Download or read book Polycrystalline Thin film Cadmium Telluride Solar Cells Fabricated by Electrodeposition Annual Technical Report written by and published by . This book was released on 1998 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the past year, Colorado School of Mines (CSM) researchers performed systematic studies of the growth and properties of electrodeposition CdS and back-contact formation using Cu-doped ZnTe, with an emphasis on low Cu concentrations. CSM also started to explore the stability of its ZnTe-Cu contacted CdTe solar cells. Researchers investigated the electrodeposition of CdS and its application in fabricating CdTe/CdS solar cells. The experimental conditions they explored in this study were pH from 2.0 to 3.0; temperatures of 80 and 90 C; CdCl2 concentration of 0.2 M; deposition potential from -550 to -600 mV vs. Ag/AgCl electrode; [Na2S2O4] concentration between 0.005 and 0.05 M. The deposition rate increases with increase of the thiosulfate concentration and decrease of solution pH. Researchers also extended their previous research of ZnTe:Cu films by investigating films doped with low Cu concentrations (

Download or read book Polycrystalline Thin Film Cadmium Telluride Solar Cells Fabricated by Electrodeposition written by J. U. Trefny and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 performances of the CdTe-based cells.

Download or read book Polycrystalline Thin film Cadmium Telluride Solar Cells Fabricated by Electrodeposition written by J. U. Trefny and published by . This book was released on 1993 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Polycrystalline Thin film Cadmium telluride Solar Cells Fabricated by Electrodeposition written by and published by . This book was released on 1995 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Polycrystalline Thin Film Cadmium Telluride Solar Cells Fabricated by Electrodeposition Annual Technical Report 20 March 1995 19 March 1996 written by and published by . This book was released on 1997 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 CdCl2 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/cm2, 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.

Download or read book Polycrystalline Thin film Cadmium Telluride Solar Cells Fabricated by Electrodeposition written by John U. Trefny and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the past year, Colorado School of Mines (CSM) researchers performed systematic studies of the growth and properties of electrodeposition CdS and back-contact formation using Cu-doped ZnTe, with an emphasis on low Cu concentrations. CSM also started to explore the stability of its ZnTe-Cu contacted CdTe solar cells. Researchers investigated the electrodeposition of CdS and its application in fabricating CdTe/CdS solar cells. The experimental conditions they explored in this study were pH from 2.0 to 3.0; temperatures of 80 and 90 deg. C; CdCl2 concentration of 0.2 M; deposition potential from -550 to -600 mV vs. Ag/AgCl electrode; [Na2S2O4] concentration between 0.005 and 0.05 M. The deposition rate increases with increase of the thiosulfate concentration and decrease of solution pH. Researchers also extended their previous research of ZnTe:Cu films by investigating films doped with low Cu concentrations (

Download or read book Polycrystalline Thin Film Cadmium Telluride Solar Cells Fabricated by Electrodeposition Final Technical Report 20 March 1995 15 June 1998 written by and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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. The improvement came from 1) optimization of CdS initial thickness taking into account CdS consumption of CdTe during the CdTe/CdSpost-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. 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.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Energy Research Abstracts written by and published by . This book was released on 1994-11 with total page 486 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Polycrystalline Thin film Cadmium telluride Solar Cells Fabricated by Electrodeposition written by J. U. Trefny and published by . This book was released on 1994 with total page 57 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994-03 with total page 812 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synerjy written by and published by . This book was released on 1996 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book High Efficiency Thin Film Cadmium Telluride Photovoltaic Cells Final Subcontract Report Final Technical Report 21 January 1994 31 March 1998 written by and published by . This book was released on 1998 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes work performed during the past year by The University of Toledo photovoltaics group. Researchers continued to develop rf sputtering for CdS/CdTe thin-film solar cells and to optimize the post-deposition process steps to match the characteristics of the sputtering process. During the fourth phase of the present contract, we focused on determining factors that limit the efficiency in our ''all-sputtered'' thin-film CdTe solar cells on soda-lime glass. These issues include controlling CdS/CdTe interdiffusion, understanding the properties of the CdS(subscript x)Te{sub 1-x} alloy, optimizing process conditions for CdCl2 treatments, manipulating the influence of ion bombardment during rf sputtering, and understanding the role of copper in quenching photoluminescence and carrier lifetimes in CdTe. To better understand the important CdS/CdTe interdiffusion process, we have continued our collaboration with the University at Buffalo and Brookhaven National Synchrotron Light Source in measurements using grazing-incidence X-rays. Interdiffusion results in the formation of the ternary alloy material CdS(subscript x)Te{sub 1-x} at or near the heterojunction, where its properties are critical to the operation of the solar cell. We have placed significant effort on characterizing this alloy, an effort begun in the last phase. A complete set of films spanning the alloy range, prepared by pulsed-laser deposition, has now been characterized by wavelength dispersive X-ray spectroscopy and optical absorption at NREL; by Raman scattering, X-ray diffraction, and electrical measurements in our lab; and by spectroscopic ellipsometry at Brooklyn College. We continued to participate in cooperative activity with the CdTe National Team. We prepared a series of depositions on borosilicate glass substrates having doped SnO2 layers coated with TiO2 (prepared by the University of South Florida and Harvard) and similar substrates having a resistive SnO2 layer on the doped tin oxide (fabricated by Golden Photon). The Golden Photon high-resistivity SnO2 structure yielded excellent cell performance.

