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Sample records for cdte films electrodeposited

  1. Synthesis of CdTe thin films on flexible metal foil by electrodeposition

    Science.gov (United States)

    Luo, H.; Ma, L. G.; Xie, W. M.; Wei, Z. L.; Gao, K. G.; Zhang, F. M.; Wu, X. S.

    2016-04-01

    CdTe thin films have been deposited onto the Mo foil from aqueous acidic bath via electrodeposition method with water-soluble Na2TeO3 instead of the usually used TeO2. X-ray diffraction studies indicate that the CdTe thin films are crystallized in zinc-blende symmetry. The effect of tellurite concentration on the morphology of the deposited thin film is investigated. In such case, the Cd:Te molar ratios in the films are both stoichiometric at different tellurite concentrations. In addition, the reduction in tellurite concentration leads to the porous thin film and weakens the crystallinity of thin film. The island growth model is used to interpret the growth mechanism of CdTe. The bandgap of the CdTe thin films is assigned to be 1.49 eV from the UV-Vis spectroscopy measurement, which is considered to serve as a promising candidate for the heterojunction solar cells.

  2. Synthesis of CdTe thin films on flexible metal foil by electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Luo, H.; Ma, L.G.; Xie, W.M.; Wei, Z.L.; Gao, K.G.; Zhang, F.M.; Wu, X.S. [Nanjing University, Collaborative Innovation Center of Advanced Microstructures, Lab of Solid State Microstructures, School of Physics, Nanjing (China)

    2016-04-15

    CdTe thin films have been deposited onto the Mo foil from aqueous acidic bath via electrodeposition method with water-soluble Na{sub 2}TeO{sub 3} instead of the usually used TeO{sub 2}. X-ray diffraction studies indicate that the CdTe thin films are crystallized in zinc-blende symmetry. The effect of tellurite concentration on the morphology of the deposited thin film is investigated. In such case, the Cd:Te molar ratios in the films are both stoichiometric at different tellurite concentrations. In addition, the reduction in tellurite concentration leads to the porous thin film and weakens the crystallinity of thin film. The island growth model is used to interpret the growth mechanism of CdTe. The bandgap of the CdTe thin films is assigned to be 1.49 eV from the UV-Vis spectroscopy measurement, which is considered to serve as a promising candidate for the heterojunction solar cells. (orig.)

  3. Electrodeposition, characterization and photo electrochemical properties of CdSe and CdTe

    Directory of Open Access Journals (Sweden)

    Atef Y. Shenouda

    2015-03-01

    Full Text Available CdSe and CdTe are electrodeposited using 0.1 M Cd2+ and different ion concentrations of Se and Te. The effect of the temperature on the electrodeposition process is also studied. The crystal structure of the deposited CdSe and CdTe is investigated by X-ray diffraction (XRD. Scanning electron microscopy (SEM of samples deposited at optimized parameters reveals that CdSe has spongy spherical grains while CdTe has coralloid morphology. Optical absorption shows the presence of direct transition with band gap energy 1.96 and 1.51 eV for CdSe and CdTe, respectively. The highest photo-conversion efficiencies of electrodeposited CdSe and CdTe films per unit area are 6% and 9.6%, respectively that achieved under simple laboratory conditions.

  4. Quantized Nanocrystalline CdTe Thin Films

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Nanocrystalline CdTe thin films were prepared by asymmetric rectangular pulse electrodeposition in organic solution at 110°C. STM image shows a porous network morphology constructed by interconnected spherical CdTe crystallites with a mean diameter of 4.2 nm. A pronounced size quantization was indicated in the action and absorption spectra. Potentials dependence dual conductive behavior was revealed in the photocurrent-potential (I-V) curves.

  5. Graded-Bandgap Solar Cells Using All-Electrodeposited ZnS, CdS and CdTe Thin-Films

    Directory of Open Access Journals (Sweden)

    Obi K. Echendu

    2015-05-01

    Full Text Available A 3-layer graded-bandgap solar cell with glass/FTO/ZnS/CdS/CdTe/Au structure has been fabricated using all-electrodeposited ZnS, CdS and CdTe thin layers. The three semiconductor layers were electrodeposited using a two-electrode system for process simplification. The incorporation of a wide bandgap amorphous ZnS as a buffer/window layer to form glass/FTO/ZnS/CdS/CdTe/Au solar cell resulted in the formation of this 3-layer graded-bandgap device structure. This has yielded corresponding improvement in all the solar cell parameters resulting in a conversion efficiency >10% under AM1.5 illumination conditions at room temperature, compared to the 8.0% efficiency of a 2-layer glass/FTO/CdS/CdTe/Au reference solar cell structure. These results demonstrate the advantages of the multi-layer graded-bandgap device architecture over the conventional 2-layer structure. In addition, they demonstrate the effective application of the two-electrode system as a simplification to the conventional three-electrode system in the electrodeposition of semiconductors with the elimination of the reference electrode as a possible impurity source.

  6. Electrodeposition, characterization and photo electrochemical properties of CdSe and CdTe

    OpenAIRE

    Atef Y. Shenouda; El Sayed, El Sayed M.

    2015-01-01

    CdSe and CdTe are electrodeposited using 0.1 M Cd2+ and different ion concentrations of Se and Te. The effect of the temperature on the electrodeposition process is also studied. The crystal structure of the deposited CdSe and CdTe is investigated by X-ray diffraction (XRD). Scanning electron microscopy (SEM) of samples deposited at optimized parameters reveals that CdSe has spongy spherical grains while CdTe has coralloid morphology. Optical absorption shows the presence of direct transition...

  7. Emerging materials for solar cell applications: electrodeposited CdTe. Second quarter report, May 16-August 15, 1980

    Energy Technology Data Exchange (ETDEWEB)

    Basol, B.; Stafsudd, O.

    1980-09-10

    Work was centered about improving electroplating processes and cell fabrication techniques, with emphasis being given to three differing n-CdTe/Au Schottky configurations. The highest values of efficiency-related parmeters achieved with a simulated solar irradiation of 100 mW/cm/sup 2/ were 0.57V for open circuit voltage, 0.6 for fill factor, and 6 mA/cm/sup 2/ for short circuit current. Four important parameters are known to control the quality of the Monosolar electrodeposition process and resultant solar cells. They are electrolyte temperature, Te concentration in the solution at a specific pH, deposition or quasi-rest potential, and flow pattern of the electrolyte (stirring). The first three considerations are believed to be fully understood and optimized. Work is underway to further understand the effects of stirring on the diffusion of ionic components and the effects on CdTe film performance. Work was accelerated during the quarter to increase the short circuit current. Parallel programs using laser irradiation of finished CdTe films, heat treatment, and changes in the electrodeposition process itself to recrystallize films were started. The surface etching technique has been highly refined, while the entire cell manufacturing process is now reproducible when defect-free substrates are used.

  8. CdTe Films Deposited by Closed-space Sublimation

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    CdTe films are prepared by closed-space sublimation technology. Dependence of film crystalline on substrate materials and substrate temperature is investigated. It is found that films exhibit higher crystallinity at substrate temperature higher than 400℃. And the CdTe films deposited on CdS films with higher crystallinity have bigger crystallite and higher uniformity. Treatment with CdCl2 methanol solution promotes the crystallite growth of CdTe films during annealing.

  9. Analysis of the electrodeposition and surface chemistry of CdTe, CdSe, and CdS thin films through substrate-overlayer surface-enhanced Raman spectroscopy.

    Science.gov (United States)

    Gu, Junsi; Fahrenkrug, Eli; Maldonado, Stephen

    2014-09-02

    The substrate-overlayer approach has been used to acquire surface enhanced Raman spectra (SERS) during and after electrochemical atomic layer deposition (ECALD) of CdSe, CdTe, and CdS thin films. The collected data suggest that SERS measurements performed with off-resonance (i.e. far from the surface plasmonic wavelength of the underlying SERS substrate) laser excitation do not introduce perturbations to the ECALD processes. Spectra acquired in this way afford rapid insight on the quality of the semiconductor film during the course of an ECALD process. For example, SERS data are used to highlight ECALD conditions that yield crystalline CdSe and CdS films. In contrast, SERS measurements with short wavelength laser excitation show evidence of photoelectrochemical effects that were not germane to the intended ECALD process. Using the semiconductor films prepared by ECALD, the substrate-overlayer SERS approach also affords analysis of semiconductor surface adsorbates. Specifically, Raman spectra of benzenethiol adsorbed onto CdSe, CdTe, and CdS films are detailed. Spectral shifts in the vibronic features of adsorbate bonding suggest subtle differences in substrate-adsorbate interactions, highlighting the sensitivity of this methodology.

  10. Electro-Plating and Characterisation of CdTe Thin Films Using CdCl2 as the Cadmium Source

    OpenAIRE

    Nor A. Abdul-Manaf; Hussein I. Salim; Mohammad L. Madugu; Olajide I. Olusola; Imyhamy M. Dharmadasa

    2015-01-01

    Cadmium telluride (CdTe) thin films have been successfully prepared from an aqueous electrolyte bath containing cadmium chloride (CdCl2)·H2O and tellurium dioxide (TeO2) using an electrodeposition technique. The structural, electrical, morphological and optical properties of these thin films have been characterised using X-ray diffraction (XRD), Raman spectroscopy, optical profilometry, DC current-voltage (I-V) measurements, photoelectrochemical (PEC) cell measurement, scanning electron micr...

  11. Thin film CdS/CdTe solar cells fabricated by electrodeposition

    Science.gov (United States)

    Kim, D.; Pozder, S.; Qi, B.; Zhu, Y.; Furtak, T. E.; Williamson, D. L.; Trefny, J. U.

    1994-06-01

    CdTe cells with efficiencies up to 9.58% were fabricated by electrodeposition. The minority-carrier lifetime in the CdTe measured by time-resolved photoluminescence was 2.39 ns. A first method to characterize CdS microstructure by small-angle x-ray scattering method has been made. Scanning tunneling microscopy performed on 1000 Å thick CdS films made by chemical bath deposition revealed a thickness fluctuation of 500 Å. Annealing of the CdS films followed by a CdCl2 treatment did not reduce the roughness, but drastically changed the contour of the grains. Some of the CdCl2-treated CdS showed white spots with diameters ranging from about 0.5 mm to 5 mm. These spots are conglomerates of dendritic patterns of either Cd metal or some Cd-rich phase. Optical transmittance of CdS films with various thicknesses (170 Å-2400 Å) showed a good correlation between thickness and transmittance for photon energies above the bandgap. The effect of CdCl2 treatment and annealing on transmittance was either negligible or slightly deleterious. CdTe films made by electrodeposition showed a dense, faceted surface morphology and films were under compressive stress after CdCl2 treatment and annealing.

  12. Electro-Plating and Characterisation of CdTe Thin Films Using CdCl2 as the Cadmium Source

    Directory of Open Access Journals (Sweden)

    Nor A. Abdul-Manaf

    2015-09-01

    Full Text Available Cadmium telluride (CdTe thin films have been successfully prepared from an aqueous electrolyte bath containing cadmium chloride (CdCl2·H2O and tellurium dioxide (TeO2 using an electrodeposition technique. The structural, electrical, morphological and optical properties of these thin films have been characterised using X-ray diffraction (XRD, Raman spectroscopy, optical profilometry, DC current-voltage (I-V measurements, photoelectrochemical (PEC cell measurement, scanning electron microscopy (SEM, atomic force microscopy (AFM and UV-Vis spectrophotometry. It is observed that the best cathodic potential is 698 mV with respect to standard calomel electrode (SCE in a three electrode system. Structural analysis using XRD shows polycrystalline crystal structure in the as-deposited CdTe thin films and the peaks intensity increase after CdCl2 treatment. PEC cell measurements show the possibility of growing p-, i- and n-type CdTe layers by varying the growth potential during electrodeposition. The electrical resistivity of the as-deposited layers are in the order of 104 Ω·cm. SEM and AFM show that the CdCl2 treated samples are more roughness and have larger grain size when compared to CdTe grown by CdSO4 precursor. Results obtained from the optical absorption reveal that the bandgap of as-deposited CdTe (1.48–1.52 eV reduce to (1.45–1.49 eV after CdCl2 treatment. Full characterisation of this material is providing new information on crucial CdCl2 treatment of CdTe thin films due to its built-in CdCl2 treatment during the material growth. The work is progressing to fabricate solar cells with this material and compare with CdTe thin films grown by conventional sulphate precursors.

  13. Patterned self-assembled film guided electrodeposition

    Institute of Scientific and Technical Information of China (English)

    ZHOU; Feng; LI; Bin; XU; Tao; CHEN; Miao; HAO; Jingcheng; LI

    2004-01-01

    The paper describes the fabrication of polypyrrole (PPy) microstructures through patterned self-assembled film guided electrodeposition. Thus the patterned self-assembled monolayer is prepared by microcontact printing (μCP) and used as the template in the electrodeposition of PPy. It has been found that the self-assembled monolayer plays completely different roles on different substrates in directing the deposition of the PPy. Namely, the electrodeposition mainly occurs on the exposed area of the gold substrates patterned with dodecanethiol (DDT) and octadecanelthiol (ODT) and on the indium tin oxide (ITO) substrate patterned with octadecyltrichlorosilane (OTS), while PPy nucleates on the OTS covered area and no deposition is found on the exposed area of a semiconductor substrate (silicon). This is attributed to the cooperative effect between the substrate conductivity and the compatibility of the PPy oligomer with the covered or exposed area of the substrate surface.

  14. Polycrystalline thin film cadmium telluride solar cells fabricated by electrodeposition. Annual technical report, 20 March 1995--19 March 1996

    Energy Technology Data Exchange (ETDEWEB)

    Trefny, J U; Mao, D [Colorado School of Mines, Golden, CO (United States)

    1997-04-01

    The objective of this project is to develop improved processes for fabricating CdTe/CdS polycrystalline thin-film solar cells. Researchers used electrodeposition to form CdTe; electrodeposition is a non-vacuum, low-cost technique that is attractive for economic, large-scale production. During the past year, research and development efforts focused on several steps that are most critical to the fabricating high-efficiency CdTe solar cells. These include the optimization of the CdTe electrodeposition process, the effect of pretreatment of CdS substrates, the post-deposition annealing of CdTe, and back-contact formation using Cu-doped ZnTe. Systematic investigations of these processing steps have led to a better understanding and improved performance of the CdTe-based cells. Researchers studied the structural properties of chemical-bath-deposited CdS thin films and their growth mechanisms by investigating CdS samples prepared at different deposition times; investigated the effect of CdCl{sub 2} treatment of CdS films on the photovoltaic performance of CdTe solar cells; studied Cu-doped ZnTe as a promising material for forming stable, low-resistance contacts to the p-type CdTe; and investigated the effect of CdTe and CdS thickness on the photovoltaic performance of the resulting cells. As a result of their systematic investigation and optimization of the processing conditions, researchers improved the efficiency of CdTe/CdS cells using ZnTe back-contact and electrodeposited CdTe. The best CdTe/CdS cell exhibited a V{sub oc} of 0.778 V, a J{sub sc} of 22.4 mA/cm{sup 2}, a FF of 74%, and an efficiency of 12.9% (verified at NREL). In terms of individual parameters, researchers obtained a V{sub oc} over 0.8 V and a FF of 76% on other cells.

  15. CdTe nanoparticles for the deposition of CdTe films using close spaced sublimation

    Science.gov (United States)

    Schumm, Benjamin; Althues, Holger; Kaskel, Stefan

    2010-08-01

    In this work a nanostructured CdTe powder was applied as a source material for CdTe film deposition via Close Spaced Sublimation (CSS). Growth kinetics and the resulting film properties were studied and compared to the films deposited from a commercially available CdTe bulk powder as source. The nanostructured powder was synthesized by a solvothermal elemental reaction of Cd and Te in ethylene diamine leading to particles of around 100-500 nm in diameter with a specific surface area of 4.1 m 2 g -1. An increase in the deposition rate by the factor of 1.7 was observed for the nanostructured powder as compared to the bulk material.

  16. High-quality CdTe films from nanoparticle precursors

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, D.L.; Pehnt, M.; Urgiles, E. [National Renewable Energy Lab., Golden, CO (United States)] [and others

    1996-05-01

    In this paper the authors demonstrate that nanoparticulate precursors coupled with spray deposition offers an attractive route into electronic materials with improved smoothness, density, and lower processing temperatures. Employing a metathesis approach, cadmium iodide was reacted with sodium telluride in methanol solvent, resulting in the formation of soluble NaI and insoluble CdTe nanoparticles. After appropriate chemical workup, methanol-capped CdTe colloids were isolated. CdTe thin film formation was achieved by spray depositing the nanoparticle colloids (25-75 {Angstrom} diameter) onto substrates at elevated temperatures (T = 280-440{degrees}C) with no further thermal treatment. These films were characterized by x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). Cubic CdTe phase formation was observed by XRD, with a contaminant oxide phase also detected. XPS analysis showed that CdTe films produced by this one-step method contained no Na or C and substantial O. AFM gave CdTe grain sizes of {approx}0.1-0.3 {mu}m for film sprayed at 400{degrees}C. A layer-by-layer film growth mechanism proposed for the one-step spray deposition of nanoparticle precursors will be discussed.

  17. Recent advances in thin film CdTe solar cells

    Science.gov (United States)

    Ferekides, Chris S.; Ceekala, Vijaya; Dugan, Kathleen; Killian, Lawrence; Oman, Daniel; Swaminathan, Rajesh; Morel, Don

    1996-01-01

    CdTe thin film solar cells have been fabricated on a variety of glass substrates (borosilicate and soda lime). The CdS films were deposited to a thickness of 500-2000 Å by the chemical bath deposition (CBD), rf sputtering, or close spaced sublimation (CSS) processes. The CdTe films were deposited by CSS in the temperature range of 450-625 °C. The main objective of this work is to fabricate high efficiency solar cells using processes that can meet low cost manufacturing requirements. In an attempt to enhance the blue response of the CdTe cells, ZnS films have also been prepared (CBD, rf sputtering, CSS) as an alternative window layer to CdS. Device behavior has been found to be consistent with a recombination model.

  18. High short-circuit current density CdTe solar cells using all-electrodeposited semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Echendu, O.K., E-mail: oechendu@yahoo.com; Fauzi, F.; Weerasinghe, A.R.; Dharmadasa, I.M.

    2014-04-01

    CdS/CdTe and ZnS/CdTe n–n heterojunction solar cells have been fabricated using all-electrodeposited semiconductors. The best devices show remarkable high short-circuit current densities of 38.5 mAcm{sup −2} and 47.8 mAcm{sup −2}, open-circuit voltages of 630 mV and 646 mV and conversion efficiencies of 8.0% and 12.0% respectively. The major strength of these device structures lies in the combination of n–n heterojunction with a large Schottky barrier at the n-CdTe/metal back contact which provides the required band bending for the separation of photo-generated charge carriers. This is in addition to the use of a high quality n-type CdTe absorber layer with high electron mobility. The potential barrier heights estimated for these devices from the current–voltage characteristics exceed 1.09 eV and 1.13 eV for CdS/CdTe and ZnS/CdTe cells respectively. The diode rectification factors of both devices are in excess of four orders of magnitude with reverse saturation current densities of 1.0 × 10{sup −7} Acm{sup −2} and 4.0 × 10{sup −7} Acm{sup −2} respectively. These all-electrodeposited solar cell device structures are currently being studied and developed as an alternative to the well-known p–n junction structures which utilise chemical bath-deposited CdS. The preliminary material growth, device fabrication and assessment results are presented in this paper. - Highlights: • Two-electrode deposition. • High J{sub sc} Schottky barrier solar cells. • CdCl{sub 2} + CdF{sub 2} treatment.

  19. Thin-film CdTe cells: Reducing the CdTe

    Energy Technology Data Exchange (ETDEWEB)

    Plotnikov, V.; Liu, X.; Paudel, N.; Kwon, D.; Wieland, K.A.; Compaan, A.D., E-mail: alvin.compaan@utoledo.edu

    2011-08-31

    Polycrystalline thin-film CdTe is currently the dominant thin-film technology in world-wide PV manufacturing. With finite Te resources world-wide, it is appropriate to consider the limits to reducing the thickness of the CdTe layer in these devices. In our laboratory we have emphasized the use of magnetron sputtering for both CdS and CdTe achieving AM1.5 efficiency over 13% on 3 mm soda-lime glass with commercial TCO and 14% on 1 mm aluminosilicate glass. This deposition technique is well suited to good control of very thin layers and yields relatively small grain size which also facilitates high performance with ultra-thin layers. This paper describes our magnetron sputtering studies for fabrication of very thin CdTe cells. Our thinnest cells had CdTe thicknesses of 1 {mu}m, 0.5 {mu}m and 0.3 {mu}m and yielded efficiencies of 12%, 9.7% and 6.8% respectively. With thinner cells Voc, FF and Jsc are reduced. Current-voltage (J-V), temperature dependent J-V (J-V-T) and apparent quantum efficiency (AQE) measurements provide valuable information for understanding and optimizing cell performance. We find that the stability under light soak appears not to depend on CdTe thickness from 2.5 to 0.5 {mu}m. The use of semitransparent back contacts allows the study of bifacial response which is particularly useful in understanding carrier collection in the very thin devices.

  20. Growth of CdTe: Al films; Crecimiento de peliculas de CdTe: Al

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez A, M.; Zapata T, M. [CICATA-IPN, 89600 Altamira, Tamaulipas (Mexico); Melendez L, M. [CINVESTAV-IPN, A.P. 14-740, 07000 Mexico D.F. (Mexico); Pena, J.L. [CINVESTAV-IPN, A.P. 73 Cordemex, 97310 Merida, Yucatan (Mexico)

    2006-07-01

    CdTe: AI films were grown by the close space vapor transport technique combined with free evaporation (CSVT-FE). The Aluminum (Al) evaporation was made by two kinds of sources: one made of graphite and the other of tantalum. The films were deposited on glass substrates. The Al source temperature was varied maintaining the CdTe source temperature fixed as well as the substrate temperature. The films were characterized by x-ray energy dispersive analysis (EDAX), x-ray diffraction and optical transmission. The results showed for the films grown with the graphite source for Al evaporation, the Al did not incorporate in the CdTe matrix, at least to the level of EDAX sensitivity; they maintained the same crystal structure and band gap. For the samples grown with the tantalum source, we were able to incorporate the Al. The x-ray diffraction patterns show that the films have a crystal structure that depends on Al concentration. They were cubic up to 2.16 at. % Al concentration; for 19.65 at. % we found a mixed phase; for Al concentration higher than 21 at. % the films were amorphous. For samples with cubic structure it was found that the lattice parameter decreases and the band gap increases with Al concentration. (Author)

  1. Characterization of CdTe Films Deposited at Various Bath Temperatures and Concentrations Using Electrophoretic Deposition

    Directory of Open Access Journals (Sweden)

    Zulkarnain Zainal

    2012-05-01

    Full Text Available CdTe film was deposited using the electrophoretic deposition technique onto an ITO glass at various bath temperatures. Four batch film compositions were used by mixing 1 to 4 wt% concentration of CdTe powder with 10 mL of a solution of methanol and toluene. X-ray Diffraction analysis showed that the films exhibited polycrystalline nature of zinc-blende structure with the (111 orientation as the most prominent peak. From the Atomic Force Microscopy, the thickness and surface roughness of the CdTe film increased with the increase of CdTe concentration. The optical energy band gap of film decreased with the increase of CdTe concentration, and with the increase of isothermal bath temperature. The film thickness increased with respect to the increase of CdTe concentration and bath temperature, and following, the numerical expression for the film thickness with respect to these two variables has been established.

  2. Characterization of CdTe films deposited at various bath temperatures and concentrations using electrophoretic deposition.

    Science.gov (United States)

    Daud, Mohd Norizam Md; Zakaria, Azmi; Jafari, Atefeh; Ghazali, Mohd Sabri Mohd; Abdullah, Wan Rafizah Wan; Zainal, Zulkarnain

    2012-01-01

    CdTe film was deposited using the electrophoretic deposition technique onto an ITO glass at various bath temperatures. Four batch film compositions were used by mixing 1 to 4 wt% concentration of CdTe powder with 10 mL of a solution of methanol and toluene. X-ray Diffraction analysis showed that the films exhibited polycrystalline nature of zinc-blende structure with the (111) orientation as the most prominent peak. From the Atomic Force Microscopy, the thickness and surface roughness of the CdTe film increased with the increase of CdTe concentration. The optical energy band gap of film decreased with the increase of CdTe concentration, and with the increase of isothermal bath temperature. The film thickness increased with respect to the increase of CdTe concentration and bath temperature, and following, the numerical expression for the film thickness with respect to these two variables has been established.

  3. Magnetic properties of electrodeposited Co-W thin films

    NARCIS (Netherlands)

    Admon, U.; Dariel, M.P.; Grunbaum, E.; Lodder, J.C.

    1987-01-01

    Thin films of Co-W, 300-500 Å thick, were electrodeposited at various compositions under a wide range of plating conditions. The saturation magnetization, coercivity, and squareness ratio of the films were derived from the parallel (in-plane) and perpendicular hysteresis loops, measured by using a v

  4. CdTe polycrystalline films on Ni foil substrates by screen printing and their photoelectric performance

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Huizhen [National Key Lab of Superhard Materials, Jilin University, Changchun 130012 (China); Ma, Jinwen [College of New Energy, Bohai University, Jinzhou, Liaoning 121013 (China); Mu, Yannan [National Key Lab of Superhard Materials, Jilin University, Changchun 130012 (China); Department of Physics and Chemistry, Heihe University, Heihe 164300 (China); Su, Shi; Lv, Pin; Zhang, Xiaoling; Zhou, Liying; Li, Xue; Liu, Li; Fu, Wuyou [National Key Lab of Superhard Materials, Jilin University, Changchun 130012 (China); Yang, Haibin, E-mail: yanghb@jlu.edu.cn [National Key Lab of Superhard Materials, Jilin University, Changchun 130012 (China)

    2015-06-15

    Highlights: • The sintered CdTe polycrystalline films by a simple screen printing. • The flexible Ni foil was chose as substrates to reduce the weight of the electrode. • The compact CdTe film was obtained at 550 °C sintering temperature. • The photoelectric activity of the CdTe polycrystalline films was excellent. - Abstract: CdTe polycrystalline films were prepared on flexible Ni foil substrates by sequential screen printing and sintering in a nitrogen atmosphere for the first time. The effect of temperature on the quality of the screen-printed film was investigated in our work. The high-quality CdTe films were obtained after sintering at 550 °C for 2 h. The properties of the sintered CdTe films were characterized by scanning electron microscopy, X-ray diffraction pattern and UV–visible spectroscopy. The high-quality CdTe films have the photocurrent was 2.04 mA/cm{sup 2}, which is higher than that of samples prepared at other temperatures. Furthermore, CdCl{sub 2} treatment reduced the band gap of the CdTe film due to the larger grain size. The photocurrent of photoelectrode based on high crystalline CdTe polycrystalline films after CdCl{sub 2} treatment improved to 2.97 mA/cm{sup 2}, indicating a potential application in photovoltaic devices.

  5. Electroplating of CdTe Thin Films from Cadmium Sulphate Precursor and Comparison of Layers Grown by 3-Electrode and 2-Electrode Systems

    Directory of Open Access Journals (Sweden)

    Imyhamy M. Dharmadasa

    2017-01-01

    Full Text Available Electrodeposition of CdTe thin films was carried out from the late 1970s using the cadmium sulphate precursor. The solar energy group at Sheffield Hallam University has carried out a comprehensive study of CdTe thin films electroplated using cadmium sulfate, cadmium nitrate and cadmium chloride precursors, in order to select the best electrolyte. Some of these results have been published elsewhere, and this manuscript presents the summary of the results obtained on CdTe layers grown from cadmium sulphate precursor. In addition, this research program has been exploring the ways of eliminating the reference electrode, since this is a possible source of detrimental impurities, such as K+ and Ag+ for CdS/CdTe solar cells. This paper compares the results obtained from CdTe layers grown by three-electrode (3E and two-electrode (2E systems for their material properties and performance in CdS/CdTe devices. Thin films were characterized using a wide range of analytical techniques for their structural, morphological, optical and electrical properties. These layers have also been used in device structures; glass/FTO/CdS/CdTe/Au and CdTe from both methods have produced solar cells to date with efficiencies in the region of 5%–13%. Comprehensive work carried out to date produced comparable and superior devices fabricated from materials grown using 2E system.

  6. Fractal features of CdTe thin films grown by RF magnetron sputtering

    Science.gov (United States)

    Hosseinpanahi, Fayegh; Raoufi, Davood; Ranjbarghanei, Khadijeh; Karimi, Bayan; Babaei, Reza; Hasani, Ebrahim

    2015-12-01

    Cadmium telluride (CdTe) thin films were prepared by RF magnetron sputtering on glass substrates at room temperature (RT). The film deposition was performed for 5, 10, and 15 min at power of 30 W with a frequency of 13.56 MHz. The crystal structure of the prepared CdTe thin films was studied by X-ray diffraction (XRD) technique. XRD analyses indicate that the CdTe films are polycrystalline, having zinc blende structure of CdTe irrespective of their deposition time. All CdTe films showed a preferred orientation along (1 1 1) crystalline plane. The surface morphology characterization of the films was studied using atomic force microscopy (AFM). The quantitative AFM characterization shows that the RMS surface roughness of the prepared CdTe thin films increases with increasing the deposition time. The detrended fluctuation analysis (DFA) and also multifractal detrended fluctuation analysis (MFDFA) methods showed that prepared CdTe thin films have multifractal nature. The complexity, roughness of the CdTe thin films and strength of the multifractality increase as deposition time increases.

  7. Preparation and properties of evaporated CdTe films

    Science.gov (United States)

    Bube, R. H.; Fahrenbruch, A. L.; Chien, K. F.

    1987-07-01

    Previous work on evaporated CdTe films for photovoltaics showed no clear path to successful p-type doping of CdTe during deposition. Post-deposition annealing of the films in various ambients thus was examined as a means of doping. Anneals were done in Te, Cd, P, and As vapors and in vacuum, air and Ar, all of which showed large effects on series resistance and diode parameters. With As, series resistance values of In/p-CdTe/graphite structures decreased markedly. This decrease was due to a decrease in grain boundary and/or back contact barrier height, and thus was due to large increases in mobility; the carrier density was not altered substantially. Although the series-resistance decreases were substantial, the diode characteristics became worse. The decreases were not observed when CdS/CdTe cells were fabricated on Te vapor-annealed films. Preparation of ZnO films by reactive evaporation yielded promising results. Deposition of p-ZnTe films by hot-wall vapor evaporation, using conventional techniques, yielded acceptable specimens.

  8. Comparative study of CdTe sources used for deposition of CdTe thin films by close spaced sublimation technique

    OpenAIRE

    Pinheiro,Wagner Anacleto; Falcão, Vivienne Denise; Cruz,Leila Rosa de Oliveira; Ferreira,Carlos Luiz

    2006-01-01

    Unlike other thin film deposition techniques, close spaced sublimation (CSS) requires a short source-substrate distance. The kind of source used in this technique strongly affects the control of the deposition parameters, especially the deposition rate. When depositing CdTe thin films by CSS, the most common CdTe sources are: single-crystal or polycrystalline wafers, powders, pellets or pieces, a thick CdTe film deposited onto glass or molybdenum substrate (CdTe source-plate) and a sintered C...

  9. Comparative study of CdTe sources used for deposition of CdTe thin films by close spaced sublimation technique

    Directory of Open Access Journals (Sweden)

    Wagner Anacleto Pinheiro

    2006-03-01

    Full Text Available Unlike other thin film deposition techniques, close spaced sublimation (CSS requires a short source-substrate distance. The kind of source used in this technique strongly affects the control of the deposition parameters, especially the deposition rate. When depositing CdTe thin films by CSS, the most common CdTe sources are: single-crystal or polycrystalline wafers, powders, pellets or pieces, a thick CdTe film deposited onto glass or molybdenum substrate (CdTe source-plate and a sintered CdTe powder. In this work, CdTe thin films were deposited by CSS technique from different CdTe sources: particles, powder, compact powder, a paste made of CdTe and propylene glycol and source-plates (CdTe/Mo and CdTe/glass. The largest deposition rate was achieved when a paste made of CdTe and propylene glycol was used as the source. CdTe source-plates led to lower rates, probably due to the poor heat transmission, caused by the introduction of the plate substrate. The results also showed that compacting the powder the deposition rate increases due to the better thermal contact between powder particles.

  10. Electrochromic Characterization of Electrodeposited WO3 Thin Films

    Science.gov (United States)

    Vijayalakshmi, R.; Jayachandran, M.; Sanjeeviraja, C.

    2002-12-01

    The electrochromic properties of certain transition metal oxides have been studied for several years resulting in commercial films are deposited as thin layers (0.1 to 0.4 microns) onto a transparent conductive automotive mirror and sun-glass products. The largest potential application of electrochromics is in window to regulate heat and light flow. Fabrication cost is one of the greatest barriers for large area development of the smart windows. Tungsten trioxide (WO3) can be colored deeply in with an optical irradiation of appropriate energy (photochromism) or with an applied electric field (electrochromism). These processes have received considerable attention because of their potential application in electrochromic windows, display devices, sensors, and so on. For these purposes, tungsten trioxide films prepared by various physical methods such as molecular beam epitaxy, CVD, etc have been reported. These methods are generally expensive and it is difficult to form large area films. However electrodeposition method is probably most economical method for making the films in addition to its relative ease in forming in large area films. In this paper, tungsten trioxide (WO3) films are prepared through the electrodeposition route and these films are used to study the electrochromic behavior in the various electrolytes by changing the concentrations. When coloration, the film attains deep blue color and in reduced state it becomes colorless. After the ion intercalation, the optical properties are also studied in the UV-Vis-NIR region.

  11. Piezoelectric film electro-deposition for optical fiber sensor with ZnO coating

    Institute of Scientific and Technical Information of China (English)

    Li Zhou; Ping Gu; Ya Zhou

    2008-01-01

    The piezoelectric film electro-deposition for optical fiber sensor with ZnO coating is studied. The zinc oxide plating film is made on the copper surface directly by cathodic electro-deposition in the Zn(NO3)2 single salt aqueous solution systems. The influences of main experimental conditions on the properties of ZnO thin film in the electro-deposition processes are analyzed and a stable, practical and economic technique is obtained.

  12. InSb thin films grown by electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-04-24

    We have grown InSb thin films on Cu substrates using the electrodeposition technique. The electrochemical bath from which the InSb thin films were grown was made up of a mixture of aqueous solutions of 0.05 M InCl{sub 3} and 0.03M SbCl{sub 3}, 0 .20M citric acid and 0.30M sodium citrate. Citric acid and sodium citrate were used as complexing agents to bring the reduction potential of In and Sb closer to maintain binary growth. The electrodeposited films were characterized by structural, morphological and optical studies. X-ray diffraction studies show that the films are polycrystalline InSb having the zinc blende structure. Scanning electron microscopy (SEM) studies reveal that the surface of the films is uniformly covered with submicron sized spherical particles. FTIR spectra of InSb thin films show a sharp absorption peak at wave number 1022 cm{sup −1} corresponding to the band gap. Hot probe analysis shows that the InSb thin films have p type conductivity.

  13. Effects of Various RF Powers on CdTe Thin Film Growth Using RF Magnetron Sputtering

    Science.gov (United States)

    Alibakhshi, Mohammad; Ghorannevis, Zohreh

    2016-09-01

    Cadmium telluride (CdTe) film was deposited using the magnetron sputtering system onto a glass substrate at various deposition times and radio frequency (RF) powers. Ar gas was used to generate plasma to sputter the CdTe atoms from CdTe target. Effects of two experimental parameters of deposition time and RF power were investigated on the physical properties of the CdTe films. X-ray Diffraction (XRD) analysis showed that the films exhibited polycrystalline nature of CdTe structure with the (111) orientation as the most prominent peak. Optimum condition to grow the CdTe film was obtained and it was found that increasing the deposition time and RF power increases the crystallinity of the films. From the profilometer and XRD data's, the thicknesses and crystal sizes of the CdTe films increased at the higher RF power and the longer deposition time, which results in affecting the band gap as well. From atomic force microscopy (AFM) analysis we found that roughnesses of the films depend on the deposition time and is independent of the RF power.

  14. Studies of the grain boundary effect in electrodeposited cadmium telluride films from optical measurements

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, J.; Bhattacharyva, D.; Maiti, A.B.; Chaudhuri, S.; Pal, A.K. (Indian Association for the Cultivation of Science, Calcutta (India). Dept. of Materials Science)

    1995-01-01

    Polycrystalline CdTe films were deposited onto SnO[sub 2] coated glass substrates using electrodeposition with different deposition potentials, ranging from -670 to -725 mV, with respect to a saturated calomel electrode (SCE). The grain boundary potential (E[sub b]), the density of trap states at the intercrystalline boundary (Q[sub t]) and the carrier concentration (p) in the films were obtained. The surface roughness ([sigma][sub o]) of the films was determined by utilising reflectance measurements while the band gap ([approx] 1.49 eV) was determined from transmittance vs wavelength traces. The barrier height was found to increase from 0.23 eV to 0.25 eV with the variation of the deposition potential from -675 to -725 mV; while the corresponding variation in the density of trap states at the grain boundary region was 1.0 x 10[sup 12]-2.1x10[sup 12]. The carrier concentration was obtained from experimental values of the Debye length, determined from the optical transmittance measurements. (Author)

  15. Properties of CdTe nanocrystalline thin films grown on different substrates by low temperature sputtering

    Institute of Scientific and Technical Information of China (English)

    Chen Huimin; Guo Fuqiang; Zhang Baohua

    2009-01-01

    CdTe nanocrystalline thin films have been prepared on glass, Si and Al2O3 substrates by radio-frequency magnetron sputtering at liquid nitrogen temperature. The crystal structure and morphology of the films were characterized by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM). The XRD examinations revealed that CdTe films on glass and Si had a better crystal quality and higher preferential orientation along the (111) plane than the Al2O3. FESEM observations revealed a continuous and dense morphology of CdTe films on glass and Si substrates. Optical properties of nanocrystalline CdTe films deposited on glass substrates for different deposited times were studied.

  16. Electrodeposition of chalcopyrite films from ionic liquid electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Shivagan, D.D. [Department of Chemistry, University of Bath, BATH BA2 7AY (United Kingdom)]. E-mail: d.shivagan@bath.ac.uk; Dale, P.J. [Department of Chemistry, University of Bath, BATH BA2 7AY (United Kingdom); Samantilleke, A.P. [Department of Chemistry, University of Bath, BATH BA2 7AY (United Kingdom); Peter, L.M. [Department of Chemistry, University of Bath, BATH BA2 7AY (United Kingdom)]. E-mail: l.m.peter@bath.ac.uk

    2007-05-31

    An air and water stable room-temperature ionic liquid based on choline chloride/urea eutectic mixture has been investigated as a system for the electrodeposition of CuInSe{sub 2} (CIS) and Cu(In,Ga)Se{sub 2} (CIGS) films for photovoltaic applications. Deposition potentials and bath compositions were optimized to obtain Cu-In, Cu-In-Se and Cu-In-Ga-Se precursor films, which were selenized in a tube furnace at 500 deg. C for 30 min to form CIS and CI(G)S films. Photo-electrochemical measurements on these selenized films showed p-type photoconductivity with band gaps of 1.0 eV and 1.09 eV, respectively, for CIS and CIGS. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), photocurrent spectroscopy and electrolyte electro-reflectance spectroscopy (EER)

  17. Properties of RF sputtered cadmium telluride (CdTe) thin films: Influence of deposition pressure

    Science.gov (United States)

    Kulkarni, R. R.; Pawbake, A. S.; Waykar, R. G.; Rondiya, S. R.; Jadhavar, A. A.; Pandharkar, S. M.; Karpe, S. D.; Diwate, K. D.; Jadkar, S. R.

    2016-04-01

    Influence of deposition pressure on structural, morphology, electrical and optical properties of CdTe thin films deposited at low substrate temperature (100°C) by RF magnetron sputtering was investigated. The formation of CdTe was confirmed by low angle XRD and Raman spectroscopy. The low angle XRD analysis revealed that the CdTe films have zinc blende (cubic) structure with crystallites having preferred orientation in (111) direction. Raman spectra show the longitudinal optical (LO) phonon mode peak ˜ 165.4 cm-1 suggesting high quality CdTe film were obtained over the entire range of deposition pressure studied. Scanning electron microscopy analysis showed that films are smooth, homogenous, and crack-free with no evidence of voids. The EDAX data revealed that CdTe films deposited at low deposition pressure are high-quality stoichiometric. However, for all deposition pressures, films are rich in Cd relative to Te. The UV-Visible spectroscopy analysis show the blue shift in absorption edge with increasing the deposition pressure while the band gap show decreasing trend. The highest electrical conductivity was obtained for the film deposited at deposition pressure 1 Pa which indicates that the optimized deposition pressure for our sputtering unit is 1 Pa. Based on the experimental results, these CdTe films can be useful for the application in the flexible solar cells and other opto-electronic devices.

  18. Electrochemical Deposition of CdTe Semiconductor Thin Films for Solar Cell Application Using Two-Electrode and Three-Electrode Configurations: A Comparative Study

    Directory of Open Access Journals (Sweden)

    O. K. Echendu

    2016-01-01

    Full Text Available Thin films of CdTe semiconductor were electrochemically deposited using two-electrode and three-electrode configurations in potentiostatic mode for comparison. Cadmium sulphate and tellurium dioxide were used as cadmium and tellurium sources, respectively. The layers obtained using both configurations exhibit similar structural, optical, and electrical properties with no specific dependence on any particular electrode configuration used. These results indicate that electrochemical deposition (electrodeposition of CdTe and semiconductors in general can equally be carried out using two-electrode system as well as the conventional three-electrode system without compromising the essential qualities of the materials produced. The results also highlight the advantages of the two-electrode configuration in process simplification, cost reduction, and removal of a possible impurity source in the growth system, especially as the reference electrode ages.

  19. Electrodeposition and Characterization of Polyaniline Film

    Institute of Scientific and Technical Information of China (English)

    WANG Hong-zhi; ZHANG Peng; ZHANG Wei-guo; YAO Su-wei

    2012-01-01

    Polyaniline film was prepared by electrochemical method in an acidic solution of aniline.The micromorphology of the polyaniline film was transformed to three-dimensional network structure instead of little particles while the deposition time was extended.The peak wavelength of the photoluminescence spectrum was 491 nm.The luminous intensity increased with the extension of deposition time,and so did the electrochemical activity.

  20. Electrodeposition of hybrid ZnO/organic dye films

    Energy Technology Data Exchange (ETDEWEB)

    Moya, Monica; Mari, Bernabe; Mollar, Miquel [Department de Fisica Aplicada-IDF, Universitat Politecnica de Valencia, Cami de Vera s/n, 46022 Valencia (Spain)

    2011-06-15

    The viability of the electrodeposition as a suitable technique for preparing new porous hybrid materials has been tested in this paper. Hybrid ZnO films with two different organic dyes: Eosin-Y and Tetrasulphonated-Cu-phtalocyanine were prepared. Their physical and chemical properties as well as their dependence on the growth conditions were investigated. It is found that the type of dye has a big influence on the morphology and porosity of hybrid films. Open and connected pores are created in hybrid ZnO/Eosin-Y films while both open and closed pores coexist in hybrid ZnO/Tetrasulfonated-Cu-phthalocyanine. As one of the promising applications of hybrid materials is photovoltaic conversion of sunlight, photoelectrochemical characterization of hybrid films is also reported. Photocurrent generation owing to both contributions ZnO and Eosin-Y is observed in ZnO/Eosin-Y films but no photocurrent has been observed in ZnO/Tetrasulfonated-Cu-phthalocyanine films. SEM micrographs of hybrid ZnO films grown in aqueous bath; (Left) ZnO/Eosin-Y films grown at 70 C, -0.9 V (Right) ZnO/Ts-CuPc films grown at 70 C, -0.9 V. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Induced Recrystallization of CdTe Thin Films Deposited by Close-Spaced Sublimation

    Energy Technology Data Exchange (ETDEWEB)

    Moutinho, H. R.; Dhere, R. G.; Al-Jassim, M. M.; Levi, D. H.; Kazmerski, L. L. (National Renewable Energy Laboratory); Mayo, B. (Southern University and A& M College, Baton Rouge, LA)

    1998-10-26

    We have deposited CdTe thin films by close-spaced sublimation at two different temperature ranges. The films deposited at the lower temperature partially recrystallized after CdCl2 treatment at 350 C and completely recrystallized after the same treatment at 400 C. The films deposited at higher temperature did not recrystallize at these two temperatures. These results confirmed that the mechanisms responsible for changes in physical properties of CdTe films treated with CdCl2 are recrystallization and grain growth, and provided an alternative method to deposit CSS films using lower temperatures.

  2. Induced recrystallization of CdTe thin films deposited by close-spaced sublimation

    Science.gov (United States)

    Moutinho, H. R.; Dhere, R. G.; Al-Jassim, M. M.; Mayo, B.; Levi, D. H.; Kazmerski, L. L.

    1999-03-01

    We have deposited CdTe thin films by close-spaced sublimation at two different temperature ranges. The films deposited at the lower temperature partially recrystallized after CdCl2 treatment at 350 °C and completely recrystallized after the same treatment at 400 °C. The films deposited at higher temperature did not recrystallize at these two temperatures. These results confirmed that the mechanisms responsible for changes in physical properties of CdTe films treated with CdCl2 are recrystallization and grain growth, and provided an alternative method to deposit CSS films using lower temperatures.

  3. Induced Recrystallization of CdTe Thin Films Deposited by Close-Spaced Sublimation

    Energy Technology Data Exchange (ETDEWEB)

    Moutinho, H. R.; Dhere, R. G.; Al-Jassim, M. M.; Levi, D. H.; Kazmerski, L. L. (National Renewable Energy Laboratory); Mayo, B. (Southern University and A& M College, LA)

    1998-10-29

    We have deposited CdTe thin films by close-spaced sublimation at two different temperature ranges. The films deposited at the lower temperature partially recrystallized after CdCl{sub 2} treatment at 350 C and completely recrystallized after the same treatment at 400 C. The films deposited at higher temperature did not recrystallize at these two temperatures. These results confirmed that the mechanisms responsible for changes in physical properties of CdTe films treated with CdCl{sub 2} are recrystallization and grain growth, and provided an alternative method to deposit CSS films using lower temperatures.

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

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

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

  5. Electrodeposition of magnetic thin films of cobalt on silicon

    Energy Technology Data Exchange (ETDEWEB)

    Munford, M.L.; Seligman, L.; Sartorelli, M.L.; Voltolini, E.; Martins, L.F.O.; Schwarzacher, W.; Pasa, A.A. E-mail: pasa@fisica.ufsc.br

    2001-05-01

    To understand the electrodeposition of Co on Si, sulphate electrolytes containing two different Co ion concentrations were tested. Thin films with uniform thickness, ranging from 10 to 700 nm, low surface roughness, compact and metallic appearance were obtained for Co concentrations of 26 and 104 mM, respectively. Transverse MOKE measurements showed in-plane magnetization with the magnitude of the coercive field being dependent on the thickness of the deposited layers. VSM measurements with the applied field perpendicular to the surface allowed the observation of an out-of-plane remanent magnetization. These properties are of considerable interest for technological applications.

  6. Grain Boundary Engineering of Electrodeposited Thin Films

    DEFF Research Database (Denmark)

    Alimadadi, Hossein

    of the favorable boundaries that break the network of general grain boundaries. Successful dedicated synthesis of a textured nickel film fulfilling the requirements of grain boundary engineered materials, suggests improved boundary specific properties. However, the textured nickel film shows fairly low......Grain boundary engineering aims for a deliberate manipulation of the grain boundary characteristics to improve the properties of polycrystalline materials. Despite the emergence of some successful industrial applications, the mechanism(s) by which the boundary specific properties can be improved...... is not yet well-understood. This, at least partly, owes to the lack of robust characterization methods for analyzing the nature of grain boundaries including the grain boundary plane characteristics, until recently. In the past decade, significant improvements in the 2-dimensional and 3-dimensional analysis...

  7. The Role of Dopant Concentration on Conductivity and Mobility of CdTe Thin Films

    Directory of Open Access Journals (Sweden)

    Ala J. Al-Douri

    2011-01-01

    Full Text Available Films of CdTe pure and doped with various atomic percentages of Al and Sb (0.5, 1.5 & 2.5 were prepared, and their electrical properties were investigated. The films were prepared by thermal evaporation on glass substrates at two substrate temperatures (Ts=RT & 423 K. The results showed that the conduction phenomena of all the investigated CdTe thin films on glass substrates are caused by two distinct mechanisms. Room temperature DC conductivity increases by a factor of four for undoped CdTe thin films as Ts increases and by 1-2 orders of magnitude with increasing dopant percentage of Al and Sb. In general, films doped with Sb are more efficient than Al-doped films. The activation energy (Ea2 decreases with increasing Ts and dopant percentage for both Al and Sb. Undoped CdTe films deposited at RT are p-type convert to n-type with increasing Ts and upon doping with Al at more than 0.5%. The carrier concentration decreases as Ts increases while it increases with increasing dopant percentage. Hall mobility decreases more than three times as Al increases whereas it increases about one order of magnitude with increasing Sb percentage in CdTe thin films deposited at 423 K and RT, respectively.

  8. On the doping problem of CdTe films: The bismuth case

    Energy Technology Data Exchange (ETDEWEB)

    Vigil-Galan, O. [Escuela Superior de Fisica y Matematicas del IPN, Edif. 9, UPALM, 07738 Mexico, D. F. (Mexico); Brown, M. [Department of Physics and Astronomy, The University of Toledo, 43606 Toledo, OH (United States); Ruiz, C.M. [Depto. Fisica de Materiales, Universidad Autonoma de Madrid, 28049 Madrid (Spain); Vidal-Borbolla, M.A. [Instituto de Investigacion en Comunicacion Optica, Av. Karakorum 1470, Lomas 4a. Secc., 78210 San Luis Potosi, SLP (Mexico); Ramirez-Bon, R. [CINVESTAV-IPN, U. Queretaro, Libramiento Norponiente No. 2000, Fracc. Real de Juriquilla, 76230 Santiago de Queretaro, Qro. (Mexico); Sanchez-Meza, E. [Escuela Superior de Fisica y Matematicas del IPN, Edif. 9, UPALM, 07738 Mexico, D. F. (Mexico); Tufino-Velazquez, M. [Escuela Superior de Fisica y Matematicas del IPN, Edif. 9, UPALM, 07738 Mexico, D. F. (Mexico)], E-mail: mtufinovel@yahoo.com.mx; Calixto, M. Estela [Escuela Superior de Fisica y Matematicas del IPN, Edif. 9, UPALM, 07738 Mexico, D. F. (Mexico); Compaan, A.D. [Department of Physics and Astronomy, The University of Toledo, 43606 Toledo, OH (United States); Contreras-Puente, G. [Escuela Superior de Fisica y Matematicas del IPN, Edif. 9, UPALM, 07738 Mexico, D. F. (Mexico)

    2008-08-30

    The controlled increase of hole concentration is an important issue and still an unsolved problem for polycrystalline CdTe-based solar cells. The typical hole concentration of as-grown CdTe thin-films goes up to 10{sup 13} cm{sup -3}, depending on the specific growth technique. The highest electron concentration obtained for CdS, the suitable window partner material of CdTe, is around 10{sup 15} cm{sup -3}. Thus, the PV-performance of a CdS/CdTe device can be optimized if the hole concentration in CdTe is increased. We have faced up this problem by studying the electrical properties of two types of CdTe films: CdTe films grown by Close Space Vapor Transport using a CdTe:Bi powder as the starting material and CdTe sputtered films doped by implantation with different Bi-doses. Temperature-dependent resistivity and Hall effect measurements and a discussion on the efficiency of both doping processes are presented.

  9. PENINGKATAN KUALITAS FILM TIPIS CdTe SEBAGAI ABSORBER SEL SURYA DENGAN MENGGUNAKAN DOPING TEMBAGA (Cu

    Directory of Open Access Journals (Sweden)

    P. Marwoto

    2012-12-01

    Full Text Available Film tipis CdTe dengan doping tembaga (Cu berkonsenterasi 2% telah berhasil ditumbuhkan di atas substrat Indium Tin Oxide (ITO dengan metode dc magnetron sputtering. Penelitian ini dilakukan untuk mengetahui pengaruh doping Cu(2% terhadap struktur morfologi, struktur kristal, fotoluminisensi dan resistivitas listrik film CdTe. Citra morfologi Scanning Electron Microscopy (SEM dan hasil analisis struktur dengan X-Ray Diffraction (XRD menunjukkan bahwa film CdTe:Cu(2% mempunyai citra permukaan dan struktur kristal yang lebih sempurna dibandingkan film CdTe tanpa doping. Hasil analisis spektrometer fotoluminisensi menunjukkan bahwa film CdTe dan CdTe(2% mempunyai puncak fotoluminisensi pada tiga panjang gelombang yang identik yaitu 685 nm (1,81 eV, 725 nm (1,71 eV dan 740 nm (1,67 eV. Film CdTe dengan doping Cu(2% memiliki intensitas puncak fotoluminisensi yang lebih tajam pada pita energi 1,81 eV dibandingkan dengan film CdTe tanpa doping. Pengukuran arus dan tegangan (I-V menunjukkan bahwa pemberian doping Cu(2% dapat menurunkan resistivitas film dari 8,40x109 Ωcm menjadi 6,92x105 Ωcm. Sebagai absorber sel surya, kualitas film tipis CdTe telah berhasil ditingkatkan dengan pemberian doping Cu(2%.CdTe:Cu(2% thin film has been successfully grown on Indium Tin Oxide (ITO substrates by using dc magnetron sputtering. This study was carried out in order to investigate the effect of Cu(2% doping on the morphologycal structure, crystal structure, photoluminesence, and resistivity of CdTe thin film. Scanning Electron Microscopy (SEM  images and X-Ray Diffraction (XRD results showed that CdTe:Cu(2% thin film has morphologycal and crystal structures more perfect than undoped CdTe film. Photoluminesence spectroscopy results showed that CdTe and CdTe:Cu(2% thin films have luminesence peak at three identical wevelength regions i.e. 685 nm (1.81 eV, 725 nm (1.71 eV and 740 nm (1.67 eV however CdTe:Cu(2% film shows sharper photoluminescence peak at band

  10. Spray Deposition of High Quality CuInSe2 and CdTe Films: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Curtis, C. J.; van Hest, M.; Miedaner, A.; Leisch, J.; Hersh, P.; Nekuda, J.; Ginley, D. S.

    2008-05-01

    A number of different ink and deposition approaches have been used for the deposition of CuInSe2 (CIS), Cu(In,Ga)Se2 (CIGS), and CdTe films. For CIS and CIGS, soluble precursors containing Cu, In, and Ga have been developed and used in two ways to produce CIS films. In the first, In-containing precursor films were sprayed on Mo-coated glass substrates and converted by rapid thermal processing (RTP) to In2Se3. Then a Cu-containing film was sprayed down on top of the In2Se3 and the stacked films were again thermally processed to give CIS. In the second approach, the Cu-, In-, and Ga-containing inks were combined in the proper ratio to produce a mixed Cu-In-Ga ink that was sprayed on substrates and thermally processed to give CIGS films directly. For CdTe deposition, ink consisting of CdTe nanoparticles dispersed in methanol was prepared and used to spray precursor films. Annealing these precursor films in the presence of CdCl2 produced large-grained CdTe films. The films were characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM). Optimized spray and processing conditions are crucial to obtain dense, crystalline films.

  11. Electrodeposition of Ni-SiC nanocomposite film

    Institute of Scientific and Technical Information of China (English)

    NIU Zhao-xia; CAO Fa-he; WANG Wei; ZHANG Zhao; ZHANG Jian-qing; CAO Chu-nan

    2007-01-01

    The point of zero charge(PZC) of SiC nanoparticles was determined by means of standard potentiometric titration method, while the influences of the main technological parameters on the microstructure of electrodeposited Ni-SiC composite film were studied and optimized. The results show that high bath pH value favors SiC nanoparticles negatively charged and high bath temperature promotes them positively charged. Under the experimental conditions, sodium dodecyl-glycol is proven to be an effective surface modification anionic surfactant for SiC nanoparticles. The results also show that the optimized Ni-SiC composite film is composed of the nanoparticles with the average grain size in the nanometer range (100 nm), and SiC nanoparticles disperse into the nickel matrix uniformly.

  12. Preparation and multicolored fluorescent properties of CdTe quantum dots/polymethylmethacrylate composite films

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yanni; Liu, Jianjun, E-mail: jjliu717@aliyun.com; Yu, Yingchun; Zuo, Shengli

    2015-10-25

    A new simple route was presented for the preparation of stable fluorescent CdTe/polymethylmethacrylate (CdTe/PMMA) composite films by using hydrophilic thioglycolic acid capped CdTe quantum dots (TGA-CdTe QDs) and polymethylmethacrylate (PMMA) as raw materials. The TGA-CdTe QDs were firstly exchanged with n-dodecanethiol (DDT) to become hydrophobic DDT-CdTe QDs via a ligand exchange strategy, and then incorporated into PMMA matrix to obtain fluorescent CdTe/PMMA composite films. The structure and optical properties of DDT-CdTe QDs and CdTe/PMMA composite films were investigated by XRD, IR, UV and PL techniques. The results indicated that the obtained DDT-CdTe QDs well preserved the intrinsic structure and the maximum emission wavelength of the initial water-soluble QDs and the resulting 6.10 wt% CdTe/PMMA composite film exhibited significantly enhanced PL intensity. Furthermore, the multicolored composite films with green, yellow-green, yellow and orange light emissions were well tuned by incorporating the CdTe QDs of various maximum emission wavelengths. The TEM image demonstrated that the CdTe QDs were well-dispersed in the PMMA matrix without aggregation. Superior photostability of QDs in the composite film was confirmed by fluorescence lifetime measurement. Thermo-gravimetric analysis of CdTe/PMMA composite films showed no obvious enhancement of thermal stability compared with pure PMMA. - Highlights: • Ligand-exchange strategy was used to render CdTe QDs oil-soluble. • CdTe QDs were incorporated into PMMA matrix to fabricate fluorescent films. • The resulting 6.10 wt% CdTe/PMMA film exhibited significantly enhanced PL intensity. • Fluorescent colors of films were tuned by varying the λ{sub em} of incorporated CdTe QDs.

  13. Studies of crystalline CdZnTe radiation detectors and polycrystalline thin film CdTe for X-ray imaging applications

    CERN Document Server

    Ede, A

    2001-01-01

    The development of a replacement to the conventional film based X-ray imaging technique is required for many reasons. One possible route for this is the use of a large area film of a suitable semiconductor overlaid on an amorphous silicon readout array. A suitable semiconductor exists in cadmium telluride and its tertiary alloy cadmium zinc telluride. In this thesis the spectroscopic characteristics of commercially available CZT X- and gamma-radiation detectors are established. The electronic, optical, electro-optic, structural and compositional properties of these detectors are then investigated. The attained data is used to infer a greater understanding for the carrier transport in a CZT radiation detector following the interaction of a high energy photon. Following this a method used to fabricate large area films of CdTe on a commercial scale is described. This is cathodic electrodeposition from an aqueous electrolyte. The theory and experimental arrangement for this technique are described in detail with ...

  14. Deposition of Cl-doped CdTe polycrystalline films by close-spaced sublimation

    Energy Technology Data Exchange (ETDEWEB)

    Okamoto, Tamotsu; Takahashi, Kohei; Akiba, Sho; Yasuda, Nao [Department of Electrical and Electronic Engineering, National Institute of Technology, Kisarazu College, 2-11-1 Kiyomidai-higashi, Kisarazu, Chiba 292-0041 (Japan); Tokuda, Satoshi; Kishihara, Hiroyuki; Ichioka, Akina; Doki, Takahiro; Sato, Toshiyuki [Technology Research Laboratory, Shimadzu Corporation, 3-9-4 Hikaridai, Seika-cho, Soraku-gun, Kyoto 619-0237 (Japan)

    2015-06-15

    The effects of Cl-doping on the CdTe layers by the close-spaced sublimation (CSS) deposition were investigated. Cl-doped CdTe polycrystalline films were deposited on graphite substrates by CSS method using a mixture of CdTe and CdCl{sub 2} powder as a source. In X-ray diffraction (XRD) patterns of the obtained films with various deposition times, many diffraction peaks other than CdTe peaks were observed in the deposition times lower than 10 min. These diffraction peaks were probably due to the formation of chlorides of Cd, Te and C, such as CdCl{sub 2}, TeCl{sub 4}, Te{sub 3}Cl{sub 2} and C{sub 10}Cl{sub 8}. X-ray fluorescence (XRF) and secondary ion mass spectrometry (SIMS) analyses revealed that a large amount of chlorine was contained in the films with the deposition times lower than 10 min, and that Cl concentration decreased with increasing the deposition time above 3 min. These results indicate that the films containing the chlorides of Cd, Te and C in addition to CdTe are formed in the initial stage of the CSS deposition using a mixture of CdTe and CdCl{sub 2} powder as a source. Cross-sectional images revealed that the grain size was decreased by the effect of Cl-doping. Furthermore, current-voltage (I -V) characteristics of the CdTe/graphite structures were measured, and it was found that the resistivity of the Cl-doped CdTe layer was much higher than that of the undoped CdTe layer. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Degradation processes occur on the CdTe thin films solar elements

    CERN Document Server

    Mirsagatov, S A; Makhmudov, M; Muzapharova, S A

    1999-01-01

    It is shown the Cu in CdTe polycristalline films is diffusing on the complex mechanism. By bringing of W atoms in thin CdTe layers it is possible to operate diffusion's speed of Cu atoms. Initiation of the (Cu sup + W sub C sub d sup -) complexes under the conditions N(W sub C sub d sup -)>=N(Cu sub i sup +) hardly reduce the diffusion velocity of Cu atoms.

  16. Electrodeposition and Characterization of CuTe and Cu2Te Thin Films

    Directory of Open Access Journals (Sweden)

    Wenya He

    2015-01-01

    Full Text Available An electrodeposition method for fabrication of CuTe and Cu2Te thin films is presented. The films’ growth is based on the epitaxial electrodeposition of Cu and Te alternately with different electrochemical parameter, respectively. The deposited thin films were characterized by X-ray diffraction (XRD, field emission scanning electronic microscopy (FE-SEM with an energy dispersive X-ray (EDX analyzer, and FTIR studies. The results suggest that the epitaxial electrodeposition is an ideal method for deposition of compound semiconductor films for photoelectric applications.

  17. Effects of ultrasonic field in pulse electrodeposition of NiFe film on Cu substrate

    Energy Technology Data Exchange (ETDEWEB)

    Balachandran, R. [Faculty of Engineering, Multimedia University, Cyberjaya Campus, 63100, Cyberjaya (Malaysia); Yow, H.K. [Faculty of Engineering, Multimedia University, Cyberjaya Campus, 63100, Cyberjaya (Malaysia)], E-mail: hkyow@mmu.edu.my; Ong, B.H. [Faculty of Engineering, Multimedia University, Cyberjaya Campus, 63100, Cyberjaya (Malaysia); Manickam, R. [Electronics Faculty, Tyndale Education Group Pte Ltd., 188942 (Singapore); Saaminathan, V. [School of Material Science and Engineering, Nanyang Technological University, 639798 (Singapore); Tan, K.B. [Department of Chemistry, Universiti Putra Malaysia, Serdang, 43400 (Malaysia)

    2009-07-29

    NiFe film was pulse electrodeposited on conductive Cu substrate under galvanostatic mode in the presence of an ultrasonic field. The NiFe film electrodeposited was subjected to structural and surface analyses by X-ray diffraction, energy dispersive X-ray spectroscopy, surface profiling and scanning electron microscopy, respectively. The results show that the ultrasonic field has significantly improved the surface roughness, reduced the spherical grain size in the range from 490-575 nm to 90-150 nm, and increased the Ni content from 76.08% to 79.74% in the NiFe film electrodeposited.

  18. Electrodeposited cerium film as chromate replacement for tinplate

    Energy Technology Data Exchange (ETDEWEB)

    Huang Xingqiao [Department of Applied Chemistry, Harbin Institute of Technology, Harbin 150001 (China); Li Ning [Department of Applied Chemistry, Harbin Institute of Technology, Harbin 150001 (China)], E-mail: lining@hit.edu.cn; Wang Huiyong; Sun Hanxiao; Sun Shanshan; Zheng Jian [Department of Applied Chemistry, Harbin Institute of Technology, Harbin 150001 (China)

    2008-01-30

    The cerium film was prepared on tinplate by electrodeposition method. Sulfide-stain resistance of the Ce-passivated, unpassivated and Cr-passivated tinplates was evaluated using a cysteine tarnish test. Corrosion behavior of these tinplates in contact with 3.5% NaCl solution and 0.1 M citric-citrate buffer solution was investigated using Tafel measurement and electrochemical impedance spectroscopy measurement, respectively. The adhesion of epoxyphenolic lacquer to the Ce-passivated tinplate was checked using a cross hatch cutter. The morphology, composition and thickness of the cerium film were studied by atomic force microscopy, X-ray photoelectron spectroscopy and X-ray fluorescence spectrometry. According to the results, the Ce-passivated tinplate shows the best sulfide-stain resistance and the best corrosion protection property compared with the unpassivated and Cr-passivated tinplates. The adhesion of epoxyphenolic lacquer to the Ce-passivated tinplate is good. The cerium film is composed of the closely packed particles of about 50-200 nm in diameter. The film mainly consists of cerium and oxygen, which mainly exist as CeO{sub 2}, Ce{sub 2}O{sub 3} and their hydrates such as Ce(OH){sub 4}, Ce(OH){sub 3}. The total cerium amount of the film is about 0.110 g/m{sup 2}.

  19. Characterization of Smooth CdTe(111) Films by the Conventional Close-Spaced Sublimation Technique

    Science.gov (United States)

    Escobedo, A.; Quinones, S.; Adame, M.; McClure, J.; Zubia, D.; Brill, G.

    2010-04-01

    Thin epitaxial CdTe films were grown on CdTe(111)B substrates by the close-spaced sublimation (CSS) technique and were characterized over a range of experimental parameters. The source temperature was varied between 480°C and 540°C, maintaining an average constant source-substrate temperature difference Δ T of ˜130°C. Helium was used as a carrier gas at pressures between 2 Torr and 10 Torr. Scanning electron microscopy (SEM) and x-ray diffraction (XRD) were used to analyze the film morphology and structure. Growth rates ranging from 1 μm/h to 4 μm/h were observed, based on profilometer thickness measurements. The addition of a pre-growth heat treatment step and post-growth annealing treatment resulted in smooth CdTe(111) films. An evolution in growth morphology was demonstrated with SEM images and film quality was confirmed with XRD.

  20. Characterization of CdTe Films Deposited at Various Bath Temperatures and Concentrations Using Electrophoretic Deposition

    OpenAIRE

    Zulkarnain Zainal; Mohd Norizam Md Daud; Azmi Zakaria; Mohd Sabri Mohd Ghazali; Atefeh Jafari; Wan Rafizah Wan Abdullah

    2012-01-01

    CdTe film was deposited using the electrophoretic deposition technique onto an ITO glass at various bath temperatures. Four batch film compositions were used by mixing 1 to 4 wt% concentration of CdTe powder with 10 mL of a solution of methanol and toluene. X-ray Diffraction analysis showed that the films exhibited polycrystalline nature of zinc-blende structure with the (111) orientation as the most prominent peak. From the Atomic Force Microscopy, the thickness and surface roughness of the ...

  1. The Role of Dopant Concentration on Conductivity and Mobility of CdTe Thin Films

    OpenAIRE

    Al-Douri, Ala J.; Al-Shakily, F. Y.; Alnajjar, Abdalla A.; Maysoon F. A. Alias

    2011-01-01

    Films of CdTe pure and doped with various atomic percentages of Al and Sb (0.5, 1.5 & 2.5) were prepared, and their electrical properties were investigated. The films were prepared by thermal evaporation on glass substrates at two substrate temperatures (Ts=RT & 423 K). The results showed that the conduction phenomena of all the investigated CdTe thin films on glass substrates are caused by two distinct mechanisms. Room temperature DC conductivity increases by a factor of four for undoped CdT...

  2. Determination of dispersion parameters of thermally deposited CdTe thin film

    Science.gov (United States)

    Dhimmar, J. M.; Desai, H. N.; Modi, B. P.

    2016-05-01

    Cadmium Telluride (CdTe) thin film was deposited onto glass substrates under a vacuum of 5 × 10-6 torr by using thermal evaporation technique. The prepared film was characterized for dispersion analysis from reflectance spectra within the wavelength range of 300 nm - 1100 nm which was recorded by using UV-Visible spectrophotometer. The dispersion parameters (oscillator strength, oscillator wavelength, high frequency dielectric constant, long wavelength refractive index, lattice dielectric constant and plasma resonance frequency) of CdTe thin film were investigated using single sellimeir oscillator model.

  3. A photoluminescence study of film structure in CdTe nanoparticle thin films.

    Science.gov (United States)

    Gardner, H C; Gallardo, D E; Dunn, S; Gaponik, N; Eychmüller, A

    2008-05-01

    The layer-by-layer deposition of thin films of CdTe nanoparticles and three different polyelectrolytes has been investigated. Photoluminescence spectra were used to monitor the energy transfer properties within the films. As the number of bilayers in a thin film was increased a decrease in the energy of the light emitted was observed. The wavelength change is a two-stage process. Deposition of the first one to two bi-layers of a thin film produced a sharp energy change (626 nm to 637 nm with the addition of a single bi-layer) whereas deposition of subsequent bi-layers produced a more gradual energy change (642 nm-646 nm with the addition of 5 bi-layers). A space-filling mechanism is suggested to account for these changes; smaller nanoparticles penetrate the earlier levels of a thin film and increase the inter-particle energy transfer opportunities within the layers.

  4. A direct solution deposition approach to CdTe thin films

    Energy Technology Data Exchange (ETDEWEB)

    Miskin, Caleb K.; Dubois-Camacho, Angela; Reese, Matthew O.; Agrawal, Rakesh

    2016-01-01

    A direct solution deposition approach to CdTe thin films is presented. The difficulty of co-dissolving Te and desirable Cd salts is overcome through a diamine-thiol solvent mixture. Thin films of densely-packed, micron-sized grains are achieved after annealing without the need for chalcogen or CdCl2 vapor treatments.

  5. Studies of recrystallization of CdTe thin films after CdCl{sub 2} treatment

    Energy Technology Data Exchange (ETDEWEB)

    Moutinho, H.R.; Al-Jassim, M.M.; Abulfotuh, F.A.; Levi, D.H.; Dippo, P.C.; Dhere, R.G.; Kazmerski, L.L. [National Renewable Energy Lab., Golden, CO (United States)

    1997-12-31

    CdTe thin films deposited by physical vapor deposition (PVD) and close-spaced sublimation (CSS) have been treated with CdCl{sub 2} at 350 and 400 C. Atomic force microscopy (AFM) analysis showed that the films started recrystallizing during the 350 C CdCl{sub 2} treatment. These results were confirmed by the presence of two lattice parameters, detected in X-ray diffraction (XRD) analysis. The PVD films treated at 400 C were completely recrystallized and grain growth was observed. The formation of Cd(S{sub 1{minus}x}Te{sub x}) alloy in these films was evidenced by the appearance of extra peaks close to the CdTe peaks in the diffraction patterns. No major changes were observed in the structural properties of CSS CdTe films treated at the same conditions. It was concluded that the effect of the CdCl{sub 2} treatment in the CdTe films is to promote recrystallization and grain growth, but only if enough lattice-strain energy is available (as is the case for PVD films). Time-resolved photoluminescence (TRPL) analysis showed, for PVD and CSS films, an increase in minority-carrier lifetime with the treatment, mainly at 400 C, probably due to elimination of deep levels within the band gap.

  6. D. C. electrical properties of vacuum-deposited CdTe films

    Energy Technology Data Exchange (ETDEWEB)

    Gogoi, S.; Barua, K.

    1982-06-18

    The current-voltage characteristics of vacuum-deposited CdTe films were studied as a function of film thickness (2500-13 000 A) at various temperatures (0-110/sup 0/C). The d.c. conduction mechanism was explained using a modified Poole-Frenkel equation.

  7. Magnetic properties of electrodeposited Co-W thin films

    Energy Technology Data Exchange (ETDEWEB)

    Admon, U.; Dariel, M.P.; Grunbaum, E.; Lodder, J.C.

    1987-09-01

    Thin films of Co-W, 300--500 A thick, were electrodeposited at various compositions under a wide range of plating conditions. The saturation magnetization, coercivity, and squareness ratio of the films were derived from the parallel (in-plane) and perpendicular hysteresis loops, measured by using a vibrating sample magnetometer. The magnetic properties of the films are strongly related to their microstructure. The nonmagnetic alloying element (W) affects the saturation magnetization via the dilution mechanism. The in-plane coercivity, which increases with increasing content of the hexagonal phase and with decreasing degree of (0001)h texture, is in the range of 100--600 Oe for the crystalline deposits and decreases to a few oersteds for amorphous deposits. The in-plane squareness ratio increases with the fcc or amorphous phase content and with decreasing degree of (0001)h texture. The magnetic measurements suggest that films that appeared amorphous according to their electron diffraction patterns are actually microcrystalline or at least partially crystallized.

  8. Cyclic Electrodeposition of Yb-Bi Thin Films

    Institute of Scientific and Technical Information of China (English)

    李高仁; 柯琴芳; 童叶翔; 刘冠昆

    2004-01-01

    Deposition of Yb-Bi thin films was carried out from a nonaqueous solution by using cyclic electrodepositon.During electrodeposition the substrate potential was continuously cycled between two potentials.The effects of several factors including the potential of deposition,time of deposition and sweep rate on the Yb content in the thin films and surface morphology were studied.Experimental results indicate that the amorphous Yb-Bi thin films containing Yb 21.04%~36.36%(mass fraction)can be prepared in 0.10 mol·L-1 YbCl3+0.10 mol*L-1 Bi(NO3)3+0.10 mol·L-1 LiCl+DMSO by controlling deposition conditions of the system.They are black,uniform,metallic luster and adhered firmly to the copper substrates.The films were characterized by X-ray energy dispersive analysis(EDS),scanning electron microcoscope(SEM)and X-ray diffraction(XRD).

  9. Facile method to prepare CdS nanostructure based on the CdTe films

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Ligang; Chen, Yuehui; Wei, Zelu; Cai, Hongling; Zhang, Fengming; Wu, Xiaoshan, E-mail: xswu@nju.edu.cn

    2015-09-15

    Graphical abstract: - Highlights: • CdS nanostructure is directly fabricated on CdTe film only by heating treatment under H{sub 2}S/N{sub 2} mixed atmosphere at a relatively low temperature (450 °C) with gold layer as the intermediate. • Nanostructure of CdS layer, varying from nanowires to nanosheets, may be controlled by the thickness of gold film. • The change of morphology adjusts its luminescence properties. - Abstract: Nanostructured cadmium sulfide (CdS) plays critical roles in electronics and optoelectronics. In this paper, we report a method to fabricate CdS nanostructure directly on CdTe film, via a thermal annealing method in H{sub 2}S/N{sub 2} mixed gas flow at a relatively low temperature (450 °C). The microstructure and optical properties of CdS nanostructure are investigated by X-ray diffraction, transmission electron microscopy, Raman, and photoluminescence. The morphology of CdS nanostructure, evolving from nanowires to nanosheets, can be controlled by the thickness of Au film deposited on the CdTe film. And CdS nanostructures are single crystalline with the hexagonal wurtzite structure. Raman spectroscopy under varying the excitation wavelengths confirm that synthesized CdS-CdTe films contain two layers, i.e., CdS nanostructure (top) and CdTe layer (bottom). The change of morphology modifies its luminescence properties. Obviously, through simply thermal annealing in H{sub 2}S/N{sub 2} mixed gas, fabricating CdS nanostructure on CdTe film can open up the new possibility for obtaining high efficient CdTe solar cell.

