain tilt (mosaicity) from 10° to 0°. Microstructural characterization shows that the films are nearly identical in thickness and grain size, and the difference in mosaicity alters the grain interface quality. This has a significant effect to thermal transport where a thermal conductivity of 4.22 W/mK vs. 8.09 W/mK are measured for samples with tilt angles of 10° vs. 0° respectively. The modified Callaway model was used to fit the theoretical curves to the experimental results using various phonon scattering mechanisms at the grain interface. It was found that using a non-gray model gives an overview of the phonon scattering at the grain boundaries, whereas treating the grain boundary as an array of dislocation lines with varying angle relative to the heat flow, best describes the mechanism of the thermal transport. Lastly, our results show that controlling the quality of the grain interface provides a tuning knob to control thermal transport in polycrystalline materials.

Using Mosaicity to Tune Thermal Transport in Polycrystalline AlN Thin Films

KAUST Repository

Singh, Shivkant; Shervin, Shahab; Sun, Haiding; Yarali, Milad; Chen, Jie; Lin, Ronghui; Li, Kuang-Hui; Li, Xiaohang; Ryou, Jae-Hyun; Mavrokefalos, Anastassios

2018-01-01

The effect of controlling the c-axis alignment (mosaicity) to the cross-plane thermal transport in textured polycrystalline aluminum nitride (AlN) thin films is experimentally and theoretically investigated. We show that by controlling the sputtering conditions we are able to deposit AlN thin films with varying c-axis grain tilt (mosaicity) from 10° to 0°. Microstructural characterization shows that the films are nearly identical in thickness and grain size, and the difference in mosaicity alters the grain interface quality. This has a significant effect to thermal transport where a thermal conductivity of 4.22 W/mK vs. 8.09 W/mK are measured for samples with tilt angles of 10° vs. 0° respectively. The modified Callaway model was used to fit the theoretical curves to the experimental results using various phonon scattering mechanisms at the grain interface. It was found that using a non-gray model gives an overview of the phonon scattering at the grain boundaries, whereas treating the grain boundary as an array of dislocation lines with varying angle relative to the heat flow, best describes the mechanism of the thermal transport. Lastly, our results show that controlling the quality of the grain interface provides a tuning knob to control thermal transport in polycrystalline materials.

Light tuning DC and AC electrical properties of ZnO-rGO based hybrid nanocomposite film

Science.gov (United States)

Nath, Debarati; Mandal, S. K.; Deb, Debajit; Rakshit, J. K.; Dey, P.; Roy, J. N.

2018-03-01

We have investigated the electrical and optoelectrical properties of a zinc oxide (ZnO):reduced graphene oxide (rGO) nanocomposite film prepared through the sol gel process on a glass substrate under dark and illumination conditions of light. The bandgap of the composite film is decreased from the pure ZnO nanofilm due to the formation of a Zn-O-C bond in the composite film. The linear behavior in the Current-Voltage curve is attributed to Ohmic contact between ZnO and rGO grains. The photocurrent of the composite film is found to increase with an increase in light intensity having two different slopes, indicating an enhancement of the mobility of carriers and dissociation rate of excitons. The observed decrement of the impedance value with the intensity of light may be due to the flow of charge carriers and the presence of the light dependent relaxation process in the system. Nyquist plots have been fitted using a parallel combination of grain boundary resistances and grain boundary capacitance at different intensities of light. The relaxation frequency is observed to shift towards the high frequency regime. Carrier transit time has been calculated from relaxation frequency showing opposite behavior with the intensity of light. These results indicate the higher generations of photogenerated carriers at the interface between rGO and ZnO grains and an enhancement of the charge transport process due to the increment of the mobility of charge carriers in the system.

Unidirectional oxide hetero-interface thin-film diode

International Nuclear Information System (INIS)

Park, Youngmin; Lee, Eungkyu; Lee, Jinwon; Lim, Keon-Hee; Kim, Youn Sang

2015-01-01

The unidirectional thin-film diode based on oxide hetero-interface, which is well compatible with conventional thin-film fabrication process, is presented. With the metal anode/electron-transporting oxide (ETO)/electron-injecting oxide (EIO)/metal cathode structure, it exhibits that electrical currents ohmically flow at the ETO/EIO hetero-interfaces for only positive voltages showing current density (J)-rectifying ratio of ∼10 5 at 5 V. The electrical properties (ex, current levels, and working device yields) of the thin-film diode (TFD) are systematically controlled by changing oxide layer thickness. Moreover, we show that the oxide hetero-interface TFD clearly rectifies an AC input within frequency (f) range of 10 2  Hz < f < 10 6  Hz, providing a high feasibility for practical applications

Unidirectional oxide hetero-interface thin-film diode

Energy Technology Data Exchange (ETDEWEB)

