Electrochemical Deposition of Cadmium-tellurium Thin Films for Solar Cell Applications PDF Download

Author: Omar E. Abdel-Salam
Publisher:
ISBN:
Category :
Languages : en
Pages : 90

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The near-ideal value of the energy gap and the high optical absorption coefficient of CdTe suggest that this material can be used for fabricating high-efficiency solar cells. Thin films of CdTe can be prepared by vacuum evaporation, chemical vapor deposition, spraying and electrodeposition, with electrodeposition being the most convienient for adaption to industrial-scale production. In this paper the electrodeposit is discussed in relation to operating parameters such as current density, temperature and stirring. The economics of the electrodeposition technique are also presented.

Author: Xiaoyue Zhang
Publisher:
ISBN:
Category :
Languages : en
Pages : 310

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This dissertation discusses the formation of cadmium telluride (CdTe) using potential pulse atomic layer deposition (PP-ALD) and metal thin films (copper and gold) using surface limited redox replacement (SLRR). Both materials play important roles in photovoltaic devices. PP-ALD is an electrodeposition methodology similar to co-deposition because it uses one solution containing all precursors. However, instead of maintaining one deposition potential as with codeposition, potentials are varied quickly between a cathodic and an anodic potential throughout deposition. Each short pulse aims to limit the amount deposited during cathodic potential and strip the excess in the following anodic potential so that thermodynamically stable compound remains without elemental excess buried beneath the later-grown film. To achieve high quality CdTe thin film, changes in deposition potential and solution flow effects were first monitored and optimized. Parametric variables for controlling the Cd/Te ratio and morphology are also established. X-ray diffraction (XRD), Scanning electron microscope (SEM), Electron probe microanalysis (EPMA), Energy dispersive X-Ray Analyzer (EDX) were used to characterize the resulting CdTe films. Results indicated that deposited CdTe was stoichiometric, high crystalline with a smooth, continuous morphology using an optimized PP-ALD method. The optimized PP-ALD method was also applied on nanostructured Au electrodes. Initial results showed high quality deposits with reproducible stoichiometry, which could open pathways for semiconductor and nanostructure incorporation. Cu and Au thin films were formed on metal and semiconductor substrates via surface limited redox replacement (SLRR). An atomic layer of cadmium was first deposited as a sacrificial layer, and then replaced with ions of more noble metals such as Cu2+ or Au3+ to form Cu or Au atomic layer. Uniform and reasonably flat metal thin films with controllable thickness were produced by multiple repetitions of SLRR cycles with great linear growth with respect to cycle numbers. The resulting metal thin films were characterized using coulometry, SEM, EDX and EPMA. They confirmed deposited metal thin films had a conformal, flat morphology with no roughness development, nor Cd incorporation in the deposition process.

Author:
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ISBN:
Category :
Languages : en
Pages : 35

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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 (

Author: Jaime Andres Perez Taborda
Publisher: BoD – Books on Demand
ISBN: 1789848709
Category : Technology & Engineering
Languages : en
Pages : 288

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Book Description
The field of coatings and thin-film technologies is rapidly advancing to keep up with new uses for semiconductor, optical, tribological, thermoelectric, solar, security, and smart sensing applications, among others. In this sense, thin-film coatings and structures are increasingly sophisticated with more specific properties, new geometries, large areas, the use of heterogeneous materials and flexible and rigid coating substrates to produce thin-film structures with improved performance and properties in response to new challenges that the industry presents. This book aims to provide the reader with a complete overview of the current state of applications and developments in thin-film technology, discussing applications, health and safety in thin films, and presenting reviews and experimental results of recognized experts in the area of coatings and thin-film technologies.

Author: John U. Trefny
Publisher:
ISBN:
Category : Cadmium telluride
Languages : en
Pages : 26

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Book Description
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 (

Author: John U. Trefny
Publisher:
ISBN:
Category : Cadmium telluride
Languages : en
Pages : 0

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Book Description
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 (

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 46

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Book Description
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.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
Preparation and properties of cadmium telluride thin films for use in solar cells are studied. CdTe sputter deposition, crystal doping, and carrier typing are discussed. Future experimental plans are described. (WHK).

Author: Jef Poortmans
Publisher: John Wiley & Sons
ISBN: 0470091266
Category : Science
Languages : en
Pages : 504

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Book Description
Thin-film solar cells are either emerging or about to emerge from the research laboratory to become commercially available devices finding practical various applications. Currently no textbook outlining the basic theoretical background, methods of fabrication and applications currently exist. Thus, this book aims to present for the first time an in-depth overview of this topic covering a broad range of thin-film solar cell technologies including both organic and inorganic materials, presented in a systematic fashion, by the scientific leaders in the respective domains. It covers a broad range of related topics, from physical principles to design, fabrication, characterization, and applications of novel photovoltaic devices.