  10. Physical properties of Bi-doped CdTe thin films deposited by cosputtering

    Energy Technology Data Exchange (ETDEWEB)

    Becerril, M.; Zelaya-Angel, O. [Departamento de Fisica, CINVESTAV-IPN, Apdo. Postal 14-740, 07000 Mexico D.F. (Mexico); Vigil-Galan, O.; Contreras-Puente, G.; Sanchez-Meza, E. [Escuela Superior de Fisica y Matematicas, Instituto Politecnico Nacional, 07738 Mexico D.F. (Mexico)

    2007-03-15

    The structural, morphological, electrical, and optical properties of CdTe-Bi cosputtered thin films related with composition are presented. The films were grown on Corning glass substrates at room temperature from a CdTe-Bi target. The composition measurements show that the Bi content in the films ranges from x = 0.0 to x = 6.37 at%, depending on the area fraction covered by the Bi piece attached to the CdTe target. The structure of the annealed films was determined from X-ray diffraction measurements. Two kinds of structures were observed, depending on the Bi content: (1) CdTe polycrystalline films containing a small amount of Bi that is probably incorporated in the Cd and Te sites of the CdTe lattice. (2) Amorphization of the polycrystalline films, with higher Bi content. From the experimental results, we concluded that using this deposition method n/p-type Bi-doped CdTe polycrystalline films can be produced with electrical resistivity between 10{sup 2}-10{sup 3} {omega} cm and electron mobility between 10{sup 1} and 10{sup 2} cm{sup 2}V{sup -1}s{sup -1}. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. Structural, optical, photoluminescence, dielectric and electrical studies of vacuum-evaporated CdTe thin films

    Indian Academy of Sciences (India)

    Ziaul Raza Khan; M Zulfequar; Mohd Shahid Khan

    2012-04-01

    Highly-oriented CdTe thin films were fabricated on quartz and glass substrates by thermal evaporation technique in the vacuum of about 2 × 10-5 torr. The CdTe thin films were characterized by X-ray diffraction (XRD), UV–VIS–NIR, photoluminescence spectroscopy and scanning electron microscopy (SEM). X-ray diffraction results showed that the films were polycrystalline with cubic structure and had preferred growth of grains along the (111) crystallographic direction. Scanning electron micrographs showed that the growth of crystallites of comparable size on both the substrates. At the room temperature, photoluminescence spectra of the films on both the substrates showed sharp peaks with a maximum at 805 nm. This band showed significant narrowing suggesting that it originates from the transitions involving grain boundary defects. The refractive index of CdTe thin films was calculated using interference pattern of transmission spectra. The optical band gap of thin films was found to allow direct transition with energy gap of 1.47–1.50 eV. a.c. conductivity of CdTe thin films was found to increase with the increase in frequency whereas dielectric constant was observed to decrease with the increase in frequency.

  12. Electrodeposition-Based Fabrication and Characteristics of Tungsten Trioxide Thin Film

    OpenAIRE

    Li Lin; Chin-Pao Cheng; Tun-Ping Teng

    2016-01-01

    In this study, tungsten trioxide (WO3) thin films were electrodeposited on indium tin oxide (ITO) glass to form WO3-coated glass. The electrodeposition (ED) time (tED) and ED current (IED) were varied to control the film thickness and morphology. Furthermore, the crystallization of the thin films was controlled by annealing them at 250°C, 500°C, and 700°C. The results showed that the thickness of the WO3 thin films increased with tED and IED. The as-deposited thin films and those annealed at ...

  13. Electronic structure, structural and optical properties of thermally evaporated CdTe thin films

    OpenAIRE

    S Lalitha; Karazhanov, S. Zh.; Ravindran, P.; Senthilarasu, S.; Sathyamoorthy, R.; Janabergenov, J.

    2006-01-01

    Thin films of CdTe were deposited on glass substrates by thermal evaporation. From the XRD measurements itis found that the films are of zinc-blende-type structure. Transmittance, absorption, extinction, and refractive coefficients are measured. Electronic structure, band parameters and optical spectra of CdTe were calculated from ab initio studies within the LDA and LDA+U approximations. It is shown that LDA underestimates the band gap, energy levels of the Cd-4d states, s-d coupling and ban...

  14. Preparation and properties of evaporated CdTe films compared with single crystal CdTe. Annual report, 1 February 1983-31 January 1984

    Energy Technology Data Exchange (ETDEWEB)

    Bube, R; Fahrenbruch, A; Huber, W; Fortmann, C; Thorpe, T

    1984-09-01

    Variation of CdS/CdTe/graphite thick film solar cell properties was investigated as a function of temperature for CdS film deposition. A maximum open-circuit voltage of 0.67 V was found for a deposition temperature of 160/sup 0/C, corresponding to a CdS film resistivity of 150 ohm-cm. The effect is not due to avoidance of higher temperature annealing of the CdTe film in higher temperature CdS film depositions nor to the diffusion of In from the outermost CdS: In layer. The effect of coating the graphite before CdTe deposition with Au or Cu was also investigated. Although high concentrations of both Au or Cu could be determined after CdTe deposition, CdTe films grown on this coated graphite had lower hole densities than films grown on uncoated graphite. Photovoltaic parameters of thin-film CdS/CdTe/graphite solar cells were investigated as a function of storage time to check the stability of these cells. Initial degradation of parameters (especially fill factor) could be reversed by heat treatment in hydrogen, with subsequent properties being stable. Heat treatment of CdS/CdTe/graphite solar cells in air increases cell resistivity and decreases fill factor; heat treatment in hydrogen produces the reverse effect. The hole density is not affected by these heat treatments, suggesting that effects are associated with grain boundaries in the film.

  15. van der Waals epitaxy of CdTe thin film on graphene

    Science.gov (United States)

    Mohanty, Dibyajyoti; Xie, Weiyu; Wang, Yiping; Lu, Zonghuan; Shi, Jian; Zhang, Shengbai; Wang, Gwo-Ching; Lu, Toh-Ming; Bhat, Ishwara B.

    2016-10-01

    van der Waals epitaxy (vdWE) facilitates the epitaxial growth of materials having a large lattice mismatch with the substrate. Although vdWE of two-dimensional (2D) materials on 2D materials have been extensively studied, the vdWE for three-dimensional (3D) materials on 2D substrates remains a challenge. It is perceived that a 2D substrate passes little information to dictate the 3D growth. In this article, we demonstrated the vdWE growth of the CdTe(111) thin film on a graphene buffered SiO2/Si substrate using metalorganic chemical vapor deposition technique, despite a 46% large lattice mismatch between CdTe and graphene and a symmetry change from cubic to hexagonal. Our CdTe films produce a very narrow X-ray rocking curve, and the X-ray pole figure analysis showed 12 CdTe (111) peaks at a chi angle of 70°. This was attributed to two sets of parallel epitaxy of CdTe on graphene with a 30° relative orientation giving rise to a 12-fold symmetry in the pole figure. First-principles calculations reveal that, despite the relatively small energy differences, the graphene buffer layer does pass epitaxial information to CdTe as the parallel epitaxy, obtained in the experiment, is energetically favored. The work paves a way for the growth of high quality CdTe film on a large area as well as on the amorphous substrates.

  16. Glow discharge optical emission spectroscopy: a complementary technique to analyze thin electrodeposited polyaniline films

    Energy Technology Data Exchange (ETDEWEB)

    Moutarlier, V. [Institut UTINAM, CNRS-UMR 6213, Université de Franche-Comté, 16 route de Gray, 25030 Besançon (France); Lakard, S., E-mail: sophie.lakard@univ-fcomte.fr [Institut UTINAM, CNRS-UMR 6213, Université de Franche-Comté, 16 route de Gray, 25030 Besançon (France); Patois, T. [Institute of Condensed Matter and Nanosciences, Université Catholique de Louvain, Croix du Sud, 1/4, 1348 Louvain-la-Neuve (Belgium); Lakard, B. [Institut UTINAM, CNRS-UMR 6213, Université de Franche-Comté, 16 route de Gray, 25030 Besançon (France)

    2014-01-01

    Glow Discharge Optical Emission Spectroscopy (GDOES) has been developed to perform depth profiles of thick metallic films, in tens of microns range. GDOES spectroscopy can also be used to analyze thin organic polymer films since this technique has a great potential thanks to its high depth resolution, multi-element capability, sensitivity, and adaptability to solids or films and to conducting or non-conducting samples. In particular thin electrodeposited conducting polymer films remain an unexplored field of investigation for GDOES technique. However GDOES was used in this work to analyze electrodeposited polyaniline films, in addition to other techniques such as profilometry, electron microscopy and X-ray diffraction (XRD). More precisely polyaniline thin films were electrodeposited from HCl solutions and the presence of an anilinium chloride excess at the top surface of the polymer film was demonstrated using GDOES and XRD. Rinsing of these films with water led to the removal of this excess and to the partial dedoping of the polymer film due to the porous structure of polymer films. Polyaniline thin films were also electrodeposited from H{sub 2}SO{sub 4} solutions and an anilinium hydrogen sulfate was similarly observed at the top surface of the polymer. This excess was removed by rinsing, contrary to hydrogen sulfate anions incorporated into the polymer film during the electrochemical polymerization that were not completely expulsed from the polyaniline films as proved using GDOES. - Highlights: • Polyaniline films were electrodeposited from HCl and H{sub 2}SO{sub 4} solutions • Polymer films were analyzed by Glow Discharge Optical Emission Spectroscopy (GDOES) • The incorporation of anions in the films was proved using GDOES depth profiles • The crystalline structure of polyaniline films was modified by water rinsing.

  17. Spectrum-per-Pixel Cathodoluminescence Imaging of CdTe Thin-Film Bevels

    Energy Technology Data Exchange (ETDEWEB)

    Moseley, John; Al-Jassim, Mowafak M.; Burst, James; Guthrey, Harvey L.; Metzger, Wyatt K.

    2016-11-21

    We conduct T=6 K cathodoluminescence (CL) spectrum imaging with a nano-scale electron beam on beveled surfaces of CdTe thin-films at different critical stages of standard CdTe device fabrication. The through-thickness total CL intensity profiles are consistent with a reduction in grain boundary recombination due to the CdCl2 treatment. Color-coded maps of the low-temperature luminescence transition energies reveal that CdTe thin films have remarkably non-uniform opto-electronic properties, which depend strongly on sample processing history. The grain-to-grain S content in the interdiffused CdTe/CdS region is estimated from a sample size of thirty-five grains, and the S content in adjacent grains varies significantly in CdCl2-treated samples. A low-temperature luminescence model is developed to interpret spectral behavior at grain boundaries and grain interiors.

  18. Electrodeposition of inorganic/organic hybrid thin films

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Tsukasa [Center of Innovative Photovoltaic Systems, Gifu University (Japan); Environmental and Renewable Energy Systems Division, Graduate School of Engineering, Gifu University (Japan); Zhang, Jingbo; Komatsu, Daisuke; Sawatani, Seiichi; Minoura, Hideki [Environmental and Renewable Energy Systems Division, Graduate School of Engineering, Gifu University (Japan); Pauporte, Thierry; Lincot, Daniel [Laboratoire d' Electrochimie et Chimie Analytique, Ecole Nationale Superieure de Chimie de Paris 11 rue P. et M. Curie, 75231 Paris cedex 05 (France); Oekermann, Torsten [Institut fuer Physikalische Chemie und Elektrochemie, Universitaet Hannover (Germany); Schlettwein, Derck [Institut fuer Angewandte Physik, Justus-Liebig-Universitaet Giessen (Germany); Tada, Hirokazu [Institute for Molecular Science, Higashiyama (Japan); Woehrle, Dieter [Institut fuer Organische und Makromolekulare Chemie, Universitaet Bremen (Germany); Funabiki, Kazumasa; Matsui, Masaki [Department of Materials Science and Technology, Faculty of Engineering, Gifu University (Japan); Miura, Hidetoshi [Chemicrea Inc., Tokyo (Japan); Yanagi, Hisao [Graduate School of Materials Science, Nara Institute of Science and Technology Takayama-cho 8916-5, Ikoma (Japan)

    2009-01-09

    Electrodeposition of inorganic compound thin films in the presence of certain organic molecules results in self-assembly of various hybrid thin films with new properties. Examples of new discoveries by the authors are reviewed, taking cathodic formation of a ZnO/dye hybrid as the leading example. Hybridization of eosinY leads to the formation of highly oriented porous crystalline ZnO as the consequence of dye loading. The hybrid formation is a highly complicated process involving complex chemistry of many molecular and ionic constituents. However, electrochemical analyses of the relevant phenomena indicate the possibility of reaching a comprehensive understanding of the mechanism, giving us the chance to further develop them into industrial technologies. The porous crystals are ideal for photoelectrodes in dye-sensitized solar cells. As the process also permits the use of non-heat-resistant substrates, the technology can be applied for the development of colorful and light-weight plastic solar cells. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  19. Synthesis and optical characterization of nanocrystalline CdTe thin films

    Science.gov (United States)

    Al-Ghamdi, A. A.; Khan, Shamshad A.; Nagat, A.; Abd El-Sadek, M. S.

    2010-11-01

    From several years the study of binary compounds has been intensified in order to find new materials for solar photocells. The development of thin film solar cells is an active area of research at this time. Much attention has been paid to the development of low cost, high efficiency thin film solar cells. CdTe is one of the suitable candidates for the production of thin film solar cells due to its ideal band gap, high absorption coefficient. The present work deals with thickness dependent study of CdTe thin films. Nanocrystalline CdTe bulk powder was synthesized by wet chemical route at pH≈11.2 using cadmium chloride and potassium telluride as starting materials. The product sample was characterized by transmission electron microscope, X-ray diffraction and scanning electron microscope. The structural characteristics studied by X-ray diffraction showed that the films are polycrystalline in nature. CdTe thin films with thickness 40, 60, 80 and 100 nm were prepared on glass substrates by using thermal evaporation onto glass substrate under a vacuum of 10 -6 Torr. The optical constants (absorption coefficient, optical band gap, refractive index, extinction coefficient, real and imaginary part of dielectric constant) of CdTe thin films was studied as a function of photon energy in the wavelength region 400-2000 nm. Analysis of the optical absorption data shows that the rule of direct transitions predominates. It has been found that the absorption coefficient, refractive index ( n) and extinction coefficient ( k) decreases while the values of optical band gap increase with an increase in thickness from 40 to 100 nm, which can be explained qualitatively by a thickness dependence of the grain size through decrease in grain boundary barrier height with grain size.

  20. Radiative recombination mechanisms in CdTe thin films deposited by elemental vapor transport

    Energy Technology Data Exchange (ETDEWEB)

    Collins, Shamara [Department of Electrical Engineering, University of South Florida, 4202 East Fowler Ave, Tampa, FL 33620 (United States); Vatavu, Sergiu, E-mail: svatavu@usm.md [Department of Electrical Engineering, University of South Florida, 4202 East Fowler Ave, Tampa, FL 33620 (United States); Faculty of Physics and Engineering, Moldova State University, 60 A. Mateevici str., Chisinau, MD-2009, Republic of Moldova (Moldova, Republic of); Evani, Vamsi; Khan, Md; Bakhshi, Sara; Palekis, Vasilios [Department of Electrical Engineering, University of South Florida, 4202 East Fowler Ave, Tampa, FL 33620 (United States); Rotaru, Corneliu [Faculty of Physics and Engineering, Moldova State University, 60 A. Mateevici str., Chisinau, MD-2009, Republic of Moldova (Moldova, Republic of); Ferekides, Chris [Department of Electrical Engineering, University of South Florida, 4202 East Fowler Ave, Tampa, FL 33620 (United States)

    2015-05-01

    A photoluminesence (PL) study of the radiative recombination mechanisms for CdTe films deposited under different Cd and Te overpressure by elemental vapor transport is presented. The experiment and analysis have been carried out in the temperature range of 12-130 K. The intensity of the PL laser excitation beam was varied by two orders of magnitude. It has been established that the bands in the 1.47-1.50 eV are determined by transitions involving shallow D and A states and the 1.36x-1.37x eV band is due to band to level transitions. Deep transitions at 1.042 eV and 1.129 eV are due to radiative transitions to levels determined by CdTe native defects. - Highlights: • Photoluminescense (PL) of CdTe thin films is present in the 0.8-1.6 eV spectral region. • High intensity excitonic peaks are among the main radiative paths. • Radiative transitions at 1.36x eV are assisted by dislocations caused levels. • Extremal Cd/Te overpressure ratios enhance PL for 1.497 eV, 1.486 eV, 1.474 eV bands. • PL intensity reaches its max value for the 0.45 and 1.25 Cd/Te overpressure ratios.

  1. Induced recrystallization of CdTe thin films deposited by close-spaced sublimation

    Energy Technology Data Exchange (ETDEWEB)

    Moutinho, H.R.; Dhere, R.G.; Al-Jassim, M.M.; Levi, D.H.; Kazmerski, L.L. [National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, Colorado 80401 (United States); Mayo, B. [Southern University and AM College, Harding Boulevard, Baton Rouge, Louisiana 70813 (United States)

    1999-03-01

    We have deposited CdTe thin films by close-spaced sublimation at two different temperature ranges. The films deposited at the lower temperature partially recrystallized after CdCl{sub 2} treatment at 350&hthinsp;{degree}C and completely recrystallized after the same treatment at 400&hthinsp;{degree}C. The films deposited at higher temperature did not recrystallize at these two temperatures. These results confirmed that the mechanisms responsible for changes in physical properties of CdTe films treated with CdCl{sub 2} are recrystallization and grain growth, and provided an alternative method to deposit CSS films using lower temperatures. {copyright} {ital 1999 American Institute of Physics.}

  2. Enhanced magnetic moment of ultrathin Co films measured by in situ electrodeposition in a SQUID

    Science.gov (United States)

    Topolovec, Stefan; Krenn, Heinz; Würschum, Roland

    2016-01-01

    A special electrochemical cell enabling in situ electrodeposition in a SQUID magnetometer is applied to study the magnetic moment of ultrathin Co films during growth on an Au(111) substrate. The in situ electrodeposition approach allows a total elimination of the magnetic background signal of the substrate, thus the magnetic moment which arises exclusively from the deposited Co film could be measured with monolayer sensitivity. The average thickness of the deposited Co films dav as determined from the transferred charge can be adjusted easily by varying the parameters of the electrodeposition. Hence, the magnetic moment of Co thin films could be determined in absolute terms as a function of the film thickness dav. For the first few atomic layers an enhancement of the magnetic moment per Co atom compared to the bulk could be observed, which increases steadily with lowering dav, reaching up to 40%.

  3. Three-dimensional defects in CdTe films obtained by pulsed laser deposition

    NARCIS (Netherlands)

    Sagan, P; Virt, IS; Zawislak, J; Rudyj, IO; Kuzma, M

    2004-01-01

    The quality of Cd chalcodenides epitaxial films can be enhanced seriously by applying a pulsed (electron beam or laser beam) method for ablation of targets. The structure of laser deposited CdTe layers was investigated by transmission high energy electron diffraction. This method is very useful for

  4. Polycrystalline Thin-Film Cadmium Telluride Solar Cells Fabricated by Electrodeposition; Final Technical Report, 20 March 1995-15 June 1998

    Energy Technology Data Exchange (ETDEWEB)

    Trefny, J. U.; Mao, D.; Kaydanov, V.; Ohno, T. R.; Williamson, D. L.; Collins, R.; Furtak, T. E.

    1999-01-27

    This report summarizes work performed by the Colorado School of Mines Department of Physics under this subcontract. Based on the studies conducted, researchers increased the efficiency of the cells with electrodeposited CdTe and CBD CdS by 3% on average ({approx}30 relative %). The improvement came from 1. Optimization of CdS initial thickness taking into account CdS consumption of CdTe during the CdTe/CdS post-deposition treatment; optimization of CdS post-deposition treatment with CdCl2 aimed at prevention of Te diffusion into CdS and improvement of the CdS film morphology and electronic properties. That led to a considerable increase in short circuit current, by 13% on average. 2. Optimization of CdTe thickness and post-deposition treatment which led to a significant increase in Voc, by {approx}70 mV. The highest Voc obtained exceeded 800 mV. 3. Development of a ZnTe:Cu/Metal back contact processing procedure that included selection of optimal Cu content, deposition regime and post-deposition treatment conditions. As a result, back contact resistance as low as 0.1W-cm2 was obtained. The cell stability was measured on exposure to accelerated stress conditions. Preliminary studies of some new approaches to improvement of CdS/CdTe structure were conducted.

  5. Effects of various deposition times and RF powers on CdTe thin film growth using magnetron sputtering

    Science.gov (United States)

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

    2016-09-01

    Cadmium telluride (CdTe) is a p-type II-VI compound semiconductor, which is an active component for producing photovoltaic solar cells in the form of thin films, due to its desirable physical properties. In this study, CdTe film was deposited using the radio frequency (RF) magnetron sputtering system onto a glass substrate. To improve the properties of the CdTe film, effects of two experimental parameters of deposition time and RF power were investigated on the physical properties of the CdTe films. X-ray Diffraction (XRD), atomic force microscopy (AFM) and spectrophotometer were used to study the structural, morphological and optical properties of the CdTe samples grown at different experimental conditions, respectively. Our results suggest that film properties strongly depend on the experimental parameters and by optimizing these parameters, it is possible to tune the desired structural, morphological and optical properties. From XRD data, it is found that increasing the deposition time and RF power leads to increasing the crystallinity as well as the crystal sizes of the grown film, and all the films represent zinc blende cubic structure. Roughness values given from AFM images suggest increasing the roughness of the CdTe films by increasing the RF power and deposition times. Finally, optical investigations reveal increasing the film band gaps by increasing the RF power and the deposition time.

  6. Fabrication, Electrical Characterization and Simulation of Thin Film Solar Cells: CdTe and CIGS Materials

    OpenAIRE

    Es'haghi Gorji, Nima

    2014-01-01

    CdTe and Cu(In,Ga)Se2 (CIGS) thin film solar cells are fabricated, electrically characterized and modelled in this thesis. We start from the fabrication of CdTe thin film devices where the R.F. magnetron sputtering system is used to deposit the CdS/CdTe based solar cells. The chlorine post-growth treatment is modified in order to uniformly cover the cell surface and reduce the probability of pinholes and shunting pathways creation which, in turn, reduces the series resistance. The deionized wat...

  7. Studies on the grain boundary effect in polycrystalline CdTe films using optical reflectance measurements

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, J. (Dept. of Materials Science, Indian Association for the Cultivation of Science, Calcutta (India)); Pal, R. (Dept. of Materials Science, Indian Association for the Cultivation of Science, Calcutta (India)); Bhattacharyya, S.K. (Central Glass and Ceramic Research Inst., Calcutta (India)); Chaudhuri, S. (Dept. of Materials Science, Indian Association for the Cultivation of Science, Calcutta (India)); Pal, A.K. (Dept. of Materials Science, Indian Association for the Cultivation of Science, Calcutta (India))

    1993-11-15

    The grain boundary effect in polycrystalline CdTe films deposited at various substrate temperatures has been studied critically. The grain boundary potential, the density of trap states at the boundary region and the carrier concentration in the films were obtained by an alternative technique that utilizes the reflectance measurements of the highly resistive films deposited on a nonabsorbing substrate. The barrier height in the CdTe films decreased from 0.34 to 0.2 eV as the grain size increased from 60 to 133 nm, owing to the increase in the deposition temperature from 373 to 523 K. Correspondingly, the density of trap states in the grain boundary region decreased from 1.63x10[sup 13] to 6.15x10[sup 12] cm[sup -2]. (orig.)

  8. Electrochemical preparation of Er-Co-Bi thin film in organic bath by cyclic electrodeposition method

    Institute of Scientific and Technical Information of China (English)

    李高仁; 童叶翔; 刘冠昆

    2004-01-01

    Cyclic electrodeposition was used to investigate the preparation of Er-Co-Bi alloy thin film in DMSO system. Experimental results indicate that Er-Co-Bi alloy thin film containing 14.83 %- 32.65 % Er is prepared from 0. 1 mol/L ErCl3 +0. 1 mol/L CoCl2 + 0.1 mol/L Bi(NO3 )3 + 0.1 mol/L LiCl+DMSO system by cyclic electrodeposition on Cu substrate. The optimum cyclic potential of electrodeposition is that upper potential is within a potential range from -0.50 V to -1.00 V and lower potential is within a potential range from -2.00 V to -2.60 V.The surface of alloy thin film observed by scanning electron microscope is black, adhesive and has metallic luster.The film is amorphous proved by the X-ray diffractometry.

  9. Pulse-plating electrodeposition and annealing treatment of CuInSe2 films

    Institute of Scientific and Technical Information of China (English)

    LIU Fang-yang; L(U) Ying; ZHANG Zhi-an; LAI Yan-qing; LI Jie; LIU Ye-xiang

    2008-01-01

    CuInSe2 (CIS) thin film was prepared on molybdenum substrate using pulse-plating electrodeposition in aqueous solution. The most suitable pulse potential range for co-deposition is found to be from -0.55 to -0.75 V (vs SCE) from linear potential scanning curve. The electrodeposited films were characterized by X-ray diffractometry (XRD), scanning electron microscopy(SEM) and energy dispersive X-ray analysis (EDS). The annealing effects on electrodeposited precursors were investigated. And the influence of pulse parameters on film quality was studied. The chalcopyrite phase CuInSe2 films with smooth surface and stoichiometric composition are obtained at a pulse potential from -0.65 to -0.7 V (vs SCE), a pulse period of 1-9 ms with a duty cycle of 33% and annealing treatment.

  10. Electrodeposition of Manganese-Nickel Oxide Films on a Graphite Sheet for Electrochemical Capacitor Applications

    Directory of Open Access Journals (Sweden)

    Hae-Min Lee

    2014-01-01

    Full Text Available Manganese-nickel (Mn-Ni oxide films were electrodeposited on a graphite sheet in a bath consisting of manganese acetate and nickel chloride, and the structural, morphological, and electrochemical properties of these films were investigated. The electrodeposited Mn-Ni oxide films had porous structures covered with nanofibers. The X-ray diffractometer pattern revealed the presence of separate manganese oxide (g-MnO2 and nickel oxide (NiO in the films. The electrodeposited Mn-Ni oxide electrode exhibited a specific capacitance of 424 F/g in Na2SO4 electrolyte. This electrode maintained 86% of its initial specific capacitance over 2000 cycles of the charge-discharge operation, showing good cycling stability.

  11. Photovoltaic devices created from electrodeposited nano-textured poly(thiophene) films

    Science.gov (United States)

    Jenkins, Judith L.; Ratcliff, Erin L.; Shallcross, R. Clayton; Head, Jeffrey L.; Armstrong, Neal R.

    2008-08-01

    Polythiophene films can be electrodeposited on modified ITO substrates, textured to increase their active surface area, doped to enhance charge transport, and then interfaced with C60 thin films to create "planar heterojunction" photovoltaic devices with power conversion efficiencies up to 1%. Preliminary results indicate that these electrodeposited films (e-P3HT) modified with appropriate ligands can serve as hosts for semi-conducting nanoparticles (CdSe NPs). These NPs may ultimately extend the device spectral sensitivity into the red and near-IR spectral regions.

  12. Post-growth CdCl₂ treatment on CdTe thin films grown on graphene layers using a close-spaced sublimation method.

    Science.gov (United States)

    Jung, Younghun; Yang, Gwangseok; Chun, Seungju; Kim, Donghwan; Kim, Jihyun

    2014-05-05

    We investigated the morphological, structural and optical properties of CdCl₂-treated cadmium telluride (CdTe) thin films deposited on defective graphene using a close-spaced sublimation (CSS) system. Heat treatment in the presence of CdCl₂ caused recrystallization of CSS-grown CdTe over the as-deposited structures. The preferential (111) orientation of as-deposited CdTe films was randomized after post-growth CdCl₂ treatment. New small grains (bumps) on the surface of CdCl₂-treated CdTe films were ascribed to nucleation of the CdTe grains during the CdCl₂ treatment. The properties of as-deposited and CdCl₂-treated CdTe films were characterized by room temperature micro-photoluminescence, micro-Raman spectroscopy, scanning electron microscopy, and X-ray diffraction analysis. Our results are useful to demonstrate a substrate configuration CdTe thin film solar cells.

  13. Effect of film thickness on microstructure parameters and optical constants of CdTe thin films

    Energy Technology Data Exchange (ETDEWEB)

    Shaaban, E.R., E-mail: esam_ramadan2008@yahoo.co [Physics Department, Faculty of Science, Qassim University, Buridah 51452 (Saudi Arabia); Physics Department, Faculty of Science, Al-Azhar University, Assiut, P.O. 71452 (Egypt); Afify, N. [Physics Department, Assiut University, Assiut (Egypt); El-Taher, A. [Physics Department, Faculty of Science, Qassim University, Buridah 51452 (Saudi Arabia); Physics Department, Faculty of Science, Al-Azhar University, Assiut, P.O. 71452 (Egypt)

    2009-08-12

    Different thickness of cadmium telluride (CdTe) thin films was deposited onto glass substrates by the thermal evaporation technique. Their structural characteristics were studied by X-ray diffraction (XRD). The XRD experiments showed that the films are polycrystalline and have a zinc-blende (cubic) structure. The microstructure parameters, crystallite size and microstrain were calculated. It is observed that the crystallite size increases and microstrain decreases with the increase in the film thickness. The fundamental optical parameters like band gap and extinction coefficient are calculated in the strong absorption region of transmittance and reflectance spectrum. The possible optical transition in these films is found to be allowed direct transition with energy gap increase from 1.481 to 1.533 eV with the increase in the film thickness. It was found that the optical band gap increases with the increase in thickness. The refractive indices have been evaluated in transparent region in terms of envelope method, which has been suggested by Swanepoul in the transparent region. The refractive index can be extrapolated by Cauchy dispersion relationship over the whole spectral range, which extended from 400 to 2500 nm. It is observed that the refractive index, n increases on increasing the film thickness up to 671 nm and then the variation of n with higher thickness lie within the experimental errors.

  14. Resistivity, carrier concentration, and carrier mobility of electrochemically deposited CdTe films

    OpenAIRE

    Takahashi, Makoto; Uosaki, Kohei; Kita, Hideaki; Yamaguchi, Shoji

    1986-01-01

    The electrical type, resistivity, and donor or acceptor concentration of CdTe films deposited electrochemically at various potentials were measured. The carrier mobilities of the films were determined from these results. The deposition potential dependence of the mobility was small and the deposition potential dependence of the resistivity was mainly controlled by the deposition potential dependence of the donor or acceptor concentration. The carrier mobilities were very small compared with t...

  15. Native Defect Control of CdTe Thin Film Solar Cells by Close-Spaced Sublimation

    Science.gov (United States)

    Okamoto, Tamotsu; Kitamoto, Shinji; Yamada, Akira; Konagai, Makoto

    2001-05-01

    The control of native defects in the CdTe thin film solar cells was investigated using a novel source for close-spaced sublimation (CSS) process which was prepared by vacuum evaporation with elemental Cd and Te (evaporated source). The evaporated sources were prepared on glass substrates at room temperature, and the Cd/Te ratio was controlled by varying the Cd and Te beam equivalent pressures. In the cells using the Te-rich source, the conversion efficiency was less than 0.2% because of the extremely low shunt resistance. On the other hand, a conversion efficiency above 15% was obtained by using the Cd-rich source. Capacitance-voltage (C-V) characteristics revealed that the acceptor concentration in the CdTe layer increased with increasing Cd/Te ratio of the evaporated source. Furthermore, photoluminescence spectra implied that the formation of the Cd vacancies in the CdTe layer was suppressed using the Cd-rich source.

  16. Magnetic vortex state and multi-domain pattern in electrodeposited hemispherical nanogranular nickel films

    Energy Technology Data Exchange (ETDEWEB)

    Samardak, Alexander; Sukovatitsina, Ekaterina; Ognev, Alexey; Stebliy, Maksim; Davydenko, Alexander; Chebotkevich, Ludmila [Laboratory of Thin Film Technologies, School of Natural Sciences, Far Eastern Federal University, Vladivostok (Russian Federation); Keun Kim, Young [Department of Materials Science and Engineering, Korea University, Seoul (Korea, Republic of); Nasirpouri, Forough [Department of Physics, University of Tabriz, Tabriz (Iran, Islamic Republic of); Janjan, Seyed-Mehdi [Faculty of Materials Engineering, Sahand University of Technology, Tabriz 51335-1996 (Iran, Islamic Republic of); Nasirpouri, Farzad, E-mail: nasirpouri@sut.ac.ir [Faculty of Materials Engineering, Sahand University of Technology, Tabriz 51335-1996 (Iran, Islamic Republic of)

    2014-12-15

    Magnetic states of nickel nanogranular films were studied in two distinct structures of individual and agglomerated granules electrodeposited on n-type Si(1 1 1) surface from a modified Watts bath at a low pH of 2. Magnetic force microscopy and micromagnetic simulations revealed three-dimensional out-of-plane magnetic vortex states in stand-alone hemispherical granules and their arrays, and multi-domain patterns in large agglomerates and integrated films. Once the granules coalesce into small chains or clusters, the coercivity values increased due to the reduction of inter-granular spacing and strengthening of the magnetostatic interaction. Further growth leads to the formation of a continuous granulated film which strongly affected the coercivity and remanence. This was characterized by the domain wall nucleation and propagation leading to a stripe domain pattern. Magnetoresistance measurements as a function of external magnetic field are indicative of anisotropic magnetoresistance (AMR) for the continuous films electrodeposited on Si substrate. - Highlights: • Magnetic states of electrodeposited nickel in isolated spherical and agglomerated nanogranules, and a continuous film. • Preferential magnetization reversal mechanism in isolated granules is vortex state. • Micromagnetic simulations confirm the three-dimensional vortex. • Transition between the vortex state and multi-domain magnetic pattern causes a significant decrease in the coercive force. • Continuous nickel films electrodeposited on silicon substrate exhibit AMR whose magnitude increases with the film thickness.

  17. Optical Properties of Al- and Sb-Doped CdTe Thin Films

    Directory of Open Access Journals (Sweden)

    A. A. J. Al-Douri

    2010-01-01

    Full Text Available Nondoped and (Al, Sb-doped CdTe thin films with 0.5, 1.5, and 2.5  wt.%, respectively, were deposited by thermal evaporation technique under vacuum onto Corning 7059 glass at substrate temperatures ( of room temperature (RT and 423 K. The optical properties of deposited CdTe films such as band gap, refractive index (n, extinction coefficient (, and dielectric coefficients were investigated as function of Al and Sb wt.% doping, respectively. The results showed that films have direct optical transition. Increasing and the wt.% of both types of dopant, the band gap decrease but the optical is constant as n, and real and imaginary parts of the dielectric coefficient increase.

  18. [Spectral analysis of the effect of annealing on CdTe polycrystalline film].

    Science.gov (United States)

    Wang, Wen-Wu; Zheng, Jia-Gui; Feng, Liang-Huan; Cai, Ya-Ping; Lei, Zhi; Zhang, Jing-Quan; Li, Bing; Li, Wei; Wu, Li-Li

    2010-03-01

    Polycrystalline CdTe thin films were prepared by close-spaced sublimation (CCS) and were annealed in different condition. The thin films were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy(XPS). The content distribution and valence state of all elements after annealing were studied. All results show that the as-deposited CdTe thin films are in a cubic phase and have the preferred orientation in (111) direction. After annealing, the peak intensity of (111), (220), (311) grows and the crystal grains grow up, while the crystal boundary decreases. So the compound probabilities of current carrier decrease, therefore shunt resistance and drain current are improved. From detailed analysis of X-ray photoelectron data, it is proposed that tellurium oxides present and its content reduces with depth increasing and that there are TeCl2O building blocks.

  19. Influence of Kilo-Electron Oxygen Ion Irradiation on Structural, Electrical and Optical Properties of CdTe Thin Films

    Science.gov (United States)

    Honey, Shehla; Thema, F. T.; Bhatti, M. T.; Ishaq, A.; Naseem, Shahzad; Maaza, M.

    2016-09-01

    In this paper, effect of oxygen (O+) ion irradiation on the properties of polycrystalline cubic structure CdTe thin films has been investigated. CdTe thin films were irradiated with O+ ions of energy 80keV at different fluence ranging from 1×1015 to 5×1016 ion/cm2 at room temperature. At 1×1015 ion/cm2 O+ ions fluence, the CdTe structure was maintained while XRD peaks of cubic phase were shifted toward lower angles. At 5×1016 ion/cm2 O+ ions fluence, cubic structure of CdTe thin films was transformed into hexagonal structure. In addition, electrical resistivity and optical bandgap were decreased with increasing O+ ion beam irradiation.

  20. Cathodoluminescence spectrum imaging analysis of CdTe thin-film bevels

    Science.gov (United States)

    Moseley, John; Al-Jassim, Mowafak M.; Guthrey, Harvey L.; Burst, James M.; Duenow, Joel N.; Ahrenkiel, Richard K.; Metzger, Wyatt K.

    2016-09-01

    We conducted T = 6 K cathodoluminescence (CL) spectrum imaging with a nanoscale electron beam on beveled surfaces of CdTe thin films at the critical stages of standard CdTe solar cell fabrication. We find that the through-thickness CL total intensity profiles are consistent with a reduction in grain-boundary recombination due to the CdCl2 treatment. The color-coded CL maps of the near-band-edge transitions indicate significant variations in the defect recombination activity at the micron and sub-micron scales within grains, from grain to grain, throughout the film depth, and between films with different processing histories. We estimated the grain-interior sulfur-alloying fraction in the interdiffused CdTe/CdS region of the CdCl2-treated films from a sample of 35 grains and found that it is not strongly correlated with CL intensity. A kinetic rate-equation model was used to simulate grain-boundary (GB) and grain-interior CL spectra. Simulations indicate that the large reduction in the exciton band intensity and relatively small decrease in the lower-energy band intensity at CdTe GBs or dislocations can be explained by an enhanced electron-hole non-radiative recombination rate at the deep GB or dislocation defects. Simulations also show that higher GB concentrations of donors and/or acceptors can increase the lower-energy band intensity, while slightly decreasing the exciton band intensity.

  1. Cathodoluminescence spectrum imaging analysis of CdTe thin-film bevels

    Energy Technology Data Exchange (ETDEWEB)

    Moseley, John [National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, USA; Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401, USA; Al-Jassim, Mowafak M. [National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, USA; Guthrey, Harvey L. [National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, USA; Burst, James M. [National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, USA; Duenow, Joel N. [National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, USA; Ahrenkiel, Richard K. [National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, USA; Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401, USA; Metzger, Wyatt K. [National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, USA

    2016-09-09

    We conducted T = 6 K cathodoluminescence (CL) spectrum imaging with a nanoscale electron beam on beveled surfaces of CdTe thin films at the critical stages of standard CdTe solar cell fabrication. We find that the through-thickness CL total intensity profiles are consistent with a reduction in grain-boundary recombination due to the CdCl2 treatment. The color-coded CL maps of the near-band-edge transitions indicate significant variations in the defect recombination activity at the micron and sub-micron scales within grains, from grain to grain, throughout the film depth, and between films with different processing histories. We estimated the grain-interior sulfur-alloying fraction in the interdiffused CdTe/CdS region of the CdCl2-treated films from a sample of 35 grains and found that it is not strongly correlated with CL intensity. A kinetic rate-equation model was used to simulate grain-boundary (GB) and grain-interior CL spectra. Simulations indicate that the large reduction in the exciton band intensity and relatively small decrease in the lower-energy band intensity at CdTe GBs or dislocations can be explained by an enhanced electron-hole non-radiative recombination rate at the deep GB or dislocation defects. Simulations also show that higher GB concentrations of donors and/or acceptors can increase the lower-energy band intensity, while slightly decreasing the exciton band intensity.

  2. K-edge EXAFS and XANES studies of Cu in CdTe thin-film solar cells

    Science.gov (United States)

    Liu, Xiangxin; Gupta, Akhlesh; Compaan, Alvin D.; Leyarovska, Nadia; Terry, Jeff

    2002-03-01

    Copper has been identified as a very important dopant element in CdTe thin-film solar cells. Cu is a deep acceptor in CdTe and is commonly used to obtain a heavily doped, low resistance back contact to polycrystalline CdTe. Cu also helps to increase the open circuit voltage of the cell. However, Cu is also a fast diffuser in CdTe, especially along grain boundaries, and can accumulate at the CdS/CdTe junction. It is suspected of leading to cell performance degradation in some cases. The present study is designed to help identify the lattice location of the Cu in CdTe. Cu K-edge, x-ray absorption (XAS) measurements were conducted on Cu in thin films of CdTe. Experiments were performed at the MR-CAT beamline at the Advanced Photon Source. The 3 mm CdTe layers were magnetron sputtered onto fused silica substrates. Some films were diffused with Cu from a 200 Å layer of evaporated Cu. XAS spectra were collected in fluorescence geometry with a 13 elements Ge detector. Quantitative fluorescence spectroscopy measurements were also performed. Details of the Cu environment and possible changes with time will be reported.

  3. Effects of temperature and deposition time on the RF- sputtered CdTe films preparation

    OpenAIRE

    E. Camacho-Espinosa; Rosendo, E.; T. Díaz; A. I. Oliva; V. Rejon; Peña, J. L.

    2014-01-01

    In this work, CdTe thin films were deposited by rf-sputtering at different substrate temperatures (room temperature (RT), 100, 150, 200, and 250 °C) and deposition times (30, 60, and 90 min). The applied power and vacuum pressure were maintained fixed for all depositions. A mean value of 18 .5 nm/s on the deposition rate was maintained for films deposition. The surface morphology, rms-roughness, and grain size of the sputtered-films were obtained from atomic force microscopy and scanning elec...

  4. Electrodeposition of Sm–Co film with high Sm content from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Long, Xiong-fei; Guo, Guang-hua, E-mail: guogh@mail.csu.edu.cn; Li, Xin-hua; Xia, Qing-lin; Zhang, Jin-fang

    2013-12-02

    Sm–Co films with high Sm content were electrodeposited by potentiostat technique from the aqueous solution containing glycine as a complexing agent. The Cyclic Voltammetry measurements showed that the glycine plays a crucial role in the electrodeposition of Sm–Co films. The forming of stable complex [Co{sup II}Sm{sup III}(Gly{sup −}){sub 2}(HGly{sup ±})]{sup 3+} facilitated the codeposition of Sm with Co at relatively low potential, which made it possible to fabricate the Sm–Co films with high Sm content. The Sm–Co film with 43 at.% Sm had been obtained. X-ray diffraction showed that the as-deposited Sm–Co films were amorphous. After annealing at 600 °C for 2 h in Ar atmosphere, the films became crystalline and the permanent Sm{sub 2}Co{sub 17} phase was formed, which significantly enhanced the coercivity of the films. - Highlights: • The Sm–Co film with high Sm content is electrodeposited from aqueous solutions. • The addition of glycine facilitates the codeposition of Sm with Co at relatively low potential. • The Sm{sub 2}Co{sub 17} phase is formed in the annealed Sm–Co film.

  5. Thermoelectric power and Hall effect measurements in polycrystalline CdTe thin films

    Energy Technology Data Exchange (ETDEWEB)

    Paez, B.A. [Pontificia Univ. Javeriana, Santafe de Bogota (Colombia). Thin Films Group

    2000-07-01

    Polycrystalline CdTe thin films deposited by close space sublimation (CSS), were characterized through thermoelectric power, {alpha}, Hall coefficient, and resistivity, {rho}, measurements in the range of 90 to 400 K. This was in order to determine the scattering mechanisms which mainly affect the electrical transport properties in CdTe thin films. The results were analyzed based on theoretical calculations of {alpha} against temperature. This model includes scattering processes within the grains and at the grain boundaries. Some of the parameters used in this calculation were determined experimentally: grain size, crystal structure, activation energy and effective mass. It is important to state that the main approximations were justified according to experimental measurements. (orig.)

  6. Identification of critical stacking faults in thin-film CdTe solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Su-Hyun; Walsh, Aron, E-mail: a.walsh@bath.ac.uk [Global E3 Institute, Department of Materials Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Centre for Sustainable Chemical Technologies and Department of Chemistry, University of Bath, Bath BA2 7AY (United Kingdom); Butler, Keith T. [Centre for Sustainable Chemical Technologies and Department of Chemistry, University of Bath, Bath BA2 7AY (United Kingdom); Soon, Aloysius [Global E3 Institute, Department of Materials Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Abbas, Ali; Walls, John M., E-mail: j.m.wall@loughborough.ac.uk [Centre for Renewable Energy Systems Technology, School of Electronic, Electrical and Systems Engineering, Loughborough University, Leicestershire LE11 3TU (United Kingdom)

    2014-08-11

    Cadmium telluride (CdTe) is a p-type semiconductor used in thin-film solar cells. To achieve high light-to-electricity conversion, annealing in the presence of CdCl{sub 2} is essential, but the underlying mechanism is still under debate. Recent evidence suggests that a reduction in the high density of stacking faults in the CdTe grains is a key process that occurs during the chemical treatment. A range of stacking faults, including intrinsic, extrinsic, and twin boundary, are computationally investigated to identify the extended defects that limit performance. The low-energy faults are found to be electrically benign, while a number of higher energy faults, consistent with atomic-resolution micrographs, are predicted to be hole traps with fluctuations in the local electrostatic potential. It is expected that stacking faults will also be important for other thin-film photovoltaic technologies.

  7. Analyses of photoluminescence spectra of CdTe thin films at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad-Bitar, R. [University of Jordan, Amman (Jordan); Moutinho, H.; Abulfotuh, F.; Kazmerski, L. [Solar Energy Research Inst., Golden, CO (United States)

    1995-11-01

    Photoluminescence (PL) spectra of thin films of CdTe grown on glass by evaporation have been obtained at different laser powers and at different temperatures near and to the red end of the band gap. We suggest an analytical method which deconvolutes the PL spectrum into peaks corresponding to the main electronic transitions. Each spectrum was analytically fitted to eight Gaussian peaks. Gaussian peaks have been found to give the best fit to the spectrum. The quality of the fit can be checked by the fact that the positions and the widths of the eight peaks of each PL spectrum should agree with the fit to another spectrum taken at a different excitation power or a different sample temperature. These results may help to identify these peaks and suggest a model for the shallow electrically active states between the conduction and valance bands of CdTe thin films. (Author)

  8. Admittance spectroscopy characterize graphite paste for back contact of CdTe thin film solar cells

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    CdTe thin film solar cells with a doped-graphite paste back contact layer were studied using admittance spectroscopy technology.The positions and the capture cross sections of energy level in the forbidden band were calculated,which are the important parameters to affect solar cell performance.The results showed that there were three defects in the CdTe thin films solar cells with the doped-graphite paste back contact layer,whose positions in the forbidden band were close to 0.34,0.46 and 0.51 eV,respectively above the valence band,and capture cross sections were 2.23×10-16,2.41×10-14,4.38×10-13 cm2,respectively.

  9. Physical properties of electron beam evaporated CdTe and CdTe:Cu thin films

    Energy Technology Data Exchange (ETDEWEB)

    Punitha, K. [Department of Physics, Alagappa University, Karaikudi 630004 (India); Sivakumar, R., E-mail: krsivakumar1979@yahoo.com [Directorate of Distance Education, Alagappa University, Karaikudi 630004 (India); Sanjeeviraja, C. [Department of Physics, Alagappa Chettiar College of Engineering and Technology, Karaikudi 630004 (India); Sathe, Vasant; Ganesan, V. [UGC-DAE Consortium for Scientific Research, Indore 452001 (India)

    2014-12-07

    In this paper, we report on physical properties of pure and Cu doped cadmium telluride (CdTe) films deposited onto corning 7059 microscopic glass substrates by electron beam evaporation technique. X-ray diffraction study showed that all the deposited films belong to amorphous nature. The average transmittance of the films is varied between 77% and 90%. The optical energy band gap of pure CdTe film is 1.57 eV and it decreased to 1.47 eV upon 4 wt. % of Cu addition, which may be due to the extension of localized states in the band structure. The refractive index of the films was calculated using Swanepoel method. It was observed that the dispersion data obeyed the single oscillator of the Wemple-Didomenico model, from which the dispersion energy (E{sub d}) parameters, dielectric constants, plasma frequency, and oscillator energy (E{sub o}) of CdTe and CdTe:Cu films were calculated and discussed in detail with the light of possible mechanisms underlying the phenomena. The variation in intensity of photoluminescence band edge emission peak observed at 820 nm with Cu dopant is due to the change in surface state density. The observed trigonal lattice of Te peaks in the micro-Raman spectra confirms the p-type conductive nature of films, which was further corroborated by the Hall effect measurement. The lowest resistivity of 6.61 × 10{sup 4} Ω cm was obtained for the CdTe:Cu (3 wt. %) film.

  10. Preparation of Bi2-xSbxTe3 thermoelectric films by electrodeposition

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Bi2-xSbxTe3 thermoelectric films were electrochemically deposited from the solution containing Bi3+, HTeO2+and SbO+.ESEM (environmental scanning electron microscope) investigations indicated that the crystalline state of Bi2-xSbxTe3 films transformed from equiaxed crystal to dendritic crystal with the negative shift of deposition potential. XRD and EDS were used to characterize the structure and composition of the electrodeposited films. The Seebeck coefficient and the temperature dependence of the resistance of Bi2-xSbxTe3 films were measured. The results showed that the composition of the film electrodeposited at -0.5 V is Bi0.5Sb1.5Te3 with the largest Seebeck coefficient of 213 μV·K-1.

  11. In-depth analysis of chloride treatments for thin-film CdTe solar cells

    OpenAIRE

    Major, J.D.; Al Turkestani, M.; Bowen, L; Brossard, M.; Li, C; Lagoudakis, P.; S. J. Pennycook; Phillips, L. J.; Treharne, R. E.; Durose, K.

    2016-01-01

    CdTe thin-film solar cells are now the main industrially established alternative to silicon-based photovoltaics. These cells remain reliant on the so-called chloride activation step in order to achieve high conversion efficiencies. Here, by comparison of effective and ineffective chloride treatments, we show the main role of the chloride process to be the modification of grain boundaries through chlorine accumulation, which leads an increase in the carrier lifetime. It is also demonstrated th...

  12. Anomalous scaling and super-roughness in the growth of CdTe polycrystalline films

    OpenAIRE

    Mata, Angélica S.; Ferreira, Jr,Augusto; Ribeiro, Igor R. B.; Ferreira, Sukarno O.

    2011-01-01

    CdTe films grown on glass substrates covered by fluorine doped tin oxide by Hot Wall Epitaxy (HWE) were studied through the interface dynamical scaling theory. Direct measures of the dynamical exponent revealed an intrinsically anomalous scaling characterized by a global roughness exponent $\\alpha$ distinct from the local one (the Hurst exponent $H$), previously reported [Ferreira \\textit{et al}., Appl. Phys. Lett. \\textbf{88}, 244103 (2006)]. A variety of scaling behaviors was obtained with ...

  13. Thin film CdTe solar cells by close spaced sublimation: Recent results from pilot line

    Energy Technology Data Exchange (ETDEWEB)

    Siepchen, B., E-mail: bastian.siepchen@ctf-solar.com [CTF Solar GmbH, Industriestraße 2, 65779 Kelkheim (Germany); Drost, C.; Späth, B.; Krishnakumar, V.; Richter, H.; Harr, M. [CTF Solar GmbH, Industriestraße 2, 65779 Kelkheim (Germany); Bossert, S.; Grimm, M. [Roth and Rau AG, An der Baumschule 6-8, 09337 Hohenstein-Ernstthal (Germany); Häfner, K.; Modes, T.; Zywitzki, O.; Morgner, H. [Fraunhofer Institute for Electron Beam and Plasma Technology FEP, Winterbergstrasse 28, 01277 Dresden (Germany)

    2013-05-01

    CdTe is an attractive material to produce high efficient and low cost thin film solar cells. The semiconducting layers of this kind of solar cell can be deposited by the Close Spaced Sublimation (CSS) process. The advantages of this technique are high deposition rates and an excellent utilization of the raw material, leading to low production costs and competitive module prices. CTF Solar GmbH is offering equipment and process knowhow for the production of CdTe solar modules. For further improvement of the technology, research is done at a pilot line, which covers all relevant process steps for manufacture of CdTe solar cells. Herein, we present the latest results from the process development and our research activities on single functional layers as well as for complete solar cell devices. Efficiencies above 13% have already been obtained with Cu-free back contacts. An additional focus is set on different transparent conducting oxide materials for the front contact and a Sb{sub 2}Te{sub 3} based back contact. - Highlights: ► Laboratory established on industrial level for CdTe solar cell research ► 13.0% cell efficiency with our standard front contact and Cu-free back contact ► Research on ZnO-based transparent conducting oxide and Sb{sub 2}Te{sub 3} back contacts ► High resolution scanning electron microscopy analysis of ion polished cross section.

  14. Characterization of Highly Efficient CdTe Thin Film Solar Cells by Low-Temperature Photoluminescence

    Science.gov (United States)

    Okamoto, Tamotsu; Matsuzaki, Yuichi; Amin, Nowshad; Yamada, Akira; Konagai, Makoto

    1998-07-01

    Highly efficient CdTe thin film solar cells prepared by close-spaced sublimation (CSS) method with a glass/ITO/CdS/CdTe/Cu-doped carbon/Ag structure were characterized by low-temperature photoluminescence (PL) measurement. A broad 1.42 eV band probably due to VCd Cl defect complexes appeared as a result of CdCl2 treatment. CdS/CdTe junction PL revealed that a CdSxTe1-x mixed crystal layer was formed at the CdS/CdTe interface region during the deposition of CdTe by CSS and that CdCl2 treatment promoted the formation of the mixed crystal layer. Furthermore, in the PL spectra of the heat-treated CdTe after screen printing of the Cu-doped carbon electrode, a neutral-acceptor bound exciton (ACu0, X) line at 1.590 eV was observed, suggesting that Cu atoms were incorporated into CdTe as effective acceptors after the heat treatment.

  15. Preparation and Properties of CdTe Polycrystalline Films for Solar Cells

    Institute of Scientific and Technical Information of China (English)

    ZHENG Huajing; ZHANG Jingquan; FENG Lianghuan; ZHENG Jiagui; CAI Wei; LI Bing; CAI Yaping

    2006-01-01

    The structure and characteristics of CdTe thin films are closely dependent on the whole deposition process in close-space sublimation (CSS). The physical mechanism of CSS was analyzed and the temperature distribution in CSS system was measured, and the influences of the increasing-temperature process and pressure on the preliminary nucleus creation were studied. The results indicate: the samples deposited at different pressures have a cubical structure of CdTe and the diffraction peaks of CdS and SnO2∶F. As the atmosphere pressure increases, the crystal size of CdTe decreases, the rate of the transparency of the thin film decreases and the absorption side moves towards the short-wave direction. After a 4-minute depositing process with a substrate temperature of 500 ℃ and a source temperature of 620 ℃, the polycrystalline thin films can be made, so the production of high-quality integrated cell with SnO2:F/CdS/CdTe/Au structure is hopeful.

  16. Modeling the defect distribution and degradation of CdTe ultrathin films

    Science.gov (United States)

    Gorji, Nima E.

    2014-12-01

    The defect distribution across an ultrathin film CdTe layer of a CdS/CdTe solar cell is modelled by solving the balance equation in steady state. The degradation of the device parameters due to the induced defects during ion implantation is considered where the degradation rate is accelerated if the defect distribution is considerable. The defect concentration is maximum at the surface of the CdTe layer where implantation is applied and it is minimum at the junction with the CdS layer. It shows that ultrathin devices degrade faster if the defect concentration is high at the junction rather than the back region (CdTe/Metal). Since the front and back contacts of the device are close in ultrathin films and the electric field is strong to drive the defects into the junction, the p-doping process might be precisely controlled during ion implantation. The modeling results presented here are in agreement with the few available experimental reports in literature about the degradation and defect configuration of the ultrathin CdTe films.

  17. Influence of deposition parameters on the properties of CdTe films deposited by close spaced sublimation

    OpenAIRE

    Falcão Vivienne Denise; Pinheiro Wagner Anacleto; Ferreira Carlos Luiz; Cruz Leila Rosa de Oliveira

    2006-01-01

    CdTe thin films are used as absorber layer in CdS/CdTe solar cells. The microstructure of this absorber layer plays a fundamental role in photovoltaic conversion and can be controlled by the deposition parameters used during the film growth. In this work, CdTe thin films were deposited by the CSS method onto glass substrates previously covered with In2O3:Sn. The effects of pressure, source temperature and substrate temperature on the microstructural properties of the films were studied. The p...

  18. The study of properties of CdTe thin films deposited in Ar/O{{2}} atmosphere

    Science.gov (United States)

    Li, Y.; Li, B.; Feng, L.; Zheng, J.; Li, W.

    2009-02-01

    The preparation and properties of CdTe thin films is of a primary interest for the CdTe thin film solar cells in both research and technology. In our work, polycrystalline CdTe thin films were deposited on pretreated glass substrates in Ar/O{2} atmosphere by closed-space sublimation (CSS) technology. Structural property was studied by X-ray diffraction (XRD), surface morphology was observed by scanning electron microscopy (SEM). The optical and electrical properties of CdTe films were investigated, as well as the effects of deposition temperatures, the ratio of gas (Ar/O{2}) and post-treatment on the properties. The high quality CdTe layer was prepared based on the above studies. These layers were used to prepared CdS/CdTe/ZnTe:Cu solar cells. Efficiency of 13.38% and fill factor of 70.3% (0.501 cm2 area) for CdTe solar cells have been achieved. Project supported by the National High Technology Research and Development Program of China (Grant No.2003AA513010) and the National Natural Science Foundation of China (Grant No.60506004).

  19. Electrodeposition of bismuth telluride thermoelectric films from a nonaqueous electrolyte using ethylene glycol

    NARCIS (Netherlands)

    Nguyen, H.P.; Wu, M.; Su, J.; Vullers, R.J.M.; Vereecken, P.M.; Fransaer, J.

    2012-01-01

    Ethylene glycol was studied as an electrolyte for the electrodeposition of thermoelectric bismuth telluride films by cyclic voltammetry, rotating ring disk electrode and electrochemical quartz crystal microbalance (EQCM). The reduction of both Bi3+ and Te4+ ions proceeds in one step without the form

  20. Challenges of sample preparation for cross sectional EBSD analysis of electrodeposited nickel films

    DEFF Research Database (Denmark)

    Alimadadi, Hossein; Pantleon, Karen

    2009-01-01

    . Different procedures for sample preparation including mechanical grinding and polishing, electropolishing and focused ion beam milling have been applied to a nickel film electrodeposited on top of an amorphous Ni-P layer on a Cu-substrate. Reliable EBSD analysis of the whole cross section can be obtained...

  1. Fabrication of solar cells based on polycrystalline CdTe thin films using an economical production. Energie

    Energy Technology Data Exchange (ETDEWEB)

    Tranchart, J.C.; Boucherez, P.

    1983-01-01

    Polycrystalline CdS and CdTe films were produced by serigraphy. High-quality CdS films were obtained, especially with CdCl as melting phase. In the field of CdTe films, further studies are required in order to improve the sintering process, the film porosity characteristics, and the electric resistivity which decides the serial conductivity of the n-CdS/p-CdTe structures. In the field of solar cells, quartz +In/sub 2/O/sub 3/+CdS+CdTe heterostructures with a photoelectric efficiency of 2.5% were obtained. This value is too low, even if the economic advantages of serigraphy are taken into account. Further studies should center on the sintering process for CdTe films.

  2. Influence of CuxS back contact on CdTe thin film solar cells

    Institute of Scientific and Technical Information of China (English)

    Lei Zhi; Feng Lianghuan; Zeng Guanggen; Li Wei; Zhang Jingquan; Wu Lili; Wang Wenwu

    2013-01-01

    We present a detailed study on CuxS polycrystalline thin films prepared by chemical bath method and utilized as back contact material for CdTe solar cells.The characteristics of the films deposited on Si-substrate are studied by XRD.The results show that as-deposited CuxS thin film is in an amorphous phase while after annealing,samples are in polycrystalline phases with increasing temperature.The thickness of CuxS thin films has great impact on the performance of CdS/CdTe solar cells.When the thickness of the film is about 75 nm the performance of CdS/CdTe thin film solar cells is found to be the best.The energy conversion efficiency can be higher than 12.19%,the filling factor is higher than 68.82% and the open-circuit voltage is more than 820 mV.

  3. Influence of CuxS back contact on CdTe thin film solar cells

    Science.gov (United States)

    Zhi, Lei; Lianghuan, Feng; Guanggen, Zeng; Wei, Li; Jingquan, Zhang; Lili, Wu; Wenwu, Wang

    2013-01-01

    We present a detailed study on CuxS polycrystalline thin films prepared by chemical bath method and utilized as back contact material for CdTe solar cells. The characteristics of the films deposited on Si-substrate are studied by XRD. The results show that as-deposited CuxS thin film is in an amorphous phase while after annealing, samples are in polycrystalline phases with increasing temperature. The thickness of CuxS thin films has great impact on the performance of CdS/CdTe solar cells. When the thickness of the film is about 75 nm the performance of CdS/CdTe thin film solar cells is found to be the best. The energy conversion efficiency can be higher than 12.19%, the filling factor is higher than 68.82% and the open-circuit voltage is more than 820 mV.

  4. Structural and optical properties of ZnS thin film grown by pulsed electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Hennayaka, H.M.M.N.; Lee, Ho Seong, E-mail: hs.lee@knu.ac.kr

    2013-12-02

    ZnS thin films were grown on indium–tin-oxide coated glass substrates using pulsed electrodeposition and the effect of the deposition temperature on the structural and optical properties of the ZnS films was investigated. Polycrystalline cubic ZnS films were obtained at all the deposition temperatures. At temperatures below 70 °C, less dense films were obtained and particle agglomeration was visible. On the other hand, at temperatures above 70 °C, more dense films with well-defined grains were obtained. With increasing deposition temperatures, the optical transmittance and bandgap of the ZnS films decreased. These results are attributed to the increase in the thickness of ZnS films and their particle size. The ZnS films grown at 90 °C exhibited the highly (200) preferred orientation and n-type conductivity with a wide bandgap of 3.75 eV. - Highlights: • This study describes the effect of the deposition temperature on the growth of the ZnS thin films. • ZnS thin films were grown using pulsed electrodeposition. • ZnS thin films exhibited the good crystal quality and chemical composition. • ZnS thin films exhibited n-type conductivity with a wide bandgap of 3.75 eV.

  5. Surface plasmon effect in nanocrystalline copper/DLC composite films by electrodeposition technique

    Indian Academy of Sciences (India)

    S Hussain; A K Pal

    2006-11-01

    Composite films of nanocrystalline copper embedded in DLC matrix prepared by electrodeposition technique were studied for their optical properties. Particle size and metal volume fractions were tailored by varying the amount of copper containing salt in the electrolyte. Blue-shift of the surface plasmon resonance peak in the absorbance spectra of the films was observed with the reduction in size and volume fraction of metal particles. Mie theory was found to describe the experimental spectra quite well.

  6. Deposition of CdTe films under microgravity: Foton M3 mission

    Energy Technology Data Exchange (ETDEWEB)

    Benz, K.W.; Croell, A. [Freiburger Materialforschungszentrum FMF, Albert-Ludwigs-Universitaet Freiburg (Germany); Zappettini, A.; Calestani, D. [CNR Parma, Instituto Materiali Speciali per Elettronica e Magnetismo IMEM, Fontani Parma (Italy); Dieguez, E. [Universidad Autonoma de Madrid (Spain). Departamento de Fisica de Materiales; Carotenuto, L.; Bassano, E. [Telespazio Napoli, Via Gianturco 31, 80146 Napoli (Italy); Fiederle, M.

    2009-10-15

    Experiments of deposition of CdTe films have been carried out under microgravity in the Russian Foton M3 mission. The influence of gravity has been studied with these experiments and compared to the results of simulations. The measured deposition rate could be confirmed by the theoretical results for lower temperatures. For higher temperatures the measured thickness of the deposited films was larger compared to the theoretical data. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. Thin-film CdTe photovoltaic cells by laser deposition and rf sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Compaan, A.; Bohn, R.G.; Bhat, A.; Tabory, C.; Shao, M.; Li, Y.; Savage, M.E.; Tsien, L. (Department of Physics and Astronomy, The University of Toledo, Toledo, Ohio 43606 (United States))

    1992-12-01

    Laser-driven physical vapor deposition (LDPVD) and radio-frequency (rf) sputtering have been used to fabricate thin-film solar cells on SnO[sub 2]-coated glass substrates. The laser-ablation process readily permits the use of several target materials in the same vacuum chamber and complete solar cell structures have been fabricated on SnO[sub 2]-coated glass using LDPVD for the CdS, CdTe, and CdCl[sub 2]. To date the best devices ([similar to]9% AM1.5) have been obtained after a post-deposition anneal at 400 [degree]C. In addition, cells have been fabricated with the combination of LDPVD CdS, rf-sputtered CdTe, and LDPVD CdCl[sub 2]. The performance of these cells indicates considerable promise for the potential of rf sputtering for CdTe photovoltaic devices. The physical mechanisms of LDPVD have been studied by transient optical spectroscopy on the laser ablation plume. These measurements have shown that, e.g., Cd is predominantly in the neutral atomic state in the plume but with a large fraction which is highly excited internally ([ge]6 eV) and that the typical neutral Cd translational kinetic energies perpendicular to the target are 20 eV and greater. Quality of as-grown and annealed films has been analyzed by optical absorption. Raman scattering, photoluminescence, electrical conductivity, Hall effect, x-ray diffraction, and SEM/EDS.

  8. Electron and hole drift mobility measurements on thin film CdTe solar cells

    Science.gov (United States)

    Long, Qi; Dinca, Steluta A.; Schiff, E. A.; Yu, Ming; Theil, Jeremy

    2014-07-01

    We report electron and hole drift mobilities in thin film polycrystalline CdTe solar cells based on photocarrier time-of-flight measurements. For a deposition process similar to that used for high-efficiency cells, the electron drift mobilities are in the range of 10-1-100 cm2/V s, and holes are in the range of 100-101 cm2/V s. The electron drift mobilities are about a thousand times smaller than those measured in single crystal CdTe with time-of-flight; the hole mobilities are about ten times smaller. Cells were examined before and after a vapor phase treatment with CdCl2; treatment had little effect on the hole drift mobility, but decreased the electron mobility. We are able to exclude bandtail trapping and dispersion as a mechanism for the small drift mobilities in thin film CdTe, but the actual mechanism reducing the mobilities from the single crystal values is not known.

  9. Epitaxial growth of CdTe oriented thin films, infrared characterization and possible applications to photo-voltaic cells

    OpenAIRE

    Gerbaux, X.; Pianelli, A.; Hadni, A.; Jeanniard, C.; Strimer, P.

    1980-01-01

    The growth of CdTe oriented thin films by the ENSH method - i.e. Epitaxial Nucleation in Sub-microscopic Holes of an intermediate layer closely applied on a bulk single crystal — has been recently described. The CdTe films are generally difficult to detach from the bulk crystal. However free films are needed to study the infrared transmission in the spectral region of high absorption. To get them, the vitreous or amorphous thin intermediate layers are substituted by quite soluble an oriented ...

  10. Investigation of polycrystalline CdTe thin films deposited by physical vapor deposition, close-spaced sublimation, and sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Moutinho, H.R.; Hasoon, F.S.; Abulfotuh, F.; Kazmerski, L.L. [National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401 (United States)

    1995-11-01

    CdTe thin films, deposited on different substrate structures by physical vapor deposition, sputtering, and close-spaced sublimation, have been treated with CdCl{sub 2} at several temperatures. The morphology of the films has been studied by atomic force microscopy, and the observations were correlated to results obtained from x-ray diffraction, cathodoluminescence, and minority-carrier lifetime measurements. The samples treated at 400 {degree}C resulted in the best device-quality films, independent of deposition method and underlying substrate structure. For the first time, a nanograin structure was observed in CdTe sputtered samples. copyright {ital 1995} {ital American} {ital Vacuum} {ital Society}.

  11. Physical and electrochemical properties of ZnO films fabricated from highly cathodic electrodeposition potentials

    Science.gov (United States)

    Ismail, Abdul Hadi; Abdullah, Abdul Halim; Sulaiman, Yusran

    2017-03-01

    The physical and electrochemical properties of zinc oxide (ZnO) film electrode that were prepared electrochemically were studied. ZnO was electrodeposited on ITO glass substrate by applying three different highly cathodic potentials (-1.3 V, -1.5 V, -1.7 V) in a solution containing 70 mM of Zn(NO3)2.xH2O and 0.1 M KCl with bath temperatures of 70 °C and 80 °C. The presence of ZnO was asserted from XRD analysis where the corresponding peaks in the spectra were assigned. SEM images revealed the plate-like hexagonal morphology of ZnO which is in agreement with the XRD analysis. The areal capacitance of the ZnO was observed to increase when the applied electrodeposition potential is increased from -1.3 V to -1.5 V. However, the areal capacitance is found to decrease when the applied electrodeposition potential is further increased to -1.7 V. The resistance of charge transfer (Rct) of the ZnO decreased when the applied electrodeposition potential varies from -1.3 V to -1.7 V due to the decreased particle size of ZnO when more cathodic electrodeposition potential is applied.

  12. Photo-responsivity characterizations of CdTe films for direct-conversion X-ray detectors

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ryun Kyung; Cha, Bo Kyung; Jeon, Sung Chae; Seo, Chang Woo [Korea Electrotechnology Research Institute, Ansan (Korea, Republic of); Yun, Seung Man [Pusan National University, Busan (Korea, Republic of)

    2014-08-15

    We have fabricated and investigated thin, polycrystalline, cadmium-telluride (CdTe) films in order to utilize them for optical switching readout layers in direct-conversion X-ray detectors. The polycrystalline CdTe films are fabricated on ITO glasses by using the physical vapor deposition (PVD) method at a slow deposition rate and a pressure of 10{sup -6} torr. CdTe films with thicknesses of 5 and 20 μm are grown. The electrical and the optical characteristics of the CdTe films are investigated by measuring the dark-current and the photo-current as functions of the applied field under different wavelengths of light. Higher photo-currents are generated at the longer wavelengths of light for the same applied voltage. When a higher electrical field is applied to the 20 μm-thick CdTe film, a higher dark-current, a higher photo-current, a larger number of charges, and a higher quantum efficiency are generated.

  13. Preparation and properties of evaporated CdTe films compared with single crystal CdTe. Progress report No. 4, August 1-October 31, 1981

    Energy Technology Data Exchange (ETDEWEB)

    Bube, R H

    1981-10-01

    The hot-wall vacuum evaporation system is nearly complete and the first films are expected in early December. CdTe homojunction cells were theoretically modelled and to some extent tested experimentally using the n-type CdTe film on p-type CdTe crystal homojunction cells previously deposited at Linz. Modelling emphasizes the known importance of surface recombination velocity for such homojunction cells. The n-type layer on the experimental cell was thinned by etching from 5 micrometers to 1.5 micrometers, with a corresponding increase in short-circuit current from 0.1 to 1 mA/cm/sup 2/. This behavior is as theoretically expected; to obtain a short-circuit current of 11 mA/cm/sup 2/, as required for a 10% cell, requires a thickness of about 0.2 micrometers for a surface recombination velocity of 10/sup 6/ cm/sec and other realistic cell parameters. By doping experiments on single crystal CdTe, it has been shown that the hole density does decrease when the P dopant density is decreased below a critical value in CdTe:P crystals, thus eliminating the possibility that the major acceptors in the P-doped crystals were not P impurity. Attempts to heavily dope CdTe with As were less successful, but this may be due to the use of elemental As as the dopant in this case rather than a compound of the dopant. Cs was shown to be an effective dopant of CdTe and resistivities as low as 0.3 ohm-cm corresponding to hole densities in the low 10/sup 17/ cm/sup -3/ range were obtained. An apparent correlation between the low-temperature barrier height associated with a grain boundary in CdTe and the angle of mismatch between the two grains has been observed. Improved capacitance of grain boundary measurements should yield defect densities.

  14. Optical and electrical characterizations of highly efficient CdTe thin film solar cells prepared by close-spaced sublimation

    Science.gov (United States)

    Okamoto, T.; Yamada, A.; Konagai, M.

    2000-06-01

    The effects of the Cu diffusion on the optical and electrical properties of CdTe thin film solar cells prepared by close-spaced sublimation (CSS) were investigated by capacitance-voltage ( C- V) measurement and low-temperature photoluminescence (PL) measurement. C- V measurement revealed that the net acceptor concentration in the CdTe layer was independent of the heat treatment after screen printing of the Cu-doped graphite electrode for Cu diffusion into the CdTe layer, although it greatly affected the solar cell performance. Furthermore, the depth profile of PL spectrum of CdTe layer implies that the heat treatment for Cu diffusion facilitates the formation of low-resistance contact to CdTe through the formation of a heavily doped (p +) region in the CdTe adjacent to the back electrode, but Cu atoms do not act as effective acceptors in the CdTe layer except the region near the back electrode.

  15. Nanocrystalline CdTe thin films by electrochemical synthesis

    Directory of Open Access Journals (Sweden)

    Ramesh S. Kapadnis

    2013-03-01

    Full Text Available Cadmium telluride thin films were deposited onto different substrates as copper, Fluorine-doped tin oxide (FTO, Indium tin oxide (ITO, Aluminum and zinc at room temperature via electrochemical route. The morphology of the film shows the nanostructures on the deposited surface of the films and their growth in vertical direction. Different nanostructures developed on different substrates. The X-ray diffraction study reveals that the deposited films are nanocrystalline in nature. UV-Visible absorption spectrum shows the wide range of absorption in the visible region. Energy-dispersive spectroscopy confirms the formation of cadmium telluride.

  16. Hydrogen-induced superabundant vacancies in electrodeposited Fe–C alloy films

    Energy Technology Data Exchange (ETDEWEB)

    Fukumuro, Naoki; Kojima, Saeka; Fujino, Moeko; Mizuta, Yasunori; Maruo, Toshiaki; Yae, Shinji [Department of Materials Science and Chemistry, Graduate School of Engineering, University of Hyogo, Himeji, Hyogo (Japan); Fukai, Yuh [Institute of Industrial Science, The University of Tokyo, Meguro-ku, Tokyo (Japan)

    2015-10-05

    Highlights: • The hydrogen behavior in electrodeposited Fe–C films was investigated. • The H content in Fe–C films increased with increasing of C content. • The changes in lattice parameters of Fe–C films were observed. • Both the contraction and expansion of lattice were reduced by heat treatments. • The limiting composition of VacCH{sub 5} clusters was estimated from the results. - Abstract: Fe–C alloy films containing supersaturated C and H were prepared by electrodeposition, and investigated for the hydrogen behavior in annealing processes utilizing X-ray diffraction and thermal desorption spectroscopy. The H content x{sub H} (x{sub H} = H/Fe) in the films increased from about 0.031 in pure Fe to about 0.36 in Fe–C alloy (x{sub C} = C/Fe = 0.073) in proportion to the C content. The lattice contraction of about 0.2% was observed in pure Fe films, whereas the lattice expansion increasing with C content was observed in Fe–C alloy films. Both the lattice contraction of the Fe films and the lattice expansion of the Fe–C alloy films were decreased as H was desorbed during heat treatments. The atomistic structure of vacancy–hydrogen and vacancy–carbon–hydrogen clusters in Fe–C alloy films is discussed, based on these experimental results.