Park, Youngmin; Lee, Eungkyu; Lee, Jinwon; Lim, Keon-Hee [Program in Nano Science and Technology, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 151-742 (Korea, Republic of); Kim, Youn Sang, E-mail: younskim@snu.ac.kr [Program in Nano Science and Technology, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 151-742 (Korea, Republic of); Advanced Institute of Convergence Technology, Gyeonggi-do 443-270 (Korea, Republic of)

2015-10-05

The unidirectional thin-film diode based on oxide hetero-interface, which is well compatible with conventional thin-film fabrication process, is presented. With the metal anode/electron-transporting oxide (ETO)/electron-injecting oxide (EIO)/metal cathode structure, it exhibits that electrical currents ohmically flow at the ETO/EIO hetero-interfaces for only positive voltages showing current density (J)-rectifying ratio of ∼10{sup 5} at 5 V. The electrical properties (ex, current levels, and working device yields) of the thin-film diode (TFD) are systematically controlled by changing oxide layer thickness. Moreover, we show that the oxide hetero-interface TFD clearly rectifies an AC input within frequency (f) range of 10{sup 2} Hz < f < 10{sup 6} Hz, providing a high feasibility for practical applications.

Thickness and microstructure effects in the optical and electrical properties of silver thin films

Energy Technology Data Exchange (ETDEWEB)

Ding, Guowen, E-mail: gding@intermolecular.com; Clavero, César; Schweigert, Daniel; Le, Minh [Intermolecular, Inc., 3011 North First Street, San Jose, CA 95134 (United States)

2015-11-15

The optical and electrical response of metal thin films approaching thicknesses in the range of the electron mean free path is highly affected by electronic scattering with the interfaces and defects. Here, we present a theoretical and experimental study on how thickness and microstructure affect the properties of Ag thin films. We are able to successfully model the electrical resistivity and IR optical response using a thickness dependent electronic scattering time. Remarkably, the product of electronic scattering time and resistivity remains constant regardless of the thickness (τx ρ = C), with a value of 59 ± 2 μΩ cm ⋅ fs for Ag films in the investigated range from 3 to 74 nm. Our findings enable us to develop a theoretically framework that allows calculating the optical response of metal thin films in the IR by using their measured thickness and resistivity. An excellent agreement is found between experimental measurements and predicted values. This study also shows the theoretical lower limit for emissivity in Ag thin films according to their microstructure and thickness. Application of the model presented here will allow rapid characterization of the IR optical response of metal thin films, with important application in a broad spectrum of fundamental and industrial applications, including optical coatings, low-emissivity windows and semiconductor industry.

Semiclassical electronic transport in MnAs thin films

International Nuclear Information System (INIS)

Helman, C.; Milano, J.; Steren, L.; Llois, A.M.

2008-01-01

Magneto-transport experiments have been recently performed on MnAs thin films. Hall effect and transverse magnetoresistance measurements have shown interesting and, until now, unknown results. For instance, the transverse magnetoresistance shows no saturation in the presence of very high magnetic fields. In order to understand the contribution of the electronic band structure to the non-saturating magnetoresistance, we perform ab initio calculations, using the Wien2K code and analyze the magneto-transport properties within the semiclassical approximation. We show that non-saturation may be due to the presence of open orbits on the majority Fermi surface

Semiclassical electronic transport in MnAs thin films

Energy Technology Data Exchange (ETDEWEB)

Helman, C. [Dpto de Fisica, ' Juan Jose Giambiagi' , Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires (Argentina); Unidad de Actividad Fisica, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Buenos Aires (Argentina)], E-mail: helman@tandar.cnea.gov.ar; Milano, J.; Steren, L. [Departamento de Fisica, Centro Atomico Bariloche, Comision Nacional de Energia Atomica, S.C. Bariloche (Argentina); Llois, A.M. [Dpto de Fisica, ' Juan Jose Giambiagi' , Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires (Argentina); Unidad de Actividad Fisica, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Buenos Aires (Argentina)

2008-07-15

Magneto-transport experiments have been recently performed on MnAs thin films. Hall effect and transverse magnetoresistance measurements have shown interesting and, until now, unknown results. For instance, the transverse magnetoresistance shows no saturation in the presence of very high magnetic fields. In order to understand the contribution of the electronic band structure to the non-saturating magnetoresistance, we perform ab initio calculations, using the Wien2K code and analyze the magneto-transport properties within the semiclassical approximation. We show that non-saturation may be due to the presence of open orbits on the majority Fermi surface.

Transmembrane molecular transport during versus after extremely large, nanosecond electric pulses.