Download or read book High Efficiency Cadmium Telluride and Zinc Telluride Based Thin film Solar Cells written by and published by . This book was released on 1992 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes work to improve the basic understanding of CdTe and ZnTe alloys by growing and characterizing these films along with cell fabrication. The major objective was to develop wide-band-gap (1.6--1.8 eV) material for the top cell, along with compatible window material and transparent ohmic contacts, so that a cascade cell design can be optimized. Front-wall solar cells were fabricated with a glass/SnO2/CdS window, where the CdS film is thin to maximize transmission and current. Wide-band-gap absorber films (E{sub g} = 1.75 eV) were grown by molecular beam epitaxy (MBE) and metal-organic chemical vapor deposition (MOCVD) techniques, which provided excellent control for tailoring the film composition and properties. CdZnTe films were grown by both MBE and MOCVD. All the as-grown films were characterized by several techniques (surface photovoltage spectroscopy, Auger electron spectroscopy (AES), and x-ray photoelectron spectroscopy (XPS)) for composition, bulk uniformity, thickness, and film and interface quality. Front-wall-type solar cells were fabricated in collaboration with Ametek Materials Research Laboratory using CdTe and CdZnTe polycrystalline absorber films. The effects of processing on ternary film were studied by AES and XPS coupled with capacitance voltage and current voltage measurements as a function of temperature. Bias-dependent spectral response and electrical measurements were used to test some models in order to identify and quantify dominant loss mechanisms.

Download or read book Solar Energy Update written by and published by . This book was released on 1982 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book High efficiency Thin film Cadmium Telluride Photovoltaic Cells written by Alvin D. Compaan and published by . This book was released on 1996 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: This annual report covers the second year of a 3-year NREL subcontract with the University of Toledo that is focused on improvements in efficiency for radio frequency (rf)-sputtered CdS/CdTe solar cells. In earlier work supported by NREL, the University of Toledo established the viability of two new deposition methods for CdS/CdTe solar cells by fabricating cells with efficiencies greater than 10% at air mass (AM) 1.5 on soda lime glass for 'all-sputtered' cells and also for 'all-laser-deposited' cells. Most of our effort has been placed on radio frequency sputtering (RFS) because it was judged to be more economical and more easily scaled to large-area deposition. However, laser physical vapor deposition (LPVD) has remained our method of choice for the deposition of CdCl2 layers and also for the exploration of new materials such as the ternary alloys including CdSxTe1-x and dopants such as Cu in ZnTe.

Download or read book Polycrystalline Thin film Cadmium telluride Solar Cells Fabricated by Electrodeposition Cells Final Subcontract Report March 20 1992 April 27 1995 written by and published by . This book was released on 1995 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this project was to develop improved processes for the fabrication of CdTe/CdS polycrystalline thin film solar cells. The technique we used for the formation of CdTe, electrodeposition, was a non-vacuum, low-cost technique that is attractive for economic, large-scale production. Annealing effects and electrical properties are discussed.