  17. Electrochemical cell for in situ electrodeposition of magnetic thin films in a superconducting quantum interference device magnetometer.

    Science.gov (United States)

    Topolovec, Stefan; Krenn, Heinz; Würschum, Roland

    2015-06-01

    An electrochemical cell is designed and applied for in situ electrodeposition of magnetic thin films in a commercial SQUID magnetometer system. The cell is constructed in such a way that any parasitic contribution of the cell and of the substrate for electrodeposition to the magnetic moment of the deposited film is reduced to a minimum. A remanent minor contribution is readily taken into account by a proper analysis of the detected signal. Thus, a precise determination of the absolute magnetic moment of the electrodeposited magnetic film during its growth and dissolution is achieved. The feasibility of the cell design is demonstrated by performing Co electrodeposition using cyclic voltammetry. For an average Co film thickness of (35.6 ± 3.0) atomic layers, a magnetic moment per Co atom of (1.75 ± 0.11) μ(B) was estimated, in good agreement with the literature bulk value.

  18. Synthesis and Characterization of Potentiostatically Electrodeposited Tungsten Oxide Thin Films for Smart Window Application

    Science.gov (United States)

    More, A. J.; Patil, R. S.; Dalavi, D. S.; Suryawanshi, M. P.; Burungale, V. V.; Kim, J. H.; Patil, P. S.

    2017-02-01

    Tungsten oxide (WO3) thin films have been synthesized using electrodeposition in potentiostatic mode and the effect of different deposition potentials on their structural, morphological, optical, and electrochromic (EC) properties investigated. The deposition potential versus saturated calomel electrode (SCE) was varied from -0.35 V to -0.50 V in steps of -0.05 V for 20 min each. The electrodeposited WO3 thin films were characterized using x-ray diffraction analysis, micro-Raman spectroscopy, field-emission scanning electron microscopy, and ultraviolet-visible (UV-Vis) spectrophotometry, revealing amorphous nature with nanograins having average size from 40 nm to 60 nm. The EC performance of the WO3 thin films exhibited response times of 1.35 s for bleaching ( t b) and 3.1 s for coloration ( t c) with excellent reversibility of 64.36%. The highest coloration efficiency of the electrodeposited WO3 thin films was found to be 87.95 cm2/C. The electrochemical reversibility and stability of the WO3 thin films obtained in this study make them promising for use in smart window applications.

  19. Study of CuInSe{sub 2} thin films prepared by electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, S.N.; Li, L.; Qiu, C.X.; Shih, I.; Champness, C.H. [Electrical Engineering Dept., McGill University, University Street, Montreal, QU (Canada)

    1995-07-30

    Thin films of p-type CuInSe{sub 2} prepared by a one-step electrodeposition method have been studied by constructing CdS/CuInSe{sub 2} junctions. After the electrodeposition, the CuInSe{sub 2} films were treated either in vacuum or in Ar. Cells of the form CdS (high {sigma})/CdS (low {sigma})/CuInSe{sub 2} were then fabricated for studying the electrodeposited films. Measurements were specifically carried out to determine the diffusion length of minority carriers in the p-type CuInSe{sub 2}. It was found that the minority carrier diffusion length in CuInSe{sub 2} films treated in Ar was generally greater than that for films treated in vacuum under similar conditions. A small area cell (active area 0.11 cm{sup 2}) with a conversion efficiency of about 7% (under 125 mW/cm{sup 2} illumination) has been fabricated

  20. Electrodeposition and characterization of magnetostrictive galfenol (FeGa) thin films for use in microelectromechanical systems

    Science.gov (United States)

    Estrine, Eliot C.; Robbins, William P.; Maqableh, Mazin M.; Stadler, Bethanie J. H.

    2013-05-01

    In this paper, we investigate the challenges related to electrodeposition and characterization of magnetostrictive galfenol thin films as well as techniques used to overcome these issues. Successful deposition and evaluation of galfenol thin films is necessary for the design of galfenol based microelectromechanical devices. Stress is a primary concern because thick films and poor adhesion to substrates (e.g., silicon oxide) can lead to delamination and peeling. In addition, magnetostriction measurements require films that are uniform in thickness and composition over the sample area. Various adhesion layers were tested, and delamination was eliminated with Cr/Cu, which provided robust adhesion to the glass substrates used in capacitance bridge measurements. Uniformity and composition were controlled by the use of a rotating disk electrode for electrodeposition, which created a uniform boundary condition across the sample during deposition. The capacitance bridge technique was calibrated with Ni/glass samples, after which a magnetostriction of 140 ppm was measured for Fe83Ga17 films. These results represent the first magnetostriction measurements of electrodeposited galfenol.

  1. Electrodeposition of photocatalytic TiO2 film on surface of alumina prepared by anodic oxidation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xin-yu; CHEN Tie-qun

    2004-01-01

    A new electrochemical method to prepare photocatalytic TiO2 thin film was developed, by which the TiO2 was electrodeposited on surface of alumina by AC electrolysis in solution consisting of K2 [TiO(C2O4 )2] and C2H2O4. The deposited TiO2 thin film was primarily characterized by X-ray diffraction (XRD), scanning electronic microscopy (SEM) and energy dispersive spectrum (EDS) methods. The photocatalytic properties of this film were also studied by the photocatalytic degradation of methyl orange. The results show that the TiO2 film electrodeposited by this method is mainly in amorphous and with a little crystalline component mixed anatase and rutile. The surface of the alumina prepared by anodic oxidation is porous and the TiO2 electrodeposited on it is scattered and incompact. TiO2 thin film fixed on the surface of alumina shows photocatalytic activity to the degradation of methyl orange.

  2. Thin film CdTe solar cells with an absorber layer thickness in micro- and sub-micrometer scale

    Science.gov (United States)

    Bai, Zhizhong; Yang, Jun; Wang, Deliang

    2011-10-01

    CdTe thin film solar cell with an absorber layer as thin as 0.5 μm was fabricated. An efficiency of 7.9% was obtained for a 1-μm-thick CdTe solar cell. An increased intensity of deep recombination states in the band gap, which was responsible for the reduced open-circuit voltage and fill factor for ultra-thin solar cells, was induced due to the not-well-developed polycrystalline CdTe microstructure and the CdS/CdTe heterojunction and the presence of Cu in the back contact. The experimental results presented in this study demonstrated that 1-μm-thick absorber layer is thick enough to fabricate CdTe solar cell with a decent efficiency.

  3. Physical properties of Bi doped CdTe thin films grown by the CSVT method

    Energy Technology Data Exchange (ETDEWEB)

    Vigil-Galan, O.; Sastre-Hernandez, J.; Cruz-Gandarilla, F.; Aguilar-Hernandez, J.; Contreras-Puente, G.; Tufino-Velazquez, M. [Escuela Superior de Fisica y Matematicas, Instituto Politecnico Nacional, 07738 Mexico D. F. (Mexico); Marin, E. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Instituto Politecnico Nacional, 11500 Mexico, D. F. (Mexico); Saucedo, E.; Ruiz, C.M.; Bermudez, V. [Departamento de Fisica de Materiales, Universidad Autonoma de Madrid, 28049 Madrid (Spain)

    2006-09-22

    A study of the physical properties of CdTe thin films doped with Bi is presented. CdTe:Bi thin films were deposited by the close space vapor transport (CSVT) technique using powdered CdTe:Bi crystals grown by the vertical Bridgman method. CdTe:Bi crystals were obtained with nominal Bi doping concentrations varying in the 1x10{sup 17}-8x10{sup 18}cm{sup -3} range. The physical properties of CdTe:Bi thin films were studied performing photoluminescence, X-ray, SEM, photoacoustic spectroscopy and resistivity measurements. We observed a decrease of the resistivity values of CdTe:Bi films with the Bi content as low as 6x10{sup 5}{omega}-cm for Bi concentrations of 8x10{sup 18}cm{sup -3}. These are meaningful results for CdTe-based solar cells. (author)

  4. Microcharacterization of CdTe films deposited by close-spaced sublimation

    Energy Technology Data Exchange (ETDEWEB)

    Matson, R.J.; Hasoon, F.S.; Jones, K.M.; Al-Jassim, M.M. (National Renewable Energy Lab., Golden, CO (United States)); Tomlinson, R.D. (Salford Univ. (United Kingdom))

    1994-07-01

    Microcharacterization of the luminescent, structural, electrical and topographical properties of thin films of close-spaced sublimation (CSS)-fabricated CdTe was performed. The film morphology was found to be dependent on the film thickness, deposition conditions and post-deposition treatment. The complementary use of electron beam-induced current (EBIC) and cathodoluminescence (CL) analysis in the scanning electron microscope demonstrated large inter- and intragrain inhomogeneities in the luminescent and electrical properties of the films. Follow-on plan-view examinations with the transmission electron microscope revealed varying densities of structural defects, such as stacking faults and threading dislocations, which could explain the variations observed in the CL and EBIC images. (author)

  5. Physical properties of spray deposited CdTe thin films: PEC performance

    Institute of Scientific and Technical Information of China (English)

    V. M. Nikale; S. S. Shinde; C. H. Bhosale; K.Y. Rajpure

    2011-01-01

    p-CdTe thin films were prepared by spray pyrolysis under different ambient conditions and characterized using photoelectrochemical (PEC),X-ray diffraction (XRD),scanning electron microscopy,energy-dispersive analysis by X-ray (EDAX),and optical transmission studies.The different preparative parameters viz solution pH,solution quantity,substrate temperature and solution concentration have been optimized by the PEC technique in order to get good-quality photosensitive material.XRD analysis shows the polycrystalline nature of the film,having cubic structure with strong (111) orientation.Micrographs reveal that grains are uniformly distributed over the surface of the substrate indicating the well-defined growth ofpolycrystalline CdTe thin film.The EDAX study for the sample deposited at optimized preparative parameters shows the nearly stoichiometric Cd:Te ratio.Optical absorption shows the presence of direct transition with band gap energy of 1.5 eV.Deposited films exhibit the highest photocurrent of 2.3 mA,a photovoltage of 462 mV,a 0.48 fill factor and 3.4% efficiency for the optimized preparative parameters.

  6. Swift heavy ion irradiation induced nanograin formation in CdTe thin films

    Science.gov (United States)

    Survase, Smita; Narayan, Himanshu; Sulania, I.; Thakurdesai, Madhavi

    2016-11-01

    Swift Heavy Ion (SHI) irradiation is a unique technique for nanograin formation through grain fragmentation. Contrary to the generally reported SHI irradiation induced grain growth on CdTe thin films, we report fragmentation leading to nanograin formation. Thermally evaporated polycrystalline CdTe thin films were irradiated with 100 MeV 197Au, 107Ag and 58Ni ions beams up to a fluence of 5 × 1012 ions/cm2. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) were carried out for surface analysis before and after irradiation. SEM micrographs indicate that the larger grains in the as-deposited films were fragmented into smaller grains due to irradiation. The extent of fragmentation was found to increase with increasing electronic energy loss (Se). AFM pictures also supported the irradiation induced fragmentation. Structural characterization was done using X-ray Diffraction (XRD) technique. The ion induced strain and dislocation density were calculated from the XRD data. Both the strain and dislocation density were found to increase with increasing Se . The observed grain fragmentation is explained on the basis of a combined effect of strain induced disintegration of grains after the Coulomb explosion, and an 'incomplete' re-crystallization of the molten thermal spikes. Moreover, the optical band gap Eg (1.5 eV for as-deposited film), determined from UV-vis spectroscopy, increased with Se, and possibly because of ion induced strain and defect annealing.

  7. Effect of Substrate Temperature on Structural and Optical Properties of Nanocrystalline CdTe Thin Films Deposited by Electron Beam Evaporation

    OpenAIRE

    M. Rigana Begam; N. Madhusudhana Rao; S. Kaleemulla; M. Shobana; N. Sai Krishna; M. Kuppan

    2013-01-01

    Nanocrystalline Cadmium Telluride (CdTe) thin films were deposited onto glass substrates using electron beam evaporation technique. The effect of substrate temperature on the structural, morphological and optical properties of CdTe thin films has been investigated. All the CdTe films exhibited zinc blende structure with (111) preferential orientation. The crystallite size of the films increased from 35 nm to 116 nm with the increase of substrate temperature and the band gap of the films decre...

  8. Effect of Substrate Temperature on Structural and Optical Properties of Nanocrystalline CdTe Thin Films Deposited by Electron Beam Evaporation

    Directory of Open Access Journals (Sweden)

    M. Rigana Begam

    2013-07-01

    Full Text Available Nanocrystalline Cadmium Telluride (CdTe thin films were deposited onto glass substrates using electron beam evaporation technique. The effect of substrate temperature on the structural, morphological and optical properties of CdTe thin films has been investigated. All the CdTe films exhibited zinc blende structure with (111 preferential orientation. The crystallite size of the films increased from 35 nm to 116 nm with the increase of substrate temperature and the band gap of the films decreased from 2.87 eV to 2.05 eV with the increase of the crystallite size.

  9. The activation of thin film CdTe solar cells using alternative chlorine containing compounds

    Energy Technology Data Exchange (ETDEWEB)

    Maniscalco, B., E-mail: B.Maniscalco@lboro.ac.uk [Centre for Renewable Energy Systems Technology (CREST), School of Electronic, Electrical and Systems Engineering (United Kingdom); Abbas, A.; Bowers, J.W.; Kaminski, P.M.; Bass, K. [Centre for Renewable Energy Systems Technology (CREST), School of Electronic, Electrical and Systems Engineering (United Kingdom); West, G. [Department of Materials, Loughborough University, Leicestershire LE11 3TU (United Kingdom); Walls, J.M. [Centre for Renewable Energy Systems Technology (CREST), School of Electronic, Electrical and Systems Engineering (United Kingdom)

    2015-05-01

    The re-crystallisation of thin film cadmium telluride (CdTe) using cadmium chloride (CdCl{sub 2}) is a vital process for obtaining high efficiency photovoltaic devices. However, the precise micro-structural mechanisms involved are not well understood. In this study, we have used alternative chlorine-containing compounds to determine if these can also assist the re-crystallisation of the CdTe layer and to understand the separate roles of cadmium and chlorine during the activation. The compounds used were: tellurium tetrachloride (TeCl{sub 4}), cadmium acetate (Cd(CH{sub 3}CO{sub 2}){sub 2}), hydrochloric acid (HCl) and zinc chloride (ZnCl{sub 2}). TeCl{sub 4} was used to assess the role of Cl and the formation of a Te-rich outer layer which may assist the formation of the back contact. (Cd(CH{sub 3}CO{sub 2}){sub 2}) and HCl were used to distinguish between the roles of cadmium and chlorine in the process. Finally, ZnCl{sub 2} was employed as an alternative to CdCl{sub 2}. We report on the efficacy of using these alternative Cl-containing compounds to remove the high density of planar defects present in untreated CdTe. - Highlights: • Cadmium chloride (CdCl{sub 2}) activation treatment • Alternative chlorine containing compounds • Microstructure analysis and electrical performances.

  10. ``CuInSe2 and CdTe thin films for photovoltaic applications''

    Science.gov (United States)

    Attar, G.; Bhethanobolta, D. P.; Dugan, K.; Karthikeyan, S.; Kazi, M.; Killian, J. L.; Muthaiah, A. B.; Nierman, D.; Oman, D. M.; Swaminathan, R.; Zafar, S. A.; Ferekides, C. S.; Morel, D. L.

    1994-06-01

    We are developing processing techniques for CuInSe2 that are manufacturing-friendly due to relaxed controls on deposition conditions. We routinely achieve Jsc's in the range 35-45+ mA/cm2, FF's of 0.55-0.63, and have recently achieved 410 mV in devices without advanced Ga alloying techniques. Our progress and analysis suggests that these processing techniques can achieve state-of-the-art efficiencies. We are also developing an understanding of the complex underlying device mechanisms and their correlation to processing. We propose that a multi-junction classical model which includes space charge recombination can adequately explain device performance and help guide development efforts. The effect of the substrate temperature on the performance of CdTe solar cells prepared by the close spaced sublimation (CSS) process is being investigated. Significant progress has been made and the maximum open-circuit voltage, short-circuit current, and fill factor obtained are 840-860 mV, 22+ mA/cm2, and 69-70% respectively. The extend of interface reaction between the CdTe and CdS layers appears to be dependent on the substrate temperature. Other process parameters such as the total pressure and spacing are of equal importance in obtaining dense CdTe films. Stability studies are also underway in order to determine whether any degradation mechanisms exist and identify their origins.

  11. The Electrochemical Degradation of Poly(3,4-ethylenedioxythiophene) Films Electrodeposited from Aqueous Solutions

    Science.gov (United States)

    Láng, Gyözö G.; Ujvári, Mária; Vesztergom, Soma; Kondratiev, Veniamin; Gubicza, Jenö; Szekeres, Krisztina J.

    2016-09-01

    In this review, results of recent studies on the electrochemical stability and degradation properties of poly(3,4-ethylenedioxythiophene) films are summarized, with particular emphasis on the structural changes induced by overoxidation and electrochemical degradation. The most important electrodeposition methods for the preparation of PEDOT films in surfactant free aqueous media have also been summarized, and several experimental techniques suitable for monitoring the degradation process have been discussed. Morphological changes in PEDOT films during overoxidation have been analyzed. Overoxidation mechanisms proposed in the literature have been surveyed.

  12. Raman characterization of a new Te-rich binary compound: CdTe2.

    Science.gov (United States)

    Rousset, Jean; Rzepka, Edouard; Lincot, Daniel

    2009-04-02

    Structural characterization by Raman spectroscopy of CdTe thin films electrodeposited in acidic conditions is considered in this work. This study focuses on the evolution of material properties as a function of the applied potential and the film thickness, demonstrating the possibility to obtain a new Te-rich compound with a II/VI ratio of 1/2 under specific bath conditions. Raman measurements carried out on etched samples first allow the elimination of the assumption of a mixture of phases CdTe + Te and tend to confirm the formation of the CdTe(2) binary compound. The signature of this phase on the Raman spectrum is the increase of the LO band intensity compared to that obtained for the CdTe. The influence of the laser power is also considered. While no effect is observed on CdTe films, the increase of the incident irradiation power leads to the decomposition of the CdTe(2) compound into two more stable phases namely CdTe and Te.

  13. Large area thin film CdTe and Zn(x)Cd(1-x)Te heterojunction solar cells

    Science.gov (United States)

    Chu, T. L.; Chu, S. S.; Firszt, F.; Naseem, H. A.; Stawski, R.

    Thin film CdTe heterojunction solar cells have been prepared by the deposition of p-type CdTe films on CdS/SnO2:F/glass substrates using chemical vapor deposition (CVD) and close-spaced sublimation (CSS) techniques. The relative merits of the two techniques are discussed, and the characteristics of solar cells prepared by CVD and CSS techniques are compared. In addition, the properties of Zn(x)Cd(1-x)Te have been investigated.

  14. SEM, EDS, PL and absorbance study of CdTe thin films grown by CSS method

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Torres, M.E.; Silva-Gonzalez, R.; Gracia-Jimenez, J.M. [Instituto de Fisica, BUAP, Apdo. Postal J-48, San Manuel, 72570 Puebla, Pue. (Mexico); Casarrubias-Segura, G. [CIE- UNAM, 62580 Temixco, Morelos (Mexico)

    2006-09-22

    Oxygen-doped CdTe films were grown on conducting glass substrates by the close spaced sublimation (CSS) method and characterized using SEM, EDS, photoluminescence (PL) and absorbance. A significant change in the polycrystalline morphology is observed when the oxygen proportion is increased in the deposition atmosphere. The EDS analysis showed that all samples are nonstoichiometric with excess Te. The PL spectra show emission bands associated with Te vacancies (V{sub Te}), whose intensities decrease as the oxygen proportion in the CSS chamber is increased. The oxygen impurities occupy Te vacancies and modify the surfaces states, improving the nonradiative process. (author)

  15. Improvement to thin film CdTe solar cells with controlled back surface oxidation

    OpenAIRE

    Rugen-Hankey, S.L.; Clayton, Andrew J; Barrioz, Vincent; Kartopu, Giray; Irvine, Stuart J; McGettrick, J.D.; Hammond, D.

    2015-01-01

    Thin film CdTe solar cells were produced by MOCVD, at atmospheric pressure, under a hydrogen atmosphere (i.e. oxygen-free). Window layer alloying with zinc (forming Cd1−xZnxS) and extrinsic p-type doping with arsenic (giving CdTe:As) have been used to improve photovoltaic solar cell performances, but as-grown MOCVD-CdTe PV cells are still typically characterised by low Voc (~620–690 mV). Post-deposition annealing in air for 30 min at low temperature (170 °C) prior to evaporation of the back c...

  16. Structural reproducibility of CdTe thin films deposited on different substrates by close space sublimation method

    Energy Technology Data Exchange (ETDEWEB)

    Potlog, T.; Spalatu, N.; Maticiuc, N. [Physics Department, Moldova State University, Chisinau (Moldova); Hiie, J.; Valdna, V.; Mikli, V.; Mere, A. [Department of Materials Science, Tallinn University of Technology, Tallinn (Estonia)

    2012-02-15

    We report on the characterization of polycrystalline CdTe thin films grown directly on glass, SnO{sub 2}-coated glass, and CdS/SnO{sub 2}/glass at relatively low temperatures by employing the close space sublimation technique (CSS). The deposited films have been characterized by using optical absorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDX). Based on the SEM and optical analysis, the CdTe/CdS/SnO{sub 2}/glass thin films exhibit a superior crystal quality and reproducibility in comparison to other CdTe films grown on glass and SnO{sub 2}/glass. XRD study reveals that films are polycrystalline with a cubic crystal structure. The EDX characterization indicates that all CdTe thin films are nearly stoichiometric. The optical absorption study shows a larger variation of band gap from 1.485 to 1.495 eV for CdTe grown on SnO{sub 2}-coated glass. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Degradation of ultrathin CdTe films with SWCNT or Graphene back contact

    Science.gov (United States)

    Gorji, Nima E.

    2015-06-01

    The degradation of ultrathin film solar cells based on CdS/CdTe materials and back contacted with nanolayers are analysed using SCAPS. The ultrathin films suffer from uncompleted photo-absorption and fast degradation. The instability in performance was mainly attributed to the back contact materials which cause roll-over and cause mobile ions inter-diffusion. Thus, in this work, three different nanolayers such as single walled carbon nanotubes and Graphene are considered as the metal-free back contacts with wide controllable work function for the CdTe films. The simulations show that the roll-over in characteristics of the device disappears when the work function of the nanolayer increases by a proper doping. The current density-voltage curves showed promising results when the CdTe thickness was thinned down to 0.7 μm. Surface coverage of the grain boundaries at the interface of CdTe/nanolayer can reduce the contact series resistance and improve the carrier collection. However, the inter-sheet resistance of the nanolayers should be re-optimized. Finally, the time dependent approach was applied to simulate the defect generation under stress condition where the Cu-doped nanolayers showed faster degradation while the nanolayer back contacted devices showed higher stability.

  18. Dual-bath electrodeposition of n-type Bi–Te/Bi–Se multilayer thin films

    Energy Technology Data Exchange (ETDEWEB)

    Matsuoka, Ken; Okuhata, Mitsuaki; Takashiri, Masayuki, E-mail: takashiri@tokai-u.jp

    2015-11-15

    N-type Bi–Te/Bi–Se multilayer thin films were prepared by dual-bath electrodeposition. We varied the number of layers from 2 to 10 while the total film thickness was maintained at approximately 1 μm. All the multilayer films displayed the X-ray diffraction peaks normally observed from individual Bi{sub 2}Te{sub 3} and Bi{sub 2}Se{sub 3} crystal structures, indicating that both phases coexist in the multilayer. The cross-section of the 10-layer Bi–Te/Bi–Se film was composed of stacked layers with nano-sized grains but the boundaries between the layers were not planar. The Seebeck coefficient was almost constant throughout the entire range of our experiment, but the electrical conductivity of the multilayer thin films increased significantly as the number of layers was increased. This may be because the electron mobility increases as the thickness of each layer is decreased. As a result of the increased electrical conductivity, the power factor also increased with the number of layers. The maximum power factor was 1.44 μW/(cm K{sup 2}) for the 10-layer Bi–Te/Bi–Se film, this was approximately 3 times higher than that of the 2-layer sample. - Highlights: • N-type Bi–Te/Bi–Se multilayer thin films were deposited by electrodeposition. • We employed a dual-bath electrodeposition process for preparing the multilayers. • The Bi–Te/Bi–Se film was composed of stacked layers with nano-sized grains. • The electrical conductivity increased as the number of layers was increased. • The power factor improved by 3 times as the number of layers was increased.

  19. Bandgap energy tuning of electrochemically grown ZnO thin films by thickness and electrodeposition potential

    Energy Technology Data Exchange (ETDEWEB)

    Marotti, R.E.; Guerra, D.N.; Machado, G.; Dalchiele, E.A. [Instituto de Fisica, Facultad de Ingenieria, Universidad de la Republica, Julio Herrera y Reissig 565, C.C. 30, Montevideo 11000 (Uruguay); Bello, C. [Unidad Central de Instrumentacion Cientifica UCIC, Facultad de Ciencias, Universidad de la Republica, Igua 4225, C.C. 10773, Montevideo 11400 (Uruguay)

    2004-05-01

    ZnO thin films were electrochemically deposited onto opaque and transparent substrates (copper and ITO). The electrolyte consisted of a 0.1M Zn(NO{sub 3}){sub 2} solution with the initial pH adjusted to 6.0, different electrodeposition potentials from E=-700 to -1200mV (saturated calomel electrode, SCE). The resulting samples have the structural, chemical and morphological properties of hexagonal ZnO, with thickness varying from less than 1{mu}m to almost 30{mu}m. The bandgap energy varies inversely with film thickness, ranging from less than 3.1 to 3.4eV. The bandgap also depends on the electrodeposition potential. This result allows to adjust the desired absorption edge within a 30nm wide region in the UV.

  20. Atmospheric pressure chemical vapor deposition of CdTe for high efficiency thin film PV devices: Annual subcontract report, 26 January 1999--25 January 2000

    Energy Technology Data Exchange (ETDEWEB)

    Meyers, P. V.; Kee, R.; Wolden, C.; Kestner, J.; Raja, L.; Kaydanov, V.; Ohno, T.; Collins, R.; Fahrenbruch, A.

    2000-05-30

    ITN's three year project Atmospheric Pressure Chemical Vapor Deposition (APCVD) of CdTe for High Efficiency Thin Film PV Devices has the overall objectives of improving thin film CdTe PV manufacturing technology and increasing CdTe PV device power conversion efficiency. CdTe deposition by APCVD employs the same reaction chemistry as has been used to deposit 16% efficient CdTe PV films, i.e., close spaced sublimation, but employs forced convection rather than diffusion as a mechanism of mass transport. Tasks of the APCVD program center on demonstration of APCVD of CdTe films, discovery of fundamental mass transport parameters, application of established engineering principles to the deposition of CdTe films, and verification of reactor design principles which could be used to design high throughput, high yield manufacturing equipment. Additional tasks relate to improved device measurement and characterization procedures that can lead to a more fundamental understanding of CdTe PV device operation and ultimately to higher device conversion efficiency and greater stability. Under the APCVD program, device analysis goes beyond conventional one-dimensional device characterization and analysis toward two dimension measurements and modeling. Accomplishments of the second year of the APCVD subcontract include: deposition of the first APCVD CdTe; identification of deficiencies in the first generation APCVD reactor; design, fabrication and testing of a ``simplified'' APCVD reactor; deposition of the first dense, adherent APCVD CdTe films; fabrication of the first APCVD CdTe PV device; modeling effects of CdSTe and SnOx layers; and electrical modeling of grain boundaries.

  1. CuInSe2 thin film solar cells synthesised from electrodeposited binary selenide precursors

    OpenAIRE

    Fischer, Johannes

    2012-01-01

    The box must contain a summary in a maximum of 1,700 characters, spaces included. The fabrication of a CuInSe2 thin film solar cell from an electrodeposited precursor stack consisting of indium selenide and copper selenide layers is demonstrated. A best conversion efficiency of 5.5% was achieved, a higher efficiency than previously reported in literature. The thesis focuses on three main parts: (i) electrochemistry of indium selenide: The incorporation of indium in the deposit require...

  2. Electrodeposition of CuInX (X=Se,Te) thin films

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharya, R.N.; Rajeshwar, K.

    1986-01-15

    CuInX (X=Se,Te) thin films were electrodeposited and characterized by X-ray diffraction, electron probe microanalyses and Auger electron spectroscopy. New data are presented on the electrochemistry of the deposition process and on the cyclic voltammetric behavior of two different electrolytes Cu/sup +//Cu/sup 2+/ with In/sup 3+/ and SeO/sub 2/ respectively. Finally, some preliminary data are presented for CdS/CuInSe heterojunctions.

  3. Effects of nitrogen atoms of benzotriazole and its derivatives on the properties of electrodeposited Cu films

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hoe Chul; Kim, Myung Jun; Lim, Taeho; Park, Kyung Ju; Kim, Kwang Hwan; Choe, Seunghoe [School of Chemical and Biological Engineering, Institute of Chemical Process, Seoul National University, Gwanak 1, Gwanak-ro, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Kim, Soo-Kil, E-mail: sookilkim@cau.ac.kr [School of Integrative Engineering, Chung-Ang University, 221 Heukseok-dong, Dongjak-gu, Seoul 156-756 (Korea, Republic of); Kim, Jae Jeong, E-mail: jjkimm@snu.ac.kr [School of Chemical and Biological Engineering, Institute of Chemical Process, Seoul National University, Gwanak 1, Gwanak-ro, Gwanak-gu, Seoul 151-744 (Korea, Republic of)

    2014-01-01

    Additives having azole groups with different numbers of nitrogen atoms, such as indole, benzimidazole, indazole, benzotriazole (BTA), and 1H-benzotriazole-methanol (BTA-MeOH) were adopted to improve the mechanical hardness of electrodeposited Cu films. The effects of these additives on the film properties were elucidated in relation to their number of nitrogen atoms. Electrochemical current–potential behaviors showed that the additives containing three nitrogen atoms (BTA and BTA-MeOH) more effectively inhibited Cu electrodeposition. The inhibition strongly affected the film properties, resulting in reduced grain size and surface roughness, and increased resistivity and hardness. Cu films deposited with BTA or BTA-MeOH also exhibited 35% reduced grain size and 1.5-time higher hardness than Cu films deposited in electrolyte containing other BTA-derivatives having fewer nitrogen atoms. This notable grain refining effect of BTA and BTA-MeOH can be evaluated with respect to the strong interaction of their nitrogen atoms with the substrate and the copper ions, as well. - Highlights: • Additives of similar structure containing 1, 2, and 3 nitrogen atoms were used. • Additives with 3 nitrogen atoms more strongly inhibited Cu deposition than others. • Additives containing 3 nitrogen atoms efficiently affected film properties. • Additives having 3 nitrogen atoms remarkably improved film hardness.

  4. Parameters controlling microstructures and resistance switching of electrodeposited cuprous oxide thin films

    Science.gov (United States)

    Yazdanparast, Sanaz

    2016-12-01

    Cuprous oxide (Cu2O) thin films were electrodeposited cathodically from a highly alkaline bath using tartrate as complexing agent. Different microstructures for Cu2O thin films were achieved by varying the applied potential from -0.285 to -0.395 V versus a reference electrode of Ag/AgCl at 50 °C in potentiostatic mode, and separately by changing the bath temperature from 25 to 50 °C in galvanostatic mode. Characterization experiments showed that both grain size and orientation of Cu2O can be controlled by changing the applied potential. Applying a high negative potential of -0.395 V resulted in smaller grain size of Cu2O thin films with a preferred orientation in [111] direction. An increase in the bath temperature in galvanostatic electrodeposition increased the grain size of Cu2O thin films. All the films in Au/Cu2O/Au-Pd cell showed unipolar resistance switching behavior after an initial FORMING process. Increasing the grain size of Cu2O thin films and decreasing the top electrode area increased the FORMING voltage and decreased the current level of high resistance state (HRS). The current in low resistance state (LRS) was independent of the top electrode area and the grain size of deposited films, suggesting a filamentary conduction mechanism in unipolar resistance switching of Cu2O.

  5. Electrodeposited porous metal oxide films with interconnected nanoparticles applied as anode of lithium ion battery

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Anguo, E-mail: hixiaoanguo@126.com; Zhou, Shibiao; Zuo, Chenggang; Zhuan, Yongbing; Ding, Xiang

    2014-12-15

    Highlights: • Highly porous NiO film is prepared by a co-electrodeposition method. • Porous NiO film is composed of interconnected nanoparticles. • Porous structure is favorable for fast ion/electron transfer. • Porous NiO film shows good lithium ion storage properties. - Abstract: Controllable synthesis of porous metal oxide films is highly desirable for high-performance electrochemical devices. In this work, a highly porous NiO film composed of interconnected nanoparticles is prepared by a simple co-electrodeposition method. The nanoparticles in the NiO film have a size ranging from 30 to 100 nm and construct large-quantity pores of 20–120 nm. As an anode material for lithium ion batteries, the highly porous NiO film electrode delivers a high discharge capacity of 700 mA h g{sup −1} at 0.2 C, as well as good high-rate performance. After 100 cycles at 0.2 C, a specific capacitance of 517 mA h g{sup −1} is attained. The good electrochemical performance is attributed to the interconnected porous structure, which facilitates the diffusion of ion and electron, and provides large reaction surface area leading to improved performance.

  6. Nanoindentation and micro-mechanical fracture toughness of electrodeposited nanocrystalline Ni-W alloy films

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, D.E.J., E-mail: david.armstrong@materials.ox.ac.uk [Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH (United Kingdom); Haseeb, A.S.M.A. [Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Roberts, S.G.; Wilkinson, A.J. [Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH (United Kingdom); Bade, K. [Institut fuer Mikrostrukturtechnik (IMT), Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

    2012-04-30

    Nanocrystalline nickel-tungsten alloys have great potential in the fabrication of components for microelectromechanical systems. Here the fracture toughness of Ni-12.7 at.%W alloy micro-cantilever beams was investigated. Micro-cantilevers were fabricated by UV lithography and electrodeposition and notched by focused ion beam machining. Load was applied using a nanoindenter and fracture toughness was calculated from the fracture load. Fracture toughness of the Ni-12.7 at.%W was in the range of 1.49-5.14 MPa {radical}m. This is higher than the fracture toughness of Si (another important microelectromechanical systems material), but considerably lower than that of electrodeposited nickel and other nickel based alloys. - Highlights: Black-Right-Pointing-Pointer Micro-scale cantilevers manufactured by electro-deposition and focused ion beam machining. Black-Right-Pointing-Pointer Nanoindenter used to perform micro-scale fracture test on Ni-13at%W micro-cantilevers. Black-Right-Pointing-Pointer Calculation of fracture toughness of electrodeposited Ni-13at%W thin films. Black-Right-Pointing-Pointer Fracture toughness values lower than that of nanocrystalline nickel.

  7. Controllable magnetic and magnetostrictive properties of FeGa films electrodeposited on curvature substrates

    Science.gov (United States)

    Cao, Derang; Wang, Zhenkun; Pan, Lining; Feng, Hongmei; Cheng, Xiaohong; Zhu, Zengtai; Wang, Jianbo; Liu, Qingfang; Han, Genliang

    2016-11-01

    Magnetic properties of magnetostrictive FeGa films deposited by electrodeposition method on flexible curvature substrates were investigated under various mechanical stresses. The stresses of the bowed substrates were realized by series of different concentric circles. FeGa films exhibit a significant uniaxial magnetic anisotropy after the application of tensile or compressive stress, and the anisotropy of the film can be regulated by the residual stress. In addition, the magnetostriction of FeGa films is estimated through approximate calculation, indicating that the saturation magnetostrictive constant of films is enhanced with the increased tensile and compressive strains. These results provide another way to tune the magnetic properties and magnetostriction of flexible thin films, which is particularly important for the development of the flexible magneto-electronic devices.

  8. Influence of support electrolytic in the electrodeposition of Cusbnd Gasbnd Se thin films

    Science.gov (United States)

    Fernandez, A. M.; Turner, J. A.; Lara-Lara, B.; Deutsch, T. G.

    2017-01-01

    CuGaSe2 is an important thin film electronic material that possesses several attributes that make it appealing for solar energy conversion. Due to its properties it can be incorporated in to various devices, among the greatest highlights are photovoltaic cells, as well as its potential use as photocathodes for hydrogen production, via the photoelectrolysis. There are several methods of its preparation, most notably electrodeposition that has the potential for large areas and high volumes. Electrodeposition of ternary and/or quaternary semiconductors generally proceeds via the formation of a binary, which is subsequently reacted to form the ternary compound. Several conditions must be controlled to form binary compounds that include the use of complexing agents, buffers, temperature, etc. In this paper, we discuss the effect of anion composition in the electrolytic bath and the type of lithium salts, in order to manipulate the atomic concentration of CuGaSe2 during the electrodeposition of thin films, yielding copper-rich, gallium-rich or stoichiometric thin films. We also present the results of a study on the morphology and structure obtained using two types of substrates both before and after performing a heat treatment.

  9. Influence of support electrolytic in the electrodeposition of CuGaSe thin films

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, A. M.; Turner, J. A.; Lara-Lara, B.; Deutsch, T. G.

    2017-01-01

    CuGaSe2 is an important thin film electronic material that possesses several attributes that make it appealing for solar energy conversion. Due to its properties it can be incorporated in to various devices, among the greatest highlights are photovoltaic cells, as well as its potential use as photocathodes for hydrogen production, via the photoelectrolysis. There are several methods of its preparation, most notably electrodeposition that has the potential for large areas and high volumes. Electrodeposition of ternary and/or quaternary semiconductors generally proceeds via the formation of a binary, which is subsequently reacted to form the ternary compound. Several conditions must be controlled to form binary compounds that include the use of complexing agents, buffers, temperature, etc. In this paper, we discuss the effect of anion composition in the electrolytic bath and the type of lithium salts, in order to manipulate the atomic concentration of CuGaSe2 during the electrodeposition of thin films, yielding copper-rich, gallium-rich or stoichiometric thin films. We also present the results of a study on the morphology and structure obtained using two types of substrates both before and after performing a heat treatment.

  10. A greener electrodeposition recipe for ZnO films in terawatt photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Bin; Han, Xiaofei [School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, AZ 85287 (United States); Feng, Qing [Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, TX 76019 (United States); Tao, Meng, E-mail: meng.tao@asu.edu [School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, AZ 85287 (United States)

    2012-09-01

    Electrodeposition of ZnO can be performed in an aqueous solution using a greener recipe, where the solution can be reused for multiple deposition runs. The solution in this greener recipe has only one function, i.e. to provide electrical conductivity for the deposition reactions. A Zn sheet serves as the anode, which dissolves during the deposition as the Zn source. O{sub 2} is bubbled into the solution and reduced to OH{sup -} ions as the O source. This recipe minimizes concentration changes in the solution as deposition proceeds, making the solution reusable. An initial Zn{sup 2+} concentration of a few mM in the solution is required, not to serve as a Zn source but to facilitate the deposition and prevent precipitation of ZnO in the solution. Multiple deposition runs for ZnO films in the same solution have been demonstrated. X-ray diffraction, optical transmittance and absorption spectra reveal that all the ZnO films have similar structural and optical properties. They all display high transmittance of {approx} 80% and low absorbance of {approx} 10%. - Highlights: Black-Right-Pointing-Pointer A new ZnO electrodeposition recipe is developed where the solution is reusable. Black-Right-Pointing-Pointer Waste solutions from ZnO electrodeposition are reduced by over four fold. Black-Right-Pointing-Pointer ZnO films from the same solution show high transmittance and low absorbance.

  11. Nitric-phosphoric acid etching effects on the surface chemical composition of CdTe thin film.

    Science.gov (United States)

    Irfan, Irfan; Ding, Huanjun; Xia, Wei; Lin, Hao; Tang, Ching W.; Gao, Yongli

    2009-03-01

    Nitric-phosphoric (NP) acid etching has been regarded as one of the most successful methods for the formation of low resistance back contact with the metal electrode in CdTe based solar cells. We report back surface chemical composition for eight different durations of NP etching of CdTe polycrystalline thin film. We studied the surfaces with x-ray photoemission spectroscopy (XPS), ultraviolet photoemission spectroscopy (UPS), inverse photoemission spectroscopy (IEPS) and atomic force microscopy (AFM). Etching dependence on the back surface composition and electronic structure was observed. Valence and conduction band shifts relative to the Fermi level of the system with different etching duration were analyzed. The sample was left in open ambient condition for three weeks and XPS data were obtained again in order to study the difference in surface chemical composition with the pristine CdTe film. Unetched and highly etched part of the sample were sputtered and the depth profile analyzed.

  12. Impact of thermal annealing on physical properties of vacuum evaporated polycrystalline CdTe thin films for solar cell applications

    Science.gov (United States)

    Chander, Subhash; Dhaka, M. S.

    2016-06-01

    A study on impact of post-deposition thermal annealing on the physical properties of CdTe thin films is undertaken in this paper. The thin films of thickness 500 nm were grown on ITO and glass substrates employing thermal vacuum evaporation followed by post-deposition thermal annealing in air atmosphere within low temperature range 150-350 °C. These films were subjected to the XRD, UV-Vis NIR spectrophotometer, source meter, SEM coupled with EDS and AFM for structural, optical, electrical and surface topographical analysis respectively. The diffraction patterns reveal that the films are having zinc-blende cubic structure with preferred orientation along (111) and polycrystalline in nature. The crystallographic parameters are calculated and discussed in detail. The optical band gap is found in the range 1.48-1.64 eV and observed to decrease with thermal annealing. The current-voltage characteristics show that the CdTe films exhibit linear ohmic behavior. The SEM studies show that the as-grown films are homogeneous, uniform and free from defects. The AFM studies reveal that the surface roughness of films is observed to increase with annealing. The experimental results reveal that the thermal annealing has significant impact on the physical properties of CdTe thin films and may be used as absorber layer to the CdTe/CdS thin films solar cells.

  13. About the use of photoacoustic spectroscopy for the optical characterization of semiconductor thin films: CdTe

    Energy Technology Data Exchange (ETDEWEB)

    Marin, E.; Calderon, A. [CICATA-IPN, Av. Legaria 694, 11500 Mexico D.F. (Mexico); Vigil G, O.; Sastre, J.; Contreras P, G.; Aguilar H, J. [ESFM-IPN, 07738 Mexico D.F. (Mexico); Saucedo, E.; Ruiz, C.M. [Departamento de Fisica de Materiales, Facultad de Ciencias, Universidad Autonoma de Madrid, 28049 Madrid (Spain)

    2006-07-01

    CdTe has been used satisfactorily in multiple and diverse technological applications such as detectors of X and gamma rays that operate at room temperature, for digital imagenology of X rays with medical and industrial applications and as active part in CdTe/CdS solar cells. In form of films, CdTe is generally grown with thicknesses ranging between 3 and 15 {mu}m, for which it is difficult to measure, by means of optical techniques, absorption coefficients greater than 10{sup 3} cm{sup -1} because nearly full absorption of light should occur below 800 nm. The exact determination of the optical absorption coefficient in detectors on the basis of CdTe is very important since this parameter determines the absorption length at which 90% of the photons with energies over the forbidden zone of the CdTe will be absorbed by this. In CdS/CdTe polycrystalline solar cells the greater efficiency of conversion have been reported for film thicknesses of 10 mm, however, the optimal value of this parameter depends strongly on the method and the variables of growth. The optical absorption coefficient spectrum can be determined by several methods, often involving several approximations and the knowledge of some minority carrier related electronic parameters that reduce their application in general way. In this work we propose to determine the absorption coefficient in CdTe thin films by photoacoustic spectroscopy (PAS), because this technique allow us to obtain the optical absorption spectra in thicker layers and therefore the study of the influence of the several growth and post-growth processes in the optical properties of this thin films. We measure by PAS the optical-absorption coefficients of CdTe thin films in the spectral region near the fundamental absorption edge ranging from 1.0 to 2.4 eV using an open cell in the transmission configuration. The films were deposited on different substrates by the CSVT-HW (hot wall) technique. In order to study the influence of several

  14. Giant magnetoresistance of electrodeposited Cu–Co–Ni alloy films

    Indian Academy of Sciences (India)

    İ H Karahan; Ö F Bakkaloğlu; M Bedir

    2007-01-01

    Electrodeposition of CuCoNi alloys was performed in an acid–citrate medium. Nickel density parameter was varied in order to analyse its influence on the magnetoresistance. The structure and giant magneto- resistance (GMR) effect of CuCoNi alloys have been investigated. The maximum value for GMR ratio, at room temperature is 1% at a field of 12 kOe, and at 20 K is 2.1% at a field of 8.5 kOe for 3.1 Ni. The MR ratio of Cu100−−CoNi alloys first increases and then decreases monotonically with increasing Ni content. The GMR and its dependence on magnetic field and temperature were discussed.

  15. Composition and growth procedure-dependent properties of electrodeposited CuInSe 2 thin films

    Science.gov (United States)

    Babu, S. Moorthy; Ennaoui, A.; Lux-Steiner, M. Ch.

    2005-02-01

    CuInSe 2 thin films were deposited on molybdenum-coated glass substrates by electrodeposition. Deposition was carried out with a variety of electrochemical bath compositions. The quality of the deposits depends very much on the source materials as well as the concentration of the same in the electrolyte. The deposition potential was varied from -0.4 to -0.75 V vs. SCE. The pH of the solution was adjusted to 1.5-2 using diluted sulphuric acid. Chloride salts containing bath yield good surface morphology, but there is always excess of the metallic content in the deposited films. Different growth procedures, like initial metallic layers of copper or indium, layers of copper selenide or indium selenide before the actual deposition of ternary chalcopyrite layers were attempted. Fabrication pathway, morphological and compositional changes due to the different precursor route has been analysed. The quality of the deposits prepared by one-step electrodeposition is better than the deposits with a two-stage process. The deposited films were characterized with XRD, SEM-EDAX, UV-visible spectroscopy and I- V characteristics. The deposited films were annealed in air as well as in nitrogen atmosphere. The influence of annealing temperature, environment and annealing time on the properties of the films are evaluated. Attempts were made to fabricate solar cell structure from the deposited absorber films. The structure of Mo/CuInSe 2/CdS/ZnO/Ni was characterized with surface, optical and electrical studies.

  16. Synthesis and characterization of Cu2SnSe3 thin films by electrodeposition route

    Science.gov (United States)

    Chihi, Adel; Bessais, Brahim

    2016-09-01

    A single phase Cu2SnSe3 polycrystalline semiconductor compound has been easily synthesized through electrodeposition technique onto conductive glass ITO substrates from an acidic solution at room temperature for the first time. The electrodeposition of CTSe films was studied using cyclic voltammetry, structural, morphological, optical, and electrical measurements. The effects of the annealing temperature on the growth of CTSe films were studied. XRD and Raman studies showed that the annealed CTSe thin films have a polycrystalline nature with a cubic crystal structure with a preferential orientation (111), and the crystalline size of the CTSe thin films increases as the annealing temperature increases. The AFM investigations show that the deposited film layer widely varies on annealing temperature. The optical band gap of CTSe alloys is inversely related to the grain size and decreases from 1.08 to 0.96 eV. Finally, the Hall effect measurements reveal that the all CTSe films are p-type semiconductors in particular a sample annealed at 300 °C exhibit a high Hall mobility 5.27 cm2/V s and low electrical resistivity 0.91 Ω cm compared to other samples.

  17. Structural and optical properties of electrodeposited ZnO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Laurent, K. [Laboratoire de Physique des Materiaux Divises et Interfaces (LPMDI), CNRS-UMR 8108, Universite Paris-Est, 5 Bd. Descartes, 77454 Marne la Vallee Cedex 2 (France); Wang, B.Q.; Yu, D.P. [School of Physics, Electron Microscopy Laboratory, and State Key Laboratory for Mesoscopic Physics, Peking University, Beijing 100871 (China); Leprince-Wang, Y. [Laboratoire de Physique des Materiaux Divises et Interfaces (LPMDI), CNRS-UMR 8108, Universite Paris-Est, 5 Bd. Descartes, 77454 Marne la Vallee Cedex 2 (France)], E-mail: yamin.leprince@univ-mlv.fr

    2008-11-28

    Zinc oxide thin films were electrodeposited on different substrates. Electrodeposition was performed with hydrogen peroxide, as hydroxide ions source, at - 1.5 V versus mercurial sulfate electrode during one hour, and a temperature maintained at 70 deg. C . The resulting thin films have a good crystallinity and a high c-axis orientation, and the unit cell parameters determined by X-ray diffraction experiment are a = 0.326 nm and c = 0.523 nm, respectively. Microstructure studies using scanning electron microscopy and atomic force microscopy show a good homogeneity of the film and a roughness around 22 nm. Optical properties were studied with Raman spectroscopy and photoluminescence spectroscopy. Optical properties of the films revealed a low defect emission in photoluminescence spectra. The E{sub 2} vibration mode for ZnO was observed near 439 cm{sup -1}, indicating that the as-deposited films were under compressive stress. Oscillations were observed in the photoluminescence spectra, from which the refractive index of ZnO thin films was extracted, that is {approx} 1.90.

  18. Physical properties of vacuum evaporated CdTe thin films with post-deposition thermal annealing

    Science.gov (United States)

    Chander, Subhash; Dhaka, M. S.

    2015-09-01

    This paper presents the physical properties of vacuum evaporated CdTe thin films with post-deposition thermal annealing. The thin films of thickness 500 nm were grown on glass and indium tin oxide (ITO) coated glass substrates employing thermal vacuum evaporation technique followed by post-deposition thermal annealing at temperature 450 °C. These films were subjected to the X-ray diffraction (XRD),UV-Vis spectrophotometer, source meter and atomic force microscopy (AFM) for structural, optical, electrical and surface morphological analysis respectively. The X-ray diffraction patterns reveal that the films have zinc-blende structure of single cubic phase with preferred orientation (111) and polycrystalline in nature. The crystallographic and optical parameters are calculated and discussed in brief. The optical band gap is found to be 1.62 eV and 1.52 eV for as-grown and annealed films respectively. The I-V characteristics show that the conductivity is decreased for annealed thin films. The AFM studies reveal that the surface roughness is observed to be increased for thermally annealed films.

  19. SCAPS Modeling for Degradation of Ultrathin CdTe Films: Materials Interdiffusion

    Science.gov (United States)

    Houshmand, Mohammad; Zandi, M. Hossein; Gorji, Nima E.

    2015-09-01

    Ultrathin film solar cells based on CdS/CdTe ( d CdTe ≤ 1 µm) suffer from two main issues: incomplete photo absorption and high degradation rate. The former is cured by light-trapping techniques, whereas the latter is a matter of fabrication details. Interdiffusion of the material components and formation of subsequent interlayers at the front/back region can change the optical/electrical properties and performance/stability of the device. We model the degradation of the ultrathin CdTe film devices considering the material interdiffusion and interlayers formation: CdTeS, CdZnTe, Cu x Te (i.e., Te/Cu bilayer), and oxide interlayers (i.e., CdTeO3). The diffusion rate of the materials is considered separately and the reactions that change the interlayer's properties are studied. Additionally, a back contact of single-walled carbon nanotube showed a higher stability than the metallic contacts. A new time-dependent approach is applied to simulate the degradation rate due to formation of any interlayer. It is shown that the materials interdiffusion causes a defect increment under thermal stress and illumination. The metallic back contact accelerates the degradation, whereas single-walled carbon nanotubes show the highest stability. A SCAPS simulator was used because of its ability in defining the properties of the back contact and metastabilities at the interface layers. The properties of the layers were taken from the experimental data reported in the literature.

  20. 14% sputtered thin-film solar cells based on CdTe

    Science.gov (United States)

    Compaan, A. D.; Gupta, A.; Drayton, J.; Lee, S.-H.; Wang, S.

    2004-02-01

    Polycrystalline II-VI semiconductor materials show great promise for thin-film photovoltaic cells and modules. Large-area deposition of these II-VI semiconductors such as CdTe is possible by a variety of methods but the use of a plasma-based method such as magnetron sputtering can have significant advantages. Here we present recent results in the fabrication of CdS/CdTe cells using rf magnetron sputtering and discuss some of the advantages that appear possible from the use of sputtering methods in this class of materials. Some of these advantages are particularly relevant as the polycrystalline thin-film PV community addresses issues related to the challenges of fabricating high efficiency tandem cells with efficiencies over 25%. Our best results have been obtained with sputtered ZnO:Al to achieve a CdTe solar cell with 14.0% efficiency at one sun for an air-mass-1.5 global spectrum. In addition, we have studied reactive sputtering of ZnTe:N which shows promise for use as a transparent back contact or recombination junction for alloyed II-VI-based top cells in a tandem solar-cell configuration.

  1. Crystallization from amorphous structure to hexagonal quantum dots induced by an electron beam on CdTe thin films

    Science.gov (United States)

    Becerril, M.; Zelaya-Angel, O.; Medina-Torres, A. C.; Aguilar-Hernández, J. R.; Ramírez-Bon, R.; Espinoza-Beltran, F. J.

    2009-02-01

    Amorphous cadmium-telluride films were prepared by rf sputtering on Corning 7059 glass substrates at room temperature. The deposition time was 10 and 12 h with a thickness of 400 and 480 (±40 nm), respectively. As-prepared films were amorphous according to X-ray diffraction (XRD) patterns, but a win-fit-software analysis of the main XRD broad band suggests a wurtzite structure at short range. Transmission electron microscopy (TEM) at 200 keV produces crystallization of the amorphous CdTe. The TEM-electron beam induces the formation of CdTe quantum dots with the wurtzite hexagonal structure (the metastable structure of CdTe) and with ˜6 nm of average grain size. As effect of a probable distortion of the CdTe crystalline lattice, the unit cell volume (UCV) shrinks to about 30% with respect to the bulk-UCV of CdTe. Besides, the energy band gap increases as expected, according to literature data on quantum confinement.

  2. Structural and optical properties of Cu-doped CdTe films with hexagonal phase grown by pulsed laser deposition

    Directory of Open Access Journals (Sweden)

    F. de Moure-Flores

    2012-06-01

    Full Text Available Cu-doped CdTe thin films were prepared by pulsed laser deposition on Corning glass substrates using powders as target. Films were deposited at substrate temperatures ranging from 100 to 300 °C. The X-ray diffraction shows that both the Cu-doping and the increase in the substrate temperature promote the presence of the hexagonal CdTe phase. For a substrate temperature of 300 °C a CdTe:Cu film with hexagonal phase was obtained. Raman and EDS analysis indicate that the films grew with an excess of Te, which indicates that CdTe:Cu films have p-type conductivity.

  3. Impact of thermal annealing on optical properties of vacuum evaporated CdTe thin films for solar cells

    Science.gov (United States)

    Chander, Subhash; Purohit, A.; Lal, C.; Nehra, S. P.; Dhaka, M. S.

    2016-05-01

    In this paper, the impact of thermal annealing on optical properties of cadmium telluride (CdTe) thin films is investigated. The films of thickness 650 nm were deposited on thoroughly cleaned glass substrate employing vacuum evaporation followed by thermal annealing in the temperature range 250-450 °C. The as-deposited and annealed films were characterized using UV-Vis spectrophotometer. The optical band gap is found to be decreased from 1.88 eV to 1.48 eV with thermal annealing. The refractive index is found to be in the range 2.73-2.92 and observed to increase with annealing treatment. The experimental results reveal that the thermal annealing plays an important role to enhance the optical properties of CdTe thin films and annealed films may be used as absorber layer in CdTe/CdS solar cells.

  4. Investigation of induced recrystallization and stress in close-spaced sublimated and radio-frequency magnetron sputtered CdTe thin films

    Energy Technology Data Exchange (ETDEWEB)

    Moutinho, H.R.; Dhere, R.G.; Al-Jassim, M.M.; Levi, D.H.; Kazmerski, L.L. [National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401 (United States)

    1999-07-01

    We have induced recrystallization of small grain CdTe thin films deposited at low temperatures by close-spaced sublimation (CSS), using a standard CdCl{sub 2} annealing treatment. We also studied the changes in the physical properties of CdTe films deposited by radio-frequency magnetron sputtering after the same post-deposition processing. We demonstrated that the effects of CdCl{sub 2} on the physical properties of CdTe films are similar, and independent of the deposition method. The recrystallization process is linked directly to the grain size and stress in the films. These studies indicated the feasibility of using lower-temperature processes in fabricating efficient CSS CdTe solar cells. We believe that, after the optimization of the parameters of the chemical treatment, these films can attain a quality similar to CSS films grown using current standard conditions. {copyright} {ital 1999 American Vacuum Society.}

  5. Development of high-efficiency, thin-film CdTe solar cells. Annual subcontract report, January 1, 1993--December 31, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Rohatgi, A.; Chou, H.C.; Kamra, S.; Bhat, A. [Georgia Institute of Technology, Atlanta, GA (United States)

    1994-09-01

    Polycrystalline thin film CdTe solar cells are one of the leading candidates for terrestrial photovoltaic applications. Theoretical calculations project an efficiency of 27% for single crystal, single junction CdTe cells, and the practically achievable efficiency for polycrystalline CdTe cells is 18-20%. Polycrystalline CdTe cells made by different groups show a significant variation in short circuit currents, open circuit voltages, and cell efficiencies. A better understanding of carrier loss and transport mechanism is crucial for explaining these differences, improving the yield, and bridging the gap between current and practically achievable limits in CdTe cell efficiencies. The goal of this program is to improve the understanding of the loss mechanisms in thin film CdS/CdTe solar cells and to improve their efficiency by characterizing the properties of the films as well as the finished devices.

  6. Change in planar hall effect ratio of Ni–Co films produced by electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Karpuz, Ali, E-mail: alikarpuz@kmu.edu.tr [Physics Department, Science and Literature Faculty, Balikesir University, 10145 Balikesir (Turkey); Kockar, Hakan [Physics Department, Science and Literature Faculty, Balikesir University, 10145 Balikesir (Turkey); Alper, Mursel [Physics Department, Science and Literature Faculty, Uludag University, 16059 Bursa (Turkey)

    2015-01-01

    Ni–Co films were produced by the electrodeposition technique and their magnetotransport properties were studied. The anisotropic magnetoresistance (AMR) and the planar Hall effect (PHE) ratios were found using the van der Pauw setup at room temperature. It was observed that the PHE ratios were larger than the obtained AMR ratios. While the maximum changes in longitudinal and transversal magnetoresistance ratios were 6.8% and 11.0%, respectively, the change in PHE values was up to 500%. In the PHE measurements, the magnetoresistance orientation depends on the electrical resistance values which occur in branches of the films.

  7. Local Electrical Response in Alkaline-Doped Electrodeposited CuInSe2/Cu Films

    Directory of Open Access Journals (Sweden)

    Javier A. Barón-Miranda

    2016-12-01

    Full Text Available The local electrical response in alkaline-doped CuInSe2 films prepared by single-step electrodeposition onto Cu substrates was studied by current-sensing atomic force microscopy. The CuInSe2 (CIS films were prepared from single baths containing the dopant ions (Li, Na, K or Cs and were studied by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and photocurrent response. Increased crystallinity and surface texturing as the ion size increased were observed, as well as an enhanced photocurrent response in Cs-doped CIS. Li- and Na-doped films had larger conductivity than the undoped film while the K- and Cs-doped samples displayed shorter currents and the current images indicated strong charge accumulation in the K- and Cs-doped films, forming surface capacitors. Corrected current-sensing AFM IV curves were adjusted with the Shockley equation.

  8. Metal-insulator transition in nanocomposite VO{sub x} films formed by anodic electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Tsui, Lok-kun; Lu, Jiwei; Zangari, Giovanni, E-mail: gz3e@virginia.edu [Department of Materials Science and Engineering, University of Virginia, 395 McCormick Rd., Charlottesville, Virginia 22904 (United States); Hildebrand, Helga; Schmuki, Patrik [Department for Materials Science LKO, University of Erlangen-Nuremberg, Martensstr. 7, D-91058 Erlangen (Germany)

    2013-11-11

    The ability to grow VO{sub 2} films by electrochemical methods would open a low-cost, easily scalable production route to a number of electronic devices. We have synthesized VO{sub x} films by anodic electrodeposition of V{sub 2}O{sub 5}, followed by partial reduction by annealing in Ar. The resulting films are heterogeneous, consisting of various metallic/oxide phases and including regions with VO{sub 2} stoichiometry. A gradual metal insulator transition with a nearly two order of magnitude change in film resistance is observed between room temperature and 140 °C. In addition, the films exhibit a temperature coefficient of resistance of ∼ −2.4%/ °C from 20 to 140 °C.

  9. Improvement of the crystallinity of CdTe epitaxial film grown on Si substrates by molecular beam epitaxy using the two-step growth method

    Energy Technology Data Exchange (ETDEWEB)

    Han, M.S.; Ryu, Y.S.; Song, B.K.; Kang, T.W. [Dongguk Univ., Seoul (Korea, Republic of). Dept. of Phys.; Kim, T.W. [Department of Physics, Kwangwoon University, Seoul 139-701 (Korea, Republic of)

    1997-01-05

    Molecular beam epitaxy growth of CdTe epitaxial layers on Si (100) substrates using the two-step growth method was performed to produce high-quality CdTe thin layers. The reflection high-energy electron diffraction patterns were streaky with clear Kikuchi lines, which is direct evidence for layer-by-layer two-dimensional growth of CdTe on Si. From the X-ray diffraction analysis, the grown layer was found to be a CdTe (111) epitaxial film, regardless of the film thickness. Photoluminescence (PL) measurements at 12 K showed that the defect density of the CdTe film grown on Si using two-step growth decreased in comparison with that grown using direct growth. The bound exciton appearing in the PL measurements shifted to the low energy side as the thickness of the CdTe increased. When the CdTe thickness increased from 1 to 1.8 {mu}m, the peak position of the bound exciton shifted by 7.2 meV, and the stress obtained from the exciton peak shift was -12.405 kbar. These results indicate that high quality CdTe films grown by two-step growth hold promise for applications as buffer layers for the subsequent growth of Hg{sub x}Cd{sub 1-x}Te. (orig.) 16 refs.

  10. Cu-doped CdS and its application in CdTe thin film solar cell

    Directory of Open Access Journals (Sweden)

    Yi Deng

    2016-01-01

    Full Text Available Cu is widely used in the back contact formation of CdTe thin film solar cells. However, Cu is easily to diffuse from the back contact into the CdTe absorber layer and even to the cell junction interface CdS/CdTe. This phenomenon is generally believed to be the main factor affecting the CdTe solar cell stability. In this study Cu was intentionally doped in CdS thin film to study its effect on the microstructural, optical and electrical properties of the CdS material. Upon Cu doping, the VCd− and the surface-state-related photoluminescence emissions were dramatically decreased/quenched. The presence of Cu atom hindered the recrystallization/coalescence of the nano-sized grains in the as-deposited CdS film during the air and the CdCl2 annealing. CdTe thin film solar cell fabricated with Cu-doped CdS window layers demonstrated much decreased fill factor, which was induced by the increased space-charge recombination near the p-n junction and the worsened junction crystalline quality. Temperature dependent current-voltage curve measurement indicated that the doped Cu in the CdS window layer was not stable at both room and higher temperatures.

  11. Cu-doped CdS and its application in CdTe thin film solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Yi [School of Automation, Wuhan University of Technology, Wuhan, Hubei 430070 (China); College of Electronic and Information Engineering, Hankou University, Wuhan, Hubei 430212 (China); Yang, Jun; Yang, Ruilong; Shen, Kai; Wang, Dezhao [Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Wang, Deliang, E-mail: eedewang@ustc.edu.cn [Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Key Laboratory of Materials for Energy Conversion, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2016-01-15

    Cu is widely used in the back contact formation of CdTe thin film solar cells. However, Cu is easily to diffuse from the back contact into the CdTe absorber layer and even to the cell junction interface CdS/CdTe. This phenomenon is generally believed to be the main factor affecting the CdTe solar cell stability. In this study Cu was intentionally doped in CdS thin film to study its effect on the microstructural, optical and electrical properties of the CdS material. Upon Cu doping, the V{sub Cd{sup −}} and the surface-state-related photoluminescence emissions were dramatically decreased/quenched. The presence of Cu atom hindered the recrystallization/coalescence of the nano-sized grains in the as-deposited CdS film during the air and the CdCl{sub 2} annealing. CdTe thin film solar cell fabricated with Cu-doped CdS window layers demonstrated much decreased fill factor, which was induced by the increased space-charge recombination near the p-n junction and the worsened junction crystalline quality. Temperature dependent current-voltage curve measurement indicated that the doped Cu in the CdS window layer was not stable at both room and higher temperatures.

  12. Enhanced electrical properties at boundaries including twin boundaries of polycrystalline CdTe thin-film solar cells.

    Science.gov (United States)

    Li, H; Liu, X X; Lin, Y S; Yang, B; Du, Z M

    2015-05-07

    The effect of grain boundaries (GBs), in particular twin boundaries (TBs), on CdTe polycrystalline thin films is studied by conductive atomic force microscopy (C-AFM), electron-beam-induced current (EBIC), scanning Kelvin probe microscopy (SKPM), electron backscatter diffraction (EBSD), and scanning transmission electron microscopy (STEM). Four types of CdTe grains with various densities of {111} Σ3 twin boundaries (TBs) are found in Cl-treated CdTe polycrystalline thin films: (1) grains having multiple {111} Σ3 TBs with a low angle to the film surface; (2) grains having multiple {111} Σ3 TBs parallel to the film surfaces; (3) small grains on a scale of not more than 500 nm, composed of Cd, Cl, Te, and O; and (4) CdTe grains with not more than two {111} Σ3 TBs. Grain boundaries (including TBs) exhibit enhanced current transport phenomena. However, the {111} Σ3 TB is much more beneficial to micro-current transport. The enhanced current transport can be explained by the lower electron potential at GBs (including TBs) than the grain interiors (GIs). Our results open new opportunities for enhancing solar cell performances by controlling the grain boundaries, and in particular TBs.

  13. Cu-doped CdS and its application in CdTe thin film solar cell

    Science.gov (United States)

    Deng, Yi; Yang, Jun; Yang, Ruilong; Shen, Kai; Wang, Dezhao; Wang, Deliang

    2016-01-01

    Cu is widely used in the back contact formation of CdTe thin film solar cells. However, Cu is easily to diffuse from the back contact into the CdTe absorber layer and even to the cell junction interface CdS/CdTe. This phenomenon is generally believed to be the main factor affecting the CdTe solar cell stability. In this study Cu was intentionally doped in CdS thin film to study its effect on the microstructural, optical and electrical properties of the CdS material. Upon Cu doping, the VCd- and the surface-state-related photoluminescence emissions were dramatically decreased/quenched. The presence of Cu atom hindered the recrystallization/coalescence of the nano-sized grains in the as-deposited CdS film during the air and the CdCl2 annealing. CdTe thin film solar cell fabricated with Cu-doped CdS window layers demonstrated much decreased fill factor, which was induced by the increased space-charge recombination near the p-n junction and the worsened junction crystalline quality. Temperature dependent current-voltage curve measurement indicated that the doped Cu in the CdS window layer was not stable at both room and higher temperatures.

  14. Nanogoniometry with scanning force microscopy: a model study of CdTe thin films.

    Science.gov (United States)

    Palacios-Lidón, Elisa; Guanter, Luis; Zúñiga-Pérez, Jesús; Muñoz-Sanjosé, Vicente; Colchero, Jaime

    2007-03-01

    In this paper scanning force microscopy is combined with simple but powerful data processing to determine quantitatively, on a sub-micrometer scale, the orientation of surface facets present on crystalline materials. A high-quality scanning force topography image is used to determine an angular histogram of the surface normal at each image point. In addition to the known method for the assignment of Miller indices to the facets appearing on the surface, a quantitative analysis is presented that allows the characterization of the relative population and morphological quality of each of these facets. Two different CdTe thin films are used as model systems to probe the capabilities of this method, which enables further information to be obtained about the thermodynamic stability of particular crystallographic facets. The method, which is referred to as nanogoniometry, will be a powerful tool to study in detail the surface of crystalline materials, particularly thin films, with sub-micrometer resolution.

  15. Roughness of CdTe thin films grown on glass by hot wall epitaxy.

    Science.gov (United States)

    Leal, F F; Ferreira, S O; Menezes-Sobrinho, I L; Faria, T E

    2005-01-12

    Cadmium telluride films were grown on glass substrates using the hot wall epitaxy (HWE) technique. The samples were polycrystalline with a preferential (111) orientation. Scanning electron micrographs reveal a grain size between 0.1 and 0.5 µm. The surface morphology of the samples was studied by measuring the roughness profile using a stylus profiler. The roughness as a function of growth time and scale size were investigated to determine the growth and roughness exponents, β and α, respectively. From the results we can conclude that the growth surface has a self-affine character with a roughness exponent α equal to 0.69 ± 0.03 and almost independent of growth time. The growth exponent β was equal to 0.38 ± 0.06. These values agree with that determined previously for CdTe(111) films grown on GaAs(100).

  16. Optical properties of swift ion beam irradiated CdTe thin films

    Energy Technology Data Exchange (ETDEWEB)

    Chandramohan, S. [PG and Research Department of Physics, Kongunadu Arts and Science College, Coimbatore, Tamilnadu 641029 (India); Sathyamoorthy, R. [PG and Research Department of Physics, Kongunadu Arts and Science College, Coimbatore, Tamilnadu 641029 (India)], E-mail: rsathya59@yahoo.co.in; Sudhagar, P. [PG and Research Department of Physics, Kongunadu Arts and Science College, Coimbatore, Tamilnadu 641029 (India); Kanjilal, D.; Kabiraj, D.; Asokan, K. [Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India)

    2008-06-30

    This paper reports the effect of swift (80 MeV) oxygen (O{sup +6}) ion irradiation on the optical properties of CdTe thin films grown by conventional thermal evaporation on glass substrates. The films are found to be slightly Te-rich in composition and irradiation results no change in the elemental composition. The optical constants such as refractive index (n), absorption coefficient ({alpha}) and the optical band gap energy show significant variation in their values with increase in ion fluence. Upon irradiation the band gap energy decreased from a value of 1.53 eV to 1.46 eV whereas the refractive index (n) increased from 2.38 to 3.12 at {lambda} = 850 nm. The photoluminescence spectrum shows high density of native defects whose density strongly depends on the ion fluence. Both analyses indicate considerable defect production after swift ion beam irradiation.

  17. The Potentiostatic Electrodeposition of Indium doped Aluminium Selenide Thin Films

    Directory of Open Access Journals (Sweden)

    R.K. Pathak and Sipi Mohan

    2013-12-01

    Full Text Available The In containing AlSe thin films were electrosynthesized by electrochemical co-deposition technique. The morphological properties of thin films were studied through the Scanning Electron Micrograph (SEM while the structural features through X-Ray Diffraction technique (XRD. The deposition current along with the film thickness values, the charge carrier density, flat band potential, corrosion characteristics i.e., corrosion current, corrosion potential and corrosion rate were calculated.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-10-01

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

  19. Rocking disc electro-deposition of copper films on Mo/MoSe{sub 2} substrates

    Energy Technology Data Exchange (ETDEWEB)

    Cummings, Charles Y.; Frith, Paul E. [Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom); Zoppi, Guillaume; Forbes, Ian [Northumbria Photovoltaics Applications Centre, Northumbria University, NE1 8ST (United Kingdom); Rogers, Keith D. [Cranfield Health, Cranfield University, Shrivenham Campus, Swindon, SN6 8LA (United Kingdom); Lane, David W. [Department of Applied Science, Security and Resilience, Cranfield University, Shrivenham, Swindon, SN6 8LA (United Kingdom); Marken, Frank, E-mail: F.Marken@bath.ac.uk [Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom)

    2011-08-31

    A novel electro-deposition method based on a rocking disc system with {pi}/3 amplitude and variable frequency is introduced. Uniform copper films were deposited from a 0.1 M CuSO{sub 4}/3.0 M NaOH/0.2 M sorbitol bath directly onto 12.1 cm{sup 2} Mo/MoSe{sub 2} substrates with X-ray diffraction showing a thickness variation of {+-}5% over this area. Investigation of the mass transport conditions suggests (i) uniform diffusion over the sample, (ii) a rate of mass transport proportional to the square root of the rocking rate, and (iii) turbulent conditions, which are able to dislodge gas bubbles during electro-deposition.

  20. Electrodeposition and characterization of CaF{sub 2} and rare earth doped CaF{sub 2} films

    Energy Technology Data Exchange (ETDEWEB)

    Wang Hui; Liu Run, E-mail: runliu@zju.edu.cn; Chen Keli; Shi Xiaofang; Xu Zhude

    2011-07-29

    Calcium fluoride (CaF{sub 2}) and the rare earth doped CaF{sub 2} films have been electrodeposited on indium tin oxide (ITO) electrode through electrochemical generation of acid in aqueous solutions near room temperature. For CaF{sub 2} film electrodeposition, the local pH at ITO surface is lowered by the electrochemical oxidation of ascorbate anion, and then the Ca-ethylene diamine tetraacetic acid disodium complexes which are close to the ITO electrode are decomposed to release free Ca{sup 2+} to react with F{sup -}to form CaF{sub 2} deposit onto ITO. In the same way, RE-doped CaF{sub 2} films have been electrodeposited onto ITO electrode. The morphology of films studied by scanning electron microscopy revealed that they are agglomerated and dense. The films showed a little [111] preferred orientation by X-ray diffraction. It was also proved that doped RE ions were distributed homogeneously in the film by energy dispersive spectroscopy mapping. The optical properties of the electrodeposited CaF{sub 2}, CaF{sub 2}:Eu and CaF{sub 2}:Tb films were studied by photoluminescence, and all films exhibit intense emission peaks.

  1. Preparation of Diamond-like Carbon Films on the Surface of Ti Alloy by Electro-deposition

    Institute of Scientific and Technical Information of China (English)

    Fenglei SHEN; Hongwei WANG; Dijiang WEN

    2004-01-01

    In this paper, diamond-like carbon (DLC) fi[ms were deposited on Ti alloy by electro-deposition. DLC films were brown and composed of the compact grains whose diameter was about 400 nm. Examined by XPS, the main composition of the films was carbon. In the Raman spectrum, there were a broad peak at 1350 cm-1 and a broad peak at 1600 cm-1, which indicated that the films were DLC films.

  2. CdTe Thin Film Solar Cells and Modules Tutorial; NREL (National Renewable Energy Laboratory)

    Energy Technology Data Exchange (ETDEWEB)

    Albin, David S.

    2015-06-13

    This is a tutorial presented at the 42nd IEEE Photovoltaics Specialists Conference to cover the introduction, background, and updates on CdTe cell and module technology, including CdTe cell and module structure and fabrication.

  3. The large-area CdTe thin film for CdS/CdTe solar cell prepared by physical vapor deposition in medium pressure

    Science.gov (United States)

    Luo, Run; Liu, Bo; Yang, Xiaoyan; Bao, Zheng; Li, Bing; Zhang, Jingquan; Li, Wei; Wu, Lili; Feng, Lianghuan

    2016-01-01

    The Cadmium telluride (CdTe) thin film has been prepared by physical vapor deposition (PVD), the Ar + O2 pressure is about 0.9 kPa. This method is a newer technique to deposit CdTe thin film in large area, and the size of the film is 30 × 40 cm2. This method is much different from the close-spaced sublimation (CSS), as the relevance between the source temperature and the substrate temperature is weak, and the gas phase of CdTe is transferred to the substrate by Ar + O2 flow. Through this method, the compact and uniform CdTe film (30 × 40 cm2) has been achieved, and the performances of the CdTe thin film have been determined by transmission spectrum, SEM and XRD. The film is observed to be compact with a good crystallinity, the CdTe is polycrystalline with a cubic structure and a strongly preferred (1 1 1) orientation. Using the CdTe thin film (3 × 5 cm2) which is taken from the deposited large-area film, the 14.6% efficiency CdS/CdTe thin film solar cell has been prepared successfully. The structure of the cell is glass/FTO/CdS/CdTe/graphite slurry/Au, short circuit current density (Jsc) of the cell is 26.9 mA/cm2, open circuit voltage (Voc) is 823 mV, and filling factor (FF) is 66.05%. This technique can be a quite promising method to apply in the industrial production, as it has great prospects in the fabricating of large-area CdTe film.