Science.gov (United States)

Smith, Kyle C; Weaver, James C

2011-08-19

Recently there has been intense and growing interest in the non-thermal biological effects of nanosecond electric pulses, particularly apoptosis induction. These effects have been hypothesized to result from the widespread creation of small, lipidic pores in the plasma and organelle membranes of cells (supra-electroporation) and, more specifically, ionic and molecular transport through these pores. Here we show that transport occurs overwhelmingly after pulsing. First, we show that the electrical drift distance for typical charged solutes during nanosecond pulses (up to 100 ns), even those with very large magnitudes (up to 10 MV/m), ranges from only a fraction of the membrane thickness (5 nm) to several membrane thicknesses. This is much smaller than the diameter of a typical cell (∼16 μm), which implies that molecular drift transport during nanosecond pulses is necessarily minimal. This implication is not dependent on assumptions about pore density or the molecular flux through pores. Second, we show that molecular transport resulting from post-pulse diffusion through minimum-size pores is orders of magnitude larger than electrical drift-driven transport during nanosecond pulses. While field-assisted charge entry and the magnitude of flux favor transport during nanosecond pulses, these effects are too small to overcome the orders of magnitude more time available for post-pulse transport. Therefore, the basic conclusion that essentially all transmembrane molecular transport occurs post-pulse holds across the plausible range of relevant parameters. Our analysis shows that a primary direct consequence of nanosecond electric pulses is the creation (or maintenance) of large populations of small pores in cell membranes that govern post-pulse transmembrane transport of small ions and molecules. Copyright © 2011 Elsevier Inc. All rights reserved.

Modulation of the electrical properties in amorphous indium-gallium zinc-oxide semiconductor films using hydrogen incorporation

Science.gov (United States)

Song, Aeran; Park, Hyun-Woo; Chung, Kwun-Bum; Rim, You Seung; Son, Kyoung Seok; Lim, Jun Hyung; Chu, Hye Yong

2017-12-01

The electrical properties of amorphous-indium-gallium-zinc-oxide (a-IGZO) thin films were investigated after thermal annealing and plasma treatment under different gas conditions. The electrical resistivity of a-IGZO thin films post-treated in a hydrogen ambient were lower than those without treatment and those annealed in air, regardless of the methods used for both thermal annealing and plasma treatment. The electrical properties can be explained by the quantity of hydrogen incorporated into the samples and the changes in the electronic structure in terms of the chemical bonding states, the distribution of the near-conduction-band unoccupied states, and the band alignment. As a result, the carrier concentrations of the hydrogen treated a-IGZO thin films increased, while the mobility decreased, due to the increase in the oxygen vacancies from the occurrence of unoccupied states in both shallow and deep levels.

Influences of oxygen gas flow rate on electrical properties of Ga-doped ZnO thin films deposited on glass and sapphire substrates

International Nuclear Information System (INIS)

Makino, Hisao; Song, Huaping; Yamamoto, Tetsuya

2014-01-01

The Ga-doped ZnO (GZO) films deposited on glass and c-plane sapphire substrates have been comparatively studied in order to explore the role of grain boundaries in electrical properties. The influences of oxygen gas flow rates (OFRs) during the deposition by ion-plating were examined. The dependences of carrier concentration, lattice parameters, and characteristic of thermal desorption of Zn on the OFR showed common features between glass and sapphire substrates, however, the Hall mobility showed different behavior. The Hall mobility of GZO films on glass increased with increasing OFR of up to 15 sccm, and decreased with further increasing OFR. On the other hand, the Hall mobility of GZO films on c-sapphire increased for up to 25 sccm. The role of grain boundary in polycrystalline GZO films has been discussed. - Highlights: • Ga-doped ZnO films were deposited on glass and c-sapphire by ion-plating. • The epitaxial growth on c-sapphire was confirmed by X-ray diffraction. • Dependence of Hall mobility showed different tendency between glass and sapphire. • Grain boundaries influence transport properties at high O 2 gas flow rate

Inward transport of a toroidally confined plasma subject to strong radial electric fields

Science.gov (United States)

Roth, J. R.; Krawczonek, W. M.; Powers, E. J.; Hong, J.; Kim, Y.

1977-01-01

The paper aims at showing that the density and confinement time of a toroidal plasma can be enhanced by radial electric fields far stronger than the ambipolar values, and that, if such electric fields point into the plasma, radially inward transport can result. The investigation deals with low-frequency fluctuation-induced transport using digitally implemented spectral analysis techniques and with the role of strong applied radial electric fields and weak vertical magnetic fields on plasma density and particle confinement times in a Bumpy Torus geometry. Results indicate that application of sufficiently strong radially inward electric fields results in radially inward fluctuation-induced transport into the toroidal electrostatic potential well; this inward transport gives rise to higher average electron densities and longer particle confinement times in the toroidal plasma.