  4. Comparative study of electrical properties of Cd and Te-enriched CdTe thin films at cryogenic temperature

    Energy Technology Data Exchange (ETDEWEB)

    Shah, Nazar Abbas, E-mail: nabbasqureshi@yahoo.co [Thin Films Research Laboratory, Department of Physics, COMSATS Institute of Information Technology, Park Road, Islamabad 45320 (Pakistan)

    2010-09-17

    Cd and Te-enriched cadmium telluride (CdTe) polycrystalline thin films were grown on corning glass substrates by Close Spaced Sublimation (CSS) technique. The structural investigations performed by means of X-ray diffraction (XRD) technique, scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX) showed that the deposited films exhibit a polycrystalline structure with <1 1 1> as preferred orientation. The optical transmittance for Te-enriched CdTe sample was above 0.8 in the range of 1500-2500 nm, which was significantly below 0.8 for Cd-enriched CdTe sample. The electrical properties of these samples were analyzed as a function of the Cd and Te concentration at cryogenic temperature. The electrical resistivity dropped several orders of magnitude. These properties are significantly changed at cryogenic temperature. The comparative study revealed that using this deposition technique, n-type, and p-type Cd and Te-enriched CdTe polycrystalline films can be produced.

  5. Electrodeposition of copper selenide films from acidic bath and their properties

    Science.gov (United States)

    Mane, Rajaram S.; Shaikh, Arif V.; Joo, Oh-Shim; Han, Sung-Hwan; Pathan, Habib M.

    2012-06-01

    Copper selenide thin films are successfully deposited using electrodeposition method by combining copper sulfate and sodiumseleno sulfate precursors at room temperature in acidic bath. The chemical composition was a key factor in preparing high-quality uniform and smooth thin films of the copper selenide. We present indium-tin-oxide as a substrate for depositing copper selenide films which usually exists as copper (I) selenide or copper (II) selenide. Obtained brownish films of copper selenide are examined for their structural, morphological, compositional and optical properties by means of X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis and optical absorption measurement techniques, respectively for the structural, morphological and optical analysis.

  6. Rectifying properties of ZnO thin films deposited on FTO by electrodeposition technique

    Science.gov (United States)

    Lv, Jianguo; Sun, Yue; Zhao, Min; Cao, Li; Xu, Jiayuan; He, Gang; Zhang, Miao; Sun, Zhaoqi

    2016-03-01

    ZnO thin films were successfully grown on fluorine-doped tin oxide glass by electrodeposition technique. The crystal structure, surface morphology and optical properties of the thin films were investigated. The average crystallite size and intensity of A1(LO) mode increase with improving the absolute value of deposition potential. The best preferential orientation along c-axis and the richest oxygen interstitial defects have been observed in the sample deposited at -0.8 V. A heterojunction device consisting of ZnO thin film and n-type fluorine-doped tin oxide was fabricated. The current-voltage (I-V) characteristic of the p-n heterojunction device deposited at -0.8 V shows the best rectifying diode behavior. The p-type conductivity of the ZnO thin film could be attributed to complex defect of unintentional impurity and interstitial oxygen.

  7. Simple Formation of Nanostructured Molybdenum Disulfide Thin Films by Electrodeposition

    Directory of Open Access Journals (Sweden)

    S. K. Ghosh

    2013-01-01

    Full Text Available Nanostructured molybdenum disulfide thin films were deposited on various substrates by direct current (DC electrolysis form aqueous electrolyte containing molybdate and sulfide ions. Post deposition annealing at higher temperatures in the range 450–700°C transformed the as-deposited amorphous films to nanocrystalline structure. High temperature X-ray diffraction studies clearly recorded the crystal structure transformations associated with grain growth with increase in annealing temperature. Surface morphology investigations revealed featureless structure in case of as-deposited surface; upon annealing it converts into a surface with protruding nanotubes, nanorods, or dumbbell shape nanofeatures. UV-visible and FTIR spectra confirmed about the presence of Mo-S bonding in the deposited films. Transmission electron microscopic examination showed that the annealed MoS2 films consist of nanoballs, nanoribbons, and multiple wall nanotubes.

  8. Comparative study of sputtered and electrodeposited CI(S,Se) and CIGSe thin films

    Energy Technology Data Exchange (ETDEWEB)

    Ihlal, A. [Laboratoire Materiaux et Energies Renouvelables (LMER), Faculte des Sciences, BP 8106, Hay Dakhla, Agadir (Morocco)]. E-mail: ihlal_ahmed@yahoo.fr; Bouabid, K. [Laboratoire Materiaux et Energies Renouvelables (LMER), Faculte des Sciences, BP 8106, Hay Dakhla, Agadir (Morocco); Soubane, D. [Laboratoire Materiaux et Energies Renouvelables (LMER), Faculte des Sciences, BP 8106, Hay Dakhla, Agadir (Morocco); Structure des Interfaces et Fonctionnalite des couches minces (SIFCOM), Ensicaen, Bd du Marechal Juin, 14050 Caen (France); Nya, M. [Laboratoire Materiaux et Energies Renouvelables (LMER), Faculte des Sciences, BP 8106, Hay Dakhla, Agadir (Morocco); Ait-Taleb-Ali, O. [Laboratoire Materiaux et Energies Renouvelables (LMER), Faculte des Sciences, BP 8106, Hay Dakhla, Agadir (Morocco); Amira, Y. [Laboratoire Materiaux et Energies Renouvelables (LMER), Faculte des Sciences, BP 8106, Hay Dakhla, Agadir (Morocco); Outzourhit, A. [Laboratoire de Physique des Solides et des Couches Minces (LPSCM), Departement de physique, Faculte des sciences Semlalia, BP: S/3293, Marrakech (Morocco); Nouet, G. [Structure des Interfaces et Fonctionnalite des couches minces (SIFCOM), Ensicaen, Bd du Marechal Juin, 14050 Caen (France)

    2007-05-31

    Copper indium disulphide CuInS{sub 2} (CIS) and diselenide CuInSe{sub 2} (CISe) and their alloys with gallium CuIn{sub 1-x}Ga {sub x}Se{sub 2} (CIGSe) thin films have been prepared using both high- and non-vacuum processes. The well known two-stage process consisting in a sequential sputtering of Cu and In thin layers and a subsequent sulfurisation has led to the formation of good quality CuInS{sub 2} ternary compound. The films exhibit the well known chalcopyrite structure with a preferential orientation in the (112) plane suitable for the production of the efficient solar cells. The absorption coefficient of the films is higher than 10{sup 4} cm{sup -1} and the band gap value is about 1.43 eV. A non-vacuum technique was also used. It consists on a one step electrodeposition of Cu, In and Se and in a second time Cu, In, Se and Ga. From the morphological and structural point of view, the films obtained are similar to those prepared by the first technique. The band gap value increases up from 1 eV for the CIS films to 1.26 eV for the CuIn{sub 1-x}Ga {sub x}Se{sub 2} with 0 < x < 0.23. The resistivity at room temperature of the films was adjusted to 10 {omega}cm after annealing. The films exhibit an absorption coefficient more than 10{sup 5} cm{sup -1}. The most important conclusion of this study is the interesting potential of electrodeposition as a promising option in low-cost CISe and CIGSe thin film based solar cells processing.

  9. Effect of Annealing on the Properties of Antimony Telluride Thin Films and Their Applications in CdTe Solar Cells

    Directory of Open Access Journals (Sweden)

    Zhouling Wang

    2014-01-01

    Full Text Available Antimony telluride alloy thin films were deposited at room temperature by using the vacuum coevaporation method. The films were annealed at different temperatures in N2 ambient, and then the compositional, structural, and electrical properties of antimony telluride thin films were characterized by X-ray fluorescence, X-ray diffraction, differential thermal analysis, and Hall measurements. The results indicate that single phase antimony telluride existed when the annealing temperature was higher than 488 K. All thin films exhibited p-type conductivity with high carrier concentrations. Cell performance was greatly improved when the antimony telluride thin films were used as the back contact layer for CdTe thin film solar cells. The dark current voltage and capacitance voltage measurements were performed to investigate the formation of the back contacts for the cells with or without Sb2Te3 buffer layers. CdTe solar cells with the buffer layers can reduce the series resistance and eliminate the reverse junction between CdTe and metal electrodes.

  10. Electrodeposited polymer encapsulated nickel sulphide thin films: frequency switching material

    Energy Technology Data Exchange (ETDEWEB)

    Jana, Sumanta, E-mail: sumantajana85@gmail.com [Department of Chemistry, Bengal Engineering and Science University, Botanic Garden, Howrah 711103, WB (India); Mukherjee, Nillohit [Centre of Excellence for Green Energy and Sensor Systems, Bengal Engineering and Science University, Howrah 711103, WB (India); Chakraborty, Biswajit [Department of Chemistry, Vivekananda Mahavidyalay, Burdwan 713103, WB (India); Mitra, Bibhas Chandra [Department of Physics, Bengal Engineering and Science University, Botanic Garden, Howrah 711103, WB (India); Mondal, Anup, E-mail: anupmondal2000@yahoo.co.in [Department of Chemistry, Bengal Engineering and Science University, Botanic Garden, Howrah 711103, WB (India)

    2014-05-01

    Graphical abstract: Polyvinylpyrrolidone encapsulated NiS thin films were synthesized electrochemically. The light induced frequency switching study of the synthesized material was carried out and it was observed that the films performed well as a switching device under 1 Sun illumination. This pulse generation within an insulating polymer encapsulated semicondctor matrix (PVP NiS) might be due to surface covering which leads to reduction of recombination process. Highlights: • PVP-NiS thin films were electrochemically synthesized. • Encapsulation of PVP causes surface modification of NiS by reducing surface states. • The synthesized thin films were used as frequency switching material which generates ~ 50 Hz frequency under 1 Sun irradiation. Abstract: Polyvinylpyrrolidone (PVP) encapsulated nickel sulfide (NiS) thin films have been synthesized electrochemically from aqueous solution of hydrated nickel chloride (NiCl₂, 6H₂O), thioacetamide (CH₃C(S) NH₂) (TAA) and polyvinylpyrrolidone (PVP). Surface modification of nickel sulfide (NiS) thin films was achieved by this polymer encapsulation. X-ray diffraction (XRD), high resolution transmission electron microscope (HRTEM), field emission scanning electron microscopy (FESEM) and Energy dispersive X-radiation (EDAX) techniques were used for the characterization of thin films. Infrared spectroscopy (IR) confirmed the formation of polymer encapsulated semiconductor. Frequency switching generation study shows that the encapsulated material could be used as a frequency switching device that generates a frequency ~ 50 Hz under 1 Sun illumination. Encapsulation with PVP causes surface modification that reduces the surface states and barrier height. As a result, the width of the depletion region decreases. So the number of electron-hole pairs increases. Consequently, the number of excitons and exciton related emission increases and this leads to reduction of recombination process and shows photo induced

  11. Growth and magnetic properties dependence of the Co–Cu/Cu films electrodeposited under high magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Franczak, Agnieszka, E-mail: agnieszka.franczak@mtm.kuleuven.be [Laboratoire d’Ingénierie et Sciences des Matériaux (LISM EA 4695), Université de Reims Champagne-Ardenne, UFR Sciences et Naturelles, Bat. 6, Moulin de la Housse, BP 1039, 51687 Reims Cedex 2 (France); Department of Materials Science (MTM), KU Leuven, Kasteelpark Arenberg 44, 3001 Haverlee (Leuven) (Belgium); Levesque, Alexandra [Laboratoire d’Ingénierie et Sciences des Matériaux (LISM EA 4695), Université de Reims Champagne-Ardenne, UFR Sciences et Naturelles, Bat. 6, Moulin de la Housse, BP 1039, 51687 Reims Cedex 2 (France); Zabinski, Piotr [Laboratory of Physical Chemistry and Electrochemistry, Faculty of Non-Ferrous Metals, AGH University of Science and Technology, al. A. Mickiewicza 30, 30059 Krakow (Poland); Li, Donggang [Key Laboratory of Electromagnetic Processing of Materials (Ministry of Education), Northeastern University, 314 Box, 110004 Shenyang (China); Czapkiewicz, Maciej [Department of Electronics, AGH University of Science and Technology, al. A. Mickiewicza 30, 30059 Krakow (Poland); Kowalik, Remigiusz [Laboratory of Physical Chemistry and Electrochemistry, Faculty of Non-Ferrous Metals, AGH University of Science and Technology, al. A. Mickiewicza 30, 30059 Krakow (Poland); Bohr, Frédéric [Laboratoire d’Ingénierie et Sciences des Matériaux (LISM EA 4695), Université de Reims Champagne-Ardenne, UFR Sciences et Naturelles, Bat. 6, Moulin de la Housse, BP 1039, 51687 Reims Cedex 2 (France); and others

    2015-07-15

    The present work is focused on the investigations of magnetic properties dependence on microstructure of Co–Cu/Cu films electrodeposited under superimposed high magnetic field. The experimental results indicate a strong effect of an external magnetic field on the morphology of deposited films, more precisely on the Co:Cu ratio that determines the film growth. It is shown that the Co–Cu/Cu films electrodeposited without superimposed magnetic field consisted of two clearly visible features: compact film with incorporated granular particles. Under a superimposed external high magnetic field the privilege growth of the particles was induced. As a consequence, development of the well-defined branched structure of Co–Cu/Cu film was observed. In contrary, the phase compositional investigations do not reveal any changes in the phase formation during electrodeposition under magnetic field conditions. Thus, it is assumed that a strong growth of Co–Cu/Cu films in (111) direction under magnetic or non-magnetic electrodeposition conditions is related with the growth of Cu (111) plane and embedded into it some of the Co fcc atoms of same (111) orientation, as well as the Co hcp atoms that grows in the (002) direction. This non-equilibrium growth of Co–Cu/Cu films under magnetic deposition conditions affects strongly the magnetic properties of deposited films, revealing that films obtained under magnetic fields higher than 3 T were no more magnetic materials. - Highlights: • Co–Cu/Cu electrodeposits were obtained at elevated temperature under HMFs. • The effects of HMFs on microstructure and magnetic properties were investigated. • Interesting morphological changes due to HMFs has been observed. • Changes in Co:Cu ratio due to HMFs modified the magnetic properties of deposits.

  12. Electrodeposition of nanocrystalline CdSe thin films from dimethyl sulfoxide solution: Nucleation and growth mechanism, structural and optical studies

    Energy Technology Data Exchange (ETDEWEB)

    Henriquez, R., E-mail: rodrigo.henriquez@ucv.cl [Instituto de Quimica, Facultad de Ciencias, Pontificia Universidad Catolica de Valparaiso, Casilla 4059, Valparaiso (Chile); Badan, A. [Instituto de Fisica, Facultad de Ingenieria, Herrera y Reissig 565, C.C. 30, 11000 Montevideo (Uruguay); Grez, P.; Munoz, E.; Vera, J. [Instituto de Quimica, Facultad de Ciencias, Pontificia Universidad Catolica de Valparaiso, Casilla 4059, Valparaiso (Chile); Dalchiele, E.A.; Marotti, R.E. [Instituto de Fisica, Facultad de Ingenieria, Herrera y Reissig 565, C.C. 30, 11000 Montevideo (Uruguay); Gomez, H. [Instituto de Quimica, Facultad de Ciencias, Pontificia Universidad Catolica de Valparaiso, Casilla 4059, Valparaiso (Chile)

    2011-05-01

    Highlights: > Electrodeposition of CdSe nanocrystalline semiconductor thin films. > Polycrystalline wurtzite structure with a slight (1010) preferred orientation. > Absorption edge shifts in the optical properties due to quantum confinement effects. - Abstract: Cadmium selenide (CdSe) nanocrystalline semiconductor thin films have been synthesized by electrodeposition at controlled potential based in the electrochemical reduction process of molecular selenium in dimethyl sulfoxide (DMSO) solution. The nucleation and growth mechanism of this process has been studied. The XRD pattern shows a characteristic polycrystalline hexagonal wurtzite structure with a slight (1 0 1 0) crystallographic preferred orientation. The crystallite size of nanocrystalline CdSe thin films can be simply controlled by the electrodeposition potential. A quantum size effect is deduced from the correlation between the band gap energy and the crystallite size.

  13. Recrystallization of PVD CdTe Thin Films Induced by CdCl2 Treatment -- A Comparison Between Vapor and Solution Processes: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Mountinho, H. R.; Dhere, R. G.; Romero, M. J.; Jiang, C. S.; To, B.; Al-Jassim, M. M.

    2008-05-01

    This paper describes the large concentration of 60..deg.. <111> twin boundaries that was observed in every CdTe film analyzed in this work, even after recrystallization and grain growth, confirming the low energy of these interfaces.

  14. In-depth analysis of chloride treatments for thin-film CdTe solar cells

    Science.gov (United States)

    Major, J. D.; Al Turkestani, M.; Bowen, L.; Brossard, M.; Li, C.; Lagoudakis, P.; Pennycook, S. J.; Phillips, L. J.; Treharne, R. E.; Durose, K.

    2016-10-01

    CdTe thin-film solar cells are now the main industrially established alternative to silicon-based photovoltaics. These cells remain reliant on the so-called chloride activation step in order to achieve high conversion efficiencies. Here, by comparison of effective and ineffective chloride treatments, we show the main role of the chloride process to be the modification of grain boundaries through chlorine accumulation, which leads an increase in the carrier lifetime. It is also demonstrated that while improvements in fill factor and short circuit current may be achieved through use of the ineffective chlorides, or indeed simple air annealing, voltage improvement is linked directly to chlorine incorporation at the grain boundaries. This suggests that focus on improved or more controlled grain boundary treatments may provide a route to achieving higher cell voltages and thus efficiencies.

  15. Anomalous scaling and super-roughness in the growth of CdTe polycrystalline films

    Science.gov (United States)

    Mata, Angélica S.; Ferreira, Silvio C., Jr.; Ribeiro, Igor R. B.; Ferreira, Sukarno O.

    2008-09-01

    CdTe films grown on glass substrates covered by fluorine-doped tin oxide by hot-wall epitaxy were studied through the interface dynamical scaling theory. Direct measures of the dynamical exponent revealed an intrinsically anomalous scaling characterized by a global roughness exponent α , distinct from the local one (the Hurst exponent H ) previously reported by Ferreira [Appl. Phys. Lett.88, 244103 (2006)]. A variety of scaling behaviors was obtained with varying substrate temperature. In particular, a transition from an intrinsically anomalous scaling regime with H≠αrough regime with H≠α>1 at high temperatures was observed. The temperature is a growth parameter that controls both the interface roughness and dynamical scaling exponents. Nonlocal effects are pointed out as the factors ruling the anomalous scaling behavior.

  16. Synthesis and properties of 10% Zn layered CdTe thin films by SEL method

    Science.gov (United States)

    Shanmugan, S.; Mutharasu, D.

    2011-10-01

    Te/Cd/Te/Zn/Cd stacked layers were prepared by Stacked Elemental Layer (SEL) Method. All stacks were annealed from 200 °C to 500 °C and the prepared films were confirmed as polycrystalline nature. Cubic CdTe and Hexagonal ZnTe were identified at high annealing temperature. Transmittance spectra emphasized the significance of Zn doping by annealing the stack. The calculated optical constants n and k were 1.52-2.45 and 0.07-0.36 respectively. The band gaps (Eg) were observed between 1.38 and 1.44 eV at above 350 °C. A uniform surface morphology could be observed at high annealing temperatures. The observed results encouraged the Zn doping using SEL method.

  17. Development of high-efficiency, thin-film CdTe solar cells. Final subcontract report, 1 February 1992--30 November 1995

    Energy Technology Data Exchange (ETDEWEB)

    Rohatgi, A.; Chou, H.C.; Kamra, S.; Bhat, A. [Georgia Inst. of Tech., Atlanta, GA (United States)

    1996-01-01

    This report describes work performed by the Georgia Institute of Technology (GIT) to bring the polycrystalline CdTe cell efficiency a step closer to the practically achievable efficiency of 18% through fundamental understanding of detects and loss mechanisms, the role of chemical and heat treatments, and investigation of now process techniques. The objective was addressed by a combination of in-depth characterization, modeling, materials growth, device fabrication, and `transport analyses of Au/Cu/CdTe/CdS/SnO {sub 2} glass front-wall heterojunction solar cells. GiT attempted to understand the loss mechanism(s) in each layer and interface by a step-by-step investigation of this multilayer cell structure. The first step was to understand, quantify, and reduce the reflectance and photocurrent loss in polycrystalline CdTe solar calls. The second step involved the investigation of detects and loss mechanisms associated with the CdTe layer and the CdTe/CdS interface. The third stop was to investigate the effect of chemical and heat treatments on CdTe films and cells. The fourth step was to achieve a better and reliable contact to CdTe solar cells by improving the fundamental understanding. Of the effects of Cu on cell efficiency. Finally, the research involved the investigation of the effect of crystallinity and grain boundaries on Cu incorporation in the CdTe films, including the fabrication of CdTe solar calls with larger CdTe grain size.

  18. Preparation and photocharacterization of Cu-Sb-Se films by electrodeposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, A.M. [Departamento de Materiales Solares (CIE-UNAM), Centro de Ivestigacion en Energia, Temixco, Morelos 62580 (Mexico); Turner, J.A. [National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, CO 80401 (United States)

    2003-09-15

    Ternary semiconductor Cu-Sb-Se films were grown on 304 stainless-steel/Cr and ITO-glass using a combination of electrodeposition and chemical bath techniques. The samples were annealed in a N{sub 2} atmosphere at various temperatures and characterized by X-ray, electron probe microanalysis, current-voltage, capacitance-voltage and photocurrent spectroscopy. Photoelectrochemical studies were used to determinate the flat-band potential and the doping density of the material. These data lead to energetic considerations on the applicability of the Cu-Sb-Se electrode in the photoelectrochemical decomposition of water.

  19. Electrodeposition of lead-free, tin-based alloy solder films

    Science.gov (United States)

    Han, Chunfen

    The dominant materials used for solders in electronic assemblies over the past 60 years have been Pb-Sn alloys. Increasing pressure from environmental and health authorities has stimulated the development of various Pb-free solders. Two of the most promising replacements are eutectic Sn-Cu and Sn-Ag-Cu alloys that are produced primarily by electrodeposition. During soldering and solid state aging (storage or in service of the electronic assemblies), interactions take place at the solder/substrate metal interface and form intermetallic compounds (IMCs) which are crucial for the reliability of the solder joints. Simple and "green" Sn-citrate and Sn-Cu-citrate solutions have been developed and optimized to electrodeposit eutectic and near eutectic Sn-Cu solder films. Sn-citrate suspensions with Cu particles and Sn-Cu-citrate suspensions with Ag nano-particles have also been developed and optimized to allow for electrochemical composite deposition of eutectic and near eutectic Sn-Cu and Sn-Ag-Cu solder films. Different plating and post-plating conditions, including solution concentration, current density, agitation, additives, and aging, have been investigated by evaluating their effects on plating rate, deposit composition and microstructure. Tri-ammonium citrate is used as the only complexing agent for Sn, Sn-Cu, and Sn-Ag-Cu deposition. Speciation diagram calculations, reduction potential calculations, and polarization studies are conducted to study Sn-citrate solution chemistry and the kinetics of Sn electrodeposition. X-ray photoelectron spectroscopy (XPS) analysis is used to identify the precipitates formed in Sn-citrate solutions at low pH. Current-controlled and potential-controlled electrochemical techniques, nucleation modeling, and surface morphology characterization techniques are applied to study the nucleation and film growth mechanism of Sn and Sn-Cu electrodeposition from Sn-citrate and Sn-Cu-citrate solutions. Reflow and aging tests for deposited Sn

  20. Effects of Antimony Doping in Polycrystalline CdTe Thin-Film Solar Cells

    Science.gov (United States)

    Okamoto, Tamotsu; Ikeda, Shigeyuki; Nagatsuka, Satsuki; Hayashi, Ryoji; Yoshino, Kaoru; Kanda, Yohei; Noda, Akira; Hirano, Ryuichi

    2012-10-01

    The effects of antimony (Sb) doping of the CdTe layer in the CdTe solar cells were investigated using Sb-doped CdTe powders as source materials for CdTe deposition by the close-spaced sublimation (CSS) method. Conversion efficiency increased with increasing Sb concentration below 1×1018 cm-3, mainly owing to the improvement of the fill factor. Secondary ion microprobe mass spectrometry (SIMS) depth profile revealed that the Sb impurities at a concentration of approximately 1×1016 cm-3 were incorporated into the CdTe layer when using the Sb-doped CdTe source of 1×1018 cm-3. The observation of surface morphology showed that the grain sizes were improved by Sb addition. Therefore, the improved performance upon Sb addition to CdTe solar cells was probably due to the improvements in crystallinity, such as increased grain size.

  1. Influence of Bath Composition on Magnetic Properties of Electrodeposited Co-Pt-W Thin Films

    Institute of Scientific and Technical Information of China (English)

    GE Hong-liang; WEI Guo-ying; WU Qiong; ZHOU Qiao-ying; WANG Xin-yan

    2007-01-01

    Effect of bath composition ([Co2+]/[PtⅣ] and [WO2-4], [cit-]) and pH on the magnetic properties of electrodeposited Co-Pt-W thin films has been investigated. Electrodeposited Co-Pt-W thin films exhibited strong perpendicular magnetic anisotropy when the ratio of [Co2+] to [PtⅣ] was 10; cathode current efficiency and perpendicular magnetic anisotropy showed little variations when [WO2-4] was lower than 0.1 mol/L, but perpendicular magnetic anisotropy had strengthened when [WO2-4] was over 0.1 mol/L, which could be explained by the fact that the hydrogen evolution could produce pores as magnetic domain pinnings; citrate as complexing reagent can promote the polarization of [Co2+] and [PtⅣ]. As a result, the equilibrium electrode potentials of cobalt and platinum moved to negative direction, which led to the co-deposition of Co, Pt, and W. It was also found out that the as-deposited Co-Pt-W hard magnetic thin films were very homogeneous, smooth, and had the maximum coercivity for the bath pH 8.5 and the concentration of citrate 0.26 mol/L.

  2. Electrodeposition and Characterization of CulnSe2 Thin Films for Solar Cells

    Institute of Scientific and Technical Information of China (English)

    LI Jianzhuang; ZHAO Xiujian; XIA Donglin

    2007-01-01

    CuInSe2 (CIS) thin films were prepared by electrodeposition from the de-ionized water solution consisting of CuCl2, InCl3, H2SeO3 and Na-citrate onto Mo/soda-lime glass (SLG) substrates. A thermal processing in Se atmosphere at 450 ℃ was carried out for the electrodepositied films to improve the stoichiometry. The composition and morphology of selenized CIS thin films were studied using energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM), respectively. X-ray diffraction(XRD) studies show that the annealing in Se atmosphere at 450 ℃ promotes the structural formation of CIS chalcopyrite structure.

  3. Effect of CdCl{sub 2} treatment on structural and electronic property of CdTe thin films deposited by magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Islam, M.A. [Solar Energy Research Institute (SERI), Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Hossain, M.S.; Aliyu, M.M. [Department of Electrical, Electronic and Systems Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Karim, M.R. [Center of Excellence for Research in Engineering Materials (CEREM) College of Engineering, King Saud University, Riyadh, 11421 (Saudi Arabia); Razykov, T.; Sopian, K. [Solar Energy Research Institute (SERI), Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Amin, N., E-mail: nowshad@eng.ukm.my [Solar Energy Research Institute (SERI), Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Department of Electrical, Electronic and Systems Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Center of Excellence for Research in Engineering Materials (CEREM) College of Engineering, King Saud University, Riyadh, 11421 (Saudi Arabia)

    2013-11-01

    The structural and electrical properties of the magnetron sputtered CdTe thin films with subsequent CdCl{sub 2} solution treatment have been studied with a major focus on the influence of CdCl{sub 2} treatment to achieve high quality thin films. In this study, CdTe films with a thickness of 1.5 to 2 μm have been grown using the magnetron sputtering technique on top of glass substrate at an optimized substrate temperature of 250 °C. Aqueous CdCl{sub 2} concentration varied from 0.3 mol to 1.2 mol with the annealing temperature from 360 °C to 450 °C. The surface roughness of the films increases with the increase of solution concentration, while it fluctuates with the increase of annealing temperature. The density of nucleation centers and the strain increases for the films treated at 360 °C with 0.3 M to1.2 M while the grain growth of the films reduces. However, these strains are released at higher annealing temperatures, resulting in reduced dislocation densities, structural defects as well as increased crystalline property and grain size. The carrier concentration increases with the increase of treated CdCl{sub 2} concentration and subsequent annealing temperature. The highest carrier concentration of 1.05 × 10{sup 14}/cm{sup 3} was found for the CdTe thin films treated with 0.3 M CdCl{sub 2} solution followed by an annealing treatment at 420 °C for 20 min. - Highlights: • CdTe thin films are grown as absorption layers in CdTe solar cells by sputtering. • CdTe film quality in terms of structural and electronic properties is examined. • All growth parameters are optimized in the range of 1.5 to 2 μm CdTe films.

  4. Red shift for CdTe nanoparticle thin films and suspensions during heating.

    Science.gov (United States)

    Dunn, S; Gardner, H C; Bertoni, C; Gallardo, D E; Gaponik, N; Eychmüller, A

    2008-05-01

    The work that we have conducted shows that temperature affects the wavelength of light emitted from CdTe nanoparticle clusters that are in a suspension or deposited into thin films via a layer-by-layer process. Compared with the stock suspension, the films show an initial photoluminescent shift, of circa 6-8 nm to the red, when the particles are deposited. A shift of circa 6-8 nm is also seen when the suspensions are first heated to 85 degrees C from room temperature (20 degrees C) having been stored in a fridge at 5 degrees C. This shift is non-recoverable. With continual cycling from room temperature to 85 degrees C the suspensions show a slight tendency for the emission to move increasingly to the red; whereas the films show no such tendency. In both cases, the range in emission is ca 10 nm from the room temperature state to 80 degrees C. The intensity of the emission from the film drops abruptly (ca 50% reduction) after one cycle of heating; in the suspension there is an initial increase (ca 3-5% increase) in intensity before it decays. We see that the shift towards the red has been attributed to energy transfer or a rearrangement of the packing of the particles in the thin films. After conducting analysis of the films using scanning probe microscopy we have determined that a change in the morphology is responsible for the permanent shift in emission wavelength associated with prolonged heating. The influence of traps has not been ruled out, but the morphological change in the samples is very large and is likely to be the dominating mechanism affecting change for the red shift at room temperature.

  5. The role of inhibitors during electrodeposition of thin metallic films

    Science.gov (United States)

    Armstrong, M. J.

    1990-05-01

    The role of brightening agents during the deposition of thin metal films was analyzed. The model brightening system studied was copper deposition in the presence of benzotriazole (BTA). Emphasis was placed on the early stages of deposition. The development of microtopography was characterized with in situ scanning tunneling microscopy. Cuprous-BTA film formation was measured with impedance spectroscopy. Copper electrochemistry was measured with double-pulse potentiometry. The incorporation of BTA, including the effects of mass transport conditions, was studied with x ray photoelectron spectroscopy and secondary ion mass spectroscopy. A visual survey of deposits from 0.5 M CuSO4, 0.5 M H2SO4 indicated that brightening occurs when the concentration of BTA is greater than 100 microM and the current density is greater than 50 mA/sq cm. A passive layer was found to form during cathodic polarization of copper in 0.5 M CuSO4, 0.5 M H2SO4 with 100 and 200 microM BTA. Followingbreakdown of the passive layer, with increased polarization, the copper remains covered with a BTA film with a coverage following Langmuir adsorption kinetics. Benzotriazole was not incorporated into the copper deposits. The nucleation site density of Cu on Pt was only a function of overpotential irrespective of the BTA concentration. The presence of BTA increases the overpotential (resulting in an increase in nucleation rate) for a given current density which results in a decreased particle size. Benzotriazole altered the morphology of the deposited Cu. Deposits from BTA free electrolyte consisted of flat planes terminated with ledges with growth occurring at the ledges. Deposits from BTA containing electrolyte consisted of hemispheres with growth occurring uniformly on the surface.

  6. The role of inhibitors during electrodeposition of thin metallic films

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, M.J. (California Univ., Berkeley, CA (USA). Dept. of Chemical Engineering Lawrence Berkeley Lab., CA (USA))

    1990-05-01

    The role of brightening agents during the deposition of thin metal films was analyzed. The model brightening system studied was copper deposition in the presence of benzotriazole (BTA). Emphasis was placed on the early stages of deposition. The development of microtopography was characterized with in situ scanning tunneling microscopy. Cuprous-BTA film formation was measured with impedance spectroscopy. Copper electrochemistry was measured with double-pulse potentiometry. The incorporation of BTA, including the effects of mass transport conditions, was studied with x-ray photoelectron spectroscopy and secondary ion mass spectroscopy. A visual survey of deposits from 0.5 M CuSO{sub 4}, 0.5 M H{sub 2}SO{sub 4} indicated that brightening occurs when the concentration of BTA is greater than 100 {mu}M and the current density is greater than 50 mA/cm{sup 2}. A passive layer was found to form during cathodic polarization of copper in 0.5 M CuSO{sub 4}, 0.5 M H{sub 2}SO{sub 4} with 100 and 200 {mu}M BTA. Following breakdown of the passive layer, with increased polarization, the copper remains covered with a BTA film with a coverage following Langmuir adsorption kinetics. Benzotriazole was not incorporated into the copper deposits. The nucleation site density of Cu on Pt was only a function of overpotential irrespective of the BTA concentration. The presence of BTA increases the overpotential (resulting in an increase in nucleation rate) for a given current density which results in a decreased particle size. Benzotriazole altered the morphology of the deposited Cu. Deposits from BTA free electrolyte consisted of flat planes terminated with ledges with growth occurring at the ledges. Deposits from BTA containing electrolyte consisted of hemispheres with growth occurring uniformly on the surface.

  7. Thin Film Electrodeposition of Ir(III Cyclometallated Complexes

    Directory of Open Access Journals (Sweden)

    Andreea Ionescu

    2016-01-01

    Full Text Available Novel electropolymerizable Ir(III cyclometallated complexes have been synthesized and characterized. In these complexes the cyclometallated ligands are either 2-phenylpyridine H(PhPy or benzothiazole-triphenylamine H(BzTh-tpa, while the Ir(III coordination sphere is completed by a Schiff base substituted with a triphenylamine fragment. A complete electrochemical study has been conducted on all complexes, in order to verify the feasibility of electropolymerization and to elucidate the role of the specific position of the triphenylamine moiety in the molecular structure. Homogeneous thin films of Ir(III metallopolymers have been successfully obtained through electropolymerization process.

  8. Physical properties of Bi doped CdTe thin films grown by CSVT and their influence on the CdS/CdTe solar cells PV-properties

    Energy Technology Data Exchange (ETDEWEB)

    Vigil-Galan, O. [Escuela Superior de Fisica y Matematicas-I.P.N., Edificio de Fisica Avanzada, av. IPN y Juan de Dios Batiz s/n U.P.A.L.M. 07738 Mexico D.F. (Mexico)]. E-mail: osvaldo@esfm.ipn.mx; Sanchez-Meza, E. [Escuela Superior de Fisica y Matematicas-I.P.N., Edificio de Fisica Avanzada, av. IPN y Juan de Dios Batiz s/n U.P.A.L.M. 07738 Mexico D.F. (Mexico); Ruiz, C.M. [Departamento de Fisica de Materiales, Universidad Autonoma de Madrid, Madrid 28049 (Spain); Sastre-Hernandez, J. [Escuela Superior de Fisica y Matematicas-I.P.N., Edificio de Fisica Avanzada, av. IPN y Juan de Dios Batiz s/n U.P.A.L.M. 07738 Mexico D.F. (Mexico); Morales-Acevedo, A. [Escuela Superior de Fisica y Matematicas-I.P.N., Edificio de Fisica Avanzada, av. IPN y Juan de Dios Batiz s/n U.P.A.L.M. 07738 Mexico D.F. (Mexico); CINVESTAV-IPN, Electrical Engineering Department, Av. IPN No2508, C. P. 07360, Mexico, D. F. (Mexico); Cruz-Gandarilla, F. [Escuela Superior de Fisica y Matematicas-I.P.N., Edificio de Fisica Avanzada, av. IPN y Juan de Dios Batiz s/n U.P.A.L.M. 07738 Mexico D.F. (Mexico); Aguilar-Hernandez, J. [Escuela Superior de Fisica y Matematicas-I.P.N., Edificio de Fisica Avanzada, av. IPN y Juan de Dios Batiz s/n U.P.A.L.M. 07738 Mexico D.F. (Mexico); Saucedo, E. [Departamento de Fisica de Materiales, Universidad Autonoma de Madrid, Madrid 28049 (Spain); Contreras-Puente, G. [Escuela Superior de Fisica y Matematicas-I.P.N., Edificio de Fisica Avanzada, av. IPN y Juan de Dios Batiz s/n U.P.A.L.M. 07738 Mexico D.F. (Mexico); Bermudez, V. [Departamento de Fisica de Materiales, Universidad Autonoma de Madrid, Madrid 28049 (Spain)

    2007-05-31

    The physical properties of Bi doped CdTe films, grown on glass substrates by the Closed Space Transport Vapour (CSVT) method, from different Bi doped CdTe powders are presented. The CdTe:Bi films were characterized using Photoluminescence, Hall effect, X-Ray diffraction, SEM and Photoconductivity measurements. Moreover, CdS/CdTe:Bi solar cells were made and their characteristics like short circuit current density (J {sub sc}), open circuit voltage (V {sub OC}), fill factor (FF) and efficiency ({eta}) were determined. These devices were fabricated from Bi doped CdTe layers deposited on CdS with the same growth conditions than those used for the single CdTe:Bi layers. A correlation between the CdS/CdTe:Bi solar cell characteristics and the physical properties of the Bi doped CdTe thin films are presented and discussed.

  9. Structural and electrical properties of polycrystalline CdTe films for direct X-ray imaging detectors

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Bo Kyung, E-mail: goldrain99@kaist.ac.kr [Advanced Medical Device Research Center, Korea Electrotechnology Research Institute, Ansan, Repulic of Korea (Korea, Republic of); Yang, Keedong [Advanced Medical Device Research Center, Korea Electrotechnology Research Institute, Ansan, Repulic of Korea (Korea, Republic of); Cha, Eun Seok; Yong, Seok-Min [Department of Materials Science and Engineering, KAIST, Daejeon, Repulic of Korea (Korea, Republic of); Heo, Duchang; Kim, Ryun Kyung; Jeon, Seongchae; Seo, Chang-Woo; Kim, Cho Rong [Advanced Medical Device Research Center, Korea Electrotechnology Research Institute, Ansan, Repulic of Korea (Korea, Republic of); Ahn, Byung Tae [Department of Materials Science and Engineering, KAIST, Daejeon, Repulic of Korea (Korea, Republic of); Lee, Tae-Bum [Advanced Medical Device Research Center, Korea Electrotechnology Research Institute, Ansan, Repulic of Korea (Korea, Republic of)

    2013-12-11

    We introduce polycrystalline cadmium telluride (CdTe) with high atomic number and density, low effective energy and wide band gap for application in large area diagnostic X-ray digital imaging. In this work, polycrystalline CdTe films were fabricated on ITO/glass substrate by both physical vapor deposition (PVD) with slow deposition rate and pressure of 10{sup −6} Torr and the closed space sublimation (CSS) method with high deposition rate and low vacuum pressure(10{sup −2} Torr). The various polycrystalline CdTe films were grown at different deposition rates and substrate temperatures. Physical properties such as microstructures and the crystal structure of the polycrystalline samples were investigated by SEM and XRD patterns respectively. The PVD method resulted in microstructures with columnar shape and more uniform surface, while the CSS method produced microstructures with many larger grains and less uniform surface. The films were polycrystalline structures with a preferential (111) direction. The electrical and optical properties such as the dark current as a function of applied bias voltage and X-ray sensitivity of the fabricated films were measured and investigated under X-ray exposure.

  10. Structural and electrical properties of polycrystalline CdTe films for direct X-ray imaging detectors

    Science.gov (United States)

    Cha, Bo Kyung; Yang, Keedong; Cha, Eun Seok; Yong, Seok-Min; Heo, Duchang; Kim, Ryun Kyung; Jeon, Seongchae; Seo, Chang-Woo; Kim, Cho Rong; Ahn, Byung Tae; Lee, Tae-Bum

    2013-12-01

    We introduce polycrystalline cadmium telluride (CdTe) with high atomic number and density, low effective energy and wide band gap for application in large area diagnostic X-ray digital imaging. In this work, polycrystalline CdTe films were fabricated on ITO/glass substrate by both physical vapor deposition (PVD) with slow deposition rate and pressure of 10-6 Torr and the closed space sublimation (CSS) method with high deposition rate and low vacuum pressure(10-2 Torr). The various polycrystalline CdTe films were grown at different deposition rates and substrate temperatures. Physical properties such as microstructures and the crystal structure of the polycrystalline samples were investigated by SEM and XRD patterns respectively. The PVD method resulted in microstructures with columnar shape and more uniform surface, while the CSS method produced microstructures with many larger grains and less uniform surface. The films were polycrystalline structures with a preferential (111) direction. The electrical and optical properties such as the dark current as a function of applied bias voltage and X-ray sensitivity of the fabricated films were measured and investigated under X-ray exposure.

  11. Co{sub 100−x}Fe{sub x} magnetic thick films prepared by electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Aguirre, M. del C., E-mail: carmenaguirre@famaf.unc.edu.ar [Instituto de Física Enrique Gaviola-Conicet-Facultad de Matemática, Astronomía y Física, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba (Argentina); Farías, E. [Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba (Argentina); Abraham, J.; Urreta, S.E. [Facultad de Matemática, Astronomía y Física, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba (Argentina)

    2015-04-05

    Highlights: • Low iron containing films are compact, with rounded, relatively uniform surfaces. • Larger Fe contents exhibit nanowall networks covering the surface. • Coercivity in the out of plane configuration is larger than in the easy axis direction. • Co-rich films nucleate and grow by a 3DP diffusion controlled mechanism. • For equiatomic Fe{sub 50}Co{sub 50} films, nucleation tends to become instantaneous. - Abstract: Co–Fe films are grown onto plane pre-treated Cu foils; the effects of the alloy composition on the morphology and the crystal texture of the electrodeposited films and their anisotropic magnetic hysteresis properties are explored. Nucleation and crystallization mechanisms in these Co-rich layers are also investigated with pulse-reverse plating techniques, using the first cathodic pulse current–time transients. In the diffusion controlled regime the deposition mechanism is found to involve progressive nucleation with three-dimensional (3D) growth, except for the equiatomic Fe{sub 50}Co{sub 50} solution where nucleation tends to become instantaneous. The different morphologies and size scales observed are described and correlated with coercivity. The films are electrodeposited onto electrochemically pre-treated Cu substrates from feeds of nominal Fe/Co mol ratios between 0/100 and 50/50. The composition of the deposited layers, as determined by energy dispersive X-ray spectroscopy, are quite close to the nominal values. Cyclic voltammetry determinations exhibit only a single reduction process on the cathode, indicating that a unique (Co{sub 100−x}Fe{sub x}) phase grows. Depending on composition and on the substrate pre-treatment, these layers exhibit textures with features of different sizes. X ray diffraction patterns indicate that the nanostructures with Fe contents above 20 at.% crystallize in a body-centered cubic cell, while samples with Fe contents below this value are fcc. Regarding the effect of composition on the

  12. CdTe thin film solar cells produced using a chamberless inline process via metalorganic chemical vapour deposition

    Energy Technology Data Exchange (ETDEWEB)

    Kartopu, G., E-mail: giray.kartopu@glyndwr.ac.uk; Barrioz, V.; Monir, S.; Lamb, D.A.; Irvine, S.J.C.

    2015-03-02

    Cd{sub 1−x}Zn{sub x}S and CdTe:As thin films were deposited using a recently developed chamberless inline process via metalorganic chemical vapour deposition (MOCVD) at atmospheric pressure and assessed for fabrication of CdTe photovoltaic (PV) solar cells. Initially, CdS and Cd{sub 1−x}Zn{sub x}S coatings were applied onto 15 × 15 cm{sup 2} float glass substrates, characterised for their optical properties, and then used as the window layer in CdTe solar cells which were completed in a conventional MOCVD (batch) reactor. Such devices provided best conversion efficiency of 13.6% for Cd{sub 0.36}Zn{sub 0.64}S and 10% for CdS which compare favourably to the existing baseline MOCVD (batch reactor) devices. Next, sequential deposition of Cd{sub 0.36}Zn{sub 0.64}S and CdTe:As films was realised by the chamberless inline process. The chemical composition of a 1 μm CdTe:As/150 nm Cd{sub 0.36}Zn{sub 0.64}S bi-layer was observed via secondary ions mass spectroscopy, which showed that the key elements are uniformly distributed and the As doping level is suitable for CdTe device applications. CdTe solar cells formed using this structure provided a best efficiency of 11.8% which is promising for a reduced absorber thickness of 1.25 μm. The chamberless inline process is non-vacuum, flexible to implement and inherits from the legacy of MOCVD towards doping/alloying and low temperature operation. Thus, MOCVD enabled by the chamberless inline process is shown to be an attractive route for thin film PV applications. - Highlights: • CdS, CdZnS and CdTe thin films grown by a chamberless inline process • The inline films assessed for fabricating CdTe solar cells • 13.6% conversion efficiency obtained for CdZnS/CdTe cells.

  13. The microstructure and magnetic properties of electrodeposited Co-Pt thin films on Ru buffer layer

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, G.H. [School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)], E-mail: skk94@skku.edu; Lee, C.H.; Jang, J.H. [School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Park, N.J. [Department of Materials Science and Engineering, Kumoh National University of Technology, Kumi 730-701 (Korea, Republic of); Suh, S.J. [School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Advanced Materials and Process Research Center for IT, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2008-11-15

    For high-density magnetic recording media, this study examined the crystal structure and the texture of electrodeposited cobalt-platinum (Co-Pt) films on Ru buffer layer. A 15-nm-thick Co-Pt film exhibited very high out-of-plane coercivity and squareness, which were 6248 Oe and 0.89, respectively. The coercivity, H{sub c}, of Co-Pt films grown on Ru buffer layer decreased significantly with increasing thickness, possibly due to the lattice misfit of 5.4% between Co-Pt and Ru, leading to the decrease of perpendicular magnetic anisotropy (PMA) of Co-Pt films as indicated by the observed hexagonal-closed-packed (HCP) (1 1-bar 0 1) plane of Co-Pt films. According to nano beam diffraction pattern (NBDP), however, Co-Pt film grown on Ru layer of HCP exhibited mixed HCP and FCC phases. Also, cross-sectional TEM image suggests that the high PMA may result from the columnar structure of physically isolated Co-Pt grains with the c-axis perpendicular to the film plane.

  14. Characterization of Electrodeposited Nanoporous Ni and NiCu Films

    Science.gov (United States)

    Koboski, Kyla; Hampton, Jennifer

    2013-03-01

    Nanoporous thin films are interesting candidates to catalyze certain reactions because of their large surface areas. This project focuses on the deposition of Ni and NiCu thin films on a Au substrate and further explores the catalysis of the hydrogen evolution reaction (HER). Depositions are created using controlled potential electrolysis. Samples are then dealloyed using linear sweep voltammetry. Before and after the dealloying, all the samples are characterized using multiple techniques. Electrochemical capacitance measurements allow comparisons of sample roughness. HER measurements characterize the reactivity of the sample with respect to the specific catalytic reaction. The Tafel equation is fit to the data to obtain information about the kinetics of the HER of the samples. Other methods for characterizing the samples include scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The use of SEM allows images to be taken of the deposition to determine the change in the structure pre- and post- dealloy of the sample. EDS allows the elemental composition of the deposition to be determined before and after the dealloy stage. This material is based upon work supported by the National Science Foundation under RUI Grant DMR-1104725, MRI Grant CHE-1126462, MRI Grant CHE-0959282, and ARI grant PHY-0963317.

  15. High efficiency thin film CdTe and a-Si based solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Compaan, A. D.; Deng, X.; Bohn, R. G.

    2000-01-04

    This report describes work done by the University of Toledo during the first year of this subcontract. During this time, the CdTe group constructed a second dual magnetron sputter deposition facility; optimized reactive sputtering for ZnTe:N films to achieve 10 ohm-cm resistivity and {approximately}9% efficiency cells with a copper-free ZnTe:N/Ni contact; identified Cu-related photoluminescence features and studied their correlation with cell performance including their dependence on temperature and E-fields; studied band-tail absorption in CdS{sub x}Te{sub 1{minus}x} films at 10 K and 300 K; collaborated with the National CdTe PV Team on (1) studies of high-resistivity tin oxide (HRT) layers from ITN Energy Systems, (2) fabrication of cells on the HRT layers with 0, 300, and 800-nm CdS, and (3) preparation of ZnTe:N-based contacts on First Solar materials for stress testing; and collaborated with Brooklyn College for ellipsometry studies of CdS{sub x}Te{sub 1{minus}x} alloy films, and with the University of Buffalo/Brookhaven NSLS for synchrotron X-ray fluorescence studies of interdiffusion in CdS/CdTe bilayers. The a-Si group established a baseline for fabricating a-Si-based solar cells with single, tandem, and triple-junction structures; fabricated a-Si/a-SiGe/a-SiGe triple-junction solar cells with an initial efficiency of 9.7% during the second quarter, and 10.6% during the fourth quarter (after 1166 hours of light-soaking under 1-sun light intensity at 50 C, the 10.6% solar cells stabilized at about 9%); fabricated wide-bandgap a-Si top cells, the highest Voc achieved for the single-junction top cell was 1.02 V, and top cells with high FF (up to 74%) were fabricated routinely; fabricated high-quality narrow-bandgap a-SiGe solar cells with 8.3% efficiency; found that bandgap-graded buffer layers improve the performance (Voc and FF) of the narrow-bandgap a-SiGe bottom cells; and found that a small amount of oxygen partial pressure ({approximately}2 {times} 10

  16. Characterization of CdTe films with in situ CdCl{sub 2} treatment grown by a simple vapor phase deposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Rios Flores, Araceli, E-mail: arios@mda.cinvestav.mx [Applied Physics Department, CINVESTAV-IPN Merida, C.P. 97310 Merida, Yucatan (Mexico); Castro-Rodriguez, R.; Pena, J.L. [Applied Physics Department, CINVESTAV-IPN Merida, C.P. 97310 Merida, Yucatan (Mexico); Romeo, N.; Bosio, A. [Dipartimento di fisica, Universita di Parma, Campus Universitario, Parco Area delle Scienza, 43100 Parma (Italy)

    2009-05-15

    A unique vapor phase deposition (VPD) technique was designed and built to achieve in situ CdCl{sub 2} treatment of CdTe film. The substrate temperature was 400 deg. C, and the temperature of CdTe mixture with CdCl{sub 2} source was 500 deg. C. The structural and morphological properties of CdTe have been studied as a function of wt.% CdCl{sub 2} concentration by using X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). XRD measurements show that the presence of CdCl{sub 2} vapor induces (1 1 1)-oriented growth in the CdTe film. SEM measurements have shown enhance growth of grains, in the presence of CdCl{sub 2}. From AFM the roughness of the films showed a heavy dependence on CdCl{sub 2} concentration. In the presence of 4% CdCl{sub 2} concentration, the CdTe films roughness has a root mean square (rms) value of about 275 A. This value is about 831 A for the non-treated CdTe films.

  17. Characterization of CdTe films with in situ CdCl 2 treatment grown by a simple vapor phase deposition technique

    Science.gov (United States)

    Flores, Araceli Rios; Castro-Rodríguez, R.; Peña, J. L.; Romeo, N.; Bosio, A.

    2009-05-01

    A unique vapor phase deposition (VPD) technique was designed and built to achieve in situ CdCl 2 treatment of CdTe film. The substrate temperature was 400 °C, and the temperature of CdTe mixture with CdCl 2 source was 500 °C. The structural and morphological properties of CdTe have been studied as a function of wt.% CdCl 2 concentration by using X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). XRD measurements show that the presence of CdCl 2 vapor induces (1 1 1)-oriented growth in the CdTe film. SEM measurements have shown enhance growth of grains, in the presence of CdCl 2. From AFM the roughness of the films showed a heavy dependence on CdCl 2 concentration. In the presence of 4% CdCl 2 concentration, the CdTe films roughness has a root mean square (rms) value of about 275 Å. This value is about 831 Å for the non-treated CdTe films.

  18. Influence of thickness on physical properties of vacuum evaporated polycrystalline CdTe thin films for solar cell applications

    Science.gov (United States)

    Chander, Subhash; Dhaka, M. S.

    2016-02-01

    This paper presents the influence of thickness on physical properties of polycrystalline CdTe thin films. The thin films of thickness 450 nm, 650 nm and 850 nm were deposited employing thermal vacuum evaporation technique on glass and indium tin oxide (ITO) coated glass substrates. The physical properties of these as-grown thin films were investigated employing the X-ray diffraction (XRD), source meter, UV-Vis spectrophotometer, scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS). The structural analysis reveals that the films have zinc-blende cubic structure and polycrystalline in nature with preferred orientation (111). The structural parameters like lattice constant, interplanar spacing, grain size, strain, dislocation density and number of crystallites per unit area are calculated. The average grain size and optical band gap are found in the range 15.16-21.22 nm and 1.44-1.63 eV respectively and observed to decrease with thickness. The current-voltage characteristics show that the electrical conductivity is observed to decrease with thickness. The surface morphology shows that films are free from crystal defects like pin holes and voids as well as homogeneous and uniform. The EDS patterns show the presence of cadmium and tellurium elements in the as grown films. The experimental results reveal that the film thickness plays significant role on the physical properties of as-grown CdTe thin films and higher thickness may be used as absorber layer to solar cells applications.

  19. Controlled electrodeposition of Au monolayer film on ionic liquid

    Science.gov (United States)

    Ma, Qiang; Pang, Liuqing; Li, Man; Zhang, Yunxia; Ren, Xianpei; Liu, Shengzhong Frank

    2016-05-01

    Gold (Au) nanoparticles have been attractive for centuries for their vibrant appearance enhanced by their interaction with sunlight. Nowadays, there have been tremendous research efforts to develop them for high-tech applications including therapeutic agents, sensors, organic photovoltaics, medical applications, electronics and catalysis. However, there remains to be a challenge to fabricate a monolayer Au coating with complete coverage in controlled fashion. Here we present a facile method to deposit a uniform Au monolayer (ML) film on the [BMIM][PF6] ionic liquid substrate using an electrochemical deposition process. It demonstrates that it is feasible to prepare a solid phase coating on the liquid-based substrate. Moreover, the thickness of the monolayer coating can be controlled to a layer-by-layer accuracy.

  20. Nanostructured superhydrophobic films synthesized by electrodeposition of fluorinated polyindoles

    Science.gov (United States)

    Ramos Chagas, Gabriela; Darmanin, Thierry

    2015-01-01

    Summary Materials with bioinspired superhydrophobic properties are highly desirable for many potential applications. Here, nine novel monomers derived from indole are synthesized to obtain these properties by electropolymerization. These monomers differ by the length (C4F9, C6F13 and C8F17) and the position (4-, 5- and 6-position of indole) of the perfluorinated substituent. Polymeric films were obtained with C4F9 and C6F13 chains and differences in the surface morphology depend especially on the substituent position. The polyindoles exhibited hydrophobic and superhydrophobic properties even with a very low roughness. The best results are obtained with PIndole-6-F 6 for which superhydrophobic and highly oleophobic properties are obtained due to the presence of spherical nanoparticles and low surface energy compounds. PMID:26665079

  1. Sputtered CdTe thin film solar cells with Cu{sub 2}Te/Au back contact

    Energy Technology Data Exchange (ETDEWEB)

    Park, Yongseob [Department of Photoelectronics Information, Chosun College of Science and Technology, Pilmudaero 309-1, Dong-gu, Gwangju 501-744 (Korea, Republic of); Lee, Suho; Yi, Junsin; Choi, Byung-Duck [School of Electronic and Electrical Engineering, Sungkyunkwan University, Cheoncheon-dong 300, Jangan-gu, Suwon 440-746 (Korea, Republic of); Kim, Doyoung [School of Electricity and Electronics, Ulsan College, Daehak-ro 57, Nam-gu, Ulsan 680-749 (Korea, Republic of); Lee, Jaehyeong, E-mail: jaehyeong@skku.edu [School of Electronic and Electrical Engineering, Sungkyunkwan University, Cheoncheon-dong 300, Jangan-gu, Suwon 440-746 (Korea, Republic of)

    2013-11-01

    In this work, Cu{sub 2}Te/Au back contact for CdTe thin film solar cells were prepared by vacuum evaporation. Influence of annealing temperature on the structure and electrical properties of Cu{sub 2}Te films were investigated by field emission scanning electron microscope, X-ray diffraction, and Hall effect measurement. Also, CdS/CdTe thin film solar cells were fabricated by magnetron sputtering process, which is favorable for large area deposition and mass production, and the photovoltaic characteristics were studied. As the annealing temperature was increased, the crystal structure transformed from Cu{sub 2}Te for as-deposited film to Cu{sub 2−x}Te hexagonal phase, and the grains in the film became bigger. The electrical resistivity was slightly higher by the annealing. The cell efficiency was significantly improved by the heat treatment, and showed a maximum value of 9.14% at 180 °C. From these results, Cu{sub 2}Te/Au contact acts as the proper pseudo-ohmic contact onto CdTe film. However, further increase of annealing temperature caused the deterioration of cell performance. - Highlights: • Annealing effects of the vacuum evaporated Cu{sub 2}Te films were investigated. • The transformation from Cu{sub 2}Te to Cu{sub 2−x}Te hexagonal phase occurred by annealing. • The performance of the solar cell was highly increased by annealing at 180 °C. • Cu{sub 2}Te/Au contact acts as the proper pseudo-ohmic contact onto CdTe film.

  2. Extremely durable biofouling-resistant metallic surfaces based on electrodeposited nanoporous tungstite films on steel

    Science.gov (United States)

    Tesler, Alexander B.; Kim, Philseok; Kolle, Stefan; Howell, Caitlin; Ahanotu, Onye; Aizenberg, Joanna

    2015-10-01

    Formation of unwanted deposits on steels during their interaction with liquids is an inherent problem that often leads to corrosion, biofouling and results in reduction in durability and function. Here we report a new route to form anti-fouling steel surfaces by electrodeposition of nanoporous tungsten oxide (TO) films. TO-modified steels are as mechanically durable as bare steel and highly tolerant to compressive and tensile stresses due to chemical bonding to the substrate and island-like morphology. When inherently superhydrophilic TO coatings are converted to superhydrophobic, they remain non-wetting even after impingement with yttria-stabilized-zirconia particles, or exposure to ultraviolet light and extreme temperatures. Upon lubrication, these surfaces display omniphobicity against highly contaminating media retaining hitherto unseen mechanical durability. To illustrate the applicability of such a durable coating in biofouling conditions, we modified naval construction steels and surgical instruments and demonstrated significantly reduced marine algal film adhesion, Escherichia coli attachment and blood staining.

  3. A study on electrodeposited NiFe1− alloy films

    Indian Academy of Sciences (India)

    M Bedir; Ö F Bakkaloğlu; İ H Karahan; M Öztaş

    2006-06-01

    NiFe1− (0.22 ≤ ≤ 0.62) alloy films were grown by electrodeposition technique. A shift in diffraction peaks of NiFe and Ni3Fe was detected with increasing Ni content. The highest positive magnetoresistance ratio was detected as 5% in Ni0.51Fe0.49. Positive and negative anisotropic magnetoresistance were observed in longitudinal and transverse geometries respectively. The highest anisotropic magnetoresistance ratio of 9.8% was also detected in Ni0.51Fe0.49. The angular variation of magnetoresistance was studied. Magnetisation loop curves show that NiFe alloy films have a linear decreasing anisotropy constant with increasing Ni deposit content and show a decreasing behavior of coercivity which indicates soft magnetic property with increasing Ni deposit content.

  4. Extremely durable biofouling-resistant metallic surfaces based on electrodeposited nanoporous tungstite films on steel.

    Science.gov (United States)

    Tesler, Alexander B; Kim, Philseok; Kolle, Stefan; Howell, Caitlin; Ahanotu, Onye; Aizenberg, Joanna

    2015-10-20

    Formation of unwanted deposits on steels during their interaction with liquids is an inherent problem that often leads to corrosion, biofouling and results in reduction in durability and function. Here we report a new route to form anti-fouling steel surfaces by electrodeposition of nanoporous tungsten oxide (TO) films. TO-modified steels are as mechanically durable as bare steel and highly tolerant to compressive and tensile stresses due to chemical bonding to the substrate and island-like morphology. When inherently superhydrophilic TO coatings are converted to superhydrophobic, they remain non-wetting even after impingement with yttria-stabilized-zirconia particles, or exposure to ultraviolet light and extreme temperatures. Upon lubrication, these surfaces display omniphobicity against highly contaminating media retaining hitherto unseen mechanical durability. To illustrate the applicability of such a durable coating in biofouling conditions, we modified naval construction steels and surgical instruments and demonstrated significantly reduced marine algal film adhesion, Escherichia coli attachment and blood staining.

  5. Characterization of electrodeposited Zn1-xHgxSe thin films

    Science.gov (United States)

    Mahalingam, T.; Kathalingam, A.; Velumani, S.; Lee, Soonil; Seek Lew, Kyeung; Deak Kim, Yong

    2005-08-01

    In this work the synthesis of zinc mercury selenide thin films (Zn1-xHgxSe) by electrodeposition is carried out. The films were deposited onto conducting glass (SnO2) substrates from an aqueous solution bath containing ZnSO4, HgCl2 and SeO2 at bath temperatures between 30 °C and 70 °C. The influence of deposition parameters such as electrolyte composition, deposition potential and temperature on the crystallinity and composition of the films is studied. It is found that the amount of mercury content in the solution bath and deposition potential control the composition and structure of the alloy films. The films were characterized by x-ray diffraction (XRD), energy dispersive x-ray analysis (EDAX), optical absorption and scanning electron microscope (SEM) studies. Photoelectrochemical solar cells studies using Zn1-xHgxSe thin films showed improved performance for annealed and etched electrodes and the results are discussed.

  6. Physical and electrical characteristics of NiFe thin films using ultrasonic assisted pulse electrodeposition

    Science.gov (United States)

    Asa Deepthi, K.; Balachandran, R.; Ong, B. H.; Tan, K. B.; Wong, H. Y.; Yow, H. K.; Srimala, S.

    2016-01-01

    Nickel iron (NiFe) thin films were prepared on the copper substrate by ultrasonic assisted pulse electrodeposition under galvanostatic mode. Careful control of the thin films deposition is essential as the electrical properties of the films could be greatly affected, particularly if low quality films are produced. The preparation of NiFe/Cu thin films was aimed to reduce the grain size of NiFe particles, surface roughness and electrical resistivity of the copper substrates. Various parameters were systematically studied including current magnitude, deposition time and ultrasonic bath temperature. The optimized conditions to obtain NiFe permalloy, which subsequently applied to all investigated samples, were found at a current magnitude of 70 mA deposited for a duration of 2 min under ultrasonic bath temperature of 27 °C. The composition of NiFe permalloy was as close as Ni 80.71% and Fe 19.29% and the surface roughness was reduced from 12.76 nm to 2.25 nm. The films electrical resistivity was decreased nearly sevenfold from an initial value of 67.32 μΩ cm to 9.46 μΩ cm.

  7. Electrodeposition of nickel from low temperature sulfamate electrolytes.Part 1 :Electrochemistry and film stress.

    Energy Technology Data Exchange (ETDEWEB)

    Hachman, John T.; Kelly, J.J. (IBM/T.J. Watson Research Center, Yorktown Heights, NY); Talin, Albert Alec; Goods, Steven Howard

    2005-11-01

    The film stress of Ni films deposited at near-ambient temperatures from sulfamate electrolytes was studied. The particulate filtering of the electrolyte, a routine industrial practice, becomes an important deposition parameter at lower bath temperatures. At 28 C, elevated tensile film stress develops at low current densities (<10 mA/cm{sup 2}) if the electrolyte is filtered. Filtering at higher current densities has a negligible effect on film stress. A similar though less pronounced trend is observed at 32 C. Sulfate-based Ni plating baths display similar film stress sensitivity to filtering, suggesting that this is a general effect for Ni electrodeposition. It is shown that filtering does not significantly change the current efficiency or the pH near the surface during deposition. The observed changes in film stress are thus attributed not to adsorbed hydrogen but instead to the effects of filtering on the formation and concentration of polyborate species due to the decreased solubility of boric acid at near-ambient temperatures.

  8. Electrodeposition of Er-Ni Alloy Film in Dimethylsulfoxide

    Institute of Scientific and Technical Information of China (English)

    李高仁; 童叶翔; 刘冠昆

    2002-01-01

    The cyclic voltammetry and chronoamperometry were used to investigate the electrochemical behaviors of Er(Ⅲ) and Ni(Ⅱ) in LiClO4-DMSO(dimethylsufoxide) system on Pt and Cu electrodes. Experimental results indicated that the reduction of Er(Ⅲ) to Er and Ni(Ⅱ) to Ni were irreversible in one step on Pt and Cu electrodes. The diffusion coefficient and electron transfer coefficient of Er(Ⅲ) in 0.01 mol*L-1 ErCl3 -0.1 mol*L-1 LiClO4-DMSO system at 303K were 1.47×10-10 m2*s-1 and 0.108 respectively, and the diffusion coefficient and electron transfer coefficient of Ni(Ⅱ) in 0.01 mol*L-1 NiCl2-0.1 mol*L-1 LiClO4-DMSO system at 303K were 3.38×10-10 m2*s-1 and 0.160 respectively. The homogeneous, strong adhesive Er-Ni alloy films with metallic lu- stre was prepared by potentiostatic electrolysis on Cu electrode in ErCl3-NiCl2-LiClO4-DMSO system at -1.90~-2.55 V (vs SCE).

  9. Review of Photovoltaic Energy Production Using CdTe Thin-Film Modules: Extended Abstract Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Gessert, T. A.

    2008-09-01

    CdTe has near-optimum bandgap, excellent deposition traits, and leads other technologies in commercial PV module production volume. Better understanding materials properties will accelerate deployment.

  10. CdTe devices and method of manufacturing same

    Energy Technology Data Exchange (ETDEWEB)

    Gessert, Timothy A.; Noufi, Rommel; Dhere, Ramesh G.; Albin, David S.; Barnes, Teresa; Burst, James; Duenow, Joel N.; Reese, Matthew

    2015-09-29

    A method of producing polycrystalline CdTe materials and devices that incorporate the polycrystalline CdTe materials are provided. In particular, a method of producing polycrystalline p-doped CdTe thin films for use in CdTe solar cells in which the CdTe thin films possess enhanced acceptor densities and minority carrier lifetimes, resulting in enhanced efficiency of the solar cells containing the CdTe material are provided.

  11. Influence of deposition parameters on the properties of CdTe films deposited by close spaced sublimation

    Directory of Open Access Journals (Sweden)

    Vivienne Denise Falcão

    2006-03-01

    Full Text Available CdTe thin films are used as absorber layer in CdS/CdTe solar cells. The microstructure of this absorber layer plays a fundamental role in photovoltaic conversion and can be controlled by the deposition parameters used during the film growth. In this work, CdTe thin films were deposited by the CSS method onto glass substrates previously covered with In2O3:Sn. The effects of pressure, source temperature and substrate temperature on the microstructural properties of the films were studied. The properties were mainly influenced by the pressure, the presence of oxygen in the reaction chamber, and the substrate temperature. For films deposited under an argon atmosphere, an increase in grain size and a reduction of the texture were observed as the pressure and substrate temperature were increased. The introduction of oxygen in the atmosphere led to a decrease in the deposition rate and affected the microstructure and composition of the film. Films deposited under an argon-oxygen atmosphere have smaller grains than those deposited under argon and are richer in Te. The addition of oxygen to the atmosphere apparently did not result in the formation of oxides.

  12. The growth of CdTe thin film by close space sublimation system

    Science.gov (United States)

    Alamri, S. N.

    2003-12-01

    The effects of source and substrate temperature, ambient gas pressure and the separation between source and substrate on the growth rate of CdTe using the close space sublimation (CSS) system have been investigated. The growth rate increased as the source temperature increased with an activation energy of 1.9 eV and it was constant and independent of the substrate temperature, up to some breakpoint temperature, above which the rate decreased rapidly to zero. Free sublimation and transport is involved at low pressures such as 7.5 × 10-5 mbar, whereas diffusion-limited transport was involved at pressures of 2 and 6 mbar of N2. The growth rate increased as the separation between the source and the substrate decreased. The film's grain size increased from <1 m at 335 °C to more than 2.5 m at above 445 °C. Analysis of the XRD traces indicated that the films grown at 335 °C were a highly preferred (111) orientation and the (111) texture coefficient reduced when the substrate temperature increased. (

  13. Stoichiometry dependence of the optical and minority-carrier lifetime behaviors of CdTe epitaxial films: A low-temperature and time-resolved photoluminescence study

    Science.gov (United States)

    Tang, Kai; Zhu, Xuanting; Zhu, Liangqing; Bai, Wei; Bai, Jiawei; Dong, Wenxia; Yang, Jing; Zhang, Yuanyuan; Chen, Ye; Tang, Xiaodong; Chu, Junhao

    2016-11-01

    Cadmium telluride (CdTe) epitaxial films (EFs) were grown on near-lattice-matched Cd0.96Zn0.04Te (CZT) substrates by molecular beam epitaxy at different ambients to achieve Cd-rich samples with extra Cd molecular flux or Te-rich samples with extra Te molecular flux. The evolution of epitaxial growth was in situ monitored by reflection high-energy electron diffraction (RHEED). A two-dimensional growth mode was indicated by the streaky RHEED patterns. Crystal structures of the CdTe EFs were characterised by X-ray diffraction (XRD). XRD data suggested that the crystal quality of the CdTe EFs was improved by controlling the Cd and Te flux ratio. Low-temperature photoluminescence (PL) spectra were carried out in these CdTe EFs. The typical characteristic peak at ∼1.552 eV denoted as the bound-to-free transition was only found in CdTe samples grown under an extra Cd flux, and Cd vacancy-related defects were absent in the Cd-rich EFs, confirming the Cd-rich or Te-rich states of the epitaxial CdTe films. Finally, minority-carrier lifetime was prolonged in Cd-rich CdTe EFs as supported by time-resolved photoluminescence (TRPL) measurement.

  14. Structural and optical properties of Cu{sub 2}O crystalline electrodeposited films

    Energy Technology Data Exchange (ETDEWEB)

    Brandt, Iuri S.; Martins, Cesar A.; Zoldan, Vinicius C.; Viegas, Alexandre D.C. [Laboratório de Filmes Finos e Superfícies, Departamento de Física, Universidade Federal de Santa Catarina, Florianópolis-SC 88040-900 (Brazil); Dias da Silva, José H. [Laboratório de Filmes Semicondutores, Faculdade de Ciências, Universidade Estadual Paulista, Bauru-SP 17033-360 (Brazil); Pasa, André A., E-mail: andre.pasa@ufsc.br [Laboratório de Filmes Finos e Superfícies, Departamento de Física, Universidade Federal de Santa Catarina, Florianópolis-SC 88040-900 (Brazil)

    2014-07-01

    Cuprous oxide (Cu{sub 2}O) films were electrodeposited on Ni/Si(100), Au/Si(100), and Si(100) substrates from aqueous solution at room temperature. The thicknesses of the films were varied in the range of 250 to 1250 nm. It was shown that at pH 10.00, an increase of just 1% can change the Cu{sub 2}O texture from [100] to [111]. Atomic force microscopy reveals that Cu{sub 2}O(100) and Cu{sub 2}O(111) films present rounded and faceted grains, respectively. For the thinner films, it was also observed that the substrate has a strong influence on the Cu{sub 2}O orientation. The Cu{sub 2}O refraction index (n) and band gap energy (E{sub g}) were obtained from reflectance measurements. The Wemple and DiDomenico single oscillator model was applied to n data, and the dispersion energy E{sub d} of this model was addressed to describe the density of Cu vacancies in the Cu{sub 2}O lattice. It was found out that the density of this kind of defect is higher for [111] oriented Cu{sub 2}O films and decreases as a function of the film thickness. This analysis also indicated that the dynamics of formation of the Cu vacancy depends on the Cu{sub 2}O lattice parameter. This parameter showed that Cu{sub 2}O films are initially under compressive misfit stress, but at a critical thickness, the lattice parameter abruptly increases in order to relax the Cu{sub 2}O lattice structure. This sudden transition is also observed in the E{sub g} data and is attributed to the enhancement of Cu–Cu internetwork interaction that is inversely proportional to E{sub g}. - Highlights: • Cu{sub 2}O films were electrodeposited on Au/Si(100), Ni/Si(100), and Si(100) substrates. • Growth orientation can be selected by small changes of 1% on electrolyte pH. • Cu–Cu internetwork strengthening reduces Cu{sub 2}O band gap energy. • We report that Wemple–DiDomenico model can describe density of Cu vacancies (V{sub Cu}). • Density of V{sub Cu} in Cu{sub 2}O lattice depends strongly on deposition

  15. A study on the electrodeposition of NiFe alloy thin films using chronocoulometry and electrochemical quartz crystal microgravimetry

    CERN Document Server

    Myung, N S

    2001-01-01

    Ni, Fe and NiFe alloy thin films were electrodeposited at a polycrystalline Au surface using a range of electrolytes and potentials. Coulometry and EQCM were used for real-time monitoring of electroplating efficiency of the Ni and Fe. The plating efficiency of NiFe alloy thin films was computed with the aid of ICP spectrometry. In general, plating efficiency increased to a steady value with deposition time. Plating efficiency of Fe was lower than that of Ni at -0.85 and -1.0 V but the efficiency approached to the similar plateau value to that of Ni at more negative potentials. The films with higher content of Fe showed different stripping behavior from the ones with higher content of Ni. Finally, compositional data and real-time plating efficiency are presented for films electrodeposited using a range of electrolytes and potentials.

  16. Structural characterization of InSb thin films grown by electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-06-24

    In the present work we have grown InSb thin films on brass substrates, using the electrodeposition technique. The electrochemical baths used in the growth were made up of aqueous solutions of InCl{sub 3} and SbCl{sub 3} mixed together in various proportions. The films grown were characterized by X-Ray diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive Analysis of X-rays (EDAX). Compositional studies show that stoichiometric InSb films can be prepared from a bath containing 0.05M InCl{sub 3} and 0.04M SbCl{sub 3}. XRD studies reveal that the films grown are polycrystalline having the zinc blende structure with (111) orientation. Crystallite size, dislocation density and strain were calculated using the XRD results. Optical transmission spectra were recorded using an FTIR spectrophotometer. The value of direct band gap was found to be around 0.20 eV for the thin films having the best stoichiometry.

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

    Indian Academy of Sciences (India)

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

    2013-08-01

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

  18. Easy Formation of Nanodisk-Dendritic ZnO Film via Controlled Electrodeposition Process

    Directory of Open Access Journals (Sweden)

    Nur Azimah Abd Samad

    2015-01-01

    Full Text Available A facile electrodeposition synthesis was introduced to prepare the nanodisk-dendritic ZnO film using a mixture solution of zinc chloride (ZnCl2 with potassium chloride (KCl that acted as a directing agent. This study aims to determine the best photoelectrochemical response for solar-induced water splitting. Based on our results obtained, it was found that an average diagonal of nanodisk was approximately 1.70 µm with the thickness of ≈150 nm that was successfully grown on the surface of substrate. The photocatalytic and photoelectrochemical responses of the resultant wurtzite type based-nanodisk-dendrite ZnO film as compared to the as-prepared ZnO film were monitored and evaluated. A photocurrent density of 19.87 mA/cm2 under ultraviolet rays and 14.05 mA/cm2 under visible light (500 nm was recorded for the newly developed nanodisk-dendritic ZnO thin film. It was believed that nanodisk-dendritic ZnO film can harvest more incident photons from the illumination to generate more photoinduced charge carriers to trigger the photocatalytic and photoelectrochemical reactions. Moreover, strong light scattering effects and high specific surface area of 2D nanostructures aid in the incident light absorption from any direction.

  19. Electrodeposition and characterization of undoped and nitrogen-doped ZnSe films

    Energy Technology Data Exchange (ETDEWEB)

    Manzoli, A., E-mail: alexandra@cnpdia.embrapa.br [Institute of Chemistry of Sao Carlos (IQSC) - University of Sao Paulo (USP), P. O. Box 780, 13560-970, Sao Carlos, SP (Brazil); National Nanotechnology Laboratory for Agribusiness (LNNA), Embrapa Agricultural Instrumentation, P. O. Box 741, 13560-970, Sao Carlos, SP (Brazil); Eguiluz, K.I.B.; Salazar-Banda, G.R. [Institute of Chemistry of Sao Carlos (IQSC) - University of Sao Paulo (USP), P. O. Box 780, 13560-970, Sao Carlos, SP (Brazil); Institute of Technology and Research/University of Tiradentes, Av. Murilo Dantas, 300, 49032-490, Aracaju, SE (Brazil); Machado, S.A.S. [Institute of Chemistry of Sao Carlos (IQSC) - University of Sao Paulo (USP), P. O. Box 780, 13560-970, Sao Carlos, SP (Brazil)

    2010-05-15

    Semiconducting films of (n-type) ZnSe and (p-type) nitrogen-doped ZnSe were electrodeposited by a linear-sweep voltammetric technique on to a substrate of fluorine-tin oxide (FTO) glass ceramics. The films were characterized by scanning electron microscopy, energy-dispersive X-ray analysis and grazing-incidence X-ray diffraction. The results indicated that the material was deposited uniformly over the substrate, forming clusters when the Zn content of the bath was 0.1 mol L{sup -1} and a film when it was 0.2 or 0.3 mol L{sup -1}. The effectiveness of doping the films with nitrogen by adding ammonium sulfate to the deposition solution was assessed by measuring the film-electrolyte interface capacitance (C) at various applied potentials (E{sub ap}) and plotting Mott-Schottky curves (C{sup -2} vs E{sub ap}), whose slope sign was used to identify p-type ZnSe.

  20. Wiring-up carbon single wall nanotubes to polycrystalline inorganic semiconductor thin films: low-barrier, copper-free back contact to CdTe solar cells.

    Science.gov (United States)

    Phillips, Adam B; Khanal, Rajendra R; Song, Zhaoning; Zartman, Rosa M; DeWitt, Jonathan L; Stone, Jon M; Roland, Paul J; Plotnikov, Victor V; Carter, Chad W; Stayancho, John M; Ellingson, Randall J; Compaan, Alvin D; Heben, Michael J

    2013-11-13

    We have discovered that films of carbon single wall nanotubes (SWNTs) make excellent back contacts to CdTe devices without any modification to the CdTe surface. Efficiencies of SWNT-contacted devices are slightly higher than otherwise identical devices formed with standard Au/Cu back contacts. The SWNT layer is thermally stable and easily applied with a spray process, and SWNT-contacted devices show no signs of degradation during accelerated life testing.

  1. Influence of bath composition on the electrodeposition of cobalt-molybdenum amorphous alloy thin films

    Institute of Scientific and Technical Information of China (English)

    Qiaoying Zhou; Hongliang Ge; Guoying Wei; Qiong Wu

    2008-01-01

    Cobalt-molybdenum (Co-Mo) amorphous alloy thin films were deposited on copper substrates by the electrochemical method at pH 4.0. Among the experimental electrodeposition parameters, only the concentration ratio of molybdate to cobalt ions ([ MoO2-4 ]/[CO2+]) was varied to analyze its influence on the mechanism of induced cobalt-molybdenum codeposition. Voltammetry was one of the main techniques, which was used to examine the voltammetric response, revealing that cobalt-molybdenum codeposi-tion depended on the nature of the species in solution. To correlate the type of the film to the electrochemical response, various co-bait-molybdenum alloy thin films obtained from different [ MoO2-4]/[Co2+] solutions were tested. Crack-free homogeneous films could be easily obtained from the low molybdate concentrations ([ MoO2-4]/[Co2+]≈0.05) applying low deposition potentials.Moreover, the content of molybdenum up to 30wt% could be obtained from high molybdate concentration; in this case, the films showed cracks. The formation of these cracked films could be predicted from the observed distortions in the curves of electric cur-rent-time (j-t) deposition transients. The films with amorphous stmeture were obtained. The hysteresis loops suggested that the easily film were obtained when the deposition potential was -1025 mV, and [ MoO2-4]/[Co2+] was 0.05 in solution, which exhibited a nicer soft-magnetic response.

  2. Adsorption of organic layers over electrodeposited magnetite (Fe{sub 3}O{sub 4}) thin films

    Energy Technology Data Exchange (ETDEWEB)

    Cortes, M., E-mail: m.cortes@ub.ed [Electrodep, Departament de Quimica Fisica and Institut de Nanociencia i Nanotecnologia (IN2UB), Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain); Gomez, E. [Electrodep, Departament de Quimica Fisica and Institut de Nanociencia i Nanotecnologia (IN2UB), Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain); Sadler, J. [H.H. Wills Physics Laboratory, Royal Fort, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Valles, E. [Electrodep, Departament de Quimica Fisica and Institut de Nanociencia i Nanotecnologia (IN2UB), Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain)

    2011-04-15

    Research highlights: {yields} Adherent low roughness magnetite films ranging from 80 nm to 3.75 {mu}m-thick were electrodeposited on Au/glass substrates under galvanostatic control. {yields} X-ray diffraction and magnetic measurements corroborates the purity of the electrodeposited magnetite. {yields} Both dodecanethiol and oleic acid are shown to adsorb on the magnetite prepared at low temperature, significantly inducing the hydrophobicity of the surface. {yields} Contact angle and voltammetric measurements, as well as XPS confirm the monolayers formation. - Abstract: The formation of monolayers of two organic compounds (oleic acid and dodecanethiol) over magnetite films was studied. Magnetite films ranging from 80 nm to 3.75 {mu}m-thick were electrodeposited on Au on glass substrates under galvanostatic control, with deposition parameters optimized for minimum surface roughness. Films were characterised by SEM and AFM, showing granular deposits with a low rms roughness of 5-40 nm measured over an area of 1 {mu}m{sup 2}. The growth rate was estimated by measuring cross-sections of the thin films. Pure magnetite with an fcc structure is observed in XRD diffractograms. The adsorption of both oleic acid and dodecanethiol on the magnetite films was tested by immersing them in ethanol solutions containing the organic molecules, for different deposition time, temperature and cleaning procedure. Monolayer formation in both cases was studied by contact angle and voltammetric measurements, as well as XPS.

  3. Optical and structural characterization of oleic acid-stabilized CdTe nanocrystals for solution thin film processing

    OpenAIRE

    Claudio Davet Gutiérrez-Lazos; Mauricio Ortega-López; Manuel A. Pérez-Guzmán; A. Mauricio Espinoza-Rivas; Francisco Solís-Pomar; Rebeca Ortega-Amaya; L. Gerardo Silva-Vidaurri; Castro-Peña, Virginia C; Eduardo Pérez-Tijerina

    2014-01-01

    This work presents results of the optical and structural characterization of oleic acid-stabilized cadmium telluride nanocrystals (CdTe-NC) synthesized by an organometallic route. After being cleaned, the CdTe-NC were dispersed in toluene to obtain an ink-like dispersion, which was drop-cast on glass substrate to deposit a thin film. The CdTe-NC colloidal dispersion as well as the CdTe drop-cast thin films were characterized with regard to the optical and structural properties. TEM analysis i...

  4. Non-coherent growth patches in pseudomorphic films: Unusual strain relief in electrodeposited Co on Cu(001)

    DEFF Research Database (Denmark)

    Schindler, W.; Koop, T.; Kazimirov, A.

    2000-01-01

    The critical thickness for pseudomorphic Co growth on Cu(001) is found to be independent of the onset of lattice constant relaxation. The pseudomorphic film relieves strain by local formation of orthomorphic growth patches within the pseudomorphic matrix. This unusual relaxation mechanism...... of electrodeposited films is in contrast to current belief of film relaxation. Moreover, a tetragonal distortion of the fee Co unit cell in the orthomorphic growth regime indicates residual strain in films of up to at least 100 monolayers thickness. (C) 2000 Elsevier Science B.V. All rights reserved....

  5. 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.

  6. Corrosion behaviour of super-hydrophobic electrodeposited nickel-cobalt alloy film

    Science.gov (United States)

    Khorsand, S.; Raeissi, K.; Ashrafizadeh, F.; Arenas, M. A.; Conde, A.

    2016-02-01

    Hierarchical super-hydrophobic Ni-Co film with enhanced corrosion resistance was fabricated on a copper substrate by one-step electrodeposition process. The contact angle and water repellence properties of the Ni-Co film were measured to determine its wettability. The Ni-Co film exhibited excellent super-hydrophobic properties with a static water contact angle of 158° and a sliding angle of ≤5°. The corrosion performance of the super-hydrophobic surface (SHS) was investigated by electrochemical potentiodynamic measurements and electrochemical impedance spectroscopy in NaCl solution (3.5 wt.%). Moreover, to study the long-term stability of the super-hydrophobic film, SHS samples were immersed into NaCl solution and their corrosion behaviour was investigated by the electrochemical impedance spectroscopy. Additionally, the changes of surface wettability were also monitored over the whole immersion time up to 11 days. Experimental results indicated that super-hydrophobic samples had much more corrosion resistance in comparison with freshly prepared samples or the bare substrate.

  7. On the interpretation of {sup 57}Fe Moessbauer spectra from CdTe thin films with substitutions of Fe, In, and Sb

    Energy Technology Data Exchange (ETDEWEB)

    Yee-Madeira, H. [Centro de Investigacion y de Estudios Avanzados, IPN, Mexico City (Mexico). Dept. de Fisica]|[Depto. de Fisica, Esc. Sup. de Fisica y Matematicas (ESFM) del IPN, Edif. 9, U. P. ALM, 07738, Mexico D.F. (Mexico); Reguera, E.; Zelaya-Angel, O.; Sanchez-Sinencio, F. [Centro de Investigacion y de Estudios Avanzados, IPN, Mexico City (Mexico). Dept. de Fisica; Montiel-Sanchez, H. [Depto. de Fisica, Esc. Sup. de Fisica y Matematicas (ESFM) del IPN, Edif. 9, U. P. ALM, 07738, Mexico D.F. (Mexico); Scorzelli, R.B. [Centro Brasileiro de Pesquisas Fisicas, Rua Xavier Sigaud 150, CEP 22290, Urca, Rio de Janeiro (Brazil)

    1999-02-26

    {sup 57}Fe Moessbauer spectra of well characterized CdTe thin films with substitutions of Fe, In and Sb were recorded and interpreted according to the changes in the ionic radii and electronic properties of these substitutions relative to Cd in the CdTe framework. The literature reports of certain correlations among the iron valence, Fe{sup 2+} or Fe{sup 3+}, and the crystallinity of the films are critically discussed and an explanation of their origin is provided. The Moessbauer results also allow direct understanding of the effect of In and Sb substitutions on the properties of the films. (orig.) 22 refs.

  8. Characterization of Sputtered CdTe Thin Films with Electron Backscatter Diffraction and Correlation with Device Performance.

    Science.gov (United States)

    Nowell, Matthew M; Scarpulla, Michael A; Paudel, Naba R; Wieland, Kristopher A; Compaan, Alvin D; Liu, Xiangxin

    2015-08-01

    The performance of polycrystalline CdTe photovoltaic thin films is expected to depend on the grain boundary density and corresponding grain size of the film microstructure. However, the electrical performance of grain boundaries within these films is not well understood, and can be beneficial, harmful, or neutral in terms of film performance. Electron backscatter diffraction has been used to characterize the grain size, grain boundary structure, and crystallographic texture of sputtered CdTe at varying deposition pressures before and after CdCl2 treatment in order to correlate performance with microstructure. Weak fiber textures were observed in the as-deposited films, with (111) textures present at lower deposition pressures and (110) textures observed at higher deposition pressures. The CdCl2-treated samples exhibited significant grain recrystallization with a high fraction of twin boundaries. Good correlation of solar cell efficiency was observed with twin-corrected grain size while poor correlation was found if the twin boundaries were considered as grain boundaries in the grain size determination. This implies that the twin boundaries are neutral with respect to recombination and carrier transport.

  9. Creep Behavior and Its Influence on the Mechanics of Electrodeposited Nickel Films

    Institute of Scientific and Technical Information of China (English)

    Zengsheng Ma; Shiguo Long; Yong Pan; Yichun Zhou

    2009-01-01

    In order to improve the accuracy and comparability of hardness and elastic modulus measurements in nanoin-dentation, an evaluation of the creep behavior and its influence on the mechanical properties of the electrode-posited nickel film has been conducted. The influence of loading time and hold period on the hardness and elastic modulus results at maximum load 5000 μN has also been examined. It is found that with increasing the loading time, the creep value is decreased. However, the creep value is increased when the hold period is increased. The elastic modulus results are more reliable if the hold period is longer. If the hold period is long enough, the loading time has no remarkable effect on the hardness and elastic modulus measured.

  10. Electrodeposition of ZnO thin films on n-Si(100)

    Energy Technology Data Exchange (ETDEWEB)

    Dalchiele, E.A.; Giorgi, P.; Marotti, R.E. [Facultad de Ingenieria, Instituto de Fisica, Herrera y Reissig 565, C.C. 30, 11000 Montevideo (Uruguay); Martin, F.; Ramos-Barrado, J.R.; Ayouci, R.; Leinen, D. [Laboratorio de Materiales y Superficie, Unidad asociada al CSIC, Departamento de Fisica Aplicada and Ingenieria Quimica, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga (Spain)

    2001-12-31

    In this study, ZnO thin films have been deposited onto monocrystalline n-type Si(100) by electrodeposition at different applied potentials. XRD shows a preferential orientation (0002) that increases when the applied cathodic potential increases. The XPS analysis presents a Zn/O composition close to stoichiometric. SEM micrographs show a compact structure with localized platelets with a grain size of about 10{mu}m. However, crystallite size determined by the Scherrer method shows a size close to 2.50x10{sup -2}{mu}m, then the grains can be considered as clusters of crystallites. Optical measurements were made on samples deposited on ITO/glass through the same procedures giving a band gap of 3.3eV in agreement with the reported values for ZnO at room temperature.

  11. Analysis of Electrodeposited Nickel-Iron Alloy Film Composition Using Particle-Induced X-Ray Emission

    Directory of Open Access Journals (Sweden)

    Alyssa A. Frey

    2011-01-01

    Full Text Available The elemental composition of electrodeposited NiFe thin films was analyzed with particle-induced X-ray emission (PIXE. The thin films were electrodeposited on polycrystalline Au substrates from a 100 mM NiSO4, 10 mM FeSO4, 0.5 M H3BO3, and 1 M Na2SO4 solution. PIXE spectra of these films were analyzed to obtain relative amounts of Ni and Fe as a function of deposition potential and deposition time. The results show that PIXE can measure the total deposited metal in a sample over at least four orders of magnitude with similar fractional uncertainties. The technique is also sensitive enough to observe the variations in alloy composition due to sample nonuniformity or variations in deposition parameters.

  12. Innovative sputtering techniques for CIS and CdTe submodule fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, J.M.; Misra, M.S.; Lanning, B. (Martin Marietta Aerospace, Denver, CO (United States). Astronautics Group)

    1993-03-01

    This report describes work done during Phase 1 of the subject subcontract. The subcontract was designed to study innovative deposition techniques, such as the rotating cylindrical magnetron sputtering system and electrodeposition for large-area, low-cost copper indium diselenide (CIS) and cadmium telluride (CdTe) devices. A key issue for photovoltaics (PV) in terrestrial and future space applications is producibility, particularly for applications using a large quantity of PV. Among the concerns for fabrication of polycrystalline thin-film PV, such as CIS and CdTe, are production volume, cost, and minimization of waste. Both rotating cylindrical magnetron (C-Mag[trademark]) sputtering and electrodeposition have tremendous potential for the fabrication of polycrystalline thin-film PV due to scaleability, efficient utilization of source materials, and inherently higher deposition rates. In the case of sputtering, the unique geometry of the C-Mae facilitates innovative cosputtering and reactive sputtering that could lead to greater throughput reduced health and safety risks, and, ultimately, lower fabrication cost. Electrodeposited films appear to be adherent and comparable with low-cost fabrication techniques. Phase I involved the initial film and device fabrication using the two techniques mentioned herein. Devices were tested by both internal facilities, as well as NREL and ISET.

  13. Epitaxial electrodeposition of ZnO thin film on GaN(0001) bulk single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Ichinose, Keigo; Yoshida, Tsukasa [Center of Innovative Photovoltaic Systems (CIPS), Environmental and Renewable Energy Systems (ERES) Division, Graduate School of Engineering, Gifu University (Japan)

    2008-10-15

    Ga terminated surface of heavily doped conductive GaN(0001) bulk single crystal was used as a rotating disk electrode (RDE) to electrodeposit ZnO thin film employing reduction of O{sub 2}. Although the native surface was rather inactive for the reduction of O{sub 2}, it was activated by dipping in HCl and further by prolonged electrolysis to reduce O{sub 2} in a Zn{sup 2+} free solution. Koutecky-Levich analysis revealed important kinetic constants, such as the standard charge transfer rate constant (k{sup 0}) of 2.4 x 10{sup -14} cm s{sup -1} and the transfer coefficient ({alpha}) of 0.11 at 70 C for the reduction of O{sub 2} at the most activated GaN(0001). Electrodeposition of ZnO from the bath containing ZnCl{sub 2} lead to an epitaxial growth of ZnO in a ZnO[100] parallel GaN[100] alignment as confirmed from the XRD {omega} scan with {theta} adjusted to ZnO(10 anti 12). The higher level of epitaxy was achieved for the more active surfaces of GaN as estimated from narrowing of the full width at half maximum (fwhm) of the peaks in the XRD {omega} -scan. Such films were also fully covering the surface of GaN as found in the SEM observation. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. One-step electrodeposition for targeted off-stoichiometry Cu2ZnSnS4 thin films

    Science.gov (United States)

    Tang, Aiyue; Liu, Jingjun; Ji, Jing; Dou, Meiling; Li, Zhilin; Wang, Feng

    2016-10-01

    Cu2ZnSnS4 (CZTS) is a promising quaternary compound suitable for absorber layer of thin film solar cells. The precise control of the atomic ratio of the films are difficult for the electrodeposition of CZTS thin films. Here, we reported targeted off-stoichiometry CZTS thin films synthesized by one-step electrodeposition. We obtained Cu-poor thin films and the chemical composition of the as-deposited thin films were tailored to targeted off-stoichiometry. Based on the different kinetics of the metallic ion reduction, we successfully controlled the chemical composition by varying deposition time. After annealing, pure kesterite structure was obtained and the electronic interactions between Cu and Sn was verified in the films, which contributes to high carrier mobility. The band gap of the thin films were in the range of 1.43-1.52 eV, which is suitable for absorber layers of thin film solar cells. The carrier mobility reached a value of 28.20 cm2/V s with carrier concentration of 2.09 × 1018 cm-3 when Cu/(Zn + Sn) and Zn/Sn ratios were 0.97 and 1.13, respectively. This work paves a way for synthesizing targeted off-stoichiometry compounds by controlling kinetics and reaction time in large scale.

  15. Highly Luminescent Hybrid SiO2-Coated CdTe Quantum Dots Retained Initial Photoluminescence Efficiency in Sol-Gel SiO2 Film.

    Science.gov (United States)

    Sun, Hongsheng; Xing, Yugui; Wu, Qinan; Yang, Ping

    2015-02-01

    A highly luminescent silica film was fabricated using tetraethyl orthosilicate (TEOS) and 3-aminopropyltrimethoxysilane (APS) through a controlled sol-gel reaction. The pre-hydrolysis of TEOS and APS which resulted in the mixture of TEOS and APS in a molecular level is a key for the formation of homogenous films. The aminopropyl groups in APS play an important role for obtaining homogeneous film with high photoluminescence (PL). Red-emitting hybrid SiO2-coated CdTe nano-crystals (NCs) were fabricated by a two-step synthesis including a thin SiO2 coating via a sol-gel process and a subsequent refluxing using green-emitting CdTe NCs. The hybrid SiO2-coated CdTe NCs were embedded in a functional SiO2 film via a two-step process including adding the NCs in SiO2 sol with a high viscosity and almost without ethanol and a subsequent spinning coating. The hybrid SiO2-coated CdTe NCs retained their initial PL efficiency (54%) in the film. Being encapsulated with the hybrid NCs in the film, no change on the absorption and PL spectra of red-emitting CdTe NCs (632 nm) was observed. This indicates the hybrid NCs is stable enough during preparation. This phenomenon is ascribed to the controlled sol-gel process and a hybrid SiO2 shell on CdTe NCs. Because these films exhibited high PL efficiency and stability, they will be utilizable for potential applications in many fields.

  16. Electrochemical characterization of ion selectivity in electrodeposited nickel hexacyanoferrate thin films

    Institute of Scientific and Technical Information of China (English)

    Jinxia Guo; Xiaogang Hao; Xuli Ma; Zhonglin Zhang; Shibin Liu

    2008-01-01

    The ion selectivity of electrodeposited nickel hexacyanoferrate (NiHCF) thin films was investigated using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). NiHCF thin films were prepared by cathodic deposition on Pt and AI substrates. EIS and CV curves were determined in 1 mol/L (KNO3+CsNO3) and 1 mol/L (NaNO3+CsNO3) mixture solutions, which were sensitive to the concentration of Cs+ in the electrolytes. Experimental results show that all Nyqnist impedance plots show de-pressed semicircles in the high-frequency range changing over into straight lines at lower frequencies. With increasing amounts of Cs+, the redox potentials in CV curves shift toward more positive values and the redox peaks broaden; the semicircle radius in corre-sponding EIS curves and the charge transfer resistance also increase. EIS combining CV is able to provide valuable insights into the ion selectivity of NiHCF thin films.

  17. Spatial luminescence imaging of dopant incorporation in CdTe Films

    Science.gov (United States)

    Guthrey, Harvey; Moseley, John; Colegrove, Eric; Burst, James; Albin, David; Metzger, Wyatt K.; Al-Jassim, Mowafak

    2017-01-01

    State-of-the-art cathodoluminescence (CL) spectrum imaging with spectrum-per-pixel CL emission mapping is applied to spatially profile how dopant elements are incorporated into Cadmium telluride (CdTe). Emission spectra and intensity monitor the spatial distribution of additional charge carriers through characteristic variations in the CL emission based on computational modeling. Our results show that grain boundaries play a role in incorporating dopants in CdTe exposed to copper, phosphorus, and intrinsic point defects in CdTe. The image analysis provides critical, unique feedback to understand dopant incorporation and activation in the inhomogeneous CdTe material, which has struggled to reach high levels of hole density.

  18. Spatial luminescence imaging of dopant incorporation in CdTe Films

    Energy Technology Data Exchange (ETDEWEB)

    Guthrey, Harvey; Moseley, John; Colegrove, Eric; Burst, James; Albin, David; Metzger, Wyatt K.; Al-Jassim, Mowafak

    2017-01-28

    State-of-the-art cathodoluminescence (CL) spectrum imaging with spectrum-per-pixel CL emission mapping is applied to spatially profile how dopant elements are incorporated into Cadmium telluride (CdTe). Emission spectra and intensity monitor the spatial distribution of additional charge carriers through characteristic variations in the CL emission based on computational modeling. Our results show that grain boundaries play a role in incorporating dopants in CdTe exposed to copper, phosphorus, and intrinsic point defects in CdTe. The image analysis provides critical, unique feedback to understand dopant incorporation and activation in the inhomogeneous CdTe material, which has struggled to reach high levels of hole density.

  19. Photoconductivity of CdTe Nanocrystal-Based Thin Films. Te2- Ligands Lead To Charge Carrier Diffusion Lengths Over 2 Micrometers

    Energy Technology Data Exchange (ETDEWEB)

    Crisp, Ryan W. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Callahan, Rebecca [National Renewable Energy Lab. (NREL), Golden, CO (United States); Reid, Obadiah G. [Univ. of Colorado, Boulder, CO (United States); Dolzhnikov, Dmitriy S. [Univ. of Chicago, IL (United States); Talapin, Dmitri V. [Univ. of Chicago, IL (United States); Rumbles, Garry [National Renewable Energy Lab. (NREL), Golden, CO (United States); Luther, Joseph M. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Kopidakis, Nikos [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-11-16

    We report on photoconductivity of films of CdTe nanocrystals (NCs) using time-resolved microwave photoconductivity (TRMC). Spherical and tetrapodal CdTe NCs with tunable size-dependent properties are studied as a function of surface ligand (including inorganic molecular chalcogenide species) and annealing temperature. Relatively high carrier mobility is measured for films of sintered tetrapod NCs (4 cm2/(V s)). Our TRMC findings show that Te2- capped CdTe NCs show a marked improvement in carrier mobility (11 cm2/(V s)), indicating that NC surface termination can be altered to play a crucial role in charge-carrier mobility even after the NC solids are sintered into bulk films.

  20. Photoconductivity of CdTe Nanocrystal-Based Thin Films: Te(2-) Ligands Lead To Charge Carrier Diffusion Lengths Over 2 μm.

    Science.gov (United States)

    Crisp, Ryan W; Callahan, Rebecca; Reid, Obadiah G; Dolzhnikov, Dmitriy S; Talapin, Dmitri V; Rumbles, Garry; Luther, Joseph M; Kopidakis, Nikos

    2015-12-03

    We report on photoconductivity of films of CdTe nanocrystals (NCs) using time-resolved microwave photoconductivity (TRMC). Spherical and tetrapodal CdTe NCs with tunable size-dependent properties are studied as a function of surface ligand (including inorganic molecular chalcogenide species) and annealing temperature. Relatively high carrier mobility is measured for films of sintered tetrapod NCs (4 cm(2)/(V s)). Our TRMC findings show that Te(2-) capped CdTe NCs show a marked improvement in carrier mobility (11 cm(2)/(V s)), indicating that NC surface termination can be altered to play a crucial role in charge-carrier mobility even after the NC solids are sintered into bulk films.

  1. Effects of CdCl{sub 2} treatment on the recrystallization and electro-optical properties of CdTe thin films

    Energy Technology Data Exchange (ETDEWEB)

    Moutinho, H.R.; Al-Jassim, M.M.; Levi, D.H.; Dippo, P.C.; Kazmerski, L.L. [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States)

    1998-05-01

    The effects of CdCl{sub 2} processing on the physical and electro-optical properties of CdTe were evaluated for thin films produced by physical vapor deposition and close-spaced sublimation (CSS). Two substrates (CdS and Indium{endash}tin{endash}oxide) were used with the physical vapor deposition (PVD) films specifically to isolate the effects of the Cd(S{sub x}Te{sub 1{minus}x}) alloy formed during the treatment of films deposited on CdS. The samples were analyzed by x-ray diffraction (XRD), atomic force microscopy (AFM), and photoluminescence. The observed changes in microstructure were caused by recrystallization, which consisted of the nucleation and development of a new CdTe structure and subsequent grain growth. Nevertheless, for these processes to take place, it was necessary that enough lattice-strain energy was available in the films. For this reason, PVD films did recrystallize, while CSS films did not. For the first time, recrystallization was observed directly in AFM images of CdTe films and confirmed by XRD analysis, which indicated the existence of two lattice parameters in PVD samples treated at 350{degree}C. For samples treated at 400{degree}C, the CdCl{sub 2} treatment improved the minority-carrier lifetime of the films by more than one order of magnitude. This improvement was attributed to the elimination of deep defect levels within the band gap of the CdTe films as a result of the treatment. The sulfur diffusion into CdTe films deposited on CdS, during the CdCl{sub 2} treatment at 400{degree}C, strongly affected the defect structure.

  2. Morphology, structure, and magnetism of FeCo thin films electrodeposited on hydrogen-terminated Si(111) surfaces.

    Science.gov (United States)

    Zarpellon, J; Jurca, H F; Mattoso, N; Klein, J J; Schreiner, W H; Ardisson, J D; Macedo, W A A; Mosca, D H

    2007-12-15

    In this work we describe the fabrication of FeCo alloy (less than 10 at% Co) thin films from aqueous ammonium sulfate solutions onto n-type Si(111) substrates using potentiostatic electrodeposition at room temperature. The incorporation of Co into the deposits tends to inhibit Fe silicide formation and to protect deposits against oxidation under air exposure. As the incorporation of Co was progressively increased, the sizes of nuclei consisting of FeCo alloy increased, leading to films with a highly oriented body-centered cubic structure with crystalline texture, where (110) planes remain preferentially oriented parallel to the film surface.

  3. M(o)ssbauer study of the field induced uniaxial anisotropy in electro-deposited FeCo alloy films

    Institute of Scientific and Technical Information of China (English)

    Li Zhi-Wei; Yang Xu; Wang Hai-Bo; Liu Xin; Li Fa-Shen

    2009-01-01

    Thin ferromagnetic films with in-plane magnetic anisotropy are promising materials for obtaining high microwave permeability. The paper reports a M(o)ssbauer study of the field induced in-plane uniaxial anisotropy in electro-deposited FeCo alloy films. The FeCo alloy films were prepared by the electro-deposition method with and without an external magnetic field applied parallel to the film plane during deposition, Vibrating sample magnetometry and M(o)ssbauer spectroscopy measurements at room temperature indicate that the film deposited in external field shows an in-plane uniaxial anisotropy with an easy direction coinciding with the external field direction and a hard direction perpendicular to the field direction, whereas the film deposited without external field does not show any in-plane anisotropy. M(o)ssbauer spectra taken in three geometric arrangements show that the magnetic moments are almost constrained in the film plane for the film deposited with applied magnetic field. Also, the magnetic moments tend to align in the direction of the applied external magnetic field during deposition, indicating that the observed anisotropy should be attributed to directional ordering of atomic pairs.

  4. Electrical and magnetic properties of electrodeposited nickel incorporated diamond-like carbon thin films

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, B., E-mail: pandey.beauty@yahoo.com [Department of Applied Physics, Indian School of Mines, Dhanbad 826004 (India); Das, D. [UGC-DAE CSR, Sector III/LB-8, Bidhan Nagar, Kolkata 700098 (India); Kar, A.K. [Department of Applied Physics, Indian School of Mines, Dhanbad 826004 (India)

    2015-05-15

    Highlights: • Electrical and magnetic properties of DLC and Ni-DLC thin films are studied. • The ohmicity and conductivity of DLC films rise with nickel addition. • The ohmicity of Ni-DLC is enhanced with increase in dilution of electrolyte. • Dielectric loss is high for Ni-DLC and decreases with frequency till 100 kHz. • (m–H) and (m–T) curves of Ni-DLC indicate superparamagnetic behavior. - Abstract: Nanocomposite diamond-like carbon (DLC) thin films have been synthesized by incorporating nickel (Ni) nanoparticles in DLC matrix with varying concentration of nickel. DLC and Ni-DLC thin films have been deposited on ITO coated glass substrates employing low voltage electrodeposition method. Electrical properties of the samples were studied by measuring current–voltage characteristics and dielectric properties. The current approaches toward an ohmic behavior with metal addition. This tendency of increasing ohmicity is enhanced with increase in dilution of the electrolyte. The conductivity increases with Ni addition and interestingly it continues to increase with dilution of Ni concentration in the electrolyte in the range of our study. Magnetic properties for DLC and Ni-DLC thin film samples were examined by electron paramagnetic resonance (EPR) measurements and Super Conducting Quantum Interference Device (SQUID) measurements. g-Value for DLC is 2.074, whereas it decreases to 2.055 with Ni addition in the electrolyte. This decrement arises from the increased sp{sup 2} content in DLC matrix. The magnetic moment vs. magnetic field (m–H) curves of Ni-DLC indicate superparamagnetic behavior which may be due to ferromagnetic contribution from the incorporated nickel nanoparticles in the DLC matrix. The ZFC curve of Ni-DLC after the blocking temperature shows a combined contribution of ferromagnetic, superparamagnetic and paramagnetic nature of the materials persisting up to 300 K.

  5. [Spectral analyzing effects of atmosphere states on the structure and characteristics of CdTe polycrystalline thin films made by close-spaced sublimation].

    Science.gov (United States)

    Zheng, Hua-jing; Zheng, Jia-gui; Feng, Liang-huan; Zhang, Jing-quan; Xie, Er-qing

    2005-07-01

    The structure and characteristics of CdTe thin films are dependent on the working atmosphere states in close-spaced sublimation. In the present paper, CdTe polycrystalline thin films were deposited by CSS in mixture atmosphere of argon and oxygen. The physical mechanism of CSS was analyzed, and the temperature distribution in CSS system was measured. The dependence of preliminary nucleus creation on the atmosphere states (involving component and pressure) was studied. Transparencies were measured and optic energy gaps were calculated. The results show that: (1) The CdTe films deposited in different atmospheres are cubic structure. With increasing oxygen concentration, a increases and reaches the maximum at 6% oxygen concentration, then reduces, and increases again after passing the point at 12% oxygen concentration. Among them, the sample depositing at 9% oxygen concentration is the best. The optic energy gaps are 1.50-1.51 eV for all CdTe films. (2) The samples depositing at different pressures at 9% oxygen concentration are all cubical structure of CdTe, and the diffraction peaks of CdS and SnO2:F still appear. With the gas pressure increasing, the crystal size of CdTe minishes, the transparency of the thin film goes down, and the absorption side shifts to the short-wave direction. (3) The polycrystalline thin films with high quality deposit in 4 minutes under the depositing condition that the substrate temperature is 550 degrees C, and source temperature is 620 degrees C at 9% oxygen concentration.

  6. Addendum to "Anomalous scaling and super-roughness in the growth of CdTe polycrystalline films"

    OpenAIRE

    Fábio S. Nascimento; Mata, Angélica S.; Ferreira, Silvio C.; Ferreira, Sukarno O.

    2011-01-01

    The scaling of the growth of CdTe films on glass substrates was investigated by Mata \\textit{et al.} [Phys. Rev. B \\textbf{78}, 115305 (2008)]. Part of the analysis consisted of the estimation of the correlation length $\\xi$ using the decay in the height-height correlation function. Afterwards, the dynamical exponent $z$ was determined using the scaling hypothesis $\\xi\\sim t^{1/z}$. In this Addendum, we show that the correlation lengths obtained by Mata \\textit{et al.} provide a long waveleng...

  7. Thin film CdTe based neutron detectors with high thermal neutron efficiency and gamma rejection for security applications

    Science.gov (United States)

    Smith, L.; Murphy, J. W.; Kim, J.; Rozhdestvenskyy, S.; Mejia, I.; Park, H.; Allee, D. R.; Quevedo-Lopez, M.; Gnade, B.

    2016-12-01

    Solid-state neutron detectors offer an alternative to 3He based detectors, but suffer from limited neutron efficiencies that make their use in security applications impractical. Solid-state neutron detectors based on single crystal silicon also have relatively high gamma-ray efficiencies that lead to false positives. Thin film polycrystalline CdTe based detectors require less complex processing with significantly lower gamma-ray efficiencies. Advanced geometries can also be implemented to achieve high thermal neutron efficiencies competitive with silicon based technology. This study evaluates these strategies by simulation and experimentation and demonstrates an approach to achieve >10% intrinsic efficiency with <10-6 gamma-ray efficiency.

  8. Characterization of Highly Efficient CdTe Thin Film Solar Cells by the Capacitance-Voltage Profiling Technique

    Science.gov (United States)

    Okamoto, Tamotsu; Yamada, Akira; Konagai, Makoto

    2000-05-01

    The electrical properties of highly efficient CdTe thin film solar cells prepared by close-spaced sublimation (CSS) were investigated by capacitance-voltage (C-V) measurement. According to the dependence of the cell performance on the substrate temperature in the CSS process, the open-circuit voltage (Voc) increased with increasing the substrate temperature below 630°C@. The carrier concentration profiles revealed that the net acceptor concentration exponentially increased from the CdS/CdTe interface to the rear and that the acceptor concentration increased with increasing substrate temperature. This result suggests that Voc is improved as a result of the increase in the acceptor concentration.

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

    Directory of Open Access Journals (Sweden)

    Umut Sarac

    2013-01-01

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

  10. Corrosion resistance and long-term durability of super-hydrophobic nickel film prepared by electrodeposition process

    Energy Technology Data Exchange (ETDEWEB)

    Khorsand, S., E-mail: s.khorsand@ma.iut.ac.ir; Raeissi, K., E-mail: k_raeissi@cc.iut.ac.ir; Ashrafizadeh, F., E-mail: ashrafif@cc.iut.ac.ir

    2014-06-01

    A super-hydrophobic nickel film with micro-nano structure was successfully fabricated by electrodeposition process. By controlling electrodeposition parameters and considering different storage times for the coatings in air, various nickel films with different wettability were fabricated. Surface morphology of nickel films was examined by means of scanning electron microscopy (SEM). The results showed that the micro-nano nickel film was well-crystallized and exhibited pine cone-like microstructure with nano-cone arrays randomly dispersed on each micro-protrusion. The wettability of the micro-nano nickel film varied from super-hydrophilicity (water contact angle 5.3°) to super-hydrophobicity (water contact angle 155.7°) by exposing the surface in air at room temperature. The corrosion resistance of the super-hydrophobic film was estimated by electrochemical impedance spectroscopy (EIS) and Tafel polarization measurements. The potentiodynamic curves revealed that the corrosion rate of superhydrophobic surface was only 0.16% of the bare copper substrate. Moreover, EIS measurements and appropriate equivalent circuit models revealed that the corrosion resistance of nickel films considerably improved with an increase in the hydrophobicity. The superhydrophobic surface also exhibited an excellent long-term durability in neutral 3.5 wt.% NaCl solution.

  11. Phase-Change Memory Properties of Electrodeposited Ge-Sb-Te Thin Film

    OpenAIRE

    Huang, Ruomeng; Kissling, Gabriela; Jolleys, Andrew; Bartlett, Philip; Hector, Andrew; Levason, William; Reid, Gillian; De Groot, Cornelis

    2015-01-01

    We report the properties of a series of electrodeposited Ge-Sb-Te alloys with various compositions. It is shown that the Sb/Ge ratio can be varied in a controlled way by changing the electrodeposition potential. This method opens up the prospect of depositing Ge-Sb-Te super-lattice structures by electrodeposition. Material and electrical characteristics of various compositions have been investigated in detail, showing up to three orders of magnitude resistance ratio between the amorphous and ...

  12. Electrodeposition and characterisation of lead tin superconducting films for application in heavy ion booster

    Energy Technology Data Exchange (ETDEWEB)

    Lobanov, Nikolai R., E-mail: Nikolai.Lobanov@anu.edu.au

    2015-12-15

    The ANU has developed experimental systems and procedures for lead–tin (PbSn) film deposition and characterisation. The 12 split loop resonators have been electroplated with 96%Pb4%Sn film to the final thickness of 1.5 micron using methanesulfonic acid (MSA) chemistry. As a result, an average acceleration field of 3.6 MV/m off-line at 6 W rf power was achieved at extremely low technological cost. Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Heavy Ion Elastic Detection Analyses (HIERDA), Rutherford Backscattering Spectroscopy (RBS), Secondary Ion Mass Spectroscopy (SIMS) and Electron Backscattering Diffraction (EBSD) revealed correlation between the substrate and film structure, morphology and the rf performance of the cavity. The PbSn plating, exercised on the existing split loop resonators (SLR), has been extended to the two stub quarter wave resonator (QWR) as a straightforward step to quickly explore the superconducting performance of the new geometry. The oxygen free copper (OHFC) substrate for two stub QWR was prepared by reverse pulse electropolishing. The ultimate superconducting properties and long-term stability of the coatings have been assessed by operation of the ANU superconducting linac over the last few years. - Highlights: • PbSn alloy is investigated as a material for superconducting low and medium velocity rf resonators. • It is easily electrodeposited with MSA chemistry at very low cost, has high T{sub c}, and good performance at high fields. • The optimum substrate preparation and coating conditions are established based on examination of the properties of substrate and superconducting films. • A long term stability of the electroplated resonators has been showing no evidence of degradation of the rf properties over the last decade. • The resonators high field performance limiting factors and their possible elimination have been evaluated.

  13. Atomic-resolution characterization of the effects of CdCl{sub 2} treatment on poly-crystalline CdTe thin films

    Energy Technology Data Exchange (ETDEWEB)

    Paulauskas, T., E-mail: tpaula2@uic.edu; Buurma, C.; Colegrove, E.; Guo, Z.; Sivananthan, S.; Klie, R. F. [Department of Physics, University of Illinois at Chicago, 845 W. Taylor St. M/C 273, Chicago, Illinois 60607-7059 (United States); Chan, M. K. Y. [Center for Nanoscale Materials, Argonne National Laboratory, 9700 S. Cass Ave., Building 440, Argonne, Illinois 60439 (United States)

    2014-08-18

    Poly-crystalline CdTe thin films on glass are used in commercial solar-cell superstrate devices. It is well known that post-deposition annealing of the CdTe thin films in a CdCl{sub 2} environment significantly increases the device performance, but a fundamental understanding of the effects of such annealing has not been achieved. In this Letter, we report a change in the stoichiometry across twin boundaries in CdTe and propose that native point defects alone cannot account for this variation. Upon annealing in CdCl{sub 2}, we find that the stoichiometry is restored. Our experimental measurements using atomic-resolution high-angle annular dark field imaging, electron energy-loss spectroscopy, and energy dispersive X-ray spectroscopy in a scanning transmission electron microscope are supported by first-principles density functional theory calculations.

  14. CZTS absorber layer for thin film solar cells from electrodeposited metallic stacked precursors (Zn/Cu-Sn)

    Science.gov (United States)

    Khalil, M. I.; Atici, O.; Lucotti, A.; Binetti, S.; Le Donne, A.; Magagnin, L.

    2016-08-01

    In the present work, Kesterite-Cu2ZnSnS4 (CZTS) thin films were successfully synthesized from stacked bilayer precursor (Zn/Cu-Sn) through electrodeposition-annealing route. Adherent and homogeneous Cu-poor, Zn-rich stacked metal Cu-Zn-Sn precursors with different compositions were sequentially electrodeposited, in the order of Zn/Cu-Sn onto Mo foil substrates. Subsequently, stacked layers were soft annealed at 350 °C for 20 min in flowing N2 atmosphere in order to improve intermixing of the elements. Then, sulfurization was completed at 585 °C for 15 min in elemental sulfur environment in a quartz tube furnace with N2 atmosphere. Morphological, compositional and structural properties of the films were investigated using SEM, EDS and XRD methods. Raman spectroscopy with two different excitation lines (514.5 and 785 nm), has been carried out on the sulfurized films in order to fully characterize the CZTS phase. Higher excitation wavelength showed more secondary phases, but with low intensities. Glow discharge optical emission spectroscopy (GDOES) has also been performed on films showing well formed Kesterite CZTS along the film thickness as compositions of the elements do not change along the thickness. In order to investigate the electronic structure of the CZTS, Photoluminescence (PL) spectroscopy has been carried out on the films, whose results matched up with the literatures.

  15. Studies of antimony telluride and copper telluride films electrodeposition from choline chloride containing ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Catrangiu, Adriana-Simona; Sin, Ion [Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry, POLITEHNICA University of Bucharest, Calea Grivitei 132, Bucharest (Romania); Prioteasa, Paula [INCDIE ICPE-Advanced Research, Splaiul Unirii 313, Bucharest (Romania); Cotarta, Adina [Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry, POLITEHNICA University of Bucharest, Calea Grivitei 132, Bucharest (Romania); Cojocaru, Anca, E-mail: a_cojocaru@chim.upb.ro [Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry, POLITEHNICA University of Bucharest, Calea Grivitei 132, Bucharest (Romania); Anicai, Liana [Center of Surface Science and Nanotechnology, University POLITEHNICA of Bucharest, Splaiul Independentei 313, Bucharest (Romania); Visan, Teodor [Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry, POLITEHNICA University of Bucharest, Calea Grivitei 132, Bucharest (Romania)

    2016-07-29

    Cyclic voltammetry and electrochemical impedance spectroscopy were used to investigate the deposition of antimony telluride or copper telluride from ionic liquid consisting in mixture of choline chloride with oxalic acid. In addition, the cathodic process during copper telluride formation was studied in the mixture of choline chloride with ethylene glycol. The results indicate that the Pt electrode is first covered with a Te layer, and then the more negative polarisation leads to the deposition of Sb{sub x}Te{sub y} or Cu{sub x}Te{sub y} semiconductor compounds. Thin films were deposited on copper and carbon steel at 60–70 °C and were characterised by scanning electron microscopy, energy X-ray dispersive spectroscopy (EDS), and X-ray diffraction (XRD). Their stoichiometry depends on the bath composition and applied potential. EDS and XRD patterns indicate the possible synthesis of stoichiometric Sb{sub 2}Te{sub 3} phase and Cu{sub 2}Te, Cu{sub 5}Te{sub 3}, and Cu{sub 2.8}Te{sub 2} phases, respectively, by controlling the ratio of ion concentrations in ionic liquid electrolytes and deposition potential. - Highlights: • Sb{sub x}Te{sub y} and Cu{sub x}Te{sub y} films electrodeposited from choline-chloride-based ionic liquids. • The stoichiometry of film depends on the bath composition and deposition potential. • Sb{sub 2}Te{sub 3}, Cu{sub 2}Te, Cu{sub 5}Te{sub 3}, Cu{sub 2.8}Te{sub 2} phases were identified in X-ray diffraction patterns.

  16. A pilot investigation on laser annealing for thin-film solar cells: Crystallinity and optical properties of laser-annealed CdTe thin films by using an 808-nm diode laser

    Science.gov (United States)

    Kim, Nam-Hoon; Park, Chan Il; Park, Jinseong

    2013-02-01

    Compared to conventional furnace and rapid thermal annealing, laser annealing for heterojunctioned thin-film solar cells has several advantages including excellent annealing selectivity to the under-layers with a localized high temperature for a short process time. A continuous wave 808-nm diode laser was used for the laser annealing process of CdTe thin films for various output powers. The grains in the laser-annealed CdTe thin films grew along the C (111), H (110), and C (311) planes. Laser annealing resulted in an increase in grain size and a decrease in surface roughness. The optical band gap energy of the CdTe thin films was affected directly by the grain size, showing 1.460 eV and 1.415 eV for the as-deposited and laser-annealed CdTe thin films, respectively. The absorbance of the CdTe thin films with better crystallinity showed an improved value of 99.5-99.9% in the visible spectral region after laser annealing at an output power of 0.91 W.

  17. Preparation and characterization of Cu(In,Ga)(Se,S){sub 2} thin films from electrodeposited precursors for hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Leisch, Jennifer E.; Bhattacharya, Raghu N.; Teeter, Glenn; Turner, John A. [National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, CO 80401-3393 (United States)

    2004-02-06

    Semiconducting Cu(In,Ga)(Se,S){sub 2} thin films were made from electrodeposited Cu(In,Ga)Se{sub 2} precursors, followed by physical vapor deposition of In{sub 2}S{sub 3}, Ga, and Se. The bandgaps of these materials were found to be between 1.6 and 2.0eV, which spans the optimal bandgap necessary for application for the top junction in photovoltaic multijunction devices and for unassisted water photolysis. These films were characterized by electron-probe microanalysis, scanning Auger spectroscopy, X-ray diffraction, and photocurrent spectroscopy.

  18. Optical and structural characterization of oleic acid-stabilized CdTe nanocrystals for solution thin film processing

    Directory of Open Access Journals (Sweden)

    Claudio Davet Gutiérrez-Lazos

    2014-06-01

    Full Text Available This work presents results of the optical and structural characterization of oleic acid-stabilized cadmium telluride nanocrystals (CdTe-NC synthesized by an organometallic route. After being cleaned, the CdTe-NC were dispersed in toluene to obtain an ink-like dispersion, which was drop-cast on glass substrate to deposit a thin film. The CdTe-NC colloidal dispersion as well as the CdTe drop-cast thin films were characterized with regard to the optical and structural properties. TEM analysis indicates that the CdTe-NC have a nearly spherical shape (3.5 nm as mean size. Electron diffraction and XRD diffraction analyses indicated the bulk-CdTe face-centered cubic structure for CdTe-NC. An additional diffraction line corresponding to the octahedral Cd3P2 was also detected as a secondary phase, which probably originates by reacting free cadmium ions with trioctylphosphine (the tellurium reducing agent. The Raman spectrum exhibits two broad bands centered at 141.6 and 162.3 cm−1, which could be associated to the TO and LO modes of cubic CdTe nanocrystals, respectively. Additional peaks located in the 222 to 324 cm−1 range, agree fairly well with the wavenumbers reported for TO modes of octahedral Cd3P2.

  19. Optical and structural characterization of oleic acid-stabilized CdTe nanocrystals for solution thin film processing.

    Science.gov (United States)

    Gutiérrez-Lazos, Claudio Davet; Ortega-López, Mauricio; Pérez-Guzmán, Manuel A; Espinoza-Rivas, A Mauricio; Solís-Pomar, Francisco; Ortega-Amaya, Rebeca; Silva-Vidaurri, L Gerardo; Castro-Peña, Virginia C; Pérez-Tijerina, Eduardo

    2014-01-01

    This work presents results of the optical and structural characterization of oleic acid-stabilized cadmium telluride nanocrystals (CdTe-NC) synthesized by an organometallic route. After being cleaned, the CdTe-NC were dispersed in toluene to obtain an ink-like dispersion, which was drop-cast on glass substrate to deposit a thin film. The CdTe-NC colloidal dispersion as well as the CdTe drop-cast thin films were characterized with regard to the optical and structural properties. TEM analysis indicates that the CdTe-NC have a nearly spherical shape (3.5 nm as mean size). Electron diffraction and XRD diffraction analyses indicated the bulk-CdTe face-centered cubic structure for CdTe-NC. An additional diffraction line corresponding to the octahedral Cd3P2 was also detected as a secondary phase, which probably originates by reacting free cadmium ions with trioctylphosphine (the tellurium reducing agent). The Raman spectrum exhibits two broad bands centered at 141.6 and 162.3 cm(-1), which could be associated to the TO and LO modes of cubic CdTe nanocrystals, respectively. Additional peaks located in the 222 to 324 cm(-1) range, agree fairly well with the wavenumbers reported for TO modes of octahedral Cd3P2.

  20. One-pot electrodeposition, characterization and photoactivity of stoichiometric copper indium gallium diselenide (CIGS) thin films for solar cells.

    Science.gov (United States)

    Harati, Mohammad; Jia, Jia; Giffard, Kévin; Pellarin, Kyle; Hewson, Carly; Love, David A; Lau, Woon Ming; Ding, Zhifeng

    2010-12-14

    Herein we report the one-pot electrodeposition of copper indium gallium diselenide, CuIn(1-x)Ga(x)Se(2) (CIGS), thin films as the p-type semiconductor in an ionic liquid medium consisting of choline chloride/urea eutectic mixture known as Reline. The thin films were characterized by scanning electron microscopy with energy dispersive X-ray analysis, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman microspectroscopy, and UV-visible spectroscopy. Based on the results of the characterizations, the electrochemical bath recipe was optimized to obtain stoichiometric CIGS films with x between 0.2 and 0.4. The chemical activity and photoreactivity of the optimized CIGS films were found to be uniform using scanning electrochemical microscopy and scanning photoelectrochemical microscopy. Low-cost stoichiometric CIGS thin films in one-pot were successfully fabricated.

  1. Enhancement in as-grown CuInSe{sub 2} film microstructure by a three potential pulsed electrodeposition method

    Energy Technology Data Exchange (ETDEWEB)

    Palacios-Padros, A. [Department of Physical Chemistry, University of Barcelona (UB), Institute for Bioengineering of Catalonia (IBEC) Marti i Franques 1, 08028 Barcelona (Spain); Caballero-Briones, F.; Sanz, Fausto [Department of Physical Chemistry, University of Barcelona (UB), Institute for Bioengineering of Catalonia (IBEC) Marti i Franques 1, 08028 Barcelona (Spain); CIBER-BBN, Maria de Luna 11, 50018 Zaragoza (Spain)

    2010-08-15

    P-type copper indium diselenide (CuInSe{sub 2}) films have been prepared onto ITO substrates by an electrodeposition method, that sequentially applies potential pulses at the deposition potential of each element Cu, Se and In, and then step it back in cyclically to induce the solid state reaction between the elements. Two electrolyte concentrations as well as three different pulse durations were assessed. The resulting films were compared with those deposited at fixed electrode potentials. As-grown films are nanocrystalline and have an E{sub g} {proportional_to} 0.95 eV. Raman spectroscopy shows that Se and Cu-Se contents decrease while pulse duration increases and electrolyte concentration decreases. Cu-Se phases are even absent for films grown at the low electrolyte concentration. These results represent a great improvement in the film phase purity reducing the need of post-deposition treatments. (author)

  2. Rf sputtering of CdTE and CdS for thin film PV

    Energy Technology Data Exchange (ETDEWEB)

    Compaan, A.D.; Tabory, C.N.; Shao, M.; Fischer, A.; Feng, Z.; Bohn, R.G. (Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606 (United States))

    1994-06-30

    In late 1992 we demonstrated the first rf sputtered CdS/CdTe photovoltaic cell with efficiency exceeding 10%. In this cell both CdS and CdTe layers were deposited by rf sputtering. In this paper we report preliminary measurements of (1) optical emission spectroscopy of the rf plasma, (2) the width of the phonon Raman line as a function of deposition temperature for CdS, and (3) studies of oxygen doping during pulsed laser deposition of CdTe.

  3. Long Lifetime Hole Traps at Grain Boundaries in CdTe Thin-Film Photovoltaics

    Science.gov (United States)

    Mendis, B. G.; Gachet, D.; Major, J. D.; Durose, K.

    2015-11-01

    A novel time-resolved cathodoluminescence method, where a pulsed electron beam is generated via the photoelectric effect, is used to probe individual CdTe grain boundaries. Excitons have a short lifetime (≤100 ps ) within the grains and are rapidly quenched at the grain boundary. However, a ˜47 meV shallow acceptor, believed to be due to oxygen, can act as a long lifetime hole trap, even at the grain boundaries where their concentration is higher. This provides direct evidence supporting recent observations of hopping conduction across grain boundaries in highly doped CdTe at low temperature.

  4. Thin-film CdTe detector for microdosimetric study of radiation dose enhancement at gold-tissue interface.

    Science.gov (United States)

    Paudel, Nava Raj; Shvydka, Diana; Parsai, E Ishmael

    2016-09-08

    Presence of interfaces between high and low atomic number (Z) materials, often encountered in diagnostic imaging and radiation therapy, leads to radiation dose perturbation. It is characterized by a very narrow region of sharp dose enhancement at the interface. A rapid falloff of dose enhancement over a very short distance from the interface makes the experimental dosimetry nontrivial. We use an in-house-built inexpensive thin-film Cadmium Telluride (CdTe) photodetector to study this effect at the gold-tissue interface and verify our experimental results with Monte Carlo (MC) modeling. Three-micron thick thin-film CdTe photodetectors were fabricated in our lab. One-, ten- or one hundred-micron thick gold foils placed in a tissue-equivalent-phantom were irradiated with a clinical Ir-192 high-dose-rate (HDR) source and current measured with a CdTe detector in each case was compared with the current measured for all uniform tissue-equivalent phantom. Percentage signal enhancement (PSE) due to each gold foil was then compared against MC modeled percentage dose enhancement (PDE), obtained from the geometry mimicking the experimental setup. The experimental PSEs due to 1, 10, and 100 μm thick gold foils at the closest measured distance of 12.5μm from the interface were 42.6 ± 10.8 , 137.0 ± 11.9, and 203.0 ± 15.4, respectively. The corresponding MC modeled PDEs were 38.1 ± 1, 164 ± 1, and 249 ± 1, respectively. The experimental and MC modeled values showed a closer agreement at the larger distances from the interface. The dose enhancement in the vicinity of gold-tissue interface was successfully measured using an in-house-built, high-resolution CdTe-based photodetector and validated with MC simulations. A close agreement between experimental and the MC modeled results shows that CdTe detector can be utilized for mapping interface dose distribution encountered in the application of ionizing radiation.

  5. Recent Developments of Flexible CdTe Solar Cells on Metallic Substrates: Issues and Prospects

    Directory of Open Access Journals (Sweden)

    M. M. Aliyu

    2012-01-01

    Full Text Available This study investigates the key issues in the fabrication of CdTe solar cells on metallic substrates, their trends, and characteristics as well as effects on solar cell performance. Previous research works are reviewed while the successes, potentials, and problems of such technology are highlighted. Flexible solar cells offer several advantages in terms of production, cost, and application over glass-based types. Of all the metals studied as substrates for CdTe solar cells, molybdenum appears the most favorable candidate, while close spaced sublimation (CSS, electrodeposition (ED, magnetic sputtering (MS, and high vacuum thermal evaporation (HVE have been found to be most common deposition technologies used for CdTe on metal foils. The advantages of these techniques include large grain size (CSS, ease of constituent control (ED, high material incorporation (MS, and low temperature process (MS, HVE, ED. These invert-structured thin film CdTe solar cells, like their superstrate counterparts, suffer from problems of poor ohmic contact at the back electrode. Thus similar strategies are applied to minimize this problem. Despite the challenges faced by flexible structures, efficiencies of up to 13.8% and 7.8% have been achieved in superstrate and substrate cell, respectively. Based on these analyses, new strategies have been proposed for obtaining cheaper, more efficient, and viable flexible CdTe solar cells of the future.

  6. Kinetics of copper electrodeposition onto Polypyrrole films previously synthesised onto iron in oxalic aqueous solution. Application to electrocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Aitout, R. [Laboratoire de Recherche en Electrochimie et Corrosion, Departement de Genie des Procedes, Faculte des Sciences et des Sciences de l' Ingenieur, Universite de Bejaia, 06000 Bejaia (Algeria); Makhloufi, L. [Laboratoire de Recherche en Electrochimie et Corrosion, Departement de Genie des Procedes, Faculte des Sciences et des Sciences de l' Ingenieur, Universite de Bejaia, 06000 Bejaia (Algeria)]. E-mail: laid_mak@yahoo.fr; Saidani, B. [Laboratoire de Recherche en Electrochimie et Corrosion, Departement de Genie des Procedes, Faculte des Sciences et des Sciences de l' Ingenieur, Universite de Bejaia, 06000 Bejaia (Algeria)

    2006-12-05

    Copper electrodeposition onto previously synthesised Polypyrrole (PPy) onto iron in oxalic medium has been investigated using polarization and electrochemical impedance spectroscopy. This investigation was done at potential range where hydrogen evolution does not occur. The kinetics of this reaction was found to be under diffusion control and the diffusion coefficient of reactive species was found to be 6.4 {+-} 0.1 x 10{sup -6} cm{sup 2} s{sup -1}. The electrochemical impedance spectroscopy was used to estimate the roughness variation of the electrode surface during copper electrodeposition. Scanning Electron Microscopy observation of Fe/PPy/Cu films provide strong evidence of the close relationship between deposit morphology and electrocatalytic activity.

  7. Optimization of the Electrodeposition Parameters to Improve the Stoichiometry of In2S3 Films for Solar Applications Using the Taguchi Method

    Directory of Open Access Journals (Sweden)

    Maqsood Ali Mughal

    2014-01-01

    Full Text Available Properties of electrodeposited semiconductor thin films are dependent upon the electrolyte composition, plating time, and temperature as well as the current density and the nature of the substrate. In this study, the influence of the electrodeposition parameters such as deposition voltage, deposition time, composition of solution, and deposition temperature upon the properties of In2S3 films was analyzed by the Taguchi Method. According to Taguchi analysis, the interaction between deposition voltage and deposition time was significant. Deposition voltage had the largest impact upon the stoichiometry of In2S3 films and deposition temperature had the least impact. The stoichiometric ratios between sulfur and indium (S/In: 3/2 obtained from experiments performed with optimized electrodeposition parameters were in agreement with predicted values from the Taguchi Method. The experiments were carried out according to Taguchi orthogonal array L27 (3^4 design of experiments (DOE. Approximately 600 nm thick In2S3 films were electrodeposited from an organic bath (ethylene glycol-based containing indium chloride (InCl3, sodium chloride (NaCl, and sodium thiosulfate (Na2S2O3·5H2O, the latter used as an additional sulfur source along with elemental sulfur (S. An X-ray diffractometer (XRD, energy dispersive X-ray spectroscopy (EDS unit, and scanning electron microscope (SEM were, respectively, used to analyze the phases, elemental composition, and morphology of the electrodeposited In2S3 films.

  8. High-Efficiency CdTe and CIGS Thin-Film Solar Cells: Highlights and Challenges; Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Noufi, R.; Zweibel, K.

    2006-05-01

    Thin-film photovoltaic (PV) modules of CdTe and Cu(In,Ga)Se2 (CIGS) have the potential to reach cost-effective PV-generated electricity. These technologies have transitioned from the laboratory to the market place. Pilot production and first-time manufacturing are ramping up to higher capacity and enjoying a flood of venture-capital funding. CIGS solar cells and modules have achieved 19.5% and 13% efficiencies, respectively. Likewise, CdTe cells and modules have reached 16.5% and 10.2% efficiencies, respectively. Even higher efficiencies from the laboratory and from the manufacturing line are only a matter of time. Manufacturing-line yield continues to improve and is surpassing 85%. Long-term stability has been demonstrated for both technologies; however, some failures in the field have also been observed, emphasizing the critical need for understanding degradation mechanisms and packaging options. The long-term potential of the two technologies require R&D emphasis on science and engineering-based challenges to find solutions to achieve targeted cost-effective module performance, and in-field durability. Some of the challenges are common to both, e.g., in-situ process control and diagnostics, thinner absorber, understanding degradation mechanisms, protection from water vapor, and innovation in high-speed processing and module design. Other topics are specific to the technology, such as lower-cost and fast-deposition processes for CIGS, and improved back contact and voltage for CdTe devices.

  9. A Comparative Study on the Optical Properties of Multilayer CdSe / CdTe Thin Film with Single Layer CdTe and CdSe Films

    Directory of Open Access Journals (Sweden)

    M. Melvin David Kumar

    2013-07-01

    Full Text Available CdTe and CdSe single layer thin films and CdSe / CdTe multilayer (ML thin film were prepared by using physical vapour deposition method. Optical properties of CdSe / CdTe multilayer thin film shows different behavior due to type II band structure alignment. Energy band gap value of CdSe / CdTe ML thin film is shifted to higher value than that of single layer CdTe film. This is due to decrease in crystallite size to dimension smaller than the Bohr exciton radius of CdTe (14 nm. Crystallite size of the multilayer sample was calculated with the predictions of the effective mass approximation model (i.e., Brus model. It is observed that the photoluminescence peak of CdSe / CdTe ML thin film is red shifted compared to the peaks corresponding to individual CdSe and CdTe thin films. This may be due to the presence of type II quantum dot formation in the CdSe / CdTe heterostructure multilayer thin film.

  10. Preparation of CuInSe2 films by ultrasonic electrodeposition-selenization and the improvement of their surface morphology

    Institute of Scientific and Technical Information of China (English)

    WANG Yanlai; NIE Hongbo; GUO Shiju

    2010-01-01

    The CuInSe2 compound was prepared by selenization of Cu-In precursor,which was ultrasonic electrodeposited at constant current.CuInSe2films were compacted to improve surface morphology.The films were characterized by X-ray diffractometry(XRD),scanning electron microscopy(SEM),and energy dispersive spectroscopy(EDS).It is indicated that ideal stoichiometric CuInSe2 films can be obtained by the selanization of Cu-In precursor deposited at a current density of 20 mA/cm2.Single-phase CuInSe2 is formed in the selenization process,and it exhibits preferred orientation along the(112)plane.The CuInSe2 films with smooth surface can be obtained under the pressure of 500 MPa at 60℃.

  11. Electrodeposition of FeCoCd films with in-plane uniaxial magnetic anisotropy for microwave applications.

    Science.gov (United States)

    Feng, Erxi; Wang, Zhenkun; Du, Hongwei; Wei, Jinwu; Cao, Derang; Liu, Qingfang; Wang, Jianbo

    2014-05-07

    FeCoCd thin films with 500 nm thickness are directly prepared through electrodeposition in the sulphate bath in which glycine and citric acid were added as complex agents. The composition, structure, and magnetic of FeCoCd films were investigated as a function of Cd(2+) concentration, cathode current density, and deposition temperature. A wonderful soft magnetic FeCoCd film was prepared and its coercivity of easy axis and hard axis are 5 Oe and 4 Oe, respectively. The natural resonance frequency is about 3.0 GHz, which imply that the FeCoCd film is potential candidate for high frequency applications.

  12. Influence of Zn2+ doping on the crystal structure and optical-electrical properties of CdTe thin films

    Science.gov (United States)

    Kavitha, R.; Sakthivel, K.

    2015-10-01

    The present study reports the synthesis of Cd1-xZnxTe (x = 0, 0.025, 0.050, 0.075 and 0.100) nanocrystalline thin film through a simple two step method. In the first step fine nanoparticles of Cd1-xZnxTe was prepared by solvothermal microwave irradiation (SMI) technique and then deposited as thin film using dip-coating technique. X-ray diffraction study showed that films are polycrystalline with cubic phase, which are preferentially oriented along the (1 1 1) direction. No impurity phase was observed in the XRD pattern even after higher concentration of doping (x = 0.100) of Zn. FESEM study revealed that the films are homogeneous without cracks and pinholes. TEM micrographs revealed the particles are slightly agglomerated and lesser than 25 nm. The optical absorption study revealed that pure and doped CdTe films possess a direct band gap material with bandgap values between 2.39 and 2.63 eV (±0.02 eV). The values of optical bandgap increase with an increase in dopant (Zn) concentration from x = 0.025 to 0.10. The pure cadmium telluride (CdTe) nanocrystalline film shows a strong green emission peak centered at about 525 nm. The emission peaks of Cd1-xZnxTe nanocrystalline films are red shifted from 525 nm to 611 nm according to the dopant (Zn2+) concentration. The grains in the prepared films are uniformly distributed, which was confirmed by narrow full width at half maximum (FWHM) of the emission peaks (40-65 nm). The DC conductivity has increased by 1.25 and 4 orders as the concentration of dopant increases from x = 0.025 to 0.10 at room temperature (30 °C) and 150 °C respectively. The higher conductivity value is underpinned by the smaller activation energy value and is explained by thermionic emission mechanism.

  13. Influence of secondary phases during annealing on re-crystallization of CuInSe{sub 2} electrodeposited films

    Energy Technology Data Exchange (ETDEWEB)

    Gobeaut, A. [Laboratoire de Reactivite et Chimie des Solides, 33 rue St Leu, 80039 Amiens (France); Laffont, L., E-mail: lydia.laffont@u-picardie.f [Laboratoire de Reactivite et Chimie des Solides, 33 rue St Leu, 80039 Amiens (France); Tarascon, J.-M. [Laboratoire de Reactivite et Chimie des Solides, 33 rue St Leu, 80039 Amiens (France); Parissi, L.; Kerrec, O. [Institut de Recherche et de Developpement de l' Energie Photovoltaique, 6 quai Watier, 78401 Chatou cedex (France)

    2009-06-01

    Electrodeposited CuInSe{sub 2} thin films are of potential importance, as light absorber material, in the next generation of photovoltaic cells as long as we can optimize their annealing process to obtain dense and highly crystalline films. The intent of this study was to gain a basic understanding of the key experimental parameters governing the structural-textural-composition evolution of thin films as function of the annealing temperature via X-ray diffraction, scanning/transmission electron microscopy and thermal analysis measurements. The crystallization of the electrodeposited CuInSe{sub 2} films, with the presence of Se and orthorhombic Cu{sub 2} {sub -} {sub x}Se (o-Cu{sub 2} {sub -} {sub x}Se) phases, occurs over two distinct temperature ranges, between 220 {sup o}C and 250 {sup o}C and beyond 520 {sup o}C. Such domains of temperature are consistent with the melting of elemental Se and the binary CuSe phase, respectively. The CuSe phase forming during annealing results from the reaction between the two secondary species o-Cu{sub 2} {sub -} {sub x}Se and Se (o-Cu{sub 2} {sub -} {sub x}Se + Se {yields} 2 CuSe) but can be decomposed into the cubic {beta}-Cu{sub 2} {sub -} {sub x}Se phase by slowing down the heating rate. Formation of liquid CuSe beyond 520{sup o}C seems to govern both the grain size of the films and the porosity of the substrate-CuInSe{sub 2} film interface. A simple model explaining the competitive interplay between the film crystallinity and the interface porosity is proposed, aiming at an improved protocol based on temperature range, which will enable to enhance the film crystalline nature while limiting the interface porosity.

  14. Layered Ni(OH)2-Co(OH)2 films prepared by electrodeposition as charge storage electrodes for hybrid supercapacitors

    Science.gov (United States)

    Nguyen, Tuyen; Boudard, Michel; Carmezim, M. João; Montemor, M. Fátima

    2017-01-01

    Consecutive layers of Ni(OH)2 and Co(OH)2 were electrodeposited on stainless steel current collectors for preparing charge storage electrodes of high specific capacity with potential application in hybrid supercapacitors. Different electrodes were prepared consisting on films of Ni(OH)2, Co(OH)2, Ni1/2Co1/2(OH)2 and layered films of Ni(OH)2 on Co(OH)2 and Co(OH)2 on Ni(OH)2 to highlight the advantages of the new architecture. The microscopy studies revealed the formation of nanosheets in the Co(OH)2 films and of particles agglomerates in the Ni(OH)2 films. Important morphological changes were observed in the double hydroxides films and layered films. Film growth by electrodeposition was governed by instantaneous nucleation mechanism. The new architecture composed of Ni(OH)2 on Co(OH)2 displayed a redox response characterized by the presence of two peaks in the cyclic voltammograms, arising from redox reactions of the metallic species present in the layered film. These electrodes revealed a specific capacity of 762 C g−1 at the specific current of 1 A g−1. The hybrid cell using Ni(OH)2 on Co(OH)2 as positive electrode and carbon nanofoam paper as negative electrode display specific energies of 101.3 W h g−1 and 37.8 W h g−1 at specific powers of 0.2 W g−1 and 2.45 W g−1, respectively. PMID:28051143

  15. Influence of post-deposition heat treatment on optical properties derived from UV–vis of cadmium telluride (CdTe) thin films deposited on amorphous substrate

    Energy Technology Data Exchange (ETDEWEB)

    Punitha, K. [Department of Physics, Alagappa University, Karaikudi 630004 (India); Sivakumar, R., E-mail: krsivakumar1979@yahoo.com [Directorate of Distance Education, Alagappa University, Karaikudi 630004 (India); Sanjeeviraja, C. [Department of Physics, Alagappa Chettiar College of Engineering and Technology, Karaikudi 630004 (India); Ganesan, V. [UGC-DAE Consortium for Scientific Research, Indore 452001 (India)

    2015-07-30

    Graphical abstract: - Highlights: • Annealing-induced change in optical parameters of CdTe film was derived from UV–vis study. • Optical constants of the films were evaluated using Swanepoel method. • Dispersion energy data obeyed the single oscillator of the Wemple−Didomenico model. • Cd deficiency of the film confirmed the p-type conductive nature. - Abstract: In this work, we report on post-deposition heat treatment (annealing)-induced change in optical properties derived from UV–vis study of CdTe thin films prepared on amorphous glass substrate by electron beam evaporation technique. Annealing effect gives rise to the enhancement in crystalline nature (zinc blende structure) of CdTe films with (1 1 1) preferred orientation. The average transmittance was increased with the annealing temperature and the slight shift in transmission threshold towards higher wavelength region revealed the systematic reduction in optical energy band gap. The existence of shallow level just below the conduction band, within the band gap was identified in the range of 0.23 and 0.14 eV for the films annealed at 200 and 450 °C, respectively. The optical quality of deposited films was confirmed by the photoluminescence study. In addition, the scanning electron microscopic measurement supports the result of X-ray diffraction study. The Swanepoel, Hervé-Vandamme, and Wemple−DiDomenico models have been employed to evaluate the various optical parameters of CdTe films. These results are correlated well with other physical properties and discussed with the possible concepts underlying the phenomena.

  16. Cd-Te-In oxide thin films as possible transparent buffer layer in CdTe based solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Castro-Rodriguez, R; Camacho, J M; Pena, J L [Applied Physics Department, CINVESTAV-IPN Merida, C.P. 97310, Merida, Yucatan (Mexico); Martel, A; Mendez-Gamboa, J, E-mail: romano@mda.cinvestav.m [Facultad de Ingenieria, Universidad Autonoma de Yucatan. AP 150 Cordemex, 97310 Merida, Yucatan (Mexico)

    2009-05-01

    Cd-Te-In-oxide thin films were grown by Pulsed Laser Deposition (PLD) technique using CdTe powder embedded in a matrix of indium metallic as target. The films were deposited at different oxygen pressures (P{sub o2}) from 15 to 50 mTorr at substrate temperature of 420{sup 0}C. Sheet resistance (R{sub sheet}) and transmission spectrum were measured as a function of P{sub o2}. From measurements of optical transmission, the Photonic Flux Density (PFD) spectrum were obtained and the integral of these PFD for each film were evaluated between energy range of 1.5 eV and 2.4 eV for obtain the amount of photons that can be transferred across the film in this range of solar energy spectrum. These values were evaluated over the R{sub sheet} to be used as a figure of merit. The best choice in our conditions was the films with P{sub o2} =28.5 mTorr, where the figure of merit reaches the maximum value.

  17. Growth of ZnO nanowires through thermal oxidation of metallic zinc films on CdTe substrates

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, O., E-mail: oscar@fmc.uva.es [Optronlab Group, Dpto. Fisica Materia Condensada, Edificio I-D, Universidad de Valladolid, Paseo de Belen 1, 47011, Valladolid (Spain); Hortelano, V.; Jimenez, J. [Optronlab Group, Dpto. Fisica Materia Condensada, Edificio I-D, Universidad de Valladolid, Paseo de Belen 1, 47011, Valladolid (Spain); Plaza, J.L.; Dios, S. de; Olvera, J.; Dieguez, E. [Laboratorio de Crecimiento de Cristales, Departamento de Fisica de Materiales, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Fath, R.; Lozano, J.G.; Ben, T.; Gonzalez, D. [Dpto. Ciencia de los Materiales e Ingenieria Metalurgica y Q.I., Facultad de Ciencias, Apdo. 40, 11510 Puerto Real, Cadiz (Spain); Mass, J. [Dpto. de Fisica, Universidad del Norte, Km.5 Via Puerto Colombia, Barranquilla (Colombia)

    2011-04-28

    Research highlights: > ZnO nanowires grown from thermal Zn oxidation. > TEM reveals high quality thin nanowires several microns long. > New phase formation at long oxidation time. > Good spectroscopic properties measured by Raman, Photo and Cathodoluminsecence spectroscopies. - Abstract: <112-bar 0> wurtzite ZnO nanowires (NWs) have been obtained by oxidizing in air at 500 deg. C thermally evaporated Zn metal films deposited onto CdTe substrates. The presence of Cd atoms from the substrate on the ZnO seeding layer and NWs seems to affect the growth of the NWs. The effects of the oxidation time on the structural and optical properties of the NWs are described in detail. It is shown that the NWs density decreases and their length increases when increasing the oxidation time. Thicker Zn layers result in thinner and longer ZnO NWs. Very long oxidation times also lead to the formation of a new CdO phase which is related to the partial destruction and quality reduction of the NWs. The possible process for ZnO NW formation on CdTe substrates is discussed.

  18. Synthesis of CuInSe2 thin films from electrodeposited Cu11In9 precursors by two-step annealing

    Directory of Open Access Journals (Sweden)

    TSUNG-WEI CHANG

    2014-02-01

    Full Text Available In this study, copper indium selenide (CIS films were synthesized from electrodeposited Cu-In-Se precursors by two-step annealing. The agglomeration phenomenon of the electrodeposited In layer usually occurred on the Cu surface. A thermal process was adopted to turn Cu-In precursors into uniform Cu11In9 binary compounds. After deposition of the Se layer, annealing was employed to form chalcopyrite CIS. However, synthesis of CIS from Cu11In9 requires sufficient thermal energy. Annealing temperature and time were investigated to grow high quality CIS film. Various electrodeposition conditions were investigated to achieve the proper atomic ratio of CIS. The properties of the CIS films were characterized by scanning electron microscopy (SEM, X-ray Diffraction (XRD, and Raman spectra.

  19. The influence of the effective physical properties of tin electrodeposited films on the growth of tin whiskers

    Science.gov (United States)

    Pedigo, Aaron E.

    The purpose of the present study was to characterize and calculate the effective film properties of electrodeposited tin films to determine factors influencing the growth of tin (Sn) whiskers. The growth of Sn whiskers represents an increased risk to the reliability of electronic devices, and is a particular concern in the high reliability environments demanded in aerospace and defense applications. Efforts to prevent whisker growth have proven difficult, in part, due to the lack of understanding concerning the fundamental mechanisms responsible for whisker growth. In the present study, Sn, Sn-Cu, and Sn Cu Pb films were electrodeposited from commercial electrolytes with different deposition parameters. The morphology of Sn hillocks and whiskers were characterized leading to a growth model considering the role of grain boundary mobility. Crystallographic texture measurements revealed non-random textures, dependent on electrolyte type, electrolyte additives, deposition current density, and film thickness. The crystallographic texture was also found to evolve with time, indicating recrystallization and grain growth. The corresponding textures were used to calculate the effective physical properties of the films, showing significant differences in the linear modulus of elasticity, biaxial modulus of elasticity, and coefficient of thermal expansion. The influence of these effective properties on the strain energy density of the film was analyzed with respect to the evolution of crystallographic texture and film stress. The results show that the reduction of strain energy and surface energy is not the only driving force dictating the evolution of the crystallographic texture. Recommendations are made for future studies to apply the analysis tools developed in this study for future whisker research, as well as for industrial applications.

  20. Electrodeposition of polymer electrolyte in nanostructured electrodes for enhanced electrochemical performance of thin-film Li-ion microbatteries

    Science.gov (United States)

    Salian, Girish D.; Lebouin, Chrystelle; Demoulin, A.; Lepihin, M. S.; Maria, S.; Galeyeva, A. K.; Kurbatov, A. P.; Djenizian, Thierry

    2017-02-01

    We report that electrodeposition of polymer electrolyte in nanostructured electrodes has a strong influence on the electrochemical properties of thin-film Li-ion microbatteries. Electropolymerization of PMMA-PEG (polymethyl methacrylate-polyethylene glycol) was carried out on both the anode (self-supported titania nanotubes) and the cathode (porous LiNi0.5Mn1.5O4) by cyclic voltammetry and the resulting electrode-electrolyte interface was examined by scanning electron microscopy. The electrochemical characterizations performed by galvanostatic experiments reveal that the capacity values obtained at different C-rates are doubled when the electrodes are completely filled by the polymer electrolyte.

  1. Electrodeposition of Water-Repellent Organic Dielectric Film as an Anti-Sticking Coating on Microelectromechanical System Devices

    Science.gov (United States)

    Sakata, Tomomi; Kuwabara, Kei; Shimamura, Toshishige; Sato, Norio; Nagase, Masao; Shimoyama, Nobuhiro; Kudou, Kazuhisa; Machida, Katsuyuki; Ishii, Hiromu

    2007-09-01

    In this paper, we propose a technique of preventing both wet-release-related and in-use sticking of actuators in microelectromechanical system (MEMS) devices. The technique involves the electrodeposition of a water-repellent organic dielectric film that renders the microstructure surface inactive towards the water used for rinsing. The source material is a core/shell emulsion, which consists of sulfonium cations with epoxy groups containing water-repellent silicone polymers. Applying this technique to the encapsulation of a microstructure confirms its effectiveness in preventing both release-related sticking and in-use sticking of a MEMS structure.

  2. Electrodeposition of nickel-phosphorus nanoparticles film as a Janus electrocatalyst for electro-splitting of water

    Science.gov (United States)

    Liu, Qian; Gu, Shuang; Li, Chang Ming

    2015-12-01

    Nickel-phosphorus nanoparticles film on copper foam (Ni-P/CF) was prepared by electrodeposition. This electrocatalyst shows high catalytic activity and durability toward both hydrogen and oxygen evolution reactions in basic electrolytes. The results show that Ni-P/CF can deliver a current density of 10 mA cm-2 at an overpotential of 98 mV for hydrogen production and 325 mV for oxygen generating. A two-electrode water electrolyzer using Ni-P/CF as cathode and anode produces 10 mA cm-2 at a cell voltage of 1.68 V with high stability.

  3. Electrodeposited Structurally Stable V2O5 Inverse Opal Networks as High Performance Thin Film Lithium Batteries.

    Science.gov (United States)

    Armstrong, Eileen; McNulty, David; Geaney, Hugh; O'Dwyer, Colm

    2015-12-01

    High performance thin film lithium batteries using structurally stable electrodeposited V2O5 inverse opal (IO) networks as cathodes provide high capacity and outstanding cycling capability and also were demonstrated on transparent conducting oxide current collectors. The superior electrochemical performance of the inverse opal structures was evaluated through galvanostatic and potentiodynamic cycling, and the IO thin film battery offers increased capacity retention compared to micron-scale bulk particles from improved mechanical stability and electrical contact to stainless steel or transparent conducting current collectors from bottom-up electrodeposition growth. Li(+) is inserted into planar and IO structures at different potentials, and correlated to a preferential exposure of insertion sites of the IO network to the electrolyte. Additionally, potentiodynamic testing quantified the portion of the capacity stored as surface bound capacitive charge. Raman scattering and XRD characterization showed how the IO allows swelling into the pore volume rather than away from the current collector. V2O5 IO coin cells offer high initial capacities, but capacity fading can occur with limited electrolyte. Finally, we demonstrate that a V2O5 IO thin film battery prepared on a transparent conducting current collector with excess electrolyte exhibits high capacities (∼200 mAh g(-1)) and outstanding capacity retention and rate capability.

  4. Electrodeposition of unsubstituted iron phthalocyanine nano-structure film in a functionalized ionic liquid and its electrocatalytic and electroanalysis applications.

    Science.gov (United States)

    Wang, Kun; Dai, Lina; Liu, Qian; Li, Henan; Ju, Chang; Wu, Jun; Li, Huaming

    2011-10-21

    We report a novel and facile electrodeposition method to fabricate a nano-structure film of the unsubstituted metal phthalocyanine on a glassy carbon electrode (GCE). In this electrodeposition system, unsubstituted iron(II) phthalocyanine (u-FePc) was chosen as the model complex of the unsubstituted metalphthalocyanine, and the ionic liquid 1-octyl-3-methylimidazolium trifluoroacetate was employed as the solvent and electrolyte, thus avoiding the use of additional costly supporting electrolyte. Excellent electrocatalytic performance of the u-FePc nano-structure film was first evaluated by electrocatalytic oxidation of ascorbic acid (AA). Compared with the bare GCE, the oxidation peak potential of AA at u-FePc/GCE shifted negatively about 264 mV, and the oxidation peak current increased about 1.8 times. Furthermore, the as-prepared film was employed for the investigation of luminol electrochemiluminescence (ECL) behavior in neutral solution, which showed excellent performance including under selected experimental conditions, the ECL intensity showing an acceptable linear relationship for luminol concentrations between 5 × 10(-8) and 5 × 10(-6) M, and a linear response to H(2)O(2) over a wide concentration range, from 1.0 × 10(-8) to 1.0 × 10(-5) M in 3.0 μM luminol solution.

  5. Effect of different nickel precursors on capacitive behavior of electrodeposited NiO thin films

    Science.gov (United States)

    Kore, R. M.; Ghadge, T. S.; Ambare, R. C.; Lokhande, B. J.

    2016-04-01

    In the present study, the effect of nickel precursors containing different anions like nitrate, chloride and sulphate on the morphology and pseudocapacitance behavior of NiO is investigated. The NiO samples were prepared by using a potentiondynamic electrodeposition technique in the three electrode cell. Cyclic voltammetry technique was exploited for potentiodynamic deposition of the films. The obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), etc. The XRD reveals the cubic crystal structure for all samples. The SEM micrograph shows nanoflakelike, up grown nanoflakes and honeycomb like nanostructured morphologies for nitrate, chloride and sulphate precursors respectively. The capacitive behavior of these samples was recorded using cyclic voltammetry (CV), charge-discharge and electrochemical impedance spectroscopy (EIS) in 1 M KOH electrolyte. The specific capacitance values of NiO samples obtained using CV for nitrate, chloride and sulphate precursors were 136, 214 and 893 Fg-1 respectively, at the scan rate of 5 mVs-1. The charge discharge study shows high specific energy for the sample obtained from sulphate (23.98 Whkg-1) as compared to chloride (9.67 Whkg-1) and nitrate (4.9 Whkg-1), whereas samples of cholride (13.9 kWkg-1 and nitrate (10.5 kWkg-1) shows comparatively more specific power than samples obtained from sulphate (7.6 kWkg-1). The equivalent series resistance of NiO samples observed from EIS study are 1.34, 1.29 and 1.27 Ω respectively for nitrate, chloride and sulphate precursors. These results emphasizes that the samples obtained from sulphate precursors provides very low impedance through honeycomb like nanostructured morphology which supports good capacitive behavior of NiO.

  6. Flexible photodiodes constructed with CdTe nanoparticle thin films and single ZnO nanowires on plastics.

    Science.gov (United States)

    Kwak, Kiyeol; Cho, Kyoungah; Kim, Sangsig

    2011-10-14

    We construct a flexible pn heterostructured photodiode using a CdTe nanoparticle thin film and a single ZnO nanowire (NW) on a plastic substrate. The photocurrent characteristics of the flexible photodiode are examined under illumination with 325 nm wavelength light and the photocurrent efficiencies at bias voltages of ± 2.5 V are estimated to be 8.0 and 2.1 µA W(-1) under forward and reverse bias conditions, respectively. The photocurrent generation of the pn heterostructured photodiode is dominantly associated with the transport of the photogenerated charge carriers in the single ZnO NW. Furthermore, the operations of our flexible photodiode are investigated in the upwardly and downwardly bent states, as well as in the flat state.

  7. Electrodeposition of diamond-like carbon films on titanium alloy using organic liquids: Corrosion and wear resistance

    Energy Technology Data Exchange (ETDEWEB)

    Falcade, Tiago, E-mail: tiago.falcade@ufrgs.br [Federal University of Rio Grande do Sul, 9500 Bento Goncalves Ave. Sector 4, Building 75, 2nd floor, Porto Alegre, RS (Brazil); Shmitzhaus, Tobias Eduardo, E-mail: tobiasschmitzhaus@gmail.com [Federal University of Rio Grande do Sul, Porto Alegre, RS (Brazil); Gomes dos Reis, Otavio, E-mail: otavio_gomes214@hotmail.com [Federal University of Rio Grande do Sul, Porto Alegre, RS (Brazil); Vargas, Andre Luis Marin; Huebler, Roberto [Pontificia Universidade Catolica do Rio Grande do Sul (Brazil); Mueller, Iduvirges Lourdes, E-mail: ilmuller@ufrgs.br [Federal University of Rio Grande do Sul, Porto Alegre, RS (Brazil); Fraga Malfatti, Celia de, E-mail: celia.malfatti@ufrgs.br [Federal University of Rio Grande do Sul, Porto Alegre, RS (Brazil)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer The electrodeposition may be conducted at room temperature. Black-Right-Pointing-Pointer The DLC films have good resistance to corrosion in saline environments. Black-Right-Pointing-Pointer The films have lower coefficient of friction than the uncoated substrate. Black-Right-Pointing-Pointer The abrasive wear protection is evident in coated systems. - Abstract: Diamond-like carbon (DLC) films have been studied as coatings for corrosion protection and wear resistance because they have excellent chemical inertness in traditional corrosive environments, besides presenting a significant reduction in coefficient of friction. Diamond-like carbon (DLC) films obtained by electrochemical deposition techniques have attracted a lot of interest, regarding their potential in relation to the vapor phase deposition techniques. The electrochemical deposition techniques are carried out at room temperature and do not need vacuum system, making easier this way the technological transfer. At high electric fields, the organic molecules polarize and react on the electrode surface, forming carbon films. The aim of this work was to obtain DLC films onto Ti6Al4V substrate using as electrolyte: acetonitrile (ACN) and N,N-dimethylformamide (DMF). The films were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), Raman spectroscopy, potentiodynamic polarization and wear tests. The results show that these films can improve, significantly, the corrosion resistance of titanium and its alloys and their wear resistance.

  8. Effect of methanol ratio in mixed solvents on optical properties and wettability of ZnO films by cathodic electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Miao; Xu, Kai; Jiang, Xishun; Yang, Lei; He, Gang; Song, Xueping [School of Physics and Material Science, Anhui University, Hefei 230601 (China); Sun, Zhaoqi, E-mail: szq@ahu.edu.cn [School of Physics and Material Science, Anhui University, Hefei 230601 (China); Lv, Jianguo, E-mail: lvjg1@163.com [School of Electronic and Information Engineering, Hefei Normal University, Hefei 230601 (China)

    2014-12-05

    Highlights: • Different surface morphologies of ZnO films were prepared by cathodic electrodeposition. • The surface morphologies are controlled through add different ratio methanol to electrolyte. • The morphology changes from nanorods with hexagonal structure to net-like nanostructure. • The wettability of films shows obvious change with increasing methanol ratio. • The maximum light-induced CA change has been observed with the methanol ratio of 0.8. - Abstract: ZnO thin films were prepared in the electrolyte with different methanol ratio by cathodic electrodeposition method. Microstructure, surface morphology, optical properties and wettability of the thin films were investigated by X-ray diffractometer, field-emission scanning electron microscope, ultraviolet–visible spectroscope, fluorescence spectrometer and water contact angle apparatus. Increase of methanol ratio in the solvents may restrain the (0 0 2) plane preferential orientation in some extent. Change of current density curves with the ratio of methanol in the solution play a vital role on electrochemical reaction kinetics, microstructure and/or surface morphology of ZnO thin films. With the methanol ratio increase from 0 to 0.8, the surface morphology changes from nanorods to net-like nanostructure. The adsorbed NO{sub 3}{sup −} ions on the polar planes hinder the crystal growth along the c-axis and redirect the growth direction along the nonpolar planes. The maximum and minimum band gaps have been obtained in the ZnO thin films with the methanol ratio of 0.4 and 0.6, respectively. Change of contact angle before UV irradiation may be related to surface morphology and oxygen vacancies. The maximum light-induced water contact angle change has been observed in the sample with the methanol ratio of 0.8. The results may be attributed to the higher surface roughness and net-like morphology.

  9. Effect of Deposition Time on the Photoelectrochemical Properties of Cupric Oxide Thin Films Synthesized via Electrodeposition Method

    Directory of Open Access Journals (Sweden)

    Yaw Chong Siang

    2016-01-01

    Full Text Available The main aim of this study was to investigate the effect of deposition time on the physicochemical and photoelectrochemical properties of cupric oxide (CuO thin films synthesized via electrodeposition method. Firstly, the electrodeposition of amorphous CuO films on fluorine-doped tin oxide (FTO working electrodes with varying deposition time between 5 and 30 min was carried out, followed by annealing treatment at 500 °C. Resultant nanocrystalline CuO thin films were characterised using field emission-scanning electron microscopy (FE-SEM, photocurrent density, and photoluminescence measurements. Through FE-SEM analysis, it was observed that the surface of thin films was composed of irregular-sized CuO nanocrystals. A smaller CuO nanocrystals size will lead to a higher photoactivity due to the increase in overall catalytic surface area. In addition, the smaller CuO nanocrystals size will prolongs the electron-hole recombination rate due to the increase in copious amount of surface defects. From this study, it was revealed that the relationship between deposition time and CuO film thickness was non-linear. This could be due to the detachment of CuO thin films from the FTO surface at an increasing amount of CuO mass being deposited. It was observed that the amount of light absorbed by CuO thin films increased with film thickness until a certain extent whereby, any further increase in the film thickness will result in a reduction of light photon penetration. Therefore, the CuO nanocrystals size and film thickness have to be compromised in order to yield a higher catalytic surface area and a lower rate of surface charge recombination. Finally, it was found that the deposition time of 15 min resulted in an average CuO nanocrystals size of 73.7 nm, optimum film thickness of 0.73 μm, and corresponding photocurrent density of 0.23 mA/cm2 at the potential bias of - 0.3 V (versus Ag/AgCl. The PL spectra for the deposition time of 15 min has the lowest

  10. Effects of high magnetic field assisted annealing on structure and optical, electric properties of electrodeposited ZnO films

    Science.gov (United States)

    Gao, Yang; Li, Guojian; Wu, Chun; Sui, Xudong; Du, Jiaojiao; Wang, Qiang

    2017-01-01

    Electrodeposited ZnO films have been annealed at 300 °C for 2 h under 12 T high magnetic field (HMF) with the directions of parallel and perpendicular to the films, respectively. The structural, optical and electric properties were characterized by scanning electron microscopy, X-ray diffraction, photoluminescence (PL) spectra, X-ray photoemission spectroscopy (XPS) and Seebeck coefficient/electrical resistance measuring system. The results show that HMF has a significant effect on the growth of ZnO films along c-axis and leads to hexagonal platelets of ZnO growing parallel to the direction of HMF. Furthermore, the hexagonal platelets become bulky platelets with an obvious trendy rotating their c-axis parallel to the substrate. The PL spectra of all the films exhibits the UV and blue emission, moreover, the blue emission plays the main role. The resistivity of ZnO films increases with the increase of measure temperature, which shows a typical degenerate semiconductor characteristic. HMF reduces significantly the intensity of whole emission peaks and the resistivity of ZnO films. These may be attribute to the significant changes of the structure and morphology of ZnO films, leading to various amounts of the defects in the ZnO crystal.

  11. Electrodeposition of Mg doped ZnO thin film for the window layer of CIGS solar cell

    Science.gov (United States)

    Wang, Mang; Yi, Jie; Yang, Sui; Cao, Zhou; Huang, Xiaopan; Li, Yuanhong; Li, Hongxing; Zhong, Jianxin

    2016-09-01

    Mg doped ZnO (ZMO) film with the tunable bandgap can adjust the conduction band offset of the window/chalcopyrite absorber heterointerface to positive to reduce the interface recombination and resulting in an increasement of chalcopyrite based solar cell efficiency. A systematic study of the effect of the electrodeposition potential on morphology, crystalline structure, crystallographic orientation and optical properties of ZMO films was investigated. It is interestingly found that the prepared doped samples undergo a significant morphological change induced by the deposition potential. With negative shift of deposition potential, an obvious morphology evolution from nanorod structrue to particle covered films was observed. A possible growth mechanism for explaining the morphological change is proposed and briefly discussed. The combined optical techniques including absorption, transmission and photoluminescence were used to study the obtained ZMO films deposited at different potential. The sample deposited at -0.9 V with the hexagonal nanorods morphology shows the highest optical transparency of 92%. The photoluminescence spectra reveal that the crystallization of the hexagonal nanorod ZMO thin film deoposited at -0.9 V is much better than the particles covered ZMO thin film. Combining the structural and optical properties analysis, the obtained normal hexagonal nanorod ZMO thin film could potentially be useful in nanostructured chalcopyrite solar cells to improve the device performance.

  12. Fabrication of electrodeposited Ni-Cu/Cu multilayered films and study of their nanostructures before and after annealing

    Directory of Open Access Journals (Sweden)

    I Kazeminezhad

    2008-07-01

    Full Text Available  In this work electrodeposited Ni-Cu/Cu metallic multilayered films with different thicknesses of Ni and Cu were prepared on (100 polycrystalline Cu substrates. The nanostructure of the multilayers was studied using XRD. The existence of satellite peaks in the XRD patterns showed that the multilayered films have superlattice structures. The difference between the intensity of ML(200 and ML(111 peaks showed that the multilayers have a strong texture of (100 as their substrate structures which confirms the epitaxial growth. The morphology of the films was studied by SEM. The SEM images showed that the surface of the films is rough. The samples were also analyzed using EDX and the results showed that the real content of Ni is less than its nominal content this refers to the current efficiency which is less than unity due to hydrogen evolution. In the second stage of the work some identical samples which have the highest order of satellite peaks were electrodeposited. The samples were annealed at different temperatures and times. Their structures were then studied by XRD. The XRD patterns of the annealed samples showed that if the temperature and time of annealing increase, the satellite peaks begin to disappear. It means by increasing these two parameters, the sharpness of the bilayer interface decreases and the multilayered structure tends to become alloy structure. The morphology of the samples was also studied by SEM. The SEM images showed that the surface of the annealed films becomes approximately uniform due to the diffusion of Ni and Cu atoms to Cu and Ni layers, respectively.

  13. Synthesis and magnetic characterization of a Cu{sub 80}Co{sub 20} thin film obtained by electrodeposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Bran, Julien; Jean, Malick; Lardé, Rodrigue; Sauvage, Xavier [Groupe de Physique des Matériaux, UMR 6634 CNRS, Université et INSA de Rouen, 76801 St Etienne du Rouvray (France); Breton, Jean-Marie Le, E-mail: jean-marie.lebreton@univ-rouen.fr [Groupe de Physique des Matériaux, UMR 6634 CNRS, Université et INSA de Rouen, 76801 St Etienne du Rouvray (France); Morin-Grognet, Sandrine [Laboratoire de Biophysique et Biomatériaux, MERCI EA 3829, Centre Universitaire d’Evreux, Université de Rouen, 1 rue du 7ème Chasseurs, 27002 Evreux Cedex (France); Pautrat, Alain [Laboratoire Crismat, UMR 6508 CNRS ENSICAEN, 6 boulevard du maréchal Juin, 14050 Caen Cedex (France)

    2014-05-01

    Highlights: • A Cu{sub 80}Co{sub 20} alloy was obtained by low cost electrodeposition. • The structure was investigated down to the atomic scale. • No oxides were formed. • Magnetoresistance is clearly related to superparamagnetic Co nanoparticles. - Abstract: A granular Cu{sub 80}Co{sub 20} alloy was elaborated by a low cost electrodeposition technique consisting in reducing simultaneously the Cu{sup 2+} and Co{sup 2+} ions onto a silicon substrate. The deposition parameters were determined from current-potential curves. The structure of the film was characterized down to the atomic scale by transmission electron microscopy and atom probe tomography. The results show that the as-deposited Cu{sub 80}Co{sub 20} thin film consists mainly of a paramagnetic Cu–Co solid solution containing 10–30% of Co, in which pure Co superparamagnetic nanoparticles are dissolved. Annealing at 500 °C for 1 h leads to the decomposition of the Cu–Co solid solution into purified Cu matrix containing ferromagnetic Co-rich precipitates. The magnetoresistance effect decreases after the heat treatment, in relation with the disappearance of the superparamagnetic Co nanoparticles upon annealing.

  14. Grain boundaries in CdTe thin film solar cells: a review

    Science.gov (United States)

    Major, Jonathan D.

    2016-09-01

    The current state of knowledge on the impact of grain boundaries in CdTe solar cells is reviewed with emphasis being placed on working cell structures. The role of the chemical composition of grain boundaries as well as growth processes are discussed, along with characterisation techniques such as electron beam induced current and cathodoluminescence, which are capable of extracting information on a level of resolution comparable to the size of the grain boundaries. Work which attempts to relate grain boundaries to device efficiency is also assessed and gaps in the current knowledge are highlighted.

  15. Innovative sputtering techniques for CIS and CdTe submodule fabrication. Annual subcontract report, 1 September 1991--31 August 1992

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, J.M.; Misra, M.S.; Lanning, B. [Martin Marietta Aerospace, Denver, CO (United States). Astronautics Group

    1993-03-01

    This report describes work done during Phase 1 of the subject subcontract. The subcontract was designed to study innovative deposition techniques, such as the rotating cylindrical magnetron sputtering system and electrodeposition for large-area, low-cost copper indium diselenide (CIS) and cadmium telluride (CdTe) devices. A key issue for photovoltaics (PV) in terrestrial and future space applications is producibility, particularly for applications using a large quantity of PV. Among the concerns for fabrication of polycrystalline thin-film PV, such as CIS and CdTe, are production volume, cost, and minimization of waste. Both rotating cylindrical magnetron (C-Mag{trademark}) sputtering and electrodeposition have tremendous potential for the fabrication of polycrystalline thin-film PV due to scaleability, efficient utilization of source materials, and inherently higher deposition rates. In the case of sputtering, the unique geometry of the C-Mae facilitates innovative cosputtering and reactive sputtering that could lead to greater throughput reduced health and safety risks, and, ultimately, lower fabrication cost. Electrodeposited films appear to be adherent and comparable with low-cost fabrication techniques. Phase I involved the initial film and device fabrication using the two techniques mentioned herein. Devices were tested by both internal facilities, as well as NREL and ISET.

  16. Influence of plasma parameters and substrate temperature on the structural and optical properties of CdTe thin films deposited on glass by laser ablation

    Energy Technology Data Exchange (ETDEWEB)

    Quiñones-Galván, J. G.; Santana-Aranda, M. A.; Pérez-Centeno, A. [Departamento de Física, Centro Universitario de Ciencias Exactas e Ingenierías, Universidad de Guadalajara, Boulevard Marcelino García Barragán 1421, Guadalajara, Jalisco C.P. 44430 (Mexico); Camps, Enrique [Departamento de Física, Instituto Nacional de Investigaciones Nucleares, Apartado Postal 18-1027, D.F., C.P. 11801 (Mexico); Campos-González, E.; Guillén-Cervantes, A.; Santoyo-Salazar, J.; Zelaya-Angel, O. [Departamento de Física, CINVESTAV-IPN, Apartado Postal 14-740, D. F. C.P. 07360 (Mexico); Hernández-Hernández, A. [Escuela Superior de Apan, Universidad Autónoma del Estado de Hidalgo, Calle Ejido de Chimalpa Tlalayote s/n Colonia Chimalpa, Apan Hidalgo (Mexico); Moure-Flores, F. de [Facultad de Química, Materiales, Universidad Autónoma de Querétaro, Querétaro C.P. 76010 (Mexico)

    2015-09-28

    In the pulsed laser deposition of thin films, plasma parameters such as energy and density of ions play an important role in the properties of materials. In the present work, cadmium telluride thin films were obtained by laser ablation of a stoichiometric CdTe target in vacuum, using two different values for: substrate temperature (RT and 200 °C) and plasma energy (120 and 200 eV). Structural characterization revealed that the crystalline phase can be changed by controlling both plasma energy and substrate temperature; which affects the corresponding band gap energy. All the thin films showed smooth surfaces and a Te rich composition.

  17. Study of the defect levels, electrooptics, and interface properties of polycrystalline CdTe and CdS thin films and their junction

    Energy Technology Data Exchange (ETDEWEB)

    Abulfotuh, F.A.; Balcioglu, A.; Wangensteen, T.; Moutinho, H.R.; Hassoon, F.; Kazmerski, L.L. [National Renewable Energy Lab., Golden, CO (United States); Al-Douri, A.; Alnajjar, A. [United Arab Emirates Univ., Al-Ain (United Arab Emirates). Physics Dept.

    1997-12-31

    In this study, the electrical behavior of CdS/CdTe junctions was investigated using deep-level transient spectroscopy (DLTS) and capacitance-voltage (c-v) measurements. The results were then correlated to chemical composition and optical properties (measured by using a wavelength-scanning ellipsometer) of the CdTe film and the dominant defect states were determined by photoluminescence (PL) emission measured before and after post-deposition CdCl{sub 2} treatments. CdTe films used in this study were prepared by electrochemical deposition (ED), close-spaced sublimation (CSS), and physical vapor deposition (PVD). The chemical and heat treatments are shown to decrease Cd-vacancy levels (PL measurements), which determine various parameters crucial to the device performance such as the type and concentration of the dominant defects and deep levels, greatly affect the device performance by controlling open-circuit voltage.

  18. CuInSe{sub 2} films prepared by three step pulsed electrodeposition. Deposition mechanisms, optical and photoelectrochemical studies

    Energy Technology Data Exchange (ETDEWEB)

    Caballero-Briones, F., E-mail: fcaballerobriones@ub.edu [Department of Physical Chemistry, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain); Palacios-Padros, A. [Department of Physical Chemistry, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain); Sanz, Fausto, E-mail: fsanz@ub.edu [Institute for Bioengineering of Catalonia (IBEC), Edifici Helix, Baldiri i Reixac 15-21, 08028 Barcelona (Spain); Department of Physical Chemistry, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain); CIBER-BBN, Campus Rio Ebro Edificio I-D, Bloque 5, 1a planta, C/Poeta Mariano Esquillor s/n, 50018 Zaragoza (Spain)

    2011-11-01

    p-Type semiconducting copper indium diselenide thin films have been prepared onto In{sub 2}O{sub 3}:Sn substrates by a recently developed pulse electrodeposition method that consists in repeated cycles of three potential application steps. The Cu-In-Se electrochemical system and the related single component electrolytes were studied by cyclic voltammetry to identify the electrode processes and study the deposition processes. In situ atomic force microscopy measurements during the first 100 deposition cycles denote a continuous nucleation and growth mechanism. Particles removed by film sonication from some of the films were characterized by transmission electron microscopy and determined to consist in nanoscopic and crystalline CuInSe{sub 2}. The remaining film is still crystalline CuInSe{sub 2}, as assessed by X-ray diffraction. The chemical characterization by combined X-ray photoelectron spectroscopy, X-ray fluorescence and inductively coupled plasma optical emission spectroscopy, showed that films were Cu-poor and Se-poor. Raman characterization of the as-grown films showed that film composition varies with film thickness; thinner films are Se-rich, while thicker ones have an increased Cu-Se content. Different optical absorption bands were identified by the analysis of the UV-NIR transmittance spectra that were related with the presence of CuInSe{sub 2}, ordered vacancy compounds, Se, Cu{sub 2-x}Se and In{sub 2}Se{sub 3}. The photoelectrochemical activity confirmed the p-type character and showed a better response for the films prepared with the pulse method.

  19. Preparation and characterization of electrodeposited ZnO and ZnO:Co nanorod films for heterojunction diode applications

    Energy Technology Data Exchange (ETDEWEB)

    Caglar, Yasemin, E-mail: yasemincaglar@anadolu.edu.tr [Anadolu University, Science Faculty, Physics Department, Eskisehir (Turkey); Arslan, Andaç [Eskisehir Osmangazi University, Art and Science Faculty, Chemistry Department, Eskisehir (Turkey); Ilican, Saliha [Anadolu University, Science Faculty, Physics Department, Eskisehir (Turkey); Hür, Evrim [Eskisehir Osmangazi University, Art and Science Faculty, Chemistry Department, Eskisehir (Turkey); Aksoy, Seval; Caglar, Mujdat [Anadolu University, Science Faculty, Physics Department, Eskisehir (Turkey)

    2013-10-15

    Highlights: •Undoped and Co-doped ZnO films were deposited on p-Si by electrodeposition method. •The effects of Co doping on some properties of ZnO films were investigated. •ZnO morphology was converted uniform multi-oriented rods with incorporation of Co. •Co-doped ZnO nanorod films showed a multi-oriented spear-like structure. -- Abstract: Well-aligned undoped and Co-doped nanorod ZnO films were grown by electrochemical deposition onto p-Si substrates from an aqueous route. Aqueous solution of Zn(NO{sub 3}){sub 2}⋅6H{sub 2}O and hexamethylenetetramine (HMT) were prepared using triple distilled water. Two different atomic ratios of Co(NO{sub 3}){sub 2}⋅6H{sub 2}O were used as a dopant element. Electrodepositions were carried out in a conventional three electrode cell for the working electrode (p-Si), reference electrode (Ag/AgCl, sat.) and counter electrode (platin wire). The effects of Co doping on the structural, morphological and electrical properties of ZnO films were investigated. X-ray diffraction (XRD) measurement showed that the undoped ZnO nanorod film was crystallized in the hexagonal wurtzite phase and presented a preferential orientation along the c-axis. Only one peak, corresponding to the (0 0 2) phase, appeared on the diffractograms. The lattice parameters and texture coefficient values were calculated. The nanorods were confirmed by the field emission scanning electron microscopy (FE-SEM) measurements. The FE-SEM image showed that the ZnO nanorods grow uniformly on the substrates, providing a surface with fairly homogeneous roughness. The surface morphology was transformed into uniform multi-oriented rods with incorporation of Co. Co-doped ZnO nanorod films showed a multi-oriented spear-like structure. The diffuse reflectance spectra of the films were measured and the optical band gap values were determined using Kubelka–Munk theory. The van der Pauw method was used to measure the sheet resistance of the films. The sheet resistance

  20. Optical characterization of epitaxial single crystal CdTe thin films on Al{sub 2}O{sub 3} (0001) substrates

    Energy Technology Data Exchange (ETDEWEB)

    Jovanovic, S.M.; Devenyi, G.A., E-mail: devenyga@mcmaster.ca; Jarvis, V.M.; Meinander, K.; Haapamaki, C.M.; Kuyanov, P.; Gerber, M.; LaPierre, R.R.; Preston, J.S.

    2014-11-03

    The optoelectronic properties of single crystal CdTe thin films were investigated by photoluminescence spectroscopy, photoreflectance spectroscopy and variable angle spectroscopic ellipsometry. The room temperature bandgap was measured to be 1.51 eV and was consistent between spectroscopic measurements and previously reported values. Breadth of bandgap emission was consistent with high quality material. Low temperature photoluminescence spectra indicated a dominant emission consistent with bound excitons. Emissions corresponding to self-compensation defects, doping and contaminants were not found. Variable angle spectroscopic ellipsometry measurements over the near-UV to infrared range demonstrated sharp resonance peaks. All spectroscopic measurements indicate high quality thin film material of comparable or better quality than bulk CdTe. - Highlights: • High quality epitaxial CdTe thin films were grown. • Two dimensional X-ray diffraction characterization confirmed single crystal material. • Photoluminescence indicated low defect density when compared to bulk single crystals. • Optical characterization indicated the presence of room temperature excitons.

  1. Thermal characterization and determination of recombination parameters in CdTe films on glass substrates by using open photoacoustic cell technique

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-T, M.A. [Depto. de C. Basicas, ESCOM-IPN, Av. Miguel Othon de Mendizabal S/N, Col. Lindavista, CP 07738, Mexico DF (Mexico)]. E-mail: mgonzalezt@ipn.mx; Cruz-Orea, A. [Depto. de Fisica, CINVESTAV-IPN, Av. IPN No.2508, Col. San Pedro Zacatenco, CP. 07360, Mexico DF (Mexico); Albor-A, M.L. de [Depto. de Fisica, ESFM-IPN, Edif. 9, U.P. ' Adolfo Lopez Mateos' , CP 07738, Mexico DF (Mexico); Castillo-A, F. de L [Depto. de Fisica, ESFM-IPN, Edif. 9, U.P. ' Adolfo Lopez Mateos' , CP 07738, Mexico DF (Mexico)

    2005-06-01

    CdTe is a semiconductor with a wide variety of applications and perspectives for electronic industry (high-efficiency photoelectric cells, infrared radiation detectors, etc.). In the present work, we used photoacoustic (PA) technique to study the thermal properties and the surface recombination velocity in CdTe/glass samples. Experimental PA phase signal as a function of modulation frequency in a heat transmission configuration was fitted to the theoretical expression for PA signal, which takes into account the heat sources resulting from the absorption of light in semiconductors and the nonradiative processes involved, which depend on their thermal, optical and electronic transport properties. By this procedure, it was possible to determine the thermal diffusivity and the surface recombination velocity in these samples. The studied samples were thin polycrystalline CdTe film deposited on glass slides. CdTe layers were deposited by a hot-wall closed-spaced vapor transport method, known as gradient recrystallization and growth. The values for the deposition parameters used in this study were the following: 700 deg. C for the source temperature and 450 and 550 deg. C for the substrate temperatures with three different deposition times from 5 to 20 min (then three different film thicknesses were obtained). A clear increment in the surface velocity and surface roughness is observed as the film thickness is increased.

  2. Optimization of electrodeposited p-doped Sb{sub 2}Te{sub 3} thermoelectric films by millisecond potentiostatic pulses

    Energy Technology Data Exchange (ETDEWEB)

    Schumacher, Christian; Akinsinde, Lewis; Zastrow, Sebastian; Heiderich, Sonja; Toellner, William; Nielsch, Kornelius; Bachmann, Julien [Institute of Applied Physics, University of Hamburg, Jungiusstrasse 11, 20355 Hamburg (Germany); Reinsberg, Klaus G.; Broekaert, Jose A.C. [Institute of Applied and Inorganic Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg (Germany); Rampelberg, Geert; Detavernier, Christophe [Department of Solid State Sciences, University of Ghent, Krijgslaan 281/S1, 9000 Ghent (Belgium)

    2012-03-15

    A systematic optimization of p-type Sb{sub 2}Te{sub 3} thermoelectric films made by potentiostatic electrodeposition on Au and stainless steel substrates is presented. The influence of the preparative parameters of deposition voltage, concentration, and the deposition method are investigated in a nitric acid solution. As a postdeposition step, the influence of annealing the films is investigated. The use of a potential-controlled millisecond-pulsed deposition method could improve both the morphology and the composition of the films. The samples are characterized in terms of composition, crystallinity, Seebeck coefficient, and electrical resistivity. Pulsed-deposited films exhibit Seebeck coefficients of up to 160 {mu}V K{sup -1} and an electrical conductivity of 280 S cm{sup -1} at room temperature, resulting in power factors of about 700 {mu}W m{sup -1} K{sup -2}. After annealing, power factors of maximum 852 {mu}W m{sup -1} K{sup -2} are achieved. Although the annealing of DC-deposited films significantly increased the power factor, they do not reach the values of the pulsed-deposited films in the preannealing state. Structural analysis is performed with X-ray diffraction and shows the crystalline structure of Sb{sub 2}Te{sub 3} films. The performance is tuned by annealing of deposited films up to 300 C under He atmosphere while performing in-situ X-ray diffraction and resistivity measurements. The chemical analysis of the films is performed by inductively coupled plasma optical emission spectroscopy (ICP-OES) as well as scanning electron microscope energy dispersive X-ray analysis (SEM-EDX). (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Effect of ZnTe and CdZnTe Alloys at the Back Contact of 1-μm-Thick CdTe Thin Film Solar Cells

    Science.gov (United States)

    Amin, Nowshad; Yamada, Akira; Konagai, Makoto

    2002-05-01

    N2-doped ZnTe was introduced onto 1-μm-thick CdTe absorbers in order to reduce the carrier recombination at the back contact of CdS/CdTe/C/Ag configuration solar cells. ZnTe films were grown by molecular beam epitaxy (MBE) on GaAs and Corning glass substrates to investigate the characteristics of the films. Epitaxial growth of ZnTe was realized on GaAs substrates and a hole concentration of 8 × 1018 cm-3 with a resistivity of 0.045 Ω \\cdotcm was achieved as a result of nitrogen doping. In contrast, polycrystalline ZnTe films were grown on Corning glass and CdTe thin films. Dark and photoconductivity of ZnTe films increased to 1.43 × 10-5 S/cm and 1.41 × 10-4 S/cm, respectively, while the Zn to Te ratio was decreased to 0.25 during MBE growth. These ZnTe films with different thicknesses were inserted into close-spaced sublimation (CSS)-grown 1-μm-thick CdTe solar cells. A conversion efficiency of 8.31% (Voc: 0.74 V, Jsc: 22.98 mA/cm2, FF: 0.49, area: 0.5 cm2) was achieved for a 0.2-μm-thick ZnTe layer with a cell configuration of CdS/CdTe/ZnTe/Cu-doped-C/Ag. Furthermore, to overcome the problem of possible recombination loss in the interface layer of CdTe and ZnTe, the intermediate ternary CdZnTe is investigated. The compositional factor in Cd1-xZnxTe:N alloy is varied and the dependence of the conductivity is evaluated. For instance, Cd0.5Zn0.5Te:N, with dark and photoconductivity of 2.13 × 10-6 and 2.9 × 10-5 S/cm, respectively, is inserted at the back contact of a 1-μm-thick CdTe solar cell. A conversion efficiency of 7.46% (Voc: 0.68 V, Jsc: 22.60 mA/cm2, FF: 0.49, area: 0.086 cm2) was achieved as the primary result for a 0.2-μm-thick Cd0.5Zn0.5Te:N layer with the cell configuration of CdS/CdTe/Cd0.5Zn0.5Te:N/Au.

  4. Influence of pH and bath composition on properties of Ni–Fe alloy films synthesized by electrodeposition

    Indian Academy of Sciences (India)

    Xinghua Su; Chengwen Qiang

    2012-04-01

    Fe–Ni films were electrodeposited on ITO glass substrates from the electrolytes with different molar ratio of Ni2+/Fe2+ and different pH values (2.1, 2.9, 3.7 and 4.3) at 25°C. The properties of Fe–Ni alloy films depend on both Ni2+ and Fe2+ concentrations in electrolyte and pH values. The content of Ni increases from 38% to 84% as the mole ratio of NiSO4/FeSO4 increasing from 0.50/0.50 to 0.90/0.10 in electrolyte and slightly decreases from 65% to 42% as the pH values increase from 2.1 to 4.3. The X-ray diffraction analysis reveals that the structures of the films strongly depend on the Ni content in the binary films. The magnetic performance of the films shows that the saturation magnetization (s) decreases from 1775.01 emu/cm3 to 1501.46 emu/cm3 with the pH value increasing from 2.1 to 4.3 and the saturation magnetization (s) and coercivity (c) move up from 1150.44 emu/cm3 and 58.86 Oe to 2498.88 emu/cm3 and 93.12 Oe with the increase of Ni2+ concentration in the electrolyte, respectively.

  5. Effect of Ni concentration on microstructure, magnetic and microwave properties of electrodeposited NiCoFe films

    Energy Technology Data Exchange (ETDEWEB)

    Phua, L.X., E-mail: g0700691@nus.edu.sg [Centre for Superconducting and Magnetic Materials, Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); Phuoc, N.N. [Temasek Laboratories, National University of Singapore, 5A Engineering Drive 2, Singapore 117411 (Singapore); Ong, C.K. [Centre for Superconducting and Magnetic Materials, Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore)

    2012-12-05

    Highlights: Black-Right-Pointing-Pointer BCC crystallographic structure is gradually suppressed with increment of Ni content. Black-Right-Pointing-Pointer The M{sub s} and H{sub c} values show similar behavior with increase of Ni concentration. Black-Right-Pointing-Pointer The FMR frequency has a maximum value of 1.9 GHz at Ni concentration of 0.3. Black-Right-Pointing-Pointer Sufficient addition of Ni may lead to significant enhancement of film properties. - Abstract: The influence of Ni addition on the microstructure, magnetic properties and microwave characteristics of Ni{sub x}(Co{sub 0.5}Fe{sub 0.5}){sub 1-x} (x = 0-0.7 wt. ratio) films fabricated by electrodeposition technique was investigated. It is revealed by the characterization of an X-ray Diffractometer that the films show a mixture of both FCC and BCC structures and the BCC structure is gradually suppressed with increasing Ni concentration. The morphology study by Scanning Electron Microscopy shows that with the addition of Ni, the film surface becomes smoother and grain size is reduced. The saturation magnetization and coercivity values show a similar behavior with increased Ni concentration. The ferromagnetic resonance frequency is increased from 1.07 to 1.9 GHz with the increase of Ni concentration from 0 to 0.3 and is decreased upon further Ni concentration increment which was interpreted in terms of contribution of the stress of films.

  6. Electrodeposition of In{sub 2}O{sub 3} thin films from a dimethylsulfoxide based electrolytic solution

    Energy Technology Data Exchange (ETDEWEB)

    Henriquez, R.; Munoz, E.; Gomez, H. [Instituto de Quimica, Facultad de Ciencias, Pontificia Universidad Catolica de Valparaiso, Curauma Valparaiso (Chile); Dalchiele, E.A.; Marotti, R.E. [Instituto de Fisica and CINQUIFIMA, Facultad de Ingenieria, Montevideo (Uruguay); Martin, F.; Leinen, D.; Ramos-Barrado, J.R. [Laboratorio de Materiales y Superficie, Departamento de Fisica Aplicada and Ingenieria Quimica, Universidad de Malaga (Spain)

    2013-02-15

    Indium (III) oxide (In{sub 2}O{sub 3}) thin films have been obtained after heat treatment of In(OH){sub 3} precursor layers grown by a potential cycling electrodeposition (PCED) method from a dimethylsulfoxide (DMSO) based electrolytic solution onto fluorine-doped tin oxide (FTO) coated glass substrates. X-ray diffraction (XRD) measurements indicate the formation of a polycrystalline In{sub 2}O{sub 3} phase with a cubic structure. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed a smooth morphology of the In{sub 2}O{sub 3} thin films after an optimized heat treatment had been developed. The surface composition and chemical state of the semiconductor films was established by X-ray photoelectron spectroscopy analysis. The nature of the semiconductor material, flat band potential and donor density were determined from Mott-Schottky plots. This study reveals that the In{sub 2}O{sub 3} films exhibited n-type conductivity with an average donor density of 2.2 x 10{sup 17} cm{sup -3}. The optical characteristics were determined through transmittance spectra. The direct and indirect band gap values obtained are according to the accepted values for the In{sub 2}O{sub 3} films of 2.83 and 3.54 eV for the indirect and direct band gap values. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Gordon Research Conference on Electrodeposition

    Science.gov (United States)

    2006-08-04

    ORME LAWRENCE LIVERMORE NATIONAL Speaker Registered LABORATORY ANDRE A PASA DEPARTAMENTO DE FISICA - UFSC Poster Presenter Registered GYANARANJAN...deposited at the electrode surface from molecular and ionic precursors in solution. The morphology and orientation of electrodeposited films can be precisely...topics at this year’s conference are molecular electronics, nucleation and growth, epitaxial electrodeposition, shape control, magnetic materials

  8. CdTe thin film solar cells. Optimization of material, morphology and device preparation

    Energy Technology Data Exchange (ETDEWEB)

    Schaffner, J.; Barati, A.; Krishnakumar, V.; Fu, G.; Schimper, H.J.; Haindl, A.; Swirschuk, A.; Gunnesch, E.; Schneikart, A.; Tueschen, A.; Klein, A.; Jaegermann, W. [Technische Univ. Darmstadt (Germany). Fachbereich Materialwissenschaft

    2010-07-01

    Correlations between layer-morphology and electrical properties are shown. At substrate temperatures between 330 C and 380 C the layer-morphology is similar to that obtained at the typically used high temperatures above 500 C. First results showed promising efficiencies for growth temperatures around 350 C. With optimized layer-morphology, dense, pinhole-free layers can be achieved. With a CdTe thickness below 3 {mu}m and CdS layers thinner than 100 nm, each of them deposited by a two step process using two different substrate temperatures, efficiencies of more than 10% were reached. For ANTEC CdS/CdTe cells, alternative back contacts were made in an all-dry vacuum process without any need for wet chemical etching. Cell efficiencies close to the efficiencies obtained with wet processing (NP etching and Au back contact) were obtained. This was achieved without the use of highly diffusive copper. (orig.)

  9. Polycrystalline thin film cadmium telluride solar cells fabricated by electrodeposition. Annual subcontract report, 20 March 1993--19 March 1994

    Energy Technology Data Exchange (ETDEWEB)

    Trefny, J.U.; Furtak, T.E.; Williamson, D.L.; Kim, D. [Colorado School of Mines, Golden, CO (United States)

    1994-07-01

    This report describes the principal results of work performed during the second year of a 3-year program at the Colorado School of Mines (CSM). The work on transparent conducting oxides was carried out primarily by CSM students at NREL and is described in three publications listed in Appendix C. The high-quality ZnO produced from the work was incorporated into a copper indium diselenide cell that exhibited a world-record efficiency of 16.4%. Much of the time was devoted to the improvement of cadmium sulfide films deposited by chemical bath deposition methods and annealed with or without a cadmium chloride treatment. Progress was also made in the electrochemical deposition of cadmium telluride. High-quality films yielding CdS/CdTe/Au cells of greater than 10% efficiency are now being produced on a regular basis. We explored the use of zinc telluride back contacts to form an n-i-p cell structure as previously used by Ametek. We began small-angle x-ray scattering (SAXS) studies to characterize crystal structures, residual stresses, and microstructures of both CdTe and CdS. Large SAXS signals were observed in CdS, most likely because of scattering from gain boundaries. The signals observed to date from CdTe are much weaker, indicating a more homogeneous microstructure. We began to use the ADEPT modeling program, developed at Purdue University, to guide our understanding of the CdS/CdTe cell physics and the improvements that will most likely lead to significantly enhanced efficiencies.

  10. Multilayered films incorporating CdTe quantum dots with tunable optical properties for antibacterial application

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xuelian [Institute for Clean Energy and Advanced Materials, Southwest University, 1 Tiansheng Road, Chongqing 400715 (China); School of Chemistry and Chemical Engineering, Southwest University, 1 Tiansheng Road, Chongqing 400715 (China); Lu, Zhisong, E-mail: zslu@swu.edu.cn [Institute for Clean Energy and Advanced Materials, Southwest University, 1 Tiansheng Road, Chongqing 400715 (China); Li, Qing, E-mail: qli@swu.edu.cn [School of Chemistry and Chemical Engineering, Southwest University, 1 Tiansheng Road, Chongqing 400715 (China); School of Materials Science and Engineering, Southwest University, 1 Tiansheng Road, Chongqing 400715 (China)

    2013-12-02

    Tunable absorption/emission and antibacterial activity are highly desirable for antibacterial decorative coating layers. In this study, films with both tunable optical and effective antibacterial properties were fabricated with cadmium telluride quantum dots (QDs) and poly-L-lysine (PLL) via layer-by-layer assembly. Absorption and photoluminescence spectra as well as surface morphology were examined to monitor the film growth. The films are fabricated in a logarithmic growth mode, exhibiting effective antibacterial activity against Escherichia coli and good biocompatibility to Hela cells. By changing sizes of the incorporated QDs, optical properties of the films can be easily tailored. The PLL/QDs' multilayered films may be used as colorful coating layers for applications requiring both unique optical and antibacterial properties. - Highlights: • A layer-by-layer film incorporating quantum dots and poly-L-lysine was fabricated. • The film shows tunable optical properties and antibacterial activity. • The film is built up in a logarithmic growth mode.

  11. Preparation of p-type NiO films by reactive sputtering and their application to CdTe solar cells

    Science.gov (United States)

    Ishikawa, Ryousuke; Furuya, Yasuaki; Araki, Ryouichi; Nomoto, Takahiro; Ogawa, Yohei; Hosono, Aikyo; Okamoto, Tamotsu; Tsuboi, Nozomu

    2016-02-01

    Transparent p-type NiO films were prepared by reactive sputtering using the facing-target system under Ar-diluted O2 gas at Tsub of 30 and 200 °C. The increasing intensity of dominant X-ray diffraction (XRD) peaks indicates improvements in the crystallinity of NiO films upon Cu doping. In spite of the crystallographic and optical changes after Cu-doping, the electrical properties of Cu-doped NiO films were slightly improved. Upon Ag-doping at 30 °C under low O2 concentration, on the other hand, the intensity of the dominant (111) XRD peaks was suppressed and p-type conductivity increased from ˜10-3 to ˜10-1 S cm-1. Finally, our Ag-doped NiO films were applied as the back contact of CdTe solar cells. CdTe solar cells with a glass/ITO/CdS/CdTe/NiO structure exhibited an efficiency of 6.4%, suggesting the high potential of using p-type NiO for the back-contact film in thin-film solar cells.

  12. Comparative study of Hg xCd 1-xTe films grown on CdTe thin films previously deposited from two different techniques

    Science.gov (United States)

    Ali, A.; Abbas Shah, N.; Maqsood, A.

    2009-04-01

    High quality cadmium telluride (CdTe) thin films were grown on glass substrates with two different techniques, two evaporation source (TES) and closed space sublimation (CSS). Further to the above mercury telluride (HgTe) was then deposited by using single source on both CdTe thin films for obtaining Hg xCd 1-xTe samples. The crystalline structure of the Hg xCd 1-xTe sample grown from CSS-CdTe showed the preferential (1 1 1) orientation with smoother and larger grain size than those of TES-CdTe. The optical transmission for TES-CdTe sample was above 90% in the 1000-1500 nm range whereas it was significantly below 80% for CSS-CdTe sample. The optical transmission for TES-Hg xCd 1-xTe and CSS-Hg xCd 1-xTe was ˜60%. The resistivity at room temperature of TES-CdTe and CSS-CdTe was ˜3.33×10 9 Ω cm and ˜2.20×10 8 Ω cm, respectively, while the resistivity of TES-Hg xCd 1-xTe and CSS-Hg xCd 1-xTe samples was ˜1.73 Ω cm and ˜5.34×10 5 Ω cm, respectively. The comparative study of ternary compound prepared with the above techniques has been carried out for the first time.

  13. Enhancing the perpendicular magnetic anisotropy of Co-Pt(P) films by epitaxial electrodeposition onto Cu(1 1 1) substrates

    Energy Technology Data Exchange (ETDEWEB)

    Zana, Iulica [Department of Metallurgical and Materials Engineering, Tuscaloosa, AL 35487-0209 (United States): Center for Materials for Information Technology, Tuscaloosa, AL 35487-0209 (United States)]. E-mail: iz7@mail.gatech.edu; Zangari, Giovanni [Center for Materials for Information Technology, Tuscaloosa, AL 35487-0209 (United States): Department of Materials Science and Engineering and Center for Electrochemical Science and Engineering, University of Virginia, Charlottesville, VA 22904-4745 USA (United States); Shamsuzzoha, Mohamad [Department of Metallurgical and Materials Engineering, Tuscaloosa, AL 35487-0209 (United States): School of Mines and Energy Development, University of Alabama, Tuscaloosa, AL 35487-0209 (United States)

    2005-04-15

    Co-rich, Co-Pt alloy films containing {approx}20 at% Pt and small amounts of P, with thickness from 125 to 1000 nm have been galvanostatically (constant current) grown by electroplating onto Cu seed layers with strong (1 1 1) orientation. The influence of deposition current density (cd=10-50 mA/cm{sup 2}) and film thickness on their growth morphology, structural and magnetic properties have been investigated. When electrodeposited on Cu(1 1 1), Co-Pt(P) films develop a microstructure consisting of a disordered hexagonal-closed-packed (hcp) matrix with {l_brace}0 0 0 1{r_brace} preferential orientation. At low cd, a small amount of simple cubic L1{sub 2} phase was detected, which disappears altogether by increasing cd to 50 mA/cm{sup 2}. The plated films show saturation magnetization in the range 775-832 kA/m (778-832 emu/cm{sup 3}), large perpendicular magnetic anisotropy up to 1.02 MJ/m{sup 3} (1.02x10{sup 7} erg/cm{sup 3}), and coercivity up to 486 kA/m (6.1 kOe) in the out-of-plane direction. The perpendicular anisotropy was found to originate predominantly from the high magnetocrystalline anisotropy of the hcp phase of Co-Pt(P) with c-axis perpendicular to the substrate.

  14. Effects of Substrate Local Strain on Microstructure of Electrodeposited Aluminum Film

    Institute of Scientific and Technical Information of China (English)

    TAN Yuehua; YAN Bo; GAO Ge; YANG Yuxin

    2006-01-01

    The aluminum coating layer was formed on a copper substrate with local strain region by using the electrodeposited method. It was found that the particle shape of the coating deposited on the copper substrate is very sensitive to the strain extent of substrate. The large needle-like aluminum particles were observed on the substrate region with large local strain, indicating that substrate local strain may affect the shape of the deposited particles and promote the nucleation and growth of the deposited particles.

  15. Methanol oxidation on carbon supported Pt-Ru catalysts prepared by electrodeposition - Evaluation of Nafion {sup registered} 117 film effect

    Energy Technology Data Exchange (ETDEWEB)

    Sieben, J.M. [Instituto de Ingenieria Electroquimica y Corrosion (INIEC), Universidad Nacional del Sur, Av. Alem 1253 (B8000CPB) Bahia Blanca, Buenos Aires (Argentina); Duarte, M.M.E.; Mayer, C.E. [Instituto de Ingenieria Electroquimica y Corrosion (INIEC), Universidad Nacional del Sur, Av. Alem 1253 (B8000CPB) Bahia Blanca, Buenos Aires (Argentina); Comision de Investigaciones Cientificas de la Provincia de Buenos Aires (CIC) (Argentina)

    2010-03-15

    Diverse electrochemical techniques were performed in order to obtain meaningful information about the methanol oxidation reaction on nanostructured planar carbon supported Pt-Ru electrodes prepared by electrodeposition, on which a layer of Nafion ionomer was incorporated. A metallic deposit consisting of dendritic agglomerates (between 50 and 200 nm) constituted by smaller particles (6 nm) was obtained. The average bulk Ru content obtained by EDX analysis was between 23 and 25 at. %. A decrease of the activity in the electrodes for methanol oxidation was determined when the thickness of the Nafion 117 film was increased. These results may be associated with the partial blocking of the surface active sites by hydrophobic domains of the polymer, and the presence of CO{sub 2} molecules retained within the Nafion hydrophilic microchannels. EIS results indicated that methanol electro-oxidation mechanism does not change with Nafion presence. (author)

  16. Effect of the CdCl2 Treatment on the Morphology and Structural Properties of CdTe Thin Films Deposited by the CSS Method

    Science.gov (United States)

    Infante, H.; Gordillo, G.

    CdTe thin films deposited by the CSS (close spaced sublimation) method, with adequate properties to be used as absorber layer in solar cells, were submitted to a chemical treatment in a saturated CdCl2 solution, followed by thermal annealing in air at 400°C, in order to improve the electronic properties. The effect of chemical and thermal treatments on the morphological and crystallographic properties was studied through atomic force microscopy (AFM) and X-ray diffraction (XRD) measurements. The studies revealed that the CdTe grows in the cubic phase and that the postdeposition treatments affect the morphology as well as the crystallographic properties; the effect on the morphology is significantly stronger. Increase of the grain size and roughness was observed in samples treated chemically and thermally. On the other hand, no effects were identified on the crystalline structure as induced by the treatments, although recrystallization was observed after thermal annealing.

  17. Low voltage electrodeposition of CN x films and study of the effect of the deposition voltage on bonding configurations

    Science.gov (United States)

    Sreejith, K.; Nuwad, J.; Pillai, C. G. S.

    2005-10-01

    Carbon nitride (CN x) films were deposited from acetonitrile at low voltage (150-450 V) through electrodeposition. The films were characterized by atomic force microscopy (AFM), Raman spectroscopy and Fourier transform infrared (FT-IR) spectroscopy. AFM investigations revealed that the grain size was ˜200 nm and roughness was ˜10 nm. The films were found to be continuous and close packed. IR spectra revealed existence of strong sp 3, sp 2 type bonding and weak sp type carbon nitrogen bonds and these bonds were found to increase with voltage. The fraction of sp 3-bonded species in the sample increased in low voltage range and after reaching maximum at 350 V, decreased for higher voltages. However, the concentration of sp 2 CN ring structures in the film increased with increasing voltage. Also, the peak width decreased at low voltages reaching a minimum and increased thereafter. It was observed that the voltage dependent increase in the concentration of polymeric type sp 2 CN (chain) structures was much more pronounced than that of graphitic type sp 2 CN (ring) structures. Raman spectra showed the presence of both the D and G bands. The shift in the G band indicated the presence of nitrogen in the film. The I D/I G ratio was found to increase with the incorporation of nitrogen. Auger electron spectroscopy (AES) showed a clear increase in the nitrogen content with increase in the voltage. The formation of the film could be explained on the basis of dissociation of electrolyte under applied voltage.

  18. Low voltage electrodeposition of CN {sub x} films and study of the effect of the deposition voltage on bonding configurations

    Energy Technology Data Exchange (ETDEWEB)

    Sreejith, K. [Novel Materials and Structural Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Nuwad, J. [Novel Materials and Structural Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Pillai, C.G.S. [Novel Materials and Structural Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)]. E-mail: cgspil@apsara.barc.ernet.in

    2005-10-15

    Carbon nitride (CN {sub x}) films were deposited from acetonitrile at low voltage (150-450 V) through electrodeposition. The films were characterized by atomic force microscopy (AFM), Raman spectroscopy and Fourier transform infrared (FT-IR) spectroscopy. AFM investigations revealed that the grain size was {approx}200 nm and roughness was {approx}10 nm. The films were found to be continuous and close packed. IR spectra revealed existence of strong sp{sup 3}, sp{sup 2} type bonding and weak sp type carbon nitrogen bonds and these bonds were found to increase with voltage. The fraction of sp{sup 3}-bonded species in the sample increased in low voltage range and after reaching maximum at 350 V, decreased for higher voltages. However, the concentration of sp{sup 2} CN ring structures in the film increased with increasing voltage. Also, the peak width decreased at low voltages reaching a minimum and increased thereafter. It was observed that the voltage dependent increase in the concentration of polymeric type sp{sup 2} CN (chain) structures was much more pronounced than that of graphitic type sp{sup 2} CN (ring) structures. Raman spectra showed the presence of both the D and G bands. The shift in the G band indicated the presence of nitrogen in the film. The I{sub D}/I{sub G} ratio was found to increase with the incorporation of nitrogen. Auger electron spectroscopy (AES) showed a clear increase in the nitrogen content with increase in the voltage. The formation of the film could be explained on the basis of dissociation of electrolyte under applied voltage.

  19. An investigation of silver electrodeposition from ionic liquids: Influence of atmospheric water uptake on the silver electrodeposition mechanism and film morphology

    Energy Technology Data Exchange (ETDEWEB)

    Basile, Andrew [School of Applied Sciences, RMIT University, G.P.O. Box 2476V, Melbourne, Victoria 3001 (Australia); CSIRO Energy Technology, Clayton, Victoria 3169 (Australia); Bhatt, Anand I., E-mail: anand.bhatt@csiro.a [CSIRO Energy Technology, Clayton, Victoria 3169 (Australia); O' Mullane, Anthony P., E-mail: anthony.omullane@rmit.edu.a [School of Applied Sciences, RMIT University, G.P.O. Box 2476V, Melbourne, Victoria 3001 (Australia); Bhargava, Suresh K. [School of Applied Sciences, RMIT University, G.P.O. Box 2476V, Melbourne, Victoria 3001 (Australia)

    2011-02-28

    The electrodeposition of silver from two ionic liquids, 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF{sub 4}]) and N-butyl-N-methyl-pyrrolidinium bis(trifluoromethanesulfonyl)imide ([C{sub 4}mPyr][TFSI]), and an aqueous KNO{sub 3} solution on a glassy carbon electrode was undertaken. It was found by cyclic voltammetry that the electrodeposition of silver proceeds through nucleation-growth kinetics. Analysis of chronoamperometric data indicated that the nucleation-growth mechanism is instantaneous at all potentials in the case of [BMIm][BF{sub 4}]and [C{sub 4}mPyr][TFSI], and instantaneous at low overpotentials tending to progressive at high overpotentials for KNO{sub 3}. Significantly, under ambient conditions, the silver electrodeposition mechanism changes to progressive nucleation and growth in [C{sub 4}mPyr][TFSI], which is attributed to the uptake of atmospheric water in the IL. It was found that these differences in the growth mechanism impact significantly on the morphology of the resultant electrodeposit which is characterised ex situ by scanning electron microscopy and X-ray diffraction.

  20. Effects of annealing temperature on the physicochemical, optical and photoelectrochemical properties of nanostructured hematite thin films prepared via electrodeposition method

    Energy Technology Data Exchange (ETDEWEB)

    Phuan, Yi Wen [School of Engineering, Chemical Engineering Discipline, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway 46150 Selangor DE (Malaysia); Chong, Meng Nan, E-mail: Chong.Meng.Nan@monash.edu [School of Engineering, Chemical Engineering Discipline, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway 46150 Selangor DE (Malaysia); Sustainable Water Alliance, Advanced Engineering Platform, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway 46150 Selangor DE (Malaysia); Zhu, Tao; Yong, Siek-Ting [School of Engineering, Chemical Engineering Discipline, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway 46150 Selangor DE (Malaysia); Chan, Eng Seng [School of Engineering, Chemical Engineering Discipline, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway 46150 Selangor DE (Malaysia); Sustainable Water Alliance, Advanced Engineering Platform, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway 46150 Selangor DE (Malaysia)

    2015-09-15

    Highlights: • Nanostructured hematite thin films were synthesized via electrodeposition method. • Effects of annealing on size, grain boundary and PEC properties were examined. • Photocurrents generation was enhanced when the thin films were annealed at 600 °C. • The highest photocurrent density of 1.6 mA/cm{sup 2} at 0.6 V vs Ag/AgCl was achieved. - Abstract: Hematite (α-Fe{sub 2}O{sub 3}) is a promising photoanode material for hydrogen production from photoelectrochemical (PEC) water splitting due to its wide abundance, narrow band-gap energy, efficient light absorption and high chemical stability under aqueous environment. The key challenge to the wider utilisation of nanostructured hematite-based photoanode in PEC water splitting, however, is limited by its low photo-assisted water oxidation caused by large overpotential in the nominal range of 0.5–0.6 V. The main aim of this study was to enhance the performance of hematite for photo-assisted water oxidation by optimising the annealing temperature used during the synthesis of nanostructured hematite thin films on fluorine-doped tin oxide (FTO)-based photoanodes prepared via the cathodic electrodeposition method. The resultant nanostructured hematite thin films were characterised using field emission-scanning electron microscopy (FE-SEM) coupled with energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), UV-visible spectroscopy and Fourier transform infrared spectroscopy (FTIR) for their elemental composition, average nanocrystallites size and morphology; phase and crystallinity; UV-absorptivity and band gap energy; and the functional groups, respectively. Results showed that the nanostructured hematite thin films possess good ordered nanocrystallites array and high crystallinity after annealing treatment at 400–600 °C. FE-SEM images illustrated an increase in the average hematite nanocrystallites size from 65 nm to 95 nm when the annealing temperature was varied from 400 °C to 600

  1. A statistical approach for optimizing parameters for electrodeposition of indium (III) sulfide (In2S3) films, potential low-hazard buffer layers for photovoltaic applications

    Science.gov (United States)

    Mughal, Maqsood Ali

    Clean and environmentally friendly technologies are centralizing industry focus towards obtaining long term solutions to many large-scale problems such as energy demand, pollution, and environmental safety. Thin film solar cell (TFSC) technology has emerged as an impressive photovoltaic (PV) technology to create clean energy from fast production lines with capabilities to reduce material usage and energy required to manufacture large area panels, hence, lowering the costs. Today, cost ($/kWh) and toxicity are the primary challenges for all PV technologies. In that respect, electrodeposited indium sulfide (In2S3) films are proposed as an alternate to hazardous cadmium sulfide (CdS) films, commonly used as buffer layers in solar cells. This dissertation focuses upon the optimization of electrodeposition parameters to synthesize In2S3 films of PV quality. The work describe herein has the potential to reduce the hazardous impact of cadmium (Cd) upon the environment, while reducing the manufacturing cost of TFSCs through efficient utilization of materials. Optimization was performed through use of a statistical approach to study the effect of varying electrodeposition parameters upon the properties of the films. A robust design method referred-to as the "Taguchi Method" helped in engineering the properties of the films, and improved the PV characteristics including optical bandgap, absorption coefficient, stoichiometry, morphology, crystalline structure, thickness, etc. Current density (also a function of deposition voltage) had the most significant impact upon the stoichiometry and morphology of In2S3 films, whereas, deposition temperature and composition of the solution had the least significant impact. The dissertation discusses the film growth mechanism and provides understanding of the regions of low quality (for example, cracks) in films. In2S3 films were systematically and quantitatively investigated by varying electrodeposition parameters including bath

  2. Photo-assisted electrodeposition of polypyrrole back contact to CdS/CdTe solar cell structures

    Energy Technology Data Exchange (ETDEWEB)

    Jarkov, A., E-mail: aleksjarkov@gmail.com [Tallinn University of Technology, Department of Materials Science, Ehitajate tee 5, 19086 Tallinn (Estonia); Bereznev, S.; Volobujeva, O. [Tallinn University of Technology, Department of Materials Science, Ehitajate tee 5, 19086 Tallinn (Estonia); Traksmaa, R. [Tallinn University of Technology, Materials Research Center, Ehitajate tee 5, 19086 Tallinn (Estonia); Tverjanovich, A. [Saint-Petersburg State University, 198503 Saint-Petersburg, Staryj Petergof, Ulyanovskaya 5 (Russian Federation); Öpik, A.; Mellikov, E. [Tallinn University of Technology, Department of Materials Science, Ehitajate tee 5, 19086 Tallinn (Estonia)

    2013-05-01

    Glass/indium tin oxide/CdS/CdTe photovoltaic structures were prepared using the high vacuum evaporation method, followed by a typical activation procedure, which involves annealing of the structures at 415–430 °C in the presence of CdCl{sub 2} in air. The main purpose of this work was to prepare and evaluate the performance of complete CdS/CdTe solar cell structures with polypyrrole (PPy) back contact and compare it to the structures with standard, copper containing back contact. Back contact layers of PPy doped with ß-naphthalene sulfonate were deposited onto activated CdTe layers by photo-assisted electrodeposition technique in a three-electrode electrochemical cell. It was found that intensive white light illumination from a xenon lamp facilitates PPy deposition at a lower applied potential range and improves quality of obtained polymer films. Applied technique gives the possibility to deposit the PPy layer strictly onto illuminated photoactive CdTe surface eliminating possible short-circuiting through pinholes and cracks in CdTe photoabsorber layer. Furthermore, relatively low deposition potential values give the possibility to reduce electrochemical degradation of CdS/CdTe photovoltaic structure in an electrochemical cell. - Highlights: ► Polypyrrole (PPy) conductive polymer back contact (BC) to CdTe semiconductor. ► Hybrid organic/inorganic photovoltaic structures. ► PPy layer to CdTe by photo-assisted electrodeposition technique ► Comparable efficiency of cells with PPy and conventional inorganic Cu{sub x}Te BC.

  3. Characterization and corrosion resistance of anodic electrodeposited titanium oxide/phosphate films on Ti-20Nb-10Zr-5Ta bioalloy

    Energy Technology Data Exchange (ETDEWEB)

    Popa, Monica; Vasilescu, Cora; Drob, Silviu I.; Osiceanu, Petre; Anastasescu, Mihai; Calderon-Moreno, Jose M., E-mail: josecalderonmoreno@yahoo.com [Institute of Physical Chemistry ' Ilie Murgulescu' of the Romanian Academy, Bucharest (Romania)

    2013-07-15

    In this work, the anodic galvanostatic electrodeposition of an oxidation film containing phosphates on Ti-20Nb-10Zr-5Ta alloy from orthophosphoric acid solution is presented. Its composition was determined by X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and Raman micro-spectroscopy, and its topography by atomic force microscopy (AFM). The corrosion resistance of the coated alloy in simulated human fluid (by linear polarization method and monitoring of open circuit potentials, corresponding open circuit potential gradients) as well as the characterization of the coating (by Raman spectroscopy and depth profile X-ray photoelectron spectroscopy (XPS)) deposited in a period of 300 h soaking in simulated human body fluid were studied. The electrodeposited film was composed of amorphous titanium dioxide and contained phosphate groups. The corrosion resistance of the coated Ti-20Nb-10Zr-5Ta alloy in neutral and alkaline Ringer's solutions was higher than that of the bare alloy due to the protective properties of the electrodeposited film. The corrosion parameters improved over time as result of the thickening of the surface film by the deposition from the physiological solution. The deposited coating presented a variable composition in depth: at the deeper layer nucleated nanocrystalline hydroxyapatite and at the outer layer amorphous calcium phosphate. (author)

  4. Electrodeposition of WO3 nanoparticles into surface mounted metal–organic framework HKUST-1 thin films

    Science.gov (United States)

    Yoo, Hyeonseok; Welle, Alexander; Guo, Wei; Choi, Jinsub; Redel, Engelbert

    2017-03-01

    We describe a novel procedure to fabricate WO3@surface-mounted metal–organic framework (SURMOF) hybrid materials by electrodeposition of WO3 nanoparticles into HKUST-1, also termed Cu3(BTC)2 SURMOFs. These materials have been characterized using x-ray diffraction, time-of-flight secondary ion mass spectrometry, scanning electron microscopy, x-ray photoelectron spectroscopy as well as linear sweep voltammetry. The WO3 semiconductor/SURMOF heterostructures were further tested as hybrid electrodes in their performance for hydrogen evolution reaction from water.

  5. The influence of different electrodeposition E/t programs on the photoelectrochemical properties of {alpha}-Fe{sub 2}O{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Schrebler, Ricardo S.; Altamirano, Hernan; Grez, Paula; Herrera, Francisco V.; Munoz, Eduardo C.; Ballesteros, Luis A.; Cordova, Ricardo A.; Gomez, Humberto [Instituto de Quimica, Facultad de Ciencias, Pontificia Universidad Catolica de Valparaiso, Casilla 4059, Valparaiso (Chile); Dalchiele, Enrique A., E-mail: dalchiel@fing.edu.u [Instituto de Fisica, Facultad de Ingenieria, Herrera y Reissig 565, C.C. 30, 11000 Montevideo (Uruguay)

    2010-09-30

    In this work morphological, structural and photoelectrochemical properties of n-type {alpha}-Fe{sub 2}O{sub 3} (hematite) thin films synthetized by means of two different electrochemical procedures: potential cycling electrodeposition (PC) and potential pulsed electrodeposition (PP) have been studied. The X-ray diffraction measurements showed that the films obtained after a thermal treatment at 520 {sup o}C present a nanocrystalline character. Scanning electron microscopy allowed finding that hematite films obtained by PP technique exhibit nanostructured morphology. The electrochemical and capacitance (Mott-Schottky and parallel capacitance) measurements showed that when in the PC and PP procedures the anodic limit E{sub {lambda},A} is being made more anodic, a decrease of the majority carriers concentration (N{sub D}) and the surface states number has been observed. The photovoltammetry measurements indicated that the hematite films formed with the PP technique present a photocurrent one order of magnitude higher than the ones exhibited by the iron oxide films formed by PC. For instance, PP hematite films exhibit photovoltaic conversion efficiencies of 0.96% which are 2.5 times higher than the corresponding to the PC ones (0.38%). The maximum incident photon-to-current efficiency measured at {lambda} = 370 and 600 nm was observed for hematite films grown by the PP procedure. By means of the photocurrent transient technique a decrease in the recombination process for those samples synthesized by PP was observed. The results obtained are discussed considering the influence of the anodic limit of the potential employed during the preparation of the iron oxyhydroxide ({beta}-FeOOH) precursor film, all of this related to a decrease of the oxygen defects in this material and to a decrease of Fe(II) amount that is formed during the electrodeposition process.

  6. Kardar-Parisi-Zhang universality, anomalous scaling and crossover efects in the growth of CdTe thin films

    OpenAIRE

    Almeida, Renan Augusto Lisbôa

    2015-01-01

    A relation between the mound evolution and large-wavelength fluctuations at CdTe surface has been established. One finds that short-length scales are dictated by an interplay between the effects of the for- mation of defects at colided boundaries of neighboring grains and a relaxation process which stems from the diffusion and deposition of particles (CdTe molecules) torward these regions. A Kinetic Monte Carlo model corroborates these reasonings. As T is increased, that competition gives ris...

  7. Correlations of Capacitance-Voltage Hysteresis with Thin-Film CdTe Solar Cell Performance During Accelerated Lifetime Testing

    Energy Technology Data Exchange (ETDEWEB)

    Albin, D.; del Cueto, J.

    2011-03-01

    In this paper we present the correlation of CdTe solar cell performance with capacitance-voltage hysteresis, defined presently as the difference in capacitance measured at zero-volt bias when collecting such data with different pre-measurement bias conditions. These correlations were obtained on CdTe cells stressed under conditions of 1-sun illumination, open-circuit bias, and an acceleration temperature of approximately 100 degrees C.

  8. Preparation of CuGaSe{sub 2} absorber layers for thin film solar cells by annealing of efficiently electrodeposited Cu-Ga precursor layers from ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Steichen, M., E-mail: marc.steichen@uni.lu; Larsen, J.; Guetay, L.; Siebentritt, S.; Dale, P.J.

    2011-08-31

    CuGaSe{sub 2} absorber layers were prepared on molybdenum substrates by electrochemical codeposition of copper and gallium and subsequential annealing in selenium vapour. The electrodeposition was made from a deep eutectic based ionic liquid consisting of choline chloride/urea (Reline) with a plating efficiency of over 85%. The precursor film composition is controlled by the ratio of the copper to gallium fluxes under hydrodynamic conditions and by the applied deposition potential. X-ray diffraction reveals CuGa{sub 2} alloying during the electrodeposition and CuGaSe{sub 2} formation after annealing. Photoluminescence (PL) and photocurrent spectroscopy revealed the good opto-electronic properties of the CuGaSe{sub 2} absorber films. The absorber layers have been converted to full devices with the best device achieving 4.0 % solar conversion efficiency.

  9. Nucleation and growth in electrodeposition of thin copper films on pyrolytic graphite

    Energy Technology Data Exchange (ETDEWEB)

    Kinaci, F.S.; Muller, R.H.

    1992-05-01

    Electrodeposition of Cu on graphite electrodes was studied, with emphasis on nucleation. Various ex-situ and in-situ methods were investigated for determining the number density of nuclei. Two direct methods were studied (scanning electron microscopy and scanning tunneling microscopy); indirect determinations included Raman spectroscopy and analysis of potentiostatic current transients. Though some of the techniques correctly predicted the nucleation densities under special conditions, SEM was the most reliable tool. The large scatter in the data necessitated steps to minimize this effect. To electrodeposit Cu on graphite, a nucleation overpotential of 250 mV was measured with cyclic voltammetry; such a large overpotential does not occur on a Pt or on a Cu-covered graphite electrode. The deposition potential is the dominant parameter governing nucleation density. There is a sharp increase in the nucleation density with applied potential. Cu can be deposited on highly oriented pyrolytic graphite only between the nucleation overpotential and the hydrogen evolution potential. To increase the Cu nucleation density, while avoiding excessive H evolution, a double pulse potential technique was used; nucleation densities on the order of 10{sup 10} nuclei/cm{sup 2} were achieved. The use of inhibitors (PVA, benzotriazole) was also investigated. Deposition on conducting polymer electrodes was also studied; initial results with polyaniline show promise. 57 figs, 6 tabs, refs. (DLC)

  10. Study of the Mg incorporation in CdTe for developing wide band gap Cd{sub 1-x}Mg{sub x}Te thin films for possible use as top-cell absorber in a tandem solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, Omar S. [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, 62580 Temixco, Morelos (Mexico); Universidad Politecnica del Estado de Guerrero, Comunidad de Puente Campuzano, C.P. 40325 Taxco de Alarcon, Guerrero (Mexico); Millan, Aduljay Remolina [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, 62580 Temixco, Morelos (Mexico); Huerta, L.; Santana, G. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico. C.P 04510 Mexico D.F. (Mexico); Mathews, N.R.; Ramon-Garcia, M.L.; Morales, Erik R. [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, 62580 Temixco, Morelos (Mexico); Mathew, X., E-mail: xm@cie.unam.mx [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, 62580 Temixco, Morelos (Mexico)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer Thin films of Cd{sub 1-x}Mg{sub x}Te with high spatial uniformity and band gap in the range of 1.6-1.96 eV were deposited by vacuum co-evaporation of CdTe and Mg. Black-Right-Pointing-Pointer Obtained Cd{sub 1-x}Mg{sub x}Te films have the structural characteristics of the CdTe, evidence of the change in atomic scattering due to incorporation of Mg was observed. Black-Right-Pointing-Pointer XRD and XPS data confirmed the incorporation of Mg in the lattice of CdTe. Black-Right-Pointing-Pointer SEM images revealed the impact of Mg incorporation on the morphology of the films, the changes in grain size and grain morphology are noticeable. - Abstract: Thin films of Cd{sub 1-x}Mg{sub x}Te with band gap in the range of 1.6-1.96 eV were deposited by vacuum co-evaporation of CdTe and Mg on glass substrates heated at 300 Degree-Sign C. Different experimental techniques such as XRD, UV-vis spectroscopy, SEM, and XPS were used to study the effect of Mg incorporation into the lattice of CdTe. The band gap of the films showed a clear tendency to increase as the Mg content in the film is increased. The Cd{sub 1-x}Mg{sub x}Te films maintain all the structural characteristics of the CdTe, however, diminishing of intensity for the XRD patterns is observed due to both change in preferential orientation and change in atomic scattering due to the incorporation of Mg. SEM images showed significant evidences of morphological changes due to the presence of Mg. XRD, UV-vis spectroscopy, and XPS data confirmed the incorporation of Mg in the lattice of CdTe. The significant increase in band gap of CdTe due to incorporation of Mg suggests that the Cd{sub 1-x}Mg{sub x}Te thin film is a candidate material to use as absorber layer in the top-cell of a tandem solar cell.

  11. Characterization of Cu1.4Te Thin Films for CdTe Solar Cells

    Directory of Open Access Journals (Sweden)

    Guangcan Luo

    2014-01-01

    Full Text Available The copper telluride thin films were prepared by a coevaporation technique. The single-phase Cu1.4Te thin films could be obtained after annealing, and annealing temperature higher than 220°C could induce the presence of cuprous telluride coexisting phase. Cu1.4Te thin films also demonstrate the high carrier concentration and high reflectance for potential photovoltaic applications from the UV-visible-IR transmittance and reflectance spectra, and Hall measurements. With contacts such as Cu1.4Te and Cu1.4Te/CuTe, cell efficiencies comparable to those with conventional back contacts have been achieved. Temperature cycle tests show that the Cu1.4Te contact buffer has also improved cell stability.

  12. Performance Investigation of Multilayer MoS2 Thin-Film Transistors Fabricated via Mask-free Optically Induced Electrodeposition.

    Science.gov (United States)

    Li, Meng; Liu, Na; Li, Pan; Shi, Jialin; Li, Guangyong; Xi, Ning; Wang, Yuechao; Liu, Lianqing

    2017-03-08

    Transition metal dichalcogenides, particularly MoS2, have recently received enormous interest in explorations of the physics and technology of nanodevice applications because of their excellent optical and electronic properties. Although monolayer MoS2 has been extensively investigated for various possible applications, its difficulty of fabrication renders it less appealing than multilayer MoS2. Moreover, multilayer MoS2, with its inherent high electronic/photonic state densities, has higher output driving capabilities and can better satisfy the ever-increasing demand for versatile devices. Here, we present multilayer MoS2 back-gate thin-film transistors (TFTs) that can achieve a relatively low subthreshold swing of 0.75 V/decade and a high mobility of 41 cm(2)·V(-1)·s(-1), which exceeds the typical mobility value of state-of-the-art amorphous silicon-based TFTs by a factor of 80. Ag and Au electrode-based MoS2 TFTs were fabricated by a convenient and rapid process. Then we performed a detailed analysis of the impacts of metal contacts and MoS2 film thickness on electronic performance. Our findings show that smoother metal contacts exhibit better electronic characteristics and that MoS2 film thickness should be controlled within a reasonable range of 30-40 nm to obtain the best mobility values, thereby providing valuable insights regarding performance enhancement for MoS2 TFTs. Additionally, to overcome the limitations of the conventional fabrication method, we employed a novel approach known as optically induced electrodeposition (OIE), which allows the flexible and precise patterning of metal films and enables rapid and mask-free device fabrication, for TFT fabrication.

  13. Elucidating PID Degradation Mechanisms and In Situ Dark I–V Monitoring for Modeling Degradation Rate in CdTe Thin-Film Modules

    Energy Technology Data Exchange (ETDEWEB)

    Hacke, Peter; Spataru, Sergiu; Johnston, Steve; Terwilliger, Kent; VanSant, Kaitlyn; Kempe, Michael; Wohlgemuth, John; Kurtz, Sarah; Olsson, Anders; Propst, Michelle

    2016-11-01

    A progression of potential-induced degradation (PID) mechanisms are observed in CdTe modules, including shunting/junction degradation and two different manifestations of series resistance depending on the stress level and water ingress. The dark I-V method for in-situ characterization of Pmax based on superposition was adapted for the thin-film modules undergoing PID in view of the degradation mechanisms observed. An exponential model based on module temperature and relative humidity was fit to the PID rate for multiple stress levels in chamber tests and validated by predicting the observed degradation of the module type in the field.

  14. High throughput manufacturing of thin-film CdTe photovoltaic modules. Annual subcontract report, 16 November 1993--15 November 1994

    Energy Technology Data Exchange (ETDEWEB)

    Sandwisch, D W [Solar Cells, Inc., Toledo, OH (United States)

    1995-11-01

    This report describes work performed by Solar Cells, Inc. (SCI), under a 3-year subcontract to advance SCI`s PV manufacturing technologies, reduce module production costs, increase module performance, and provide the groundwork for SCI to expand its commercial production capacities. SCI will meet these objectives in three phases by designing, debugging, and operating a 20-MW/year, automated, continuous PV manufacturing line that produces 60-cm {times} 120-cm thin-film CdTe PV modules. This report describes tasks completed under Phase 1 of the US Department of Energy`s PV Manufacturing Technology program.

  15. Hydrogen peroxide biosensor based on electrodeposition of zinc oxide nanoflowers onto carbon nanotubes film electrode

    Institute of Scientific and Technical Information of China (English)

    Hui Ping Bai; Xu Xiao Lu; Guang Ming Yang; Yun Hui Yang

    2008-01-01

    A new amperometric biosensor for hydrogen peroxide was developed based on adsorption of horseradish peroxidase at the glassy carbon electrode modified with zinc oxide nanoflowers produced by electrodeposition onto multi-walled carbon nanotubes (MWNTs) firm. The morphology of the MWNTs/nano-ZnO electrode has been investigated by scanning electron microscopy (SEM), and the electrochemical performance of the electrode has also been studied by amperometric method. The resulting electrode offered an excellent detection for hydrogen peroxide at -0.11 V with a linear response range of 9.9 × 10(-7) to 2.9 × 10(-3) mol/L with a correlation coefficient of 0.991, and response time <5 s. The biosensor displays rapid response and expanded linear response range, and excellent stability.

  16. Magnetic properties and giant magnetoresistance in electrodeposited Co-Ag granular films

    Energy Technology Data Exchange (ETDEWEB)

    Kenane, S. [Laboratoire Louis Neel, CNRS, 25 Avenue des Martyrs, BP 166, 38042 Grenoble Cedex 9 (France); Laboratoire d' Electrochimie et de Physico-Chimie des Materiaux et des Interfaces, UMR 5631-INPG-CNRS, Domaine Universitaire, BP 75, 38402 Saint Martin d' Heres (France); Laboratoire de Materiaux, Electrochimie et Corrosion, Universite Mouloud Mammeri, Tizi-Ouzou, 15000 (Algeria); Voiron, J. [Laboratoire Louis Neel, CNRS, 25 Avenue des Martyrs, BP 166, 38042 Grenoble Cedex 9 (France)]. E-mail: voiron@grenoble.cnrs.fr; Benbrahim, N. [Laboratoire de Materiaux, Electrochimie et Corrosion, Universite Mouloud Mammeri, Tizi-Ouzou, 15000 (Algeria); Chainet, E. [Laboratoire d' Electrochimie et de Physico-Chimie des Materiaux et des Interfaces, UMR 5631-INPG-CNRS, Domaine Universitaire, BP 75, 38402 Saint Martin d' Heres (France); Robaut, F. [CMTC, Consortium des Moyens Techniques communs de Grenoble (France)

    2006-02-15

    Small cobalt particles embedded in a silver matrix have been prepared using the electrodeposition technique. The size of the clusters is controlled by the deposition potential and the Co growth time. Structural, magnetic and magneto-transport properties of Co-Ag samples have been investigated as a function of the Co concentration between 2 and 40 at% cobalt. Superparamagnetic behavior is evidenced for the low contents of cobalt while long-range magnetic order appears at higher Co concentrations. The particles size has been determined from magnetic properties and from the X-ray diffraction technique, and varies between 3.5 and 9 nm. Magnetoresistance passes through a maximum as a function of the cobalt concentration. A maximum of {approx}4% GMR is obtained at room temperature while GMR reaches a value of 14% at 10 K.

  17. Effect of coating current density on the wettability of electrodeposited copper thin film on aluminum substrate

    Directory of Open Access Journals (Sweden)

    Arun Augustin

    2016-09-01

    Full Text Available Copper is the only one solid metal registered by the US Environmental Protection Agency as an antimicrobial touch surface. In touch surface applications, wettability of the surface has high significance. The killing rate of the harmful microbes depends on the wetting of pathogenic solution. Compared to the bulk copper, coated one on aluminum has the advantage of economic competitiveness and the possibility of manufacturing complex shapes. In the present work, the copper coating on the aluminum surface has successfully carried out by electrodeposition using non cyanide alkaline bath. To ensure good adhesion strength, the substrate has been pre-zincated prior to copper deposition. The coating current density is one of the important parameters which determine the nucleation density of the copper on the substrate. To understand the effect of current density on wettability, the coating has done at different current densities in the range of 3 A dm−2 to 9 A dm−2 for fixed time interval. The grain size has been measured from TEM micrographs and showed that as current density increases, grain size reduces from 62 nm to 35 nm. Since the grain size reduces, grain boundary volume has increases. As a result the value of strain energy (calculated by Williamson–Hall method has increased. The density of nodular morphology observed in SEM analysis has been increased with coating current density. Further, wettability studies with respect to double distilled water on the electrodeposited copper coatings which are coated at different current densities are carried out. At higher current density the coating is more wettable by water because at these conditions grain size of the coating decreases and morphology of grain changes to a favorable dense nodularity.

  18. Electrodeposited CdTe{emdash}optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Rakhshani, A.E. [Physics Department, Kuwait University, PO Box 5969, Safat 13060 (Kuwait)

    1997-06-01

    For the measurement of optical constants, the electrodeposited films of CdTe were lifted off their opaque substrates and transferred onto glass slides using a transparent liquid adhesive. This technique proved to give results more reliable than those obtained on samples in which CdTe is deposited on CdS-coated conducting glass. The measured optical dispersion in the photon energy range of E{lt}1.5eV is in excellent agreement with that for the single crystal. The optical absorption coefficient was determined in the E{lt}3.5eV range and was compared with that for the single crystal. The results revealed two direct allowed transitions at 1.50 eV [{Gamma}{sub 8}valenceband(VB){r_arrow}{Gamma}{sub 6}conductionband(CB)] and 2.43 eV [{Gamma}{sub 7}(VB){r_arrow}{Gamma}{sub 6}(CB)] and three indirect allowed transitions at 1.27 eV [L{sub 4,5}(VB){r_arrow}{Gamma}{sub d}], 1.83 eV [L{sub 6}(VB){r_arrow}{Gamma}{sub d}], and 2.84 eV [{Gamma}{sub 8}(VB){r_arrow}L{sub 6}(CB)]. The 1.27 and the 1.83 eV transitions, which have not been reported previously and were not detected in single-crystal data, are attributed to the transitions to a grain-boundary-related defect energy band {Gamma}{sub d}, 0.65 eV above {Gamma}{sub 8} (VB). The indirect transitions at 1.83 and 2.84 eV are assisted by phonons having energies of 80 and 84 meV, respectively. {copyright} {ital 1997 American Institute of Physics.}

  19. Electrodeposited CdTe—optical properties

    Science.gov (United States)

    Rakhshani, A. E.

    1997-06-01

    For the measurement of optical constants, the electrodeposited films of CdTe were lifted off their opaque substrates and transferred onto glass slides using a transparent liquid adhesive. This technique proved to give results more reliable than those obtained on samples in which CdTe is deposited on CdS-coated conducting glass. The measured optical dispersion in the photon energy range of E<1.5 eV is in excellent agreement with that for the single crystal. The optical absorption coefficient was determined in the E<3.5 eV range and was compared with that for the single crystal. The results revealed two direct allowed transitions at 1.50 eV [Γ8 valence band(VB)→Γ6 conduction band(CB)] and 2.43 eV [Γ7(VB)→Γ6(CB)] and three indirect allowed transitions at 1.27 eV [L4,5(VB)→Γd], 1.83 eV [L6(VB)→Γd], and 2.84 eV [Γ8(VB)→L6(CB)]. The 1.27 and the 1.83 eV transitions, which have not been reported previously and were not detected in single-crystal data, are attributed to the transitions to a grain-boundary-related defect energy band Γd, 0.65 eV above Γ8 (VB). The indirect transitions at 1.83 and 2.84 eV are assisted by phonons having energies of 80 and 84 meV, respectively.

  20. Electrodeposition of Pr-Fe alloy films in urea-dimethylsulfoxide

    Institute of Scientific and Technical Information of China (English)

    ZHOU Hao; KE Qinfang; HUANG Kaisheng; LIU Guankun; YUAN Dingsheng

    2005-01-01

    Cyclic voltammetry and chronoamperometry were used to investigate the electrochemical behavior of Pr3+ ions electrochemical parameters were measured. Potentiostatic depositions between -1.6 and -2.4 V were applied to deposit Pr-Fe films in urea-DMSO mixed solution. The Pr content in the alloy films was in the range of 34.89 wt.% to 37.15 wt.%.The Pr-Fe alloy films are proven to be amorphous by XRD (X-ray diffraction).

  1. Research Leading to High Throughput Manufacturing of Thin-Film CdTe PV Modules: Annual Subcontract Report, September 2004--September 2005

    Energy Technology Data Exchange (ETDEWEB)

    Powell, R. C.

    2006-04-01

    Specific overall objectives of this subcontract are improvement in baseline field performance of manufactured CdTe PV modules while reducing environmental, health and safety risk in the manufacturing environment. Project objectives focus on four broad categories: (1) development of advanced front-contact window layers, (2) improved semiconductor film deposition, (3) development of improved accelerated life test procedures that indicate baseline field performance, and (4) reduction of cadmium-related environmental, health and safety risks. First Solar has significantly increased manufacturing capacity from less than 2 MW/yr to more than 20 MW/yr, while increasing the average module total-area power conversion efficiency from 7% to >9%. First Solar currently manufactures and sells 50-65-W thin-film CdTe PV modules at a rate of about 1.9 MW/month. Sales backlog (booked sales less current inventory divided by production rate) is more than a year. First Solar is currently building new facilities and installing additional equipment to increase production capacity by 50 MW/yr; the additional capacity is expected to come on line in the third quarter of 2006.

  2. Correlation between physical properties and growth mechanism of In2S3 thin films fabricated by electrodeposition technique with different deposition times

    Science.gov (United States)

    Braiek, Zied; Gannouni, Mounir; Ben Assaker, Ibtissem; Bardaoui, Afrah; Lamouchi, Amina; Brayek, A.; Chtourou, Radhouane

    2015-10-01

    Indium sulfide (In2S3) thin films were grown on ITO-coated glass substrate using the electrodeposition method. The effect of the deposition time on the structural, morphological, optical and electrical properties of the as-grown In2S3 thin films was studied. XRD spectra of the obtained films reveal the polycrystalline nature of (β-In2S3) with a tetragonal crystal structure along the (109) plane, and exhibit a sharp transition to the (0012) plane when the deposition time is extended beyond 20 min. Using atomic force microscope (AFM), the surface morphology shows a remarkable change in the grain size, thickness, and surface roughness when varying the deposition time. UV-VIS spectrophotometer show that the optical band gap values of In2S3 decrease from about 2.82 to 1.93 eV by extending the electrodeposition duration from 5 to 20 min. All films were found to have an n-type character with a lower electrical resistivity of about 1.8×10-3 Ω cm for films deposited at 20 min.

  3. High-efficiency CdTe thin-film solar cells using metalorganic chemical vapor deposition techniques

    Science.gov (United States)

    Nouhi, A.; Stirn, R. J.; Meyers, P. V.; Liu, C. H.

    1989-01-01

    Energy conversion efficiency of metalorganic chemical vapor deposited CdTe as an intrinsic active layer in n-i-p solar cell structures is reported. Small-area devices with efficiencies over 9 percent have been demonstrated. I-V characteristics, photospectral response, and the results of Auger profiling of structural composition for typical devices will be presented. Also presented are preliminary results on similar photovoltaic devices having Cd(0.85)Mn(0.15)Te in place of CdTe as an i layer.

  4. Investigation of a Cu/Pd Bimetallic System Electrodeposited on Boron-Doped Diamond Films for Application in Electrocatalytic Reduction of Nitrate

    Directory of Open Access Journals (Sweden)

    Jorge T. Matsushima

    2012-01-01

    Full Text Available The Cu/Pd bimetallic system electrodeposited on boron-doped diamond (BDD films for application, as electrode material in the electrochemical reduction of nitrate was studied. The electrochemical behavior of Cu, Pd, and Cu/Pd bimetallic system was evaluated by cyclic voltammetry. From these results, the formation of the Cu/Pd composite was verified. In addition, Cu with different phases and a Cu/Pd phase in the composite were obtained. Morphological analysis by scanning electron microscopy (SEM revealed a homogeneous distribution of Cu/Pd bimetallic particles with intermediary dimensions compared to those observed in Cu or Pd electrodeposits separately. These composites were tested as electrocatalysts for nitrate reduction in Britton-Robinson buffer solution (pH 9. Electrochemical measurements showed that composites with higher Cu content displayed the best electrocatalytic activity for nitrate reduction, and the Cu/Pd phase in the bimetallic system served to improve the Cu adherence on BDD electrode.

  5. Atomic force microscopy study, kinetic roughening and multifractal analysis of electrodeposited silver films

    Science.gov (United States)

    Nasehnejad, M.; Gholipour Shahraki, M.; Nabiyouni, G.

    2016-12-01

    We used atomic force microscopy (AFM) to study surface morphology and kinetic roughening of Ag films. X-ray diffraction (XRD) technique is used to verify the films crystalline structure. The influence of film thickness on the kinetic roughening was investigated using AFM data and roughness calculation. It is revealed that the surface roughness increases with increasing the film thickness. The data also consist with a complex behavior which is called as anomalous scaling. Scaling laws analysis for Ag films presents two distinct dynamics including large local and scale roughness and indicates a power law dependency on the thickness of film. AFM images have been characterized by the multifractal analysis. This analysis shows that the self-similar and multifractal characteristics as well as anomalous scaling exist in the Ag film morphologies. Description of the quantitative growth and surface morphology was done by the multifractal spectra, f (α) - α . It is found that the multifractal spectrum shape is left hook-like (that is difference of height interval of the multifractal spectrum, Δf = f (αmin) - f (αmax) > 0). The results indicate that the surfaces having greater roughness give rise the wider multifractal spectrum width (Δα) and the greater Δf, thus, the nonuniformity of the height probabilities becomes larger. It indicates that the multifractality of the films becomes more pronounced at the higher thickness.

  6. Effects of Thickness and Annealing on Optoelectronic Properties of Electrodeposited ZnS Thin Films for Photonic Device Applications

    Science.gov (United States)

    Echendu, O. K.; Dharmadasa, I. M.

    2013-12-01

    Thin layers of ZnS with thicknesses of 400 nm, 500 nm, and 700 nm have been electrodeposited on glass/fluorine-doped tin oxide substrates using a simple two-electrode setup under similar conditions. Structural characterization of the layers using x-ray diffraction (XRD) measurements showed that they were amorphous. The results of optical characterization carried out in the wavelength range of 315 nm to 800 nm using spectrophotometry revealed that the optical properties of the layers are strongly influenced by the film thickness as well as annealing conditions. The values of the refractive index, extinction coefficient, absorption coefficient, and dielectric constant obtained from normal-incidence transmittance spectra were generally lower after annealing, showing also the influence of postdeposition annealing on the deposited ZnS layers. Electrical characterization of the layers, using direct-current current-voltage measurement under dark conditions at room temperature, shows that the resistivity of the as-deposited and annealed layers is in the range of 1.4 × 104 Ω cm to 2.5 × 104 Ω cm and 2.5 × 104 Ω cm to 3.1 × 104 Ω cm, respectively. The results suggest that the optoelectronic properties can be tuned for particular applications by adjusting the thickness of the layers appropriately.

  7. Multifunctional hybrid coating on titanium towards hydroxyapatite growth: Electrodeposition of tantalum and its molecular functionalization with organophosphonic acids films

    Energy Technology Data Exchange (ETDEWEB)

    Arnould, Christelle; Delhalle, Joseph [Laboratory of Chemistry and Electrochemistry of Surfaces, University of Namur (FUNDP), Rue de Bruxelles 61, B-5000 Namur (Belgium); Mekhalif, Zineb [Laboratory of Chemistry and Electrochemistry of Surfaces, University of Namur (FUNDP), Rue de Bruxelles 61, B-5000 Namur (Belgium)], E-mail: zineb.mekhalif@fundp.ac.be

    2008-07-20

    Titanium and its alloys are base materials used in the dental and orthopaedic fields owing to suitable intrinsic properties: good biocompatibility, high corrosion resistance and excellent mechanical properties. However, the bonding between titanium and bone tissue is not always strong enough and can become a critical problem. In this context, the two main objectives of this paper are the increase of the corrosion resistance and the improvement of the hydroxyapatite (HAp) growth. The surface modification considered here is achieved in three main steps and consists in the elaboration of different inorganic and organic coatings. The first step is the elaboration of electrodeposition of tantalum on the titanium oxide film of a titanium substrate. The second step is the modification of the tantalum oxide coating with organophosphonic acids. The last step is the nucleation and growth of HAP on the outermost layer of the system by immersion in a simulated body fluid. The hybrid coating tantalum oxide/organophosphonic acids/molecular layer is shown to be promising for orthopaedic implants.

  8. Synthesis of the CulnSe2 thin film for solar cells using the electrodeposition technique and Taguchi method

    Institute of Scientific and Technical Information of China (English)

    Wei-long Liu; Shu-huei Hsieh; Wen-jauh Chen; Pei-i Wei; Jiing-herng Lee

    2009-01-01

    The Taguchi method was used to obtain the optimum electrodeposition parameters for the synthesis of the CuInSe2 thinfilm for solar cells.The parameters consist of annealing temperature,current density,CuCl2 concentration,FeCl3 concentration,H2SeO3 concentration,TEA amount,pH value,and deposition time.The experiments were carried out according to an L18(2137) table.An X-ray diffractometer (XRD) and a scanning electron microscope (SEM) were respectively used to analyze the phases and observe the microstructure and the grain size of the CuInSe2 film before and after annealing treatment.The results showed that the CuInSe2phase was deposited with a preferred plane (112) parallel to the substrate surface.The optimum parameters are as follows:currentdensity,7 mA/cm2;CuCl2 concentration,10 raM;FeCl3 concentration,50 raM;H2SeO3 concentration,15 mM;TEA amount,0 mL;pH value,1.65;deposition time,10 min;and annealing temperature,500℃.

  9. Magnetic microstructures in electrodeposited Fe1 - xGax thin films (15 ≤ x ≤ 22 at.%)

    Science.gov (United States)

    Ranchal, R.; Fin, S.; Bisero, D.

    2015-02-01

    We have investigated the magnetic behavior of Fe1 - xGax (15 ≤ x ≤ 22 at.%) thin films grown by electrodeposition. The samples exhibit a texture although a rather small diffraction peak related to the (1 0 0) phase can also be observed. The layers do not present perpendicular magnetic anisotropy but magnetic hysteresis loops and magnetic force microscopy evidence a significant out-of-plane component for the magnetization. This component seems to increase for Ga contents around the 19 at.% value at which these alloys present a peak for the magnetostriction constant in the [1 0 0] direction. In this composition range, we have also observed an enhancement of the period of the magnetic structures. The experimental results indicate that the origin of the domain configuration is the presence of clusters with a (1 0 0) structural phase. The out-of-plane component of the magnetization seems to arise because of the compression of these nanoaggregates.

  10. Magnetic and magnetoresistance studies of nanometric electrodeposited Co films and Co/Cu layered structures: Influence of magnetic layer thickness

    Science.gov (United States)

    Zsurzsa, S.; Péter, L.; Kiss, L. F.; Bakonyi, I.

    2017-01-01

    The magnetic properties and the magnetoresistance behavior were investigated for electrodeposited nanoscale Co films, Co/Cu/Co sandwiches and Co/Cu multilayers with individual Co layer thicknesses ranging from 1 nm to 20 nm. The measured saturation magnetization values confirmed that the nominal and actual layer thicknesses are in fairly good agreement. All three types of layered structure exhibited anisotropic magnetoresistance for thick magnetic layers whereas the Co/Cu/Co sandwiches and Co/Cu multilayers with thinner magnetic layers exhibited giant magnetoresistance (GMR), the GMR magnitude being the largest for the thinnest Co layers. The decreasing values of the relative remanence and the coercive field when reducing the Co layer thickness down to below about 3 nm indicated the presence of superparamagnetic (SPM) regions in the magnetic layers which could be more firmly evidenced for these samples by a decomposition of the magnetoresistance vs. field curves into a ferromagnetic and an SPM contribution. For thicker magnetic layers, the dependence of the coercivity (Hc) on magnetic layer thickness (d) could be described for each of the layered structure types by the usual equation Hc=Hco+a/dn with an exponent around n=1. The common value of n suggests a similar mechanism for the magnetization reversal by domain wall motion in all three structure types and hints also at the absence of coupling between magnetic layers in the Co/Cu/Co sandwiches and Co/Cu multilayers.

  11. Nanostructured ZnO films in forms of rod, plate and flower: Electrodeposition mechanisms and characterization

    Science.gov (United States)

    Kıcır, Nur; Tüken, Tunç; Erken, Ozge; Gumus, Cebrail; Ufuktepe, Yuksel

    2016-07-01

    Uniformity and reproducibility of well-defined ZnO nanostructures are particularly important issues for fabrication and applications of these nanomaterials. In present study, we report selective morphology control during electrodeposition, by adjusting the hydroxyl generation rate and Zn(OH)2 deposition. In presence of remarkably high chloride concentration (0.3 M) and -1.0 V deposition potential, slow precipitation conditions were provided in 5 mM Zn(NO3)2 solution. By doing so, we have obtained highly ordered, vertically aligned and uniformly spaced hexagon shaped nanoplates, on ITO surface. We have also investigated the mechanism for shifting the morphology from rod/plate to flower like structure of ZnO, for better understanding the reproducibility. For this reason, the influence of various supporting electrolytes (sodium/ammonium salts of acetate) has been investigated for interpretation of the influence of OH- concentration nearby the surface. From rod to plate and flower nanostructures, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analysis were realized for characterization, also the optical properties were studied.

  12. Electrodeposition of Silver Nanoparticles on MWCNT Film Electrodes for Hydrogen Peroxide Sensing

    Institute of Scientific and Technical Information of China (English)

    DING,Yan-Feng; JIN,Guan-Ping; YIN,Jun-Guang

    2007-01-01

    Silver (Ag) nanoparticles were directly electrodeposited on multi-walled carbon nanotubes (MWCNT) in AgNO3/LiNO3 containing EDTA (ethylenediaminetetraacetic acid). The structure and nature of the resulting Ag/MWNT composite were characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD), and the distribution shape of Ag nanoparticles was found to be dependent on the presence of EDTA. The modified electrode showed excellent electrocatalytic activity to redox reaction of hydrogen peroxide and the mechanism of hydrogen peroxide was partly reversible procession with oxidation and reduction peaks at 0.77 and -0.83 V, respectively. The oxidation and reduction peak currents were linearly related to hydrogen peroxide concentration in the range of 1×10-6-3×10-4 and 1×10-8-7×10-4 mol·L-1 with correlation coefficients of 0.996 and 0.986, and 3s-detection limit of 9 × 10-7 and 7 × 10-9 mol·L-1.

  13. Correlations of electro-optical and nanostructural properties of CdTe thin films

    Science.gov (United States)

    Levi, D. H.; Moutinho, H. R.; Hasoon, F. S.; Ahrenkiel, R. K.; Kazmerski, L. L.; Al-Jassim, M. M.

    1996-01-01

    This paper presents correlations of macroscopic optical properties with the nanoscale physical and electronic structure of CdTe/CdS thin films used for photovoltaic cell fabrication. We have studied the evolution of these properties under systematic variation of post-growth treatment conditions for several standard deposition techniques. The electro-optical properties and nanostructure depend strongly on deposition conditions and post-growth treatments. Our results indicate that the standard CdCl2—heat treatment enhances grain size and passivates defects. We have also found strong evidence for sulfur diffusion across the CdTe—CdS interface. This interdiffusion produces a thin layer at the junction with a bandgap lower than the rest of the absorber layer. This effect could have important implications for photoexcited carrier collection in photovoltaic applications.

  14. Correlations of electro-optical and nanostructural properties of CdTe thin films

    Energy Technology Data Exchange (ETDEWEB)

    Levi, D.H.; Moutinho, H.R.; Hasoon, F.S.; Ahrenkiel, R.K.; Kazmerski, L.L.; Al-Jassim, M.M. [National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, Colorado 80401 (United States)

    1996-01-01

    This paper presents correlations of macroscopic optical properties with the nanoscale physical and electronic structure of CdTe/CdS thin films used for photovoltaic cell fabrication. We have studied the evolution of these properties under systematic variation of post-growth treatment conditions for several standard deposition techniques. The electro-optical properties and nanostructure depend strongly on deposition conditions and post-growth treatments. Our results indicate that the standard CdCl{sub 2}{emdash}heat treatment enhances grain size and passivates defects. We have also found strong evidence for sulfur diffusion across the CdTe{emdash}CdS interface. This interdiffusion produces a thin layer at the junction with a bandgap lower than the rest of the absorber layer. This effect could have important implications for photoexcited carrier collection in photovoltaic applications. {copyright} {ital 1996 American Institute of Physics.}

  15. Construção e caracterização de células solares de filmes finos de CdS e CdTe

    OpenAIRE

    Morales Morales, Oswaldo [UNESP

    2012-01-01

    Neste trabalho, o objeto de estudo foi células Solares CdS/CdTe. Estas células usam o filme de sulfeto de cádmio (CdS) como semicondutor do tipo n e o filme de telureto de cádmio (CdTe) como semicondutor do tipo p. O recorde mundial, alcançado no laboratório, para estas células é 16,5% de eficiência. Nos Laboratórios do Departamento de Física e Química de Unesp - Ilha Solteira, este trabalho é pioneiro na fabricação de Células Solares de CdS/CdTe. Para realizar este trabalho foi necessário me...

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

    Institute of Scientific and Technical Information of China (English)

    Umut Sarac; M. Celalettin Baykul

    2012-01-01

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

  17. Electrodeposition and Capacitive Behavior of Films for Electrodes of Electrochemical Supercapacitors

    Directory of Open Access Journals (Sweden)

    Shi C

    2010-01-01

    Full Text Available Abstract Polypyrrole films were deposited by anodic electropolymerization on stainless steel substrates from aqueous pyrrole solutions containing sodium salicylate and tiron additives. The deposition yield was studied under galvanostatic conditions. The amount of the deposited material was varied by the variation of deposition time at a constant current density. SEM studies showed the formation of porous films with thicknesses in the range of 0–3 μm. Cyclic voltammetry data for the films tested in 0.5 M Na2SO4 solutions showed capacitive behavior and high specific capacitance (SC in a voltage window of 0.9 V. The films prepared from pyrrole solutions containing tiron showed better capacitive behavior compared to the films prepared from the solutions containing sodium salicylate. A highest SC of 254 F g−1 was observed for the sample with a specific mass of 89 μg cm−2 at a scan rate of 2 mV s−1. The SC decreased with an increasing film thickness and scan rate. The results indicated that the polypyrrole films deposited on the stainless steel substrates by anodic electropolymerization can be used as electrodes for electrochemical supercapacitors (ES.

  18. Electrodeposition of a Pt monolayer film: using kinetic limitations for atomic layer epitaxy.

    Science.gov (United States)

    Brimaud, Sylvain; Behm, R Jürgen

    2013-08-14

    A new and facile one-step method to prepare a smooth Pt monolayer film on a metallic substrate in the absence of underpotential deposition-type stabilizations is presented as a general approach and applied to the growth of Pt monolayer films on Au. The strongly modified electronic properties of these films were demonstrated by in situ IR spectroscopy at the electrified solid-liquid interface with adsorbed carbon monoxide serving as a probe molecule. The Pt monolayer on Au is kinetically stabilized by adsorbed CO, inhibiting further Pt deposition in higher layers.

  19. Electrodeposition and Characterization of Nickel, Iron, Copper Thin Films and the Creation of Nanoporous Structures

    Science.gov (United States)

    Yarranton, Jonathan; Hampton, Jennifer

    2013-03-01

    There has been much research in creating nanoporous platinum or gold thin films for catalysis, but there has not been as much work done with other, less noble metals. This research explored the deposition of nickel, iron, and copper ternary alloys using controlled potential electrolysis (CPE) and the selective removal of the copper with DC potential amperometry (DCPA) and linear sweep voltammetry (LSV) to create nanoporous structures. These structures have the advantage of increased surface area creating more efficient catalysts. All films were characterized before and after dealloying using scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS) for composition. The roughness of each of the films was characterized by the capacitance of the film, with higher capacitances indicating a higher electrochemical surface area. This material is based upon work supported by the National Science Foundation under RUI Grant DMR-1104725, MRI Grant CHE-0959282, and ARI grant PHY-0963317.

  20. Studies on Preparation of Co-Bi Alloy Films by Electrodeposition From Nonaqueous Medium

    Institute of Scientific and Technical Information of China (English)

    LI Gao-ren; TONG Ye-xiang; LIU Guan-kun

    2003-01-01

    Cyclic voltammetry and potentiostatic electrolysis were used to investigate the preparation of Co-Bi alloy films in a LiClO4-DMSO system. The experimental results indicate that the Co-Bi alloy films containing 14.35%-29.77% Co can be prepared via potentionstatic electrolysis on Cu substrates, at deposition potential -1.10--1.65 V(vs. SCE) and by controlling the system composition and deposition condition. They are uniform gray films with a metallic luster and they are adhered firmly to the Cu substrate. The films were analyzed by EDS, SEM and XRD. After heat treatment of crystallization at 275 ℃ for 1 h, the alloy phase of Co-Bi can be confirmed via the XRD pattern.

  1. Microstructure and magnetic properties of electrodeposited Gd-Co alloy films

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Gd-Co alloy films were synthesized by potentiostatic electrolysis on Cu substrates in urea-aeetamide-NaBr-KBr melt at 353 K.The electroreduction of Co2+ and Gd3+ was investigated by cyclic voltammetry.The reduction of Co2+ is an irreversible process.Gd3+ cannot be reduced alone,but it can be inductively co-deposited with Co2+.Both the Gd content and microstructure of the prepared Gd-Co alloy films can be controlled by the deposited potential.The content of Gd was analyzed using an inductively coupled plasma emission spectrometer(ICPES),and the microstructure was observed by scanning electron mierograph (SEM).The films were crystallized by heat-treatment at 823 K for 30 s in Ar atmosphere,and then were investigated by XRD.The hysteresis loops of the Gd-Co alloy films were measured by a vibrating sample magnetometer (VSM).The experimental results reveal that the deposited Gd-Co alloy films are amorphous,while the annealing causes the samples to change from amorphous to polycrystalline,thus enhancing their magnetoerystalline anisotropy and coercivity.Moreover,the magnetic properties of the Gd-Co alloy films depend strongly on the Gd content.

  2. Preparation and Characterization of RF Magntron Sputtering CdTe Thin Film%CdTe薄膜的射频磁控溅射制备及表征

    Institute of Scientific and Technical Information of China (English)

    王波; 张静全; 王生浩; 冯良桓; 雷智; 武莉莉; 李卫; 黎兵; 曾广根

    2011-01-01

    The cadmium telluride thin film was deposited on glass substrate at room teperature by RF magnetron sputtering. The film was characterized to show the variation of its properties with the diverse deposition conditions by X-ray diffraction, UV-VIS spectrometer, scanning electrical microscope, etc. The result indicates that thc deposition speed increases with the increase of deposition power and decreases with the increase of pressure. As the pressure decreases, the CdTe film' s crystallinity gets worse. It is found that the cubic crystalline structure of deposited sample changes to the crystalline hexagonal CdTe phase as the power increased from 100 W to140 W. While the CdTe thin films is deposited under the pressure of 0.3 Pa, with the power of 100 W and at room temperature, the crystallinity is the best and the band gap is 1.45 eV.%采用射频磁控溅射技术制备了Cdre薄膜,使用探针式台阶仪、X射线衍射分析仪、紫外可见分光光度计、扫描电镜等表征了薄膜的厚度、结构、透过率、表面形貌等随溅射工艺的变化.结果表明:沉积速率随着功率的增加而增加,随气压的增加而呈线性减小;薄膜的结晶程度随气压增大而降低;功率从100W增大到180 W,出现了CdTe薄膜晶相从立方相向六方相的转变;当沉积条件为纯氩气氛、气压0.3Pa、功率100W、室温时,沉积的CdTe薄膜结晶性能最好.

  3. Nanometer-Thick Gold on Silicon as a Proxy for Single-Crystal Gold for the Electrodeposition of Epitaxial Cuprous Oxide Thin Films.

    Science.gov (United States)

    Switzer, Jay A; Hill, James C; Mahenderkar, Naveen K; Liu, Ying-Chau

    2016-06-22

    Single-crystal Au is an excellent substrate for electrochemical epitaxial growth due to its chemical inertness, but the high cost of bulk Au single crystals prohibits their use in practical applications. Here, we show that ultrathin epitaxial films of Au electrodeposited onto Si(111), Si(100), and Si(110) wafers can serve as an inexpensive proxy for bulk single-crystal Au for the deposition of epitaxial films of cuprous oxide (Cu2O). The Au films range in thickness from 7.7 nm for a film deposited for 5 min to 28.3 nm for a film deposited for 30 min. The film thicknesses are measured by low-angle X-ray reflectivity and X-ray Laue oscillations. High-resolution TEM shows that there is not an interfacial SiOx layer between the Si and Au. The Au films deposited on the Si(111) substrates are smoother and have lower mosaic spread than those deposited onto Si(100) and Si(110). The mosaic spread of the Au(111) layer on Si(111) is only 0.15° for a 28.3 nm thick film. Au films deposited onto degenerate Si(111) exhibit ohmic behavior, whereas Au films deposited onto n-type Si(111) with a resistivity of 1.15 Ω·cm are rectifying with a barrier height of 0.85 eV. The Au and the Cu2O follow the out-of-plane and in-plane orientations of the Si substrates, as determined by X-ray pole figures. The Au and Cu2O films deposited on Si(100) and Si(110) are both twinned. The films grown on Si(100) have twins with a [221] orientation, and the films grown on Si(110) have twins with a [411] orientation. An interface model is proposed for all Si orientations, in which the -24.9% mismatch for the Au/Si system is reduced to only +0.13% by a coincident site lattice in which 4 unit meshes of Au coincide with 3 unit meshes of Si. Although this study only considers the deposition of epitaxial Cu2O films on electrodeposited Au/Si, the thin Au films should serve as high-quality substrates for the deposition of a wide variety of epitaxial materials.

  4. Elaboration of ammonia gas sensors based on electrodeposited polypyrrole--cobalt phthalocyanine hybrid films.

    Science.gov (United States)

    Patois, Tilia; Sanchez, Jean-Baptiste; Berger, Franck; Fievet, Patrick; Segut, Olivier; Moutarlier, Virginie; Bouvet, Marcel; Lakard, Boris

    2013-12-15

    The electrochemical incorporation of a sulfonated cobalt phthalocyanine (sCoPc) in conducting polypyrrole (PPy) was done, in the presence or absence of LiClO4, in order to use the resulting hybrid material for the sensing of ammonia. After electrochemical deposition, the morphological features and structural properties of polypyrrole/phthalocyanine hybrid films were investigated and compared to those of polypyrrole films. A gas sensor consisting in platinum microelectrodes arrays was fabricated using silicon microtechnologies, and the polypyrrole and polypyrrole/phthalocyanine films were electrochemically deposited on the platinum microelectrodes arrays of this gas sensor. When exposed to ammonia, polymer-based gas sensors exhibited a decrease in conductance due to the electron exchange between ammonia and sensitive polymer-based layer. The characteristics of the gas sensors (response time, response amplitude, reversibility) were studied for ammonia concentrations varying from 1 ppm to 100 ppm. Polypyrrole/phthalocyanine films exhibited a high sensitivity and low detection limit to ammonia as well as a fast and reproducible response at room temperature. The response to ammonia exposition of polypyrrole films was found to be strongly enhanced thanks to the incorporation of the phthalocyanine in the polypyrrole matrix.

  5. Electrodeposited Fe{sub (100-x)}Ga{sub x} thin films with high magnetostriction

    Energy Technology Data Exchange (ETDEWEB)

    Iselt, Diana; Schultz, Ludwig [IFW Dresden, Institute for Metallic Materials, Helmholtzstr. 20, 01069 Dresden (Germany); TU Dresden, Faculty of Mechanical Engineering, 01062 Dresden (Germany); Schloerb, Heike; Faehler, Sebastian [IFW Dresden, Institute for Metallic Materials, Helmholtzstr. 20, 01069 Dresden (Germany)

    2010-07-01

    Magnetostrictive materials can be used to build up electromagnetic sensing and actuating devices. A promising candidate to overcome the mechanical limitations of Terfenol-D is Fe{sub (100-x)}Ga{sub x} with 15 to 25 at.% Ga, which shows a high mechanical strength and low saturation fields. For the application as sensors thin films, ribbons and nanowires need to be produced in a cheap way over large areas. In this study a suitable deposition process for Fe-Ga alloy thin films has been developed using electrochemical pulse plating. By optimising the deposition parameters such as electrolyte composition, deposition potential, deposition time and pulse sequences, homogeneous (110)-oriented thin films with low oxygen content have been prepared. Preliminary investigations of magnetic properties correlated to magnetostriction are presented and discussed in sense of shape anisotropy.

  6. X-Ray Magnetic Circular Dichroism Measurement of Fe-Co Alloy Films Prepared by Electrodeposition

    Institute of Scientific and Technical Information of China (English)

    LI Zong-Mu; XU Fa-Qiang; WANG Li-Wu; WANG Jie; ZHU Jun-Fa; ZHANG Wen-Hua

    2007-01-01

    The macro- and micro-magnetic properties of Fe-Co alloy films eletrodeposited on GaAs(100) are studied by synchrotron radiation x-ray magnetic circular dichroism (XMCD) in combination with the magneto-optical Kerr effect (MOKE) measurements and magnetic force microscopy (MFM). The orbital and spin magnetic moments of each element in the Fe-Co alloy are determined by the sum rules of XMCD. Element-specific hysteresis loops (ESHL) are obtained by recording the La MCD signals as a function of applied magnetic field. MOKE results reveal that the amorphous films are magnetically isotropic in the surface plane. The MFM image shows that the dimension of the magnetic domains is about 1-2 μm, which is much larger than that of the grains, indicating that there are intergranular correlations among these grains. Both ESHL and MOKE hysteresis loops indicate the strong ferromagnetic coupling of Fe and Co in the alloy films.

  7. Preparation of Dy-Bi alloy films by electrodeposition in organic bath

    Institute of Scientific and Technical Information of China (English)

    LI Gaoren; TONG Yexiang; LIU Guankun

    2004-01-01

    The cyclic voltammetry and potentiostatic electrolysis were used to investigate the preparing of Dy-Bi alloy films in LiCl-DMSO (dimethylsulfoxide) system. The effects of several factors including the potential of deposition, concentrations of main salts, and the concentration ratio of DyCl3 to Bi(NO3)3 were studied. Dy-Bi alloy films containing 4.82%-80.62% (mass fraction) dysprosium were prepared in DyCl3-Bi(NO3)3-LiCl-DMSO system by controlling the system composition and deposition conditions. The films are gray, uniform, metallic luster and adhere firmly to the copper substrates analyzed by SEM (scanning electron microscope), EDS (X-ray energy dispersive analysis), and XRD (X-ray diffraction). After heat treatment at 718 K for l h, the alloy phase of Dy-Bi was found in XRD patterns.

  8. Fabrication of stable large-area thin-film CdTe photovoltaic modules. Annual subcontract report, 10 May 1992--9 May 1993

    Energy Technology Data Exchange (ETDEWEB)

    Nolan, J.F.; Meyers, P.V. [Solar Cells, Inc., Toledo, OH (United States)

    1993-08-01

    This report highlights the progress made by Solar Cells, Inc. (SCI), in its program to produce 60-cm {times} 120-cm solar modules based on CdTe films. During the past year, confirmed efficiency has increased to 10.4% (active area) on a 1 cm{sup 2} cell, 9.8% (aperture area) on a 64-cm{sup 2} 8-cell submodule, and 6.6% (total area) on a 7200-cm{sup 2} module. A module measured in-house had a power output of 53 W, for a total-area efficiency of 7.4%. Average efficiency of modules produced is steadily increasing and standard deviation is decreasing; in a limited run of 12 modules, results were 6.3% ({plus_minus} 0.2%). Field testing has begun; a nominal 1-kW array of 24 modules was set up adjacent to SCI`s facilities. Analysis indicates that present modules are limited in efficiency by shunt resistance and optical absorption losses in the glass superstrate. Loss analysis of present devices allows us to project a module efficiency of 11.8%. A third generation deposition method -- atmospheric pressure elemental vapor deposition (APEVD) has been brought on-line and has produced good quality CdTe. In addition, SCI is expanding its proactive safety, health, environmental, and disposal program dealing with issues surrounding cadmium.

  9. Thin film growth of a topological crystal insulator SnTe on the CdTe (111) surface by molecular beam epitaxy

    Science.gov (United States)

    Ishikawa, Ryo; Yamaguchi, Tomonari; Ohtaki, Yusuke; Akiyama, Ryota; Kuroda, Shinji

    2016-11-01

    We report molecular beam epitaxial growth of a SnTe (111) layer on a CdTe template, fabricated by depositing it on a GaAs (111)A substrate, instead of BaF2 which has been conventionally used as a substrate. By optimizing temperatures for the growth of both SnTe and CdTe layers and the SnTe growth rate, we could obtain SnTe layers of the single phase grown only in the (111) orientation and of much improved surface morphology from the viewpoint of the extension and the flatness of flat regions, compared to the layers grown on BaF2. In this optimal growth condition, we have also achieved a low hole density of the order of 1017 cm-3 at 4 K, the lowest value ever reported for SnTe thin films without additional doping. In the magnetoresistance measurement on this optimized SnTe layer, we observe characteristic negative magneto-conductance which is attributed to the weak antilocalization effect of the two-dimensional transport in the topological surface state.

  10. Preparation and characterization of pulsed laser deposited a novel CdS/CdSe composite window layer for CdTe thin film solar cell

    Science.gov (United States)

    Yang, Xiaoyan; Liu, Bo; Li, Bing; Zhang, Jingquan; Li, Wei; Wu, Lili; Feng, Lianghuan

    2016-03-01

    A novel CdS/CdSe composite window structure was designed and then the corresponding films were prepared by pulsed laser deposition as an improved window layer for CdTe-based solar cells. Two types of this composite window structure with 5 cycles and 10 cycles CdS/CdSe respectively both combined with CdS layers were prepared at 200 °C compared with pure CdS window layer and finally were applied into CdTe thin film solar cells. The cross section and surface morphology of the two composite window layers were monitored by using scanning electron microscopy and the result shows that the pulsed laser deposited composite window layers with good crystallinity are stacking together as the design. The devices based on CdS/CdSe composite window layers have demonstrated the enhanced photocurrent collection from both short and long wavelength regions compared to CdS/CdTe solar cell. The efficiency of the best reference CdS/CdTe solar cell was 10.72%. And the device with 5 cycles CdS/CdSe composite window showed efficiency of 12.61% with VOC of 772.92 mV, JSC of 25.11 mA/cm2 and FF of 64.95%. In addition, there are some differences which exist within the optical transmittance spectra and QE curves between the two CdS/CdSe composite window samples, indicating that the volume proportion of CdSe may influence the performance of CdTe thin film solar cell.

  11. High quality electrodeposited Fe{sub 100-x}Ga{sub x} films for magnetostrictive applications

    Energy Technology Data Exchange (ETDEWEB)

    Iselt, Diana; Schultz, Ludwig [IFW Dresden, Institute for Metallic Materials, P.O. Box 270116, 01171 Dresden (Germany); TU Dresden, Faculty of Mechanical Engineering, 01062 Dresden (Germany); Schloerb, Heike; Faehler, Sebastian [IFW Dresden, Institute for Metallic Materials, P.O. Box 270116, 01171 Dresden (Germany)

    2011-07-01

    Magnetostrictive materials can be used to build electromagnetic sensing and actuating devices. A promising candidate to overcome the mechanical limitations of Terfenol-D is Fe{sub 100-x}Ga{sub x} with 15 to 25 at.% Ga, which exhibits high mechanical strength and low saturation fields. For sensor application an efficient, scalable preparation way is required for thin film and nanowire fabrication. In this study FeGa alloy films with a desired composition close to Fe{sub 80}Ga{sub 20} have been fabricated electrochemically on Pt substrates. For a conventional deposition at constant potentials strong interactions of the electrolyte with the platinum coated substrate are identified to cause low reproducibility and high oxygen content. The use of optimised pre-treatment and pulsed potential conditions resulted in dense and homogeneous films with a (110) {alpha}-Fe{sub 3}Ga fibre texture. Oxygen content was reduced below 1 at.% and the saturation magnetization reaches up to 1.7 T, confirming the high quality of these films. In order to understand the influence of the substrate on morphology and oxygen content deposition on gold and copper coated substrates have been carried out.

  12. Electrocatalytic Activity of Platinum Particles Electrodeposited onto Poly(vinylpyridine) Films

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The electrocatalytic properties of platinum microparticles incorporated into poly- (vinylpyridine) (PVP) films, a conducting polymer with good conductivity and stability, were investigated for hydrogen evolution and formic acid electrooxidation in acidic media. It was found that the catalytic effects depend mainly on the size and amounts of the platinum microparticles dispersed in the polymer layer.

  13. Electrodeposition of epitaxial ZnSe films on InP and GaAs from an aqueous zinc sulfate-selenosulfate solution

    Energy Technology Data Exchange (ETDEWEB)

    Riveros, G.; Guillemoles, J.F.; Lincot, D. [Laboratoire d' Electrochimie et de Chimie Analytique (UMR CNRS 7575), Ecole Nationale Superieure de Chimie de Paris, 11 rue Pierre et Marie Curie, F-75231 Paris Cedex 05 (France); Gomez Meier, H. [Instituto de Chimica, Faculdad de Ciencas Basicas y Matematicas, Universidad Catolica de Valparaiso, Avda. Brasil 2950, Casila, Valparaiso (Chile); Froment, M.; Bernard, M.C.; Cortes, R. [Laboratoire de Physique des Liquides et Electrochimie (UPR CNRS 15), Universite Pierre et Marie Curie, 4 place Jussieu, F-75232 Paris Cedex 05 (France)

    2002-09-16

    Epitaxial growth of ZnSe thin films on InP(111) and GaAs(100) substrates has been achieved by electrodeposition from a zinc sulfate/selenosulfate solution. The deposition was observed over a wide range of applied potentials (-1.6-1.9 V vs. mercury/mercury sulfate). The epitaxy was characterized by reflective high energy electron diffraction (see Figure for a ZnSe epitaxial layer) and grazing angle X-ray diffraction. (Abstract Copyright [2002], Wiley Periodicals, Inc.)

  14. Electrodeposited CuInS2 Using Dodecylbenzene Sulphonic Acid As a Suspending Agent for Thin Film Solar Cell

    Directory of Open Access Journals (Sweden)

    Shaker Ebrahim

    2012-01-01

    Full Text Available CulnS2 thin films were electrochemically deposited onto fluoride-doped tin oxide (FTO substrate in presence of dodecylbenzene sulphonic acid to adjust pH of the solution and as a suspending agent for the sulfur. Cyclic voltammetry and chronoamperometry were carried out to determine the optimum pH. The composition, crystallinity, and optical properties of the compounds synthesized were studied by energy dispersive X-ray (EDX, X-ray diffraction, and UV-Visible spectra. It was found that the increasing of pH shifts the electrodeposited voltage toward more negative and lowers the deposition current. It was concluded that CuInS2 with atomic stoichiometric ratio was prepared at pH equal to 1.5 and 150 ml of 0.1 M sodium thiosulphate, 5 ml of 0.1 M indium chloride, and 5 ml of 0.1 M cupper chloride. The energy gaps were calculated to be 1.95 and 2.2 eV for CuInS2 prepared at 1.5 and 2.5 of pH, respectively. It was found that sc, oc, and are 1.02×10−4 A/cm2, 0.52 V, and 1.3×10−2%, respectively, for FTO/CuInS2/ZnO/FTO heterojunction solar cell.

  15. Optimization of the front contact to minimize short-circuit current losses in CdTe thin-film solar cells

    Science.gov (United States)

    Kephart, Jason Michael

    With a growing population and rising standard of living, the world is in need of clean sources of energy at low cost in order to meet both economic and environmental needs. Solar energy is an abundant resource which is fundamentally adequate to meet all human energy needs. Photovoltaics are an attractive way to safely convert this energy to electricity with little to no noise, moving parts, water, or arable land. Currently, thin-film photovoltaic modules based on cadmium telluride are a low-cost solution with multiple GW/year commercial production, but have lower conversion efficiency than the dominant technology, crystalline silicon. Increasing the conversion efficiency of these panels through optimization of the electronic and optical structure of the cell can further lower the cost of these modules. The front contact of the CdTe thin-film solar cell is critical to device efficiency for three important reasons: it must transmit light to the CdTe absorber to be collected, it must form a reasonably passive interface and serve as a growth template for the CdTe, and it must allow electrons to be extracted from the CdTe. The current standard window layer material, cadmium sulfide, has a low bandgap of 2.4 eV which can block over 20% of available light from being converted to mobile charge carriers. Reducing the thickness of this layer or replacing it with a higher-bandgap material can provide a commensurate increase in device efficiency. When the CdS window is made thinner, a degradation in electronic quality of the device is observed with a reduction in open-circuit voltage and fill factor. One commonly used method to enable a thinner optimum CdS thickness is a high-resistance transparent (HRT) layer between the transparent conducting oxide electrode and window layer. The function of this layer has not been fully explained in the literature, and existing hypotheses center on the existence of pinholes in the window layer which are not consistent with observed results

  16. STUDY ON CO-ELECTRODEPOSITION OF Bi-Fe ALLOY FILMS IN ORGANIC BATH

    Institute of Scientific and Technical Information of China (English)

    G.R. Li; Y.X. Tong; G.K. Liu

    2003-01-01

    The cyclic voltametry and potentiostatic electrolysis was used to investigate the preparation of Bi-Fe alloy films in LiClO4-DMSO (dimethylsulfoxide) system. The effects of several factors including the potential of deposition, current density and concentration of iron and bismuth in the solution on the Fe content in the alloy deposits were studied. Experimental results indicated that the amorphous alloy films of Bi-Fe containing Fe 4.40wt%-33. 67wt% could be prepared by controlling the system composition and deposition conditions. They were gray, uniform, metallic luster and adhered firmly to the copper substrates analyzed by EDS, SEM and XRD. After heat treatment of crystallization at 270℃ for 1h, the crystal phase of Bi-Fe can be found in XRD patterns.

  17. Investigation on the Effect of the CdCl2 Treatment on CdTe Thin-film Solar Cells of Variable Thickness Fabricated Using Combinatorial Pulsed Laser Deposition

    Science.gov (United States)

    Kadhim, Ali Saber

    Cadmium Chloride (CdCl2) post annealing process has significant impacts on the performance of the CdS/CdTe solar cells since it affects the microstructure, crystallinity and charge carrier doping in CdTe films and also the CdS/CdTe p-n junction formed through S and Te interdiffusion at the junction interface. Therefore, this process has been investigated extensively during the past two decades, and has been optimized for polycrystalline CdS/CdTe thick film solar cells, in which the CdTe thickness is typically in the range of 3-8 microm. Nevertheless, the recent effort to develop cost-performance balanced thin film CdS/CdTe solar cells (with CdTe thickness on the order of 1 microm or less) has encountered difficulties through direct applications of the thick-film CdCl2 post annealing process. These difficulties stem from the large CdTe grain sizes typically in the range of microns in the thick film case. Grain boundaries between such large grains result in through-thickness shorts when the CdTe film thickness is comparable to or smaller than the grain size. Overcoming these difficulties to achieve precise controls of grain morphology, crystallinity and CdS/CdTe interface is important to high-performance CdS/CdTe thin film solar cells and will be the main objective of this thesis. In order to accelerate the study, a combinatorial Pulsed Laser Deposition technique (cPLD) was developed for deposition of CdTe films with different thicknesses on each sample to elucidate important physical properties of Cl diffusion through the selected thickness range at a given CdCl 2 annealing condition. Two sets of samples A and B of CdTe solar cells of multiple thicknesses of 1.5, 1.25, 1.0, and 0.75 microm have been fabricated by using cPLD. Sample A was completed without CdCl2 treatment as a reference, and sample B was treated with CdCl2 in different durations (10, 12, 15, and 17 min) at 360°C in mixed vapor of O2 and Argon (25 sccm:100 sccm). The sample that was treated at 15

  18. Structural and optical properties of electrodeposited culnSe{sub 2} thin films for photovoltaic solar cells; Propiedades estructurales y opticas de laminas delgadas de CulnSe2 electrodepositadas para su aplicacion en celulas solares fotovoltaicas

    Energy Technology Data Exchange (ETDEWEB)

    Guillen, C.; Herrero, J.; Galiano, F.

    1990-07-01

    Optical an structural properties of electrodeposited copper indium diselenide, CulnSe2, thin films were studied for its application in photovoltaic devices. X-ray diffraction patterns showed that thin films were grown in chalcopyrite phase after suitable treatments. Values of Eg for the CulnSe2 thin films showed a dependence on the deposition potential as determined by optical measurements. (Author) 47 refs.

  19. XPS Study of CdTe Thin Films Doped with Gd%掺Gd-CdTe薄膜的XPS研究

    Institute of Scientific and Technical Information of China (English)

    安晓晖; 李蓉萍; 田磊; 何志刚; 吴蓉; 李忠贤

    2012-01-01

    CdTe thin film doped with Gd has been obtained by vacuum evaporation technique with two sources , and chemical state has been studied by X-ray photo-electron spectroscopy. XPS data show that Cd,Te,O,C and Gd elements exist on the surface of the film. C1s and O1s binding energy indicates that the two elements mainly exist in the form of physical adsorption. The experiment results show that Cd and Te atoms exist in oxidation state as in well as in CdTe. Due to carbon pol-lution, Gd element does not appear on the surface, only appears in the etching process. Erosion analysis shows the Cd element s content is greater than Te, and the ratio between them tends to 1:0. 8.%应用双源法真空蒸发制备掺Gd的CdTe薄膜,并借助XPS对其进行组份分析.实验表明,Gd掺杂的CdTe薄膜的组分为Cd、Te、O、C、Gd等元素,其中C、O主要以物理吸附方式存在于薄膜表面;Cd、Te元素的存在方式为CdTe化合物及其氧化物形式;而Gd元素由于碳污染的原因在其表面未曾出现,只在刻蚀过程中出现;深度剥蚀分析表明在样品内部Cd元素的含量大于Te元素的含量,且接近于1∶0.8,趋于稳定.

  20. A Study on the Electrodeposited Cu-Zn Alloy Thin Films

    Science.gov (United States)

    Özdemir, Rasim; Karahan, İsmail Hakkı; Karabulut, Orhan

    2016-11-01

    In this article, electrochemical deposition of the nanocrystalline Cu1- x Zn x alloys on to aluminum substrates from a non-cyanide citrate electrolyte at 52.5, 105, 157.5, and 210 A m-2 current densities were described. The bath solution of the Cu1- x Zn x alloys consisted of 0.08 mol L-1 CuSO4·5H2O, 0.2 mol L-1 ZnSO4·7H2O, and 0.5 mol L-1 Na3C6H5O7. The effect of the current density on the microstrain, grainsize, phase structure, and DC electrical resistivity behavior was investigated. The electrolyte was investigated electrochemically by cyclic voltammetry (CV) studies. A scanning electron microscope (SEM) was used to study the morphologies of the deposits. Deposited alloys were investigated by energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and four-point probe electrical resistivity techniques. With an increase in applied current density values from 52.5 to 210 A m-2, the amount of deposited copper in the alloy was decreased significantly from 65.5 to 16.6 pct and zinc increased from 34.4 to 83.4 pct. An increase in the current density was accompanied by an increase in grain size values from 65 to 95 nm. SEM observations indicated that the morphology of the film surface was modified to bigger grained nanostructures by increasing the current density. The XRD analysis showed alloys have a body-centered cubic (bcc) crystal structure with preferential planes of (110) and (211). Furthermore, four-point measurements of the films revealed that the resistivity of the deposited films was tailored by varying current densities in the electrolyte.

  1. Investigation on Structure and Optical Properties of Gd-doped CdTe Films%Gd掺杂CdTe薄膜的结构和光学特性研究

    Institute of Scientific and Technical Information of China (English)

    何志刚; 李蓉萍; 董海成; 安晓晖; 吴蓉; 李忠贤

    2011-01-01

    CdTe thin films and Gd - doped CdTe thin films were prepared by vacuum thermal evaporation on glass substrates. The effect of heat - treatment and doping content of Gd on the structure, optical characteristics of CdTe films was studied. The results show that all thin films are cube sphalerite structure. Gd doping doesn't change crystal structure of thin films, but it makes average crystal size of CdTe films tum small, the lattice constant and crystal cell volume tum big appreciably, and a preferential growth orientation along [220] tum to along [ 111 ] . The transmissivity becomes higher in visible spectrad range and the optical band gap changes small by Cd doping.%用真空热蒸发法在玻璃衬底制备CdTe和Cd掺杂CdTe薄膜.研究热处理和Gd掺杂量对CdTe薄膜结构、光学特性的影响.结果表明,薄膜均为立方闪锌矿结构,Gd的掺入没有改变薄膜的晶体结构,但使薄膜的晶粒尺寸减小,晶格常数和晶胞体积略有增大,并使其择优取向由[220]晶向变为[111]晶向.掺Gd使薄膜在可见光范围透过率增强,但对光能隙影响不大.

  2. Temperature dependence of GMR and effect of annealing on electrodeposited Co-Ag granular films

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Torres, Jose, E-mail: jm.garcia@ub.ed [Electrodep., Departament de Quimica Fisica and Institut de Nanociencia i Nanotecnologia (IN2UB) de la Universitat de Barcelona, Marti i Franques, 1, 08028 Barcelona (Spain); Valles, Elisa; Gomez, Elvira [Electrodep., Departament de Quimica Fisica and Institut de Nanociencia i Nanotecnologia (IN2UB) de la Universitat de Barcelona, Marti i Franques, 1, 08028 Barcelona (Spain)

    2010-10-15

    The magnetoresistance of Co-Ag granular films composed of superparamagnetic and ferromagnetic particles was studied at different temperatures. The increase in the GMR values while decreasing temperature down to 20 K was quantified. The non-saturating behaviour of the MR(H) curves was retained even at the lowest measurement temperature, which was mainly attributed to the dipolar interaction among the superparamagnetic particles. The influence of the annealing conditions on the magnetoresistance was also studied. In all conditions, a decrease in the GMR values was measured being attributed to an increase in the particle size.

  3. Low-temperature electrodeposition approach leading to robust mesoscopic anatase TiO2 films.

    Science.gov (United States)

    Patra, Snehangshu; Andriamiadamanana, Christian; Tulodziecki, Michal; Davoisne, Carine; Taberna, Pierre-Louis; Sauvage, Frédéric

    2016-02-25

    Anatase TiO2, a wide bandgap semiconductor, likely the most worldwide studied inorganic material for many practical applications, offers unequal characteristics for applications in photocatalysis and sun energy conversion. However, the lack of controllable, cost-effective methods for scalable fabrication of homogeneous thin films of anatase TiO2 at low temperatures (ie. < 100 °C) renders up-to-date deposition processes unsuited to flexible plastic supports or to smart textile fibres, thus limiting these wearable and easy-to-integrate emerging technologies. Here, we present a very versatile template-free method for producing robust mesoporous films of nanocrystalline anatase TiO2 at temperatures of/or below 80 °C. The individual assembly of the mesoscopic particles forming ever-demonstrated high optical quality beads of TiO2 affords, with this simple methodology, efficient light capture and confinement into the photo-anode, which in flexible dye-sensitized solar cell technology translates into a remarkable power conversion efficiency of 7.2% under A.M.1.5G conditions.

  4. Dependency of the band gap of electrodeposited Copper oxide thin films on the concentration of copper sulfate (CuSO4.5H2O) and pH in bath solution for photovoltaic applications

    KAUST Repository

    Islam, Md. Anisul

    2016-03-10

    In this study, Copper oxide thin films were deposited on copper plate by electrodeposition process in an electrolytic bath containing CuSO4.5H2O, 3M lactic acid and NaOH. Copper oxide films were electrodeposited at different pH and different concentration of CuSO4.5H2O and the optical band gap was determined from their absorption spectrum which was obtained from UV-Vis absorption spectroscopy. It was found that copper oxide films which were deposited at low concentration of CuSO4.5H2O have higher band gap than those deposited at higher bath concentration. The band gap of copper oxide films also significantly changes with pH of the bath solution. It was also observed that with the increase of the pH of bath solution band gap of copper oxide film decreased. © 2015 IEEE.

  5. Preparation of Er—Fr Alloy Films in Dimethylsulfoxide by Electrodeposition Method

    Institute of Scientific and Technical Information of China (English)

    LIGao-ren; TONGYe-xiang; LIUGuan-kun

    2003-01-01

    Cyclic voltammetry and chronoamperometry were used to investigate the clectrochemical behavior of Fe(Ⅱ) and Er(Ⅲ)in a LiClO4-DMSO(dimethylsufoxide) system at Pt and Cu electrodes.Experimental results indicate that the reductions of Fe(Ⅱ) to Fe(0) and Er(Ⅲ) to Er(0) were irreversible at Pt and Cu electrodes.The diffusion coefficient and the clectron transfer coeffieient of Fe(Ⅱ)in a 0.01mol/L FeCl2-0.1mol/L LiClO4-DMSO system at 303K were 1.70×10-10 m2/s and 0.08 respectively,the diffusion coeffieient and the electron transfer coefficient of Er(Ⅲ)in a 0.01mol/L ErCl3-0.1mol/L LiClO4-DMSO system at 303 K were 1.47×10-10m2/s and 0.108 respectivealy.The homogeneous,strong adhesive Er-Fe alloy films containing Er of 31.39%-42.12% in mass fraction with metallic lustre were prepared by potentiostatic electrolysis on a Cu electrode in a ErCl3-FeCl2-LiClO4-DMSO system at -1.75— -2.05V(vs.SCE).

  6. Preparation of Er-Fe Alloy Films in Dimethylsulfoxide by Electrodeposition Method

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Cyclic voltammetry and chronoamperometry were used to investigate the electrochemical behavior of Fe(Ⅱ) and Er(Ⅲ) in a LiClO4-DMSO(dimethylsufoxide) system at Pt and Cu electrodes. Experimental results indicate that the reductions of Fe(Ⅱ) to Fe(0) and Er(Ⅲ) to Er(0) were irreversible at Pt and Cu electrodes. The diffusion coefficient and the electron transfer coefficient of Fe(Ⅱ) in a 0.01 mol/L FeCl2-0.1 mol/L LiClO4-DMSO system at 303 K were 1.70×10-10 m2/s and 0.08 respectively, the diffusion coefficient and the electron transfer coefficient of Er(Ⅲ) in a 0.01 mol/L ErCl3-0.1mol/L LiClO4-DMSO system at 303 K were 1.47×10-10 m2/s and 0.108 respectively. The homogeneous, strong adhesive Er-Fe alloy films containing Er of 31.39%-42.12% in mass fraction with metallic lustre were prepared by potentiostatic electrolysis on a Cu electrode in a ErCl3-FeCl2-LiClO4-DMSO system at -1.75--2.50 V(vs. SCE).

  7. Electrodeposition of Fe-Ni-S Soft Magnetic Film%Fe-Ni-S软磁薄膜的电沉积

    Institute of Scientific and Technical Information of China (English)

    王森林; 宋运建

    2011-01-01

    酸性镀液中以硼酸为缓冲剂、柠檬酸三钠为配合剂,在紫铜箔上电沉积得到非晶Fe-Ni-s合金薄膜.采用扫描电子显微镜和能谱分析技术(EDS)研究了镀液组成和沉积条件对镀层表面形貌和组成的影响.结果表明,在镀液中加入2 g/L C2H5O3NS(糖精)和0.4 g/L 1,4-丁炔二醇可获得表面平整无裂缝和较小内应力的合金镀层;电流密度和镀液pH值对镀层组成影响较小,但施镀温度对镀层组成影响较大.获得了理想的镀液组成和沉积条件,所得Fe73Ni95S175薄膜的X射线衍射表明其为非晶结构,在室温下具有较高的饱和磁化强度(Ms约为876.25 kA/m)和较低的矫顽力(Hc约为4.96 kA/m),具有良好的软磁性能.循环伏安曲线和阴极极化曲线均表明,镀液中CS(NH2)2会促进Fe-Ni-S共沉积.%Fe-Ni-S alloy film was prepared on red copper foil by electrodeposition from a acidic bath containing boric acid as a buffer agent and sodium citrate as a complexing agent. The effects of the bath composition, and the deposition parameters on the surface morphology and the composition of the alloy coating were studied by SEM and EDS. As a result, a smooth coating with no crack and little stress was obtained from the plating bath by adding 2 g/L saccharin and 0.4 g/L 1,4-butynediol. The cathodic current density and the plating bath pH have little effect on the coating composition, but the temperature has great effect. Fe73Ni9.5S17.5 film was prepared in optimized plating conditions, and XRD analysis showed that the coating structure is amorphous. The film has good soft magnetic performances with higher saturation magnetization (Ms≈876. 25 kA/m) and lower coercivity(Hc≈4. 96 kA/m) at room temperature. Cyclic voltammetry and the cathodic polarization curves indicated that thiourea can promote the co-deposition of Fe-Ni-S alloy.

  8. Hexa- and dodecanuclear polyoxomolybdate cyclic compounds: application toward the facile synthesis of nanoparticles and film electrodeposition.

    Science.gov (United States)

    Dolbecq, Anne; Compain, Jean-Daniel; Mialane, Pierre; Marrot, Jérôme; Sécheresse, Francis; Keita, Bineta; Holzle, Luis Roberto Brudna; Miserque, Frédéric; Nadjo, Louis

    2009-01-01

    Two new compounds based on O(3)PCH(2)PO(3)(4-) ligands and {Mo(V)(2)O(4)} dimeric units have been synthesized and structurally characterized. The dodecanuclear Mo(V) polyoxomolybdate species in (NH(4))(18)[(Mo(V)(2)O(4))(6)(OH)(6)(O(3)PCH(2)PO(3))(6)] x 33 H(2)O (1) is a cyclohexane-like ring in a chair conformation with pseudo S(6) symmetry. In the solid state, the wheels align side by side, thus delimiting large rectangular voids. The hexanuclear anion in Na(8)[(Mo(V)(2)O(4))(3)(O(3)PCH(2)PO(3))(3)(CH(3)AsO(3))] x 19 H(2)O (2) has a triangular framework and encapsulates a methylarsenato ligand. (31)P NMR spectroscopic analysis revealed the stability of 2 in various aqueous media, whereas the stability of 1 depends on the nature of the cations present in solution. It has been evidenced that the transformation of 1 into 2 occurs in the presence of CH(3)AsO(3)(2-) ions. This behavior shows that 1 can be used as a new precursor for the synthesis of Mo(V)/diphosphonate systems. The two complexes were very efficient both as reductants of Pt and Pd metallic salts and as capping agents for the resulting Pt(0) and Pd(0) nanoparticles. The size of the obtained nanoparticles depends both on the nature of the polyoxometalate (POM; i.e., 1 or 2) and on the [metallic salt]/[POM] ratio. In all cases, X-ray photoelectron spectroscopy (XPS) measurements have revealed the presence of Mo(VI) species that stabilize the nanoparticles and the absence of Mo(V) moieties. Diffuse-reflectance FTIR spectra of the Pt nanoparticles show that the capping Mo(VI) POMs are identical for both systems and contain the diphosphonato ligand. The colloidal solutions do not show any precipitate and the nanoparticles remain well-dispersed for several months. The electrochemical reduction of Mo(V) species was studied for 2. Cyclic voltammetry alone and electrochemical quartz crystal microbalance coupled with cyclic voltammetry show the deposition of a film on the electrode surface during this reduction.

  9. CdTe Photovoltaic Devices for Solar Cell Applications

    Science.gov (United States)

    2011-12-01

    July 28, 2011 14. ABSTRACT Cadmium telluride ( CdTe ) has been recognized as a promising photovoltaic material for thin - film solar cells because of...mail.mil Phone: 301 394 0963 ABSTRACT Cadmium telluride ( CdTe ) has been recognized as a promising photovoltaic material for thin - film ...absorption coefficient allows films as thin as 2 μm to absorb more than 98% of the above-bandgap radiation. Cells with efficiencies near 17% have been

  10. Technology Support for High-Throughput Processing of Thin-Film CdTe PV Modules Annual Technical Report, Phase II

    Energy Technology Data Exchange (ETDEWEB)

    Rose, D.H.; Powell, R.C.; Karpov, V.; Grecu, D.; Jayamaha, U.; Dorer, G.L. (First Solar, L.L.C.)

    2001-02-05

    Results and conclusions from Phase II of a three-year subcontract are presented. The subcontract, entitled Technology Support for High-Throughput Processing of Thin-Film CdTe PV Modules, is First Solar's portion of the Thin-Film Photovoltaic Partnership Program. The research effort of this subcontract is divided into four areas of effort: (1) process and equipment development, (2) efficiency improvement, (3) characterization and analysis, and (4) environmental, health, and safety. As part of the process and equipment development effort, a new semiconductor deposition system with a throughput of 3 m2/min was completed, and a production line in a new 75,000 ft2 facility was started and is near completion. As part of the efficiency-improvement task, research was done on cells and modules with thin CdS and buffer layers as way to increase photocurrent with no loss in the other photovoltaic characteristics. A number of activities were part of the characterization and analysis task, including developing a new admittance spectroscopy system, with a range of 0.001 Hz to 100 kHz, to characterize cells. As part of the environmental, health, and safety task, the methanol-based CdCl2 process was replaced with aqueous-CdCl2. This change enabled the retention of a De Minimus level of emissions for the manufacturing plant, so no permitting is required.

  11. Electrodeposition of magnetic, superhydrophobic, non-stick, two-phase Cu-Ni foam films and their enhanced performance for hydrogen evolution reaction in alkaline water media

    Science.gov (United States)

    Zhang, J.; Baró, M. D.; Pellicer, E.; Sort, J.

    2014-10-01

    Two-phase Cu-Ni magnetic metallic foams (MMFs) with tunable composition have been prepared by electrodeposition taking advantage of hydrogen co-evolution as a source of porosity. It is observed that Ni tends to deposit inside the porous network defined by the Cu building blocks. Contact angle measurements reveal that the prepared porous films show a remarkable superhydrophobicity (contact angle values larger than 150°) and a non-sticking property to aqueous droplets. This behavior is predominately ascribed to the morphology of the films - hierarchical micro/nanoporosity, wall thickness, and spatial arrangement. The electrochemical activity and stability towards hydrogen evolution reaction of the Cu-Ni MMFs has been investigated by cyclic voltammetry in 1 M KOH at 298 K, and the optimal Ni content is found to be 15 at%. Furthermore, all the foam-like films exhibit ferromagnetic behaviour due to the presence of the Ni-rich phase, with coercivity values ranging from 114 Oe to 300 Oe. From the technological point of view, the Cu-Ni MMFs are promising candidates for magnetically-actuated micro/nano-electromechanical systems (MEMS/NEMS) and micro/nanorobotic platforms with a large surface-area to volume ratio or in magnetic sensors or separators.Two-phase Cu-Ni magnetic metallic foams (MMFs) with tunable composition have been prepared by electrodeposition taking advantage of hydrogen co-evolution as a source of porosity. It is observed that Ni tends to deposit inside the porous network defined by the Cu building blocks. Contact angle measurements reveal that the prepared porous films show a remarkable superhydrophobicity (contact angle values larger than 150°) and a non-sticking property to aqueous droplets. This behavior is predominately ascribed to the morphology of the films - hierarchical micro/nanoporosity, wall thickness, and spatial arrangement. The electrochemical activity and stability towards hydrogen evolution reaction of the Cu-Ni MMFs has been investigated

  12. Electrochemical Properties of Porous Co(OH){sub 2} Nano-flake Thin Film Prepared by Electro-deposition for Supercapacitor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyeon Jeong; Jin, En Mei; Jeong, Sang Mun [Chungbuk National University, Cheongju (Korea, Republic of)

    2016-04-15

    Porous Co(OH){sub 2} nano-flake thin films were prepared by a potential-controlled electro-deposition technique at various deposition voltage (−0.75, −1.0, −1.2, and −1.4 V) on Ti-mesh substrates for supercapacitor application. The potential of electrode was controlled to regulate the film thickness and the amount of Co(OH){sub 2} nano-flake on the titanium substrate. The film thickness was shown to reach the maximum value of 34 μm at −1.4 V of electrode potential, where 17.2 g of Co(OH){sub 2} was deposited on the substrate. The specific discharge capacitances were measured to be 226, 370, 720, and 1008 mF cm{sup -2} in the 1st cycle corresponding to the films which were formed at −0.75, −1.0, −1.2, and −1.4 V of electrode potentials, respectively. Then the discharge capacities were decreased to be 206, 349, 586 and 866 mF/cm{sup 2}, where the persistency rates were 91, 94, 81, and 86%, respectively.

  13. 电沉积铁镍合金薄膜及其结构与磁性能的研究%The Study on Electrodeposition of FeNi Alloy Film and Its Structure and Magnetic Performance

    Institute of Scientific and Technical Information of China (English)

    杨锋; 周少雄; 朱弢; 朱熠; 孙永红

    2012-01-01

    采用电沉积工艺制备了不同成分的铁镍合金镀层,分析了镀层的微观形貌及组织结构,并测量了电沉积样品的磁化曲线和磁滞回线.研究结果表明:通过电沉积工艺可得到晶体结构的铁镍合金层,不同成分的铁镍合金层织构取向有所不同;镀层的磁性能随镍含量的变化而变化,在开路测量条件下的最大磁导率高于冷轧态1J85合金.%Different composition FeNi films were prepared through electrodeposition. The surface morphology and structure of films were analyzed. The magnetization curve and magnetic hysteresis of samples were measured. The results indicate that the Fe-Ni films with crystal structure can be prepared through electrodeposition. The Fe-Ni films of different chemical compositions possess different preferred orientation. The magnetic performances vary with Ni mass fraction. The maximum permeability of electrodeposited Fe-Ni films is superior to the cold-rolled 1J85 alloy in open circuit measurement.

  14. In situ STM imaging of bis-3-sodiumsulfopropyl-disulfide molecules adsorbed on copper film electrodeposited on Pt(111) single crystal electrode.

    Science.gov (United States)

    Tu, HsinLing; Yen, PoYu; Chen, Sihzih; Yau, ShuehLin; Dow, Wei-Ping; Lee, Yuh-Lang

    2011-06-07

    The adsorption of bis-3-sodiumsulfopropyldi-sulfide (SPS) on metal electrodes in chloride-containing media has been intensively studied to unveil its accelerating effect on Cu electrodeposition. Molecular resolution scanning tunneling microscopy (STM) imaging technique was used in this study to explore the adsorption and decomposition of SPS molecules concurring with the electrodeposition of copper on an ordered Pt(111) electrode in 0.1 M HClO(4) + 1 mM Cu(ClO(4))(2) + 1 mM KCl. Depending on the potential of Pt(111), SPS molecules could react, adsorb, and decompose at chloride-capped Cu films. A submonolayer of Cu adatoms classified as the underpotential deposition (UPD) layer at 0.4 V (vs Ag/AgCl) was completely displaced by SPS molecules, possibly occurring via RSSR (SPS) + Cl-Cu-Pt → RS(-)-Pt(+) + RS(-) (MPS) + Cu(2+) + Cl(-), where MPS is 3-mercaptopropanesulfonate. By contrast, at 0.2 V, where a full monolayer of Cu was presumed to be deposited, SPS molecules were adsorbed in local (4 × 4) structures at the lower ends of step ledges. Bulk Cu deposition driven by a small overpotential (η deposit at the very beginning (deposit, the chloride adlayer was still adsorbed to afford SPS admolecules arranged in a unique 1D striped phase. SPS molecules could decompose into MPS upon further Cu deposition, as a (2 × 2)-MPS structure was observed with prolonged in situ STM imaging. It was possible to visualize either SPS admolecules in the upper plane or chloride adlayer sitting underneath upon switching the imaging conditions. Overall, this study established a MPS molecular film adsorbed to the chloride adlayer sitting atop the Cu deposit.

  15. Influence of water-soluble conjugated/non-conjugated polyelectrolytes on electrodeposition of nanostructured MnO{sub 2} film for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eun-Kyung; Shrestha, Nabeen K. [Department of Chemistry, Hanyang University, Seoul 133-791 (Korea, Republic of); Lee, Wonjoo [Department of Chemistry, Hanyang University, Seoul 133-791 (Korea, Republic of); Department of Defense Ammunitions, Daeduk College, Daejeon 305-715 (Korea, Republic of); Cai, Gangri, E-mail: caigangri@naver.com [Department of Applied Chemistry, TianJin University of Technology, Tianjin 300384 (China); Department of Chemistry, Hanyang University, Seoul 133-791 (Korea, Republic of); Han, Sung-Hwan, E-mail: shhan@hanyang.ac.kr [Department of Chemistry, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2015-04-01

    Manganese dioxide (MnO{sub 2}) thin films are deposited electrochemically on an indium–tin-oxide (ITO) electrode using aqueous bath in presence of conjugated water soluble sulfonated polyaniline (SPAN) or a non-conjugated polyacrylic acid (PAA) polyelectrolyte surfactant. The surface morphology and nature of the electrodeposited MnO{sub 2} films are found to be influenced strongly by the amount and type of polyelectrolyte in the deposition bath. Increasing the SPAN concentration, a porous structure resulting from the reduction of voids between the MnO{sub 2} nano-flakes is obtained. In contrast, by increasing the PAA concentration, dense and spherical MnO{sub 2} nanostructures have been deposited. These results may be caused by initiation of different kinetics and orientation of nucleation of MnO{sub 2} deposits on ITO surface in presence of different types of polyelectrolytes. Cyclic voltammetry study of these films shows the supercapacitor behavior. The porous MnO{sub 2} films grown from the SPAN containing electrolyte demonstrates a specific capacitance of 368.53 F/g at scan rate of 10 mV/s, which is approximately 10 times higher (i.e., 30.29 F/g) than that of the spherical MnO{sub 2} dense films grown from PAA containing electrolyte. - Highlights: • Conjugated/non-conjugated polyelectrolytes were used in deposition of MnO{sub 2}. • The two kinds of MnO{sub 2} film showed entirely different morphology. • Conjugated polyelectrolyte worked as template and also affected the growth rate. • Non-conducting polyelectrolyte could work as template but hindered MnO{sub 2} growth. • The specific capacitance of MnO{sub 2}–S was 10 times higher than MnO{sub 2}–P.

  16. Giant magnetoresistive nanostructured materials by electrodeposition

    Science.gov (United States)

    Myung, No Sang

    NiFe/Cu and CoFe/Cu multilayers and NiFe compositional modulated alloys (CMA) electrodeposited by newly developed flow-through electrochemical reactor. Sub-micron (Ni)Cu and nano-size (CoFe)Cu granular alloys have been electrodeposited by magneto-electrodeposition method. These two methods eliminate the problems confronted by conventional methods and provide a new direction in fabrication of nanostructured materials by electrodeposition. Prior to fabrication of GMR materials, electrodeposition kinetics of individual metals (Co, NiFe, Cu) were studied. In Co electrodeposition and dissolution from sulfate bath, substrates have a great impact on the initial growth mode of film. On polycrystalline platinum metal, cobalt film grew in hemispherical shape (nodule) where it grew in right conical shape on amorphous glass carbon. In NiFe alloys electrodeposition, the effects of applied current density, solution composition, substrate and solution hydrodynamics on current efficiency, film composition, crystal structure, corrosion resistant, and magnetic properties of NiFe alloys from all-chloride and citrate-sulfate-chloride bath have been studied. Citrate ions enhance the anomalous codeposition phenomena in NiFe electrodeposition. In crystal structure studies on electrodeposited. NiFe, the narrow mixed phase solid region was noted around 50% Fe. In addition, the smallest grain size were also observed in that region. In corrosion studies, the maximum corrosion resistance was observed at 50% Fe in naturally aerated 0.5 M NaCl. In Ni/Cu and Co/Cu multilayers by single bath technique, the optimum deposition potential ranges of pure copper and nickel (cobalt) were determined to minimize copper codeposition during nickel (cobalt) deposition and to minimize cobalt dissolution during copper deposition. Well defined laminated NiFe/Cu and CoFe/Cu multilayers and NiFe compositional modulated alloys (CMA) were successfully electrodeposited by utilizing flow-through electrochemical

  17. Effect of Annealing on the Properties of Antimony Telluride Thin Films and Their Applications in CdTe Solar Cells

    OpenAIRE

    Zhouling Wang; Yu Hu; Wei Li; Guanggen Zeng; Lianghuan Feng; Jingquan Zhang; Lili Wu; Jingjing Gao

    2014-01-01

    Antimony telluride alloy thin films were deposited at room temperature by using the vacuum coevaporation method. The films were annealed at different temperatures in N2 ambient, and then the compositional, structural, and electrical properties of antimony telluride thin films were characterized by X-ray fluorescence, X-ray diffraction, differential thermal analysis, and Hall measurements. The results indicate that single phase antimony telluride existed when the annealing temperature was high...

  18. Electrochemical impedance analysis of electrodeposited Si-O-C composite thick film on Cu microcones-arrayed current collector for lithium ion battery anode

    Science.gov (United States)

    Hang, Tao; Mukoyama, Daikichi; Nara, Hiroki; Yokoshima, Tokihiko; Momma, Toshiyuki; Li, Ming; Osaka, Tetsuya

    2014-06-01

    The impedance behaviors of Si-O-C composite film electrodeposited on Cu microcones-arrayed current collector have been investigated to understand the electrochemical process kinetics that influences the cycling performance when used as a highly-durable anode in a lithium battery. The impedance was measured by using impedance spectroscopy in equilibrium conditions at various depths of discharge and during several hundred charge-discharge cycles. The measured impedance was interpreted with an equivalent circuit composed of solid electrolyte interphase (SEI) film, charge transfer and solid state diffusion. The impedance analysis shows that the change of charge transfer resistance is the main contribution to the total resistance change during discharge, but an abrupt augmentation of diffusive resistance at high depth of discharge is also observed which cannot be explained very well by the presented model. The impedance evolution of this electrode during charge-discharge cycles suggests that the slow growth of the SEI film as well as the increase of the electrode density are responsible for the capacity fading after long term cycling.

  19. Auger relative sensitivivity factors for CdTe oxide

    OpenAIRE

    P. Bartolo-Pérez; J. L. Peña; M.H. Farías

    1999-01-01

    The Auger lineshape of Te MNN in measurements of Auger spectra of CdTe oxide films with various degrees of oxidation was analyzed. By using standards from stoichiometric compounds, Auger relative sensitivity factors (RSF´s) of Cd, Te and O for CdTe oxide thin films were obtained. The value of the RFS of oxygen is about constant, 0.27-0.28, for the standard compound, CdO, TeO2 and CdTeO3 (considering the RSF of Cd as 1). However, the obtained RSF of Te changes from 0.69 in CdTe up to 0.87 in C...

  20. Process Development for High Voc CdTe Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Ferekides, C. S.; Morel, D. L.

    2011-05-01

    This is a cumulative and final report for Phases I, II and III of this NREL funded project (subcontract # XXL-5-44205-10). The main research activities of this project focused on the open-circuit voltage of the CdTe thin film solar cells. Although, thin film CdTe continues to be one of the leading materials for large-scale cost-effective production of photovoltaics, the efficiency of the CdTe solar cells have been stagnant for the last few years. This report describes and summarizes the results for this 3-year research project.

  1. Electrodeposition and electrocatalytic activity of Pt and Pt-alloy nanoparticles and thin films on highly oriented pyrolytic graphite (HOPG)

    Science.gov (United States)

    Lu, Guojin

    Pt and Pt-based alloy catalysts were synthesized by electrodeposition on HOPG. The nucleation and growth, morphology, composition and crystal structure, and electrocatalytic activity (towards relevant reactions in the frame of PEMFCs and DMFCs) of these model electrodes were systematically investigated. The presence of chlorides inhibits the Pt reduction processes. There is a transition from progressive to instantaneous nucleation with increasing overpotential for the deposition from 1 mM H2PtCl6 electrolytes. The possibility of instantaneous nucleation at large overpotential by using electrolytes with large chloride concentration is advantageous for the growth of small, well dispersed nanoparticles. The electrochemical data were confirmed by AFM and SEM imaging studies. Relatively narrow size distributed nanoparticles can be obtained from the current system. While MOR activity decreases with decreasing particle size, the HER and HOR activity of deposited Pt particles increases with decreasing deposition period. The ORR activity first increases then decreases with increasing deposition time. Interactions between Pt and Ru, or Ni or Co are observed and they form solid solution as verified by XRD. Underpotential deposition occurs for Pt-Ni or Pt-Co co-electrodeposition. Pt-Ru deposition can be described as progressive nucleation at low overpotential and instantaneous nucleation at high overpotentials. Through direct morphological observations, the Pt-Ni or Pt-Co nucleation can be approximately described as progressive. Pt-Ru deposits are superior to Pt towards MOR. The optimum Ru content is about 50 at.%. Pt-Ni and Pt-Co deposits are more active than Pt for ORR. The optimum content is about 30 at.% Ni or 50 at.% Co. Dealloying of Pt-Ru and Pt-Ni or Pt-Co electrodeposit is observed after electrochemical characterization. The extent of dealloying increases with the content of the alloying element.

  2. Research on fabrication technology for thin film solar cells for practical use. Research on low-cost fabrication technology for large-area modules (CdS/CdTe solar cell modules); Usumaku taiyo denchi seizo gijutsu no jitsuyoka kenkyu. Daimenseki module no tei cost seizo gijutsu (CdTe taiyo denchi module seizo no gijutsu kaihatsu)

    Energy Technology Data Exchange (ETDEWEB)

    Tatsuta, M. [New Energy and Industrial Technology Development Organization, Tokyo (Japan)

    1994-12-01

    This paper reports the study results on the fabrication technology of CdS/CdTe solar cell modules in fiscal 1994. (1) On the fabrication technology for high-efficiency large-area solar cells, high-quality CdTe active layer was studied. S content taken in the active layer at sintering of CdTe decreased with an increase in formed CdTe, resulting in improvement of Voc of cells. (2) On the window layer with wide band gap, the solar cell superior in collection efficiency and photoelectric characteristics could be obtained using the newly developed mixed crystal film of Cd(1-x)Zn(x)S. (3) On the forming technology of large-area coating/sintering films, improvement of CdS film quality was studied by pressurized processing of printed CdS films. As a result, improvement of film density and light transmissivity was confirmed. (4) On the leveling process technology of CdTe films, smooth surface films were obtained by experiment using an equipment simultaneously exciting samples in all directions as one of uniform coating methods of films. 7 figs.

  3. Crystallite size measurement and micro-strain analysis of electrodeposited copper thin film using Williamson-Hall method

    Science.gov (United States)

    Augustin, Arun; Udupa, K. Rajendra; Udaya Bhat, K.

    2016-05-01

    The improvement in hydrophilicity of copper coating on aluminium for better antimicrobial activity can be achieved by increase in surface energy. The surface energy depends on the micro-strain of the coating. Micro-strain in the coatingincreases with reduction in crystallite size. In this investigation, the crystallite size in the electrodeposited copper coating was varied by varying deposition current density. Crystallite size and micro-strain in the coating were estimated using Williamson-Hall method. Values of crystallite sizes using TEM micrographs were in agreement with that using Williamson-Hall method. Also, presence of nano-twins in the coating contributed for micro-strain in copper coating.

  4. Effect of Substrate Temperature on CdTe Thin Film Property and Solar Cell Performance%衬底温度对碲化镉薄膜性质及太阳电池性能的影响

    Institute of Scientific and Technical Information of China (English)

    曹胜; 武莉莉; 冯良桓; 王文武; 张静全; 郁骁骑; 李鑫鑫; 李卫; 黎兵

    2016-01-01

    Vapor transport deposition is an excellent method for preparing large area CdTe thin films with high quality and uniformity. Polycrystalline CdTe thin films were deposited by home-made vapor transport deposition system (VTD). The effects of substrate temperature on the property of CdTe film and the performance of CdTe solar cell were inves-tigated. CdTe thin films were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), UV-Vis spectrometer, and Hall Effect system. The results show that the CdTe thin films deposited by vapor transport deposi-tion are cubic phase with a preferred orientation in (111) direction. The average grain size increases from 2mm to 6mm and the carrier concentration increases from 1.93×1010 cm–3 to 2.36×1013 cm–3 when the substrate temperature increases from 520 ℃ to 620 ℃. This suggests that high substrate temperature can increase the carrier density significantly due to the suppressed defect recombination. The performance of CdTe thin film solar cells deposited at different sub-strate temperatures demonstrates that high substrate temperature (610℃) can greatly improve the efficiency, open cir-cuit voltage and fill factor of the solar cells. But the substrate temperature higher than 610℃ will reduce the spectral response of the cells in long wavelength region, which results in the degradation of solar cell performance. The small-area CdTe thin film solar cell without back contact layer deposited at substrate temperature of 610℃ obtains the best conversion efficiency of 11.2%.%蒸汽输运法是制备高质量且大面积均匀的 CdTe 薄膜的一种优良的方法。采用自主研发的一套蒸汽输运沉积系统制备了 CdTe 多晶薄膜,并研究了衬底温度对 CdTe 薄膜性质及太阳电池性能的影响。利用 XRD、SEM、UV-Vis和Hall等测试手段研究了衬底温度对薄膜的结构、光学性质和电学性质的影响。结果表明,蒸汽输运法制备的CdTe薄

  5. Research progress of particle electro-deposition and functional film within the anodic oxide film of aluminum%铝基氧化膜内粒子电沉积及其功能膜的研究进展

    Institute of Scientific and Technical Information of China (English)

    王梅丰; 倪磊; 陈东初; 常萌蕾; 叶秀芳; 魏红阳

    2015-01-01

    由于铝阳极氧化膜的特殊结构,再加上其制备的功能膜具有一系列独特性能。因此,近年来受到国内外广大科研工作者的广泛关注。本文从溶液组成综述铝基膜内单一粒子和复合粒子电沉积工艺,从电源波形介绍直流、交流和脉冲电沉积工艺,另外也叙述了溶胶凝胶和超声波电沉积工艺。列举了用电沉积方法制备功能性薄膜在催化、光学、太阳能吸收膜以及磁学领域的应用,并对制备功能性氧化膜存在问题与发展方向进行阐述。%Recent years has witnessed worldwide researchers’great attention to Al alloys,due to their excellent properties of anodic oxide film,such as unique properties in functional film as well as special structure. The anodic oxide film of alumi-num within a single particles electro-deposion and composite particles electro-deposion were comprehensively reviewed from the components of the electro-deposion. In addition,the electro-deposition methods were also discussed based on the power supply,such as direct current,alternating current,pulse,sol-gel solution,and ultrasonic. The application of the func-tional film prepared by the electro-deposition method in catalysis,optics,solar energy absorbing coating and magnetic field was introduced. Moreover,the existing problem and the future directions of further study on preparing functional oxide film by the electro-deposition method are also suggested.

  6. How grain boundaries affect the efficiency of poly-CdTe solar-cells: A fundamental atomic-scale study of grain boundary dislocation cores using CdTe bi-crystal thin films.

    Energy Technology Data Exchange (ETDEWEB)

    Klie, Robert [Univ. of Illinois, Chicago, IL (United States)

    2016-10-25

    It is now widely accepted that grain boundaries in poly-crystalline CdTe thin film devices have a detrimental effect on the minority carrier lifetimes, the open circuit voltage and therefore the overall solar-cell performance. The goal of this project was to develop a fundamental understanding of the role of grain boundaries in CdTe on the carrier life-time, open-circuit voltage, Voc, and the diffusion of impurities. To achieve this goal, i) CdTe bi-crystals were fabricated with various misorientation angels, ii) the atomic- and electronic structures of the grain boundaries were characterized using scanning transmission electron microscopy (STEM), and iii) first-principles density functional theory modeling was performed on the structures determined by STEM to predict the grain boundary potential. The transport properties and minority carrier lifetimes of the bi-crystal grain boundaries were measured using a variety of approaches, including TRPL, and provided feedback to the characterization and modeling effort about the effectiveness of the proposed models.

  7. Study of the physical properties of Bi doped CdTe thin films deposited by close space vapour transport

    Energy Technology Data Exchange (ETDEWEB)

    Vigil-Galan, O.; Sanchez-Meza, E.; Sastre-Hernandez, J.; Cruz-Gandarilla, F. [Escuela Superior de Fisica y Matematicas, Instituto Politecnico Nacional, 07738 Mexico, D. F. (Mexico); Marin, E. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Instituto Politecnico Nacional, 11500 Mexico, D. F. (Mexico)], E-mail: emarin63@yahoo.es; Contreras-Puente, G. [Escuela Superior de Fisica y Matematicas, Instituto Politecnico Nacional, 07738 Mexico, D. F. (Mexico); Saucedo, E.; Ruiz, C.M. [Departamento de Fisica de Materiales, Universidad Autonoma de Madrid, 28049 Madrid (Spain); Tufino-Velazquez, M. [Escuela Superior de Fisica y Matematicas, Instituto Politecnico Nacional, 07738 Mexico, D. F. (Mexico); Calderon, A. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Instituto Politecnico Nacional, 11500 Mexico, D. F. (Mexico)

    2008-04-30

    Bi doped cadmium telluride (CdTe:Bi) thin films were grown on glass-substrates by the close space vapour transport method. CdTe:Bi crystals grown by the vertical Bridgman method, varying the nominal Bi concentration in the range between 1 x 10{sup 17} and 8 x 10{sup 18} cm{sup -3}, were used in powder form for CdTe:Bi thin film deposition. Dark conductivity and photoconductivity measurements in the 90-300 K temperature range and determination by photoacoustic spectroscopy of the optical-absorption coefficient of the films in the 1.0 to 2.4 eV spectral region were carried out. The influence of Bi doping levels upon the intergrain barrier height and other associated grain boundary parameters of the polycrystalline CdTe:Bi thin films were determined from electrical, optical and morphological characterization.

  8. Electrodeposited ZnIn{sub 2}S{sub 4} onto TiO{sub 2} thin films for semiconductor-sensitized photocatalytic and photoelectrochemical applications

    Energy Technology Data Exchange (ETDEWEB)

    Assaker, Ibtissem Ben, E-mail: ibtissem.ben-assaker@laposte.net [Laboratoire Photovoltaïque, Centre de Recherches et des Technologies de l’Energie Technopole borj cedria, Bp 95, Hammamm lif 2050 (Tunisia); Gannouni, Mounir; Naceur, Jamila Ben [Laboratoire Photovoltaïque, Centre de Recherches et des Technologies de l’Energie Technopole borj cedria, Bp 95, Hammamm lif 2050 (Tunisia); Almessiere, Munirah Abdullah; Al-Otaibi, Amal Lafy; Ghrib, Taher [Laboratory of Physical Alloys (LPA), College of Science, University of Dammam (Saudi Arabia); Shen, Shouwen [Advanced Analysis Unit, Technical Service Division Research & Development Center Saudi Aramco, Dhahran (Saudi Arabia); Chtourou, Radhouane [Laboratoire Photovoltaïque, Centre de Recherches et des Technologies de l’Energie Technopole borj cedria, Bp 95, Hammamm lif 2050 (Tunisia)

    2015-10-01

    Graphical abstract: - Highlights: • ZnIn{sub 2}S{sub 4} thin films was grown using electrodeposition route onto TiO{sub 2}/ITO coated glass substrate. • Study of the heterostructure ZnIn{sub 2}S{sub 4}/TiO{sub 2} thin films. • Photocatalytic activity of ZnIn{sub 2}S{sub 4}/TiO{sub 2} heterostructure under visible light irradiation. • High performance of Photoelectrochemical properties in the presence of the junction ZnIn{sub 2}S{sub 4}/TiO{sub 2}. - Abstract: In this study, ZnIn{sub 2}S{sub 4}/TiO{sub 2} heterostructure was successfully synthesized on ITO-coated glass substrates via a facile two-step process from aqueous solution. First, TiO{sub 2} thin film was prepared by sol–gel and deposited onto ITO coated glass substrate by spin-coating method. Then the zinc indium sulfide semiconductor was fabricated via electrodeposition technique onto TiO{sub 2}/ITO coated glass electrode. The X-ray diffraction patterns confirm that the heterostructure is mixed of both Anatase TiO{sub 2} and Rhombohedric ZnIn{sub 2}S{sub 4}. The scanning electron microscopy (SEM) images show that the morphology change with the deposition of ZnIn{sub 2}S{sub 4} over TiO{sub 2} thin film and a total coverage of the electrode surface was obtained. Optical absorption spectroscopy study of ZnIn{sub 2}S{sub 4}/TiO{sub 2} heterostructure exhibits a remarkable red-shift compared to the TiO{sub 2} and ZnIn{sub 2}S{sub 4} achieve the best efficiency of visible light absorption. Therefore, it is expected to apply to visible-light photocatalysis and solar cells. To investigate the effect of the heterojunction on the photocatalytic activity of ZnIn{sub 2}S{sub 4}/TiO{sub 2} thin films, photodegradation of methylene blue in the presence of ZnIn{sub 2}S{sub 4} was performed. ZnIn{sub 2}S{sub 4}/TiO{sub 2} heterostructure exhibited strong photocatalytic activity, and the degradation of methylene blue eached 91% after irradiation only for 4 h. Also, the study of the photocurrent density produced

  9. Development of Electrodeposited CIGS Solar Cells: Cooperative Research and Development Final Report, CRADA Number CRD-09-357

    Energy Technology Data Exchange (ETDEWEB)

    Neale, Nathan [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-09-01

    At present, most PV materials are fabricated by vacuum technologies. Some of the many disadvantages of vacuum technology are complicated instrumentation, material waste, high cost of deposition per surface area, and instability of some compounds at the deposition temperature. Solution-based approaches for thin-film deposition on large areas are particularly desirable because of the low capital cost of the deposition equipment, relative simplicity of the processes, ease of doping, uniform deposition on a variety of substrates (including interior and exterior of tubes and various nonplanar devices), and potential compatibility with high-throughput (e.g., roll-to-roll) processing. Of the nonsilicon solar photovoltaic device modules that have been deployed to date, those based on the n-CdS/p-CdTe is a leading candidate. Two features in the optical characteristics of CdTe absorber are particularly attractive for photovoltaic conversion of sunlight; (a) its energy bandgap of 1.5 eV, which provides an optimal match with the solar spectrum and thus facilitates its efficient utilization and (b) the direct mode of the main optical transition which results in a large absorption coefficient and turn permits the use of thin layer (1-2 um) of active material. Thin films of CdTe required for these devices have been fabricated by a variety of methods (e.g., vapor transport deposition, vacuum deposition, screen printing and close-spaced sublimation). Electrodeposition is another candidate deserves more attention. This project will focus on delivering low-cost, high efficiency electrodeposited CdTe-based device.

  10. Electrodeposition of flake-like Cu2O on vertically aligned two-dimensional TiO2 nanosheet array films for enhanced photoelectrochemical properties

    Science.gov (United States)

    Yang, Lei; Zhang, Miao; Zhu, Kerong; Lv, Jianguo; He, Gang; Sun, Zhaoqi

    2017-01-01

    A novel Cu2O/TNS composite structure of single crystal TiO2 nanosheet (TNS) arrays decorated with flake-like Cu2O were synthesized by a facile hydrothermal reaction followed by the electrodeposition process. The effects of deposition potential on the microstructure, morphology, and optical property of the thin films were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-vis spectrophotometer. When the deposition potential is higher than -0.4 V, peaks corresponding to Cu appear, meanwhile, flake-like Cu2O become agglomerating, and transform into dense Cu2O particles. Additionally, photoelectrochemical experiments indicate that the films deposited at -0.4 V show the lowest resistivity and highest exciton separation efficiency. This enhanced photoelectrochemical properties can be explained by synergistic effect of p-type flake-like Cu2O and n-type TiO2 heterojunctions combined with two-dimensional TiO2 nanosheet with exposed highly reactive {001} facets.

  11. Compositional Analysis of Electrodeposited Cu-Se Compound Semiconductor Thin Films Using Combined Voltammetry and Flow-Electrochemical Quartz Crystal Microgravimetry

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Wooju; Jeong, Seonghan; Myung, Noseung [Konkuk Univ., Chungju (Korea, Republic of); Rajeshwar, Krishnan [Univ. of Texas at Arlington, Arlington (United States); Lee, Chiwoo [Korea Univ., Seoul (Korea, Republic of)

    2013-10-15

    A novel method which is species selective for the compositional analysis of electrodeposited Cu-Se semiconductor films was developed using combined voltammetry and flow-EQCM. The amounts of free Se and Se in Cu{sub 2}Se were obtained from the frequency changes at constant potentials of -0.8 V and -3 V, respectively. Potential steps to -0.8 V and -1.3 V were employed to reduce free Se to Se{sub 2}{sup -} and Cu{sub 2}Se to Cu + Se{sub 2}{sup -}, respectively. Resultant total Cu was anodically stripped at +0.8 V and the free Cu content was calculated using the difference in frequency changes observed during the stripping of total Cu and Se in Cu{sub 2}Se. The results showed that the amounts of free Se, free Cu and the targeted Cu{sub 2}Se varied with deposition potential as well as film thickness. The ternary compound semiconductor CuInSe{sub 2} (CIS) has attracted great interest due to its unique properties and wide applications.

  12. 二甲亚砜中电沉积La-CO合金膜的研究%Electrodeposition of La-Co Alloy Films in Dimethylsulfoxide (DMSO)

    Institute of Scientific and Technical Information of China (English)

    袁定胜; 黄开胜; 刘冠昆; 童叶翔

    2001-01-01

    This paper reported the electrodeposition of La-Co alloy films in dimethylsulfoxide (DMSO). Citric acid as the complexing agent and polyethylene glycol-1000 as the additive were discussed. Potentiostatic and pulse elecaolysis techniques were used to prepare La-Co alloy films. Surfaces of alloy films obtained by these two techniques are smooth, adhesive, compact and metallic luster. The contents of La in alloy films obtained by potentiostatic electrolysis technique are in the range of 22.42% to 50.29%, while deposited by pulse electrolysis technique are in the range of 1.46% to 42.63%.The size of metal grains obtained by pulse technique is about 100 nm.%研究在非水溶剂二甲亚砜中电沉积La-Co合金膜.体系中加入柠檬酸为络合剂,聚乙醇-1000为添加剂,用于改善沉积层的质量.在沉积过程中,应用了恒电位电解技术和脉冲电解技术.所得La-Co合金膜的表面是光滑,致密,粘附性好和有金属光泽.恒电位电解技术沉积得到的La-Co合金膜中La的质量分数是22.42%~50.29%.脉冲电解技术沉积得到的La-Co合金膜中La的质量分数是1.46%~42.63%.脉冲电解技术沉积得到的Ia-Co合金膜通过电镜观察发现金属粒子的大小约为100 nm.

  13. Fabrication of ionic liquid electrodeposited Cu--Sn--Zn--S--Se thin films and method of making

    Science.gov (United States)

    Bhattacharya, Raghu Nath

    2016-01-12

    A semiconductor thin-film and method for producing a semiconductor thin-films comprising a metallic salt, an ionic compound in a non-aqueous solution mixed with a solvent and processing the stacked layer in chalcogen that results in a CZTS/CZTSS thin films that may be deposited on a substrate is disclosed.

  14. Potentiostatic controlled nucleation and growth modes of electrodeposited cobalt thin films on n-Si(1 1 1)

    Science.gov (United States)

    Mechehoud, Fayçal; Khelil, Abdelbacet; Eddine Hakiki, Nour; Bubendorff, Jean-Luc

    2016-08-01

    The nucleation and growth of Co electrodeposits on n-Si(1 1 1) substrate have been investigated as a function of the applied potential in a large potential range using electrochemical techniques (voltammetry and chrono-amperometry) and surface imaging by atomic force microscopy (AFM). The surface preparation of the sample is crucial and we achieve a controlled n-Si(1 1 1) surface with mono-atomic steps and flat terraces. Using Scharifker-Hills models for fitting the current-time transients, we show that a transition from an instantaneous nucleation process to a progressive one occurs when the overpotential increases. A good agreement between the nucleation and growth parameters extracted from the models and the AFM data's is observed. The growth is of the Volmer-Weber type with a roughness and a spatial extension in the substrate plane of the deposited islands that increase with thickness.

  15. Characterization of Bi-Catalyzed Nanocrystalline CdTe Thin Films Prepared by Close Spaced Sublimation%近距离升华法制备Bi催化纳米晶CdTe薄膜的表征

    Institute of Scientific and Technical Information of China (English)

    李锦; 尚飞; 郑毓峰; 孙言飞; 简基康; 吴荣

    2009-01-01

    采用近距离升华法(Close-Spaced-Sublimation,CSS)引入Bi催化剂成功制备出了具有纳米线、近阵列排布的纳米棒等形貌的纳米晶CdTe薄膜.并利用X射线衍射(XRD)、扫描电子显微镜(SEM)、紫外可见分光光度计等研究了薄膜的结构、表面形貌和光学性能.讨论了CdTe纳米结构可能的生长机制.%Bi-catalyzed nanocrystalline CdTe films were prepared by close spaced sublimation (CSS) technique successfully.These nanocrystalline CdTe films had surface appearance of nanowires or a similar array arrangement nanorod.The structure,the surface topograph and the optical properties of these films were studied using X-ray diffraction(XRD),scanning electron microscopy(SEM) and ultroviolet-visible (UV-VIS) spectrophotometer.And the possible growth mechanisms of these nanostructures were discussed.

  16. Photoelectrochemical (PEC) studies on CdSe thin films electrodeposited from non-aqueous bath on different substrates

    Indian Academy of Sciences (India)

    Y G Gudage; N G Deshpande; A A Sagade; R P Sharma; S M Pawar; C H Bhosale

    2007-08-01

    Thin films of CdSe were deposited by potentiostatic mode on different substrates such as stainless steel, titanium and fluorine tin–oxide (FTO) coated glass using non-aqueous bath. The preparative parameters were optimized to get good quality CdSe thin films. These films were characterized by X-ray diffraction (XRD), optical absorption and photoelectrochemical (PEC) techniques. XRD study revealed that the films were polycrystalline in nature with hexagonal phase. Optical absorption study showed that CdSe films were of direct band gap type semiconductor with a band gap energy of 1.8 eV. PEC study revealed that CdSe film deposited on FTO coated glass exhibited maximum values of fill factor (FF) and efficiency () as compared to the films deposited on stainless steel and titanium substrate.

  17. CdTe Photovoltaics for Sustainable Electricity Generation

    Science.gov (United States)

    Munshi, Amit; Sampath, Walajabad

    2016-09-01

    Thin film CdTe (cadmium telluride) is an important technology in the development of sustainable and affordable electricity generation. More than 10 GW of installations have been carried out using this technology around the globe. It has been demonstrated as a sustainable, green, renewable, affordable and abundant source of electricity. An advanced sublimation tool has been developed that allows highly controlled deposition of CdTe films onto commercial soda lime glass substrates. All deposition and treatment steps can be performed without breaking the vacuum within a single chamber in an inline process that can be conveniently scaled to a commercial process. In addition, an advanced cosublimation source has been developed to allow the deposition of ternary alloys such as Cd x Mg1- x Te to form an electron reflector layer which is expected to address the voltage deficits in current CdTe devices and to achieve very high efficiency. Extensive materials characterization, including but not limited to scanning electron microscopy, transmission electron microscopy, energy dispersive x-ray spectroscopy, high resolution transmission electron microscopy and electron back-scatter diffraction, has been performed to get a better understanding of the effects of processing conditions on CdTe thin film photovoltaics. This combined with computer modeling such as density function theory modeling gives a new insight into the mechanism of CdTe photovoltaic function. With all these efforts, CdTe photovoltaics has seen great progress in the last few years. Currently, it has been recorded as the cheapest source of electricity in the USA on a commercial scale, and further improvements are predicted to further reduce the cost while increasing its utilization. Here, we give an overview of the advantages of thin film CdTe photovoltaics as well as a brief review of the challenges that need to be addressed. Some fundamental studies of processing conditions for thin film CdTe are also presented

  18. Photoluminescence and Electroluminescence Properties of CdTe Nanoparticles in Conjugated Polymer Hosts

    Institute of Scientific and Technical Information of China (English)

    GUO, Fengqi; XIE, Puhui

    2009-01-01

    The photoinduced energy transfer process from conjugated polymer (PPE4+) to CdTe nanocrystals was found both in solutions and in thin films by a fluorescence spectroscopic technique. Films of PPE4+ blended with CdTe-2 nanocrystals were formed by an electrostatic layer-by-layer assembly technique. Light emitting diodes were fabricated using CdTe-2 as an emitter in PPE4+ host. PPE4+ works as a molecular wire in the energy transfer process from the polymer to the CdTe-2 nanocrystals.

  19. 电沉积制备铜铟硫薄膜的研究%Preparation of Copper Indium Sulfide Film by Electro-Deposition Method

    Institute of Scientific and Technical Information of China (English)

    李丽波; 李琦; 王珩; 杨秀春; 田海燕; 谢菁琛; 王文涛

    2015-01-01

    Copper indium sulfide (CuinS2,CIS2) film was prepared by an electro-deposition method.Uv-vis spectrophotometer test result shows that the band gap of the electroplated CIS2 film is 1.5 eV.X-ray photoelectron spectroscopy (XPS) analysis reveals that the Cu,In and S signals corresponded to valence state (+1,+3 and-2) of three elements in CIS2 film,respectively.The photoelectrical properties of the CIS2 film were characterized by linear sweep voltammetry measurements under the dark and illumination.The I-V characteristic is linear under the dark and illumination,and the slope gap is 0.6× 10-3.We also simulated the band gap (1.5 eV) of the C[S2 film with chalcopyrite structure prepared by electroplating experiment using DMol3 and CASTEP modules,respectively.The molecular structure model of electroplated copper indium sulfide film has been established,and the X-ray diffraction simulative spectrum has been obtained by Materials Studio,which has good agreement with the experiment result.%采用电沉积的方法制备铜铟硫(CuInS2,CIS2)薄膜,紫外可见光谱仪测试结果表明电沉积制备的CIS2薄膜的禁带宽度为1.5 eV.X射线光电子能谱(XPS)分析表明,薄膜中的铜、铟、硫元素的价态分别为+1,+3和-2.采用线性伏安扫描测试了薄膜的光电性质,在黑暗和光照的条件下,I-V曲线斜率变化率为0.6×10-3.运用DMol3和CASTEP模块计算了电沉积制备的铜铟硫薄膜的禁带宽度,其数值为1.5 eV.通过Materials Studio建立了电沉积制备出的铜铟硫薄膜的结构和XRD模拟谱图,与实验结果一致.

  20. Nucleation of CdTe thin films deposited by close-space sublimation under a nitrogen ambient

    Energy Technology Data Exchange (ETDEWEB)

    Major, J.D. [Department of Physics, Durham University, South Road, Durham, DH1 3LE (United Kingdom); Proskuryakov, Y.Y. [Department of Physics, Durham University, South Road, Durham, DH1 3LE (United Kingdom); Durose, K. [Department of Physics, Durham University, South Road, Durham, DH1 3LE (United Kingdom)]. E-mail: ken.durose@durham.ac.uk; Green, S. [School of Engineering, Durham University, South Road, Durham, DH1 3LE (United Kingdom)

    2007-05-31

    The early stages of the close-space sublimation growth of CdTe/ITO (indium tin oxide) at 500deg. C under 26.7 kPa (200 Torr) of N{sub 2} were investigated, the relatively high pressure being used to slow the growth. Film development was monitored over 60 mins by ex-situ AFM (atomic force microscopy), the growth being controlled by a shutter. The films formed by the 'island' or Volmer-Weber growth mechanism. Developments in the areal island growth rate, the island density and spatial distribution type were explained using growth mechanisms. Significant changes in these phenomena at t {>=} 10 mins were attributed to a change in growth mechanism from surface migration limited, to a regime in which island coalescence and direct impingement of vapour species on the islands became important. Since the islands are characterised by distinct crystalline facets, this indicates the growth mechanism to be uninterrupted step-flow like addition of material to each island. Arguments are given to relate the final grain size in the films to the density of nuclei that are stable to re-evaporation after t = 10 mins.

  1. Studies of key technologies for CdTe solar modules

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In this paper, CdS thin films, which act as the window layer and n-type partner to the p-type CdTe layer, were prepared by chemical bath deposition (CBD). CdTe thin films were deposited by the close-spaced sublimation (CSS) method. To obtain high-quality back contacts, a Te-rich layer was created with chemical etching and back contact materials were applied after CdTe annealing. The results indicate that the ZnTe/ZnTe:Cu complex layers show superior performance over other back contacts. Finally, by using laser scribing and mechanical scribing, the CdTe mini-modules were fabricated, in which a glass/SnO2:F/CdS/CdTe/ZnTe/ZnTe:Cu/Ni solar module with a PWQC-confirmed total-area efficiency of 7.03% (54 cm2) was achieved.

  2. Dynamic effects in CdTe quantum-dot LEDs

    OpenAIRE

    Gallardo, D. E.

    2006-01-01

    In this work the electrical and electroluminescence properties CdTe nanocrystal films were analysed. The structure consisted of a multilayer of CdTe nanocrystals deposited by the layer-by-layer technique, sandwiched between an ITO anode and an aluminium cathode. The first part of this work was dedicated to structural and process improvement. Earlier devices, produced through a layer-by-layer (LbL) manual procedure, had an average thickness of 30nm per nanocrystal monolayer,...

  3. Electrodeposition of neodymium iron boron magnetic thin film%电沉积钕铁硼磁性薄膜工艺

    Institute of Scientific and Technical Information of China (English)

    唐娟; 谭澄宇; 李建梅; 蔡超; 李劲风

    2013-01-01

    采用循环伏安法在铜电极上进行了NdFeB稀土永磁薄膜电沉积的初步探索.镀液组成为:FeCl240g/L,H3BO336g/L,抗坏血酸1.2 g/L,十二烷基硫酸钠0.1 g/L,甘氨酸、氯化铵各30 g/L(作为配位剂),NdCl38~16 g/L.探讨了配位剂对该体系镀液循环伏安特性的影响,并研究了镀液中NdCl3含量和电沉积终止电位对镀层形貌和外观的影响.结果表明,镀液中加入配位剂后,Fe2+起始沉积电位负移,而Nd3+的还原电位正移.Fe元素能诱导Nd元素进行共沉积,实现在水溶液中电沉积制备稀土永磁薄膜.循环伏安沉积的终止电位和镀液中NdCl3的含量对NdFeB薄膜的形貌和外观影响较大.镀液中NdCl3为8 g/L、终止电位为-1.7 V时,可制得Nd的质量分数高达5.69%、较光亮致密的NdFeB薄膜.%The deposition of NdFeB rare earth permanent magnetic film on copper electrode by cyclic voltammetry method was preliminary explored. The bath composition is as follows: FeCl2 40 g/L, H3BO3 36 g/L, ascorbic acid 1.2 g/L, sodium dodecyl sulfate 0.1 g/L, glycine (as complexing agent) 30 g/L, ammonium chloride (as complexing agent) 30 g/L, and NdCl3 8-16 g/L. The effect of complexing agent on cyclic voltammetric characteristics of the given bath was discussed. The effects of NdCl3 content in bath and the terminal potential of electrodeposition on morphology and appearance of coatings were studied. The results show that the initial deposition potential of Fe2+ shifts negatively while the reduction potential of Nd3+ moves to positive direction after the addition of complexing agents to bath. The codeposition of Nd can be induced by Fe, realizing the electrolytic preparation of rare earth permanent magnet film in aqueous solution. The terminal potential in cyclic voltammetric electrodeposition and the NdCl3 content in bath greatly affect the morphology and appearance of NdFeB film. Bright and fine NdFeB films with a mass fraction of Nd up to 5.69% can be obtained

  4. Intrinsic Doping in Electrodeposited ZnS Thin Films for Application in Large-Area Optoelectronic Devices

    Science.gov (United States)

    Madugu, Mohammad Lamido; Olusola, Olajide Ibukun-Olu; Echendu, Obi Kingsley; Kadem, Burak; Dharmadasa, Imyhamy Mudiy

    2016-06-01

    Zinc sulphide (ZnS) thin films with both n- and p-type electrical conductivity were grown on glass/fluorine-doped tin oxide-conducting substrates from acidic and aqueous solution containing ZnSO4 and (NH4)2S2O3 by simply changing the deposition potential in a two-electrode cell configuration. After deposition, the films were characterised using various analytical techniques. X-ray diffraction analysis reveals that the materials are amorphous even after heat treatment. Optical properties (transmittance, absorbance and optical bandgap) of the films were studied. The bandgaps of the films were found to be in the range (3.68-3.86) eV depending on the growth voltage. Photoelectrochemical cell measurements show both n- and p-type electrical conductivity for the films depending on the growth voltage. Scanning electron microscopy shows material clusters on the surface with no significant change after heat treatment at different temperatures. Atomic force microscopy shows that the surface roughness of these materials remain fairly constant reducing only from 18 nm to 17 nm after heat treatment. Thickness estimation of the films was also carried out using theoretical and experimental methods. Direct current conductivity measurements on both as-deposited and annealed films show that resistivity increased after heat treatment.

  5. Catalytic and photoelectrochemical performances of Cu-Zn-Sn-Se thin films prepared using selenization of electrodeposited Cu-Zn-Sn metal precursors

    Science.gov (United States)

    Shao, Pin-Wen; Li, Chun-Ting; Ho, Kuo-Chuan; Cheng, Kong-Wei

    2015-07-01

    In this study, Cu2ZnSnSe4 (CZTSe) films are deposited onto the fluorine-doped-tin-oxide-coated glass substrate via the selenization of electrodeposited Cu-Zn-Sn metal precursors in an acidic solution with the applied potential of -0.9 V vs. an Ag/AgCl electrode. X-ray diffraction patterns reveal that the samples are the quaternary tetragonal CZTSe phase. The thicknesses and direct band gaps of the samples are in the ranges of 2.3 to 2.7 μm and 0.95 to 1.02 eV, respectively. All samples are p-type semiconductors with carrier density, mobility and flat-band potential in the ranges of 3.88 × 1017 to 1.37 × 1018 cm-3, 10.31 to 12.6 cm2 V-1 s-1 and -0.01 V to -0.08 V vs. Ag/AgCl reference electrode, respectively. The sample with [Cu]/[Zn + Sn] and [Zn]/[Sn] molar ratios of 0.87 and 0.66, respectively, has a maximum photo-enhanced current density of 0.41 mA cm-2 at an applied bias of -0.5 V vs. an Ag/AgCl electrode in 0.5 M H2SO4 solution under illumination. The best photo-conversion efficiency of dye-sensitized solar cells using CZTSe with [Cu]/[Zn + Sn] and [Zn]/[Sn] molar ratios of 0.87 and 0.66, respectively, as the counter electrode was 7.98%. The results show the high quality CZTSe films have potentials in applications of photoelectrochemical water splitting and dye-sensitized solar cells.

  6. Electrodeposition of nanoengineered thermoelectric materials

    Science.gov (United States)

    Xiao, Feng

    Thermoelectric (TE) energy converters are solid-state devices that can generate electricity by harvesting waste thermal energy, thereby improving the efficiency of a system. The many advantages of TE devices include solid-state operation, zero-emissions, vast scalability, no maintenance and a long operating lifetime. The efficiency of TE materials is directly related to a dimensionless figure of merit ZT. In order to compete with conventional refrigerators and power generators, ZT of 3 is required. Due to their limited energy conversion efficiencies (i.e. ZT thermoelectric devices currently have a rather limited set of applications. Classical and quantum mechanical size effects provide additional ways to enhance energy conversion efficiencies in nanostructured materials. Theoretical calculations predict that ZT of 5 can be achieved in one-dimensional nanostructures including nanowires and nanotubes. The goal of my work was to develop electrodeposition techniques to synthesis various thermoelectric nanostructures including 2-D superlatticed thin films, 1-D nanowires and nanotubes and quasi 0-D superlatticed nanowires and investigate their properties. Electrodeposition is selected because of the ability to "tailor-made" their morphology and properties. Specifically, the accomplishments of this thesis include the following: (1) Electrodeposition of PbTe thin films was systematically investigated in an acidic nitric bath. (2) Single crystalline PbTe cubes were electrodeposited on polycrystalline gold substrates. (3) Single crystalline PbTe nanowires were synthesized using a template-directed electrodeposition process. The temperature dependent electro-transport studies reveal that the conduction mechanism in the temperature range 150-220 K is different from that in the temperature range 220-300 K. (4) Bi1.8 Sb0.1Te3.1 and (Bi0.3Sb0.7) 2Te3 nanowires were electrodeposited from acidic tartaric-nitric baths and their temperature dependent electrical properties were

  7. Degradation sources of CdTe thin film PV: CdCl{sub 2} residue and shunting pinholes

    Energy Technology Data Exchange (ETDEWEB)

    Gorji, Nima E. [University of Bologna, Department of Electrical, Electronics and Information Engineering, Bologna (Italy)

    2014-09-15

    The present work considers two observable phenomena through the experimental fabrication and electrical characterization of the rf-sputtered CdS/CdTe thin film solar cells that extremely reduce the overall conversion efficiency of the device: CdCl{sub 2} residue on the surface of the semiconductor and shunting pinholes. The former happens through nonuniform treatment of the As-deposited solar cells before annealing at high temperature and the latter occurs by shunting pinholes when the cell surface is shunted by defects, wire-like pathways or scratches on the metallic back contact caused from the external contacts. Such physical problems may be quite common in the experimental activities and reduce the performance down to 4-5 % which leads to dismantle the device despite its precise fabrication. We present our electrical characterization on the samples that received wet CdCl{sub 2} surface treatment (uniform or nonuniform) and are damaged by the pinholes. (orig.)

  8. Elucidating PID Degradation Mechanisms and In Situ Dark I-V Monitoring for Modeling Degradation Rate in CdTe Thin-Film Modules

    DEFF Research Database (Denmark)

    Hacke, Peter; Spataru, Sergiu; Johnston, Steve

    2016-01-01

    A progression of potential-induced degradation (PID) mechanisms are observed in CdTe modules, including shunting/junction degradation and two different manifestations of series resistance depending on the stress level and water ingress. The dark I-V method for in-situ characterization of Pmax based...

  9. Study of electrodepositing Au on hollow polystyrene microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Jin Rong [Research Center of Laser Fusion, China Academy of Engineering Physics, P.O. Box 919-987, Mianyang 621900 (China); School of Material Science and Engineering, Xihua University, Chengdu 610039 (China); Zhang Yunwang [Research Center of Laser Fusion, China Academy of Engineering Physics, P.O. Box 919-987, Mianyang 621900 (China); Zhang Lin, E-mail: zhlmy@sina.com [Research Center of Laser Fusion, China Academy of Engineering Physics, P.O. Box 919-987, Mianyang 621900 (China); Wei Chengfu, E-mail: wcf@mail.xhu.edu.cn [School of Material Science and Engineering, Xihua University, Chengdu 610039 (China); Guo Jianjun [School of Material Science and Engineering, Xihua University, Chengdu 610039 (China)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer The gold is electrodeposited on hollow polystyrene microspheres by self-designed setup in this paper. Black-Right-Pointing-Pointer The Au electrodeposit is finer and more uniform on account of the microspheres freely move on the cathode. Black-Right-Pointing-Pointer The morphology, thickness and roughness of Au electrodeposits were analyzed using Scanning Electron Microscopy, X-ray diffraction and Atomic Force Microscope, respectively. - Abstract: The electrodeposited Au film on hollow polystyrene microspheres is successfully prepared by a set of self-designed device. The film is more compact and uniform on account of the microspheres freely moving on the cathode. These experiments mainly focus on the analysis of spherical symmetry, thickness and roughness of electrodeposited Au film. Under conditions of current density 1.5-3 mA cm{sup -2}, the temperature 25 Degree-Sign C, and the stirring rate 150 rpm, the electrodeposited microsphere is coated with a considerably orbicular film. The morphology, thickness and roughness of Au electrodeposits are studied by Scanning Electron Microscopy (SEM), X-ray diffraction (XRD) and Atomic Force Microscope (AFM), respectively.

  10. Development of a computer model for polycrystalline thin-film CuInSe{sub 2} and CdTe solar cells; Annual subcontract report, 1 March 1992--28 February 1993

    Energy Technology Data Exchange (ETDEWEB)

    Gray, J.L.; Schwartz, R.J.; Lee, Y.J. [Purdue Univ., West Lafayette, IN (United States)

    1994-03-01

    Solar cells operate by converting the radiation power from sun light into electrical power through photon absorption by semiconductor materials. The elemental and compound material systems widely used in photovoltaic applications can be produced in a variety of crystalline and non-crystalline forms. Although the crystalline group of materials have exhibited high conversion efficiencies, their production cost are substantially high. Several candidates in the poly- and micro-crystalline family of materials have recently gained much attention due to their potential for low cost manufacturability, stability, reliability and good performance. Among those materials, CuInSe{sub 2} and CdTe are considered to be the best choices for production of thin film solar cells because of the good optical properties and almost ideal band gap energies. Considerable progress was made with respect to cell performance and low cost manufacturing processes. Recently conversion efficiencies of 14.1 and 14.6% have been reported for CuInSe{sub 2} and CdTe based solar cells respectively. Even though the efficiencies of these cells continue to improve, they are not fully understood materials and there lies an uncertainty in their electrical properties and possible attainable performances. The best way to understand the details of current transport mechanisms and recombinations is to model the solar cells numerically. By numerical modeling, the processes which limit the cell performance can be sought and therefore, the most desirable designs for solar cells utilizing these materials as absorbers can be predicted. The problems with numerically modeling CuInSe{sub 2} and CdTe solar cells are that reported values of the pertinent material parameters vary over a wide range, and some quantities such as carrier concentration are not explicitly controlled.

  11. The mechanism of cathodic electrodeposition of epoxy coatings and the corrosion behaviour of the electrodeposited

    Directory of Open Access Journals (Sweden)

    VESNA B. MISKOVIC-STANKOVIC

    2002-05-01

    Full Text Available The model of organic film growth on a cathode during electrodeposition process proposes the current density-time and film thickness-time relationships and enables the evaluation of the rate contants for the electrochemical reaction of OH– ion evolution and for the chemical reaction of organic film deposition. The dependences of film thickness and rate constants on the applied voltage, bath temperature and resin concentration in the electrodeposition bath have also been obtained. The deposition parameters have a great effect on the cathodic electrodeposition process and on the protective properties of the obtained electrodeposited coatings. From the time dependences of the pore resistance, coating capacitance and relative permittivity, obtained from impedance measurements, the effect of applied voltage, bath temperature and resin concentration on the protective properties of electrodeposited coatings has been shown. Using electrochemical impedance spectroscopy, thermogravimetric analysis, gravimetric liquid sorption experiments, differential scanning calorimetry and optical miscroscopy, the corrosion stability of epoxy coatings was investigated. A mechanism for the penetration of electrolyte through an organic coating has been suggested and the shape and dimensions of the conducting macropores have been determined. It was shown that conduction through a coating depends only on the conduction through the macropores, although the quantity of electrolyte in the micropores of the polymer net is about one order of magnitude greater than that inside the conducting macropores.

  12. Evolution of Principle and Practice of Electrodeposited Thin Film: A Review on Effect of Temperature and Sonication

    Directory of Open Access Journals (Sweden)

    A. Mallik

    2011-01-01

    Full Text Available This review discusses briefly the important aspects of thin films. The introduction of the article is a summary of evolution of thin films from surface engineering, their deposition methods, and important issues. The fundamental aspects of electrochemical deposition with special emphasis on the effect of temperature on the phase formation have been reviewed briefly. The field of sonoelectrochemistry has been discussed in the paper. The literature regarding the effects of temperature and sonication on the structure and morphology of the deposits and nucleation mechanisms, residual stress, and mechanical properties has also been covered briefly.

  13. CdTe钝化介质膜的溅射沉积及其X射线光电子能谱研究%The Sputtering Deposition and the X-ray Photoelectron Spectroscopy Study for the CdTe Thin Film

    Institute of Scientific and Technical Information of China (English)

    周咏东; 李言谨; 吴小山; 徐国森; 方家熊; 汤定元

    2001-01-01

    用Ar+束溅射沉积技术实现了CdTe薄膜的低温沉积生长。用X射线光电子能谱(XPS)分析技术对溅射沉积CdTe薄膜以及CdTe体晶中的Cd元素、Te元素化学环境进行了对比实验研究。实验表明:溅射沉积CdTe薄膜具有很好的组份均匀性,未探测到有元素(Cd、Te)沉积存在。%The CdTe film was grown by using the low-temperature ion beam sputtering technique. The Cd and Te elements in the sputtering CdTe film sample were studied and compared with those in the CdTe bulk using X-ray photoelectron spectroscopy (XPS) technique. It is proved that the constituent elements in the sputtering CdTe film are homogeneous. No element deposition (Cd, Te) is detceted.

  14. Spatial Distribution of Dopant Incorporation in CdTe

    Energy Technology Data Exchange (ETDEWEB)

    Guthrey, Harvey; Moseley, John; Colegrove, Eric; Burst, James; Albin, David; Metzger, Wyatt; Al-Jassim, Mowafak

    2016-11-21

    In this work we use state-of-the-art cathodoluminescence (CL) spectrum imaging that provides spectrum-per-pixel mapping of the CL emission to examine how dopant elements are incorporated into CdTe. Emission spectra and intensity are used to monitor the spatial distribution of additional charge carriers through characteristic variations in the CL emission based on theoretical modeling. Our results show that grain boundaries play a role in the incorporation of dopants in CdTe, whether intrinsic or extrinsic. This type of analysis is crucial for providing feedback to design different processing schedules that optimize dopant incorporation in CdTe photovoltaic material, which has struggled to reach high carrier concentration values. Here, we present results on CdTe films exposed to copper, phosphorus, and intrinsic doping treatments.

  15. 具有复合背接触层的 CdTe多晶薄膜太阳电池%Polycrystalline CdTe thin- film solar cells with complex back contact layers

    Institute of Scientific and Technical Information of China (English)

    覃文治; 夏庚培; 郑家贵; 李卫; 蔡伟; 冯良桓; 蔡亚平; 黎兵; 张静全; 武莉莉

    2005-01-01

    To improve the properties of back contacts of CdTe solar cells, ZnTe:Cu and polycrystalline Cd1- xZnxTe films were deposited by simultaneous evaporation. Investigative data of the configuration and performance indicate that energy gap of Cd1- xZnxTe films assume quadratic connection with zinc content. With increasing of Cu content, energy gap of polycrystalline ZnTe:Cu will decrease. ZnTe/ZnTe:Cu or Cd1- xZnxTe/ZnTe:Cu back contacted cells can reduce the heterogeneous interface state density and modify the structure of energy band of the solar cells. Furthermore, diffusion of Cu can avoid by this compound films in CdTe solar cells. An efficiency of 13.38% of solar cell with dimension of 0.502cm2was fabricated.%为了提高 CdTe太阳电池的背接触性能,用共蒸发法制备了 ZnTe:Cu和 Cd1- xZnxTe多晶薄膜. 研究结果表明: Cd1- xZnxTe多晶薄膜的能隙与锌含量呈二次方关系, ZnTe:Cu多晶薄膜能隙随着掺 Cu浓度的增加而减小.分别用 ZnTe/ZnTe:Cu和 Cd1- xZnxTe/ZnTe:Cu复合膜作为背接触层,既能 修饰异质结界面,改善电池的能带结构,又能防止 Cu原子向电池内部扩散.因此获得了面积 0.502cm2,转换效率为 13.38%的 CdTe多晶薄膜太阳电池.

  16. Electrodeposition and characterization of nano-structured black nickel thin films%纳米结构黑镍薄膜的电沉积制备及其电化学行为

    Institute of Scientific and Technical Information of China (English)

    李建梅; 蔡超; 宋利晓; 李劲风; 张昭; 薛敏钊; 刘燕刚

    2013-01-01

    The electrodeposition and characterization of nano-structured black nickel coatings were presented. The influences of bath pH, electrodeposition time, stirring speed, temperature and current density on the color and microstructure of the electrodeposited nickel film were investigated through naked eyes, scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. Meanwhile, the corrosion resistance of the optimized black nickel film was evaluated by the polarization measurement and electrochemical impedance spectroscopy (EIS) in the neutral 3.5% NaCl solution. The results show that the color of the electrodeposited nickel film was highly dependent on the above technological parameters. The operating parameters were optimized mainly according to the color. The optimized black nickel film possesses nano-structure with an average grain diameter of about 50 nm. It also exhibits enhanced corrosion resistance when compared with white nickel coatings electrdodeposited under the same condition except the variation of the electroplating current density.%采用电沉积方法制备具有整体纳米结构的黑镍镀层,并通过肉眼观察结合扫描电镜、X射线衍射等测试技术研究电沉积过程中的主要参数(电解液pH、搅拌速度、制备温度及电流密度)对镀层颜色及整体微观结构的影响。进一步采用动电位极化及电化学阻抗等电化学测量技术研究黑镍镀层在中性3.5%NaCl溶液中的腐蚀行为及腐蚀机理。结果表明:黑镍镀层的颜色变化趋势决定于电沉积制备参数的选择;通过优化本工艺制备的黑镍镀层平均粒径约为50 nm。对比了近似条件下制备的光亮镍镀层,发现黑镍镀层在耐蚀性方面具有较大优势。

  17. Catalytic growth of CdTe nanowires by closed space sublimation method

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Gwangseok; Jung, Younghun [Department of Chemical and Biological Engineering, Korea University, Seoul 136-701 (Korea, Republic of); Chun, Seungju; Kim, Donghwan [Department of Materials Science and Engineering, Korea University, Seoul 136-701 (Korea, Republic of); Kim, Jihyun, E-mail: hyunhyun7@korea.ac.kr [Department of Chemical and Biological Engineering, Korea University, Seoul 136-701 (Korea, Republic of)

    2013-11-01

    CdTe nano-/micro-structures with various morphologies were grown by using the closed space sublimation (CSS) method on a sapphire substrate by Au-catalyzed vapor–liquid–solid (VLS) mechanism. Length, diameter, and morphology of the CdTe nano-/micro-structures depended on the growth time and temperature gradient between the substrate and powdered CdTe source. Scanning electron microscopy images showed that an Au catalyst droplet existed at the tips of CdTe nanowires, which confirms that CdTe nanowires were grown by an Au-catalyzed VLS mechanism. Also, we observed that the two-dimensional CdTe film layer initially formed before the growth of the CdTe nano-/micro-wires. The optical and structural properties of CdTe nano-/micro-structures were characterized by X-ray diffraction technique and micro-Raman spectroscopy. Our study demonstrates that diverse CdTe nano-/micro-structures can be fabricated by using Au-catalyzed VLS growth process in a simple CSS chamber by controlling the temperature gradient and growth time. - Highlights: • We demonstrated CdTe nanowires using closed space sublimation method. • Au-catalyst droplets at the tips confirmed vapor–liquid–solid mechanism. • Diameters and lengths increased with increasing temperature gradient and time.

  18. Interfacial investigation and strengthening behaviour of Zn-Ni multifacial TEA/MEA thin films induced by electrodeposition

    Science.gov (United States)

    Fayomi, O. S. I.; Tau, V.; Popoola, A. P. I.; Abdulwahab, M.; Madhilabar, R.

    2015-11-01

    Zinc-nickel films were obtained by electrocodeposition using electrolytic deposition techniques in the presence of TEOA (C6H15NO3) and a surfactants consisting of triethylamine and monoethylamine with other bath additives. The modified structure of the films was analysed with scanning electron microscopy attached to energy-dispersive spectrometer, atomic force microscope and X-ray diffraction. Micro-hardness and corrosion of the coated body was examined and used as a criterion to justify the adhesion of the crystal deposited. The corrosion resistance of the coated and uncoated composites was studied in 3.5 % sodium chloride static solution using linear polarization technique. The hardness value increased from 38HV—substrate to 180HV—coated body, indicating a 78.89 % improvement. Equally, the corrosion resistance of the deposited matrix was enhanced by 84.62 %.

  19. INTEGRATIION STYDY OF CdTe THIN FILMS PV MODULE%CdTe组件集成结构模拟优化及前、背电极接触电阻测定

    Institute of Scientific and Technical Information of China (English)

    汪灵; 曾广根; 蔡伟; 冯良桓; 张静全; 蔡亚平; 武莉莉; 李卫; 黎兵; 雷智; 郑家贵

    2011-01-01

    设计特定的测试结构,测量CdTe太阳电池组件的相邻单元电池的前电极与背电极的接触电阻,研究接触电阻与激光刻蚀刻痕的关系;使用module design simulator软件模拟分析相关膜层电子学性质、集成结构、单元电池性能对电池组件性能的影响.对CdTe电池组件接触电阻测量结果表明:随Ni层厚度增加,接触电阻减小,镍电极镀层较厚(410nm)时,接触电阻在10-3Ω·cm2数量级;加宽刻痕宽度使接触电阻略有下降;基频刻蚀CdTe层所得刻痕的接触电阻比倍频刻蚀高1~2个数量级.module design simulator软件模拟分析结果表明:CdTe薄膜太阳电池组件性能除与单元电池性能参数(转换效率、填充因子、短路电流、开路电压)相关外,单元电池宽度、TCO层方块电阻(或透过率)、CdTe层方块电阻、集成接触区接触电阻都对电池组件的性能存在影响.%The CdTe thin films PV module had been studied by measuring the contact resistance between the back contact metal and the front TCO film of the adjacent elementary cells. The "MODULE DESIGN SIMULATOR" software had been used to simulate the effects of the film electronic performance, the integration structure, and the contact elementary cell characteristics on module characteristics. The contact resistance decreases with the increasing of the thickness of Ni film. And the contact resistance increases 1 -2 orders of magnitude when the CdTe films were etched by basic frequency laser. The highest efficiency corresponds with the optimized cell width and the width of the notches. The unit cell width, sheet resistance of TCO & CdTe, and TCO/Ni contact resistance have great effect on the property of the module, respectively. With the increasing of TCO sheet resistance, the conversion efficiency firstly increase sharply and then decrease slowly. Increasing the sheet resistance of CdTe will lead to the increasing of both conversion efficiency and fill factor.

  20. Metalorganic Vapor Phase Epitaxial Growth of (211)B CdTe on Nanopatterned (211)Si

    Science.gov (United States)

    2012-05-15

    respectively. X-ray analysis of thin CdTe films grown on these substrates gave wider full-width half-maximum (FWHM) values when compared to the layers grown...obtained in the temperature range of 575-675 °C and 505-520 °C respectively. X-ray analy- sis of thin CdTe films grown on these substrates gave wider...An effort was also made to grow thin uniformly merged ~0.6 µm (211)B CdTe film on nanopatterned (211)Si by

  1. A novel method for fabricating hybrid biobased nanocomposites film with stable fluorescence containing CdTe quantum dots and montmorillonite-chitosan nanosheets.

    Science.gov (United States)

    Guo, Yawen; Ge, Xuesong; Guan, Jing; Wu, Lin; Zhao, Fuhua; Li, Hui; Mu, Xindong; Jiang, Yijun; Chen, Aibing

    2016-07-10

    A method was presented for fabricating the fluorescent nanocomposites containing CdTe quantum dots (QDs) and montmorillonite (MMT)-chitosan (CS). MMT-CS/CdTe QDs nanocomposites were prepared via a simple, versatile and robust approach combination of covalent and electrostatic assembly methods (Scheme 1). The negatively charged MMT was initially modified with positively charged CS through electrostatic assembly, followed by incorporation of CdTe-QDs into the MMT-CS nanosheets by covalent connections between the amino groups of CS and the carboxylic acid groups of thioglycollic acid (TGA). The X-ray diffraction (XRD), High resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM) and the FTIR were used to prove the QDs have intercalated into the MMT-CS matrix. The fluorescence emission spectra showed that the MMT-CS/CdTe QDs nanocomposites had the best fluorescence intensity compared with the bare CdTe QDs and CS-QDs.

  2. 电沉积-退火工艺制备铜铟硒太阳能电池薄膜及表征%Preparation and Characterization of Electrodeposited-Annealed CulnSe2 Thin Films for Solar Cells

    Institute of Scientific and Technical Information of China (English)

    张中伟; 郭宏艳; 李纪; 朱长飞

    2011-01-01

    CuInSe2 (CIS) films with good crystalline quality were synthesized by electrodeposition followed by annealing in Se vapor at 530 C. The morphology, composition, crystal structure,optical and electrical properties of the CIS films were investigated by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, Raman spectroscopy, UV-VISNIR spectroscopy, and admittance spectroscopy. The results reve