Title

Spectroscopic analysis of CIGS2/CdS thin film solar cell heterojunctions on stainless steel foil

Authors

Authors

N. G. Dhere; A. A. Kadam; A. H. Jahagirdar; S. S. Kulkarni; L. Weinhardt; D. Gross; C. Heske;E. Umbach

Comments

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Abbreviated Journal Title

J. Phys. Chem. Solids

Keywords

thin films; photoelectron spectroscopy; electronic structure; PERFORMANCE; Chemistry, Multidisciplinary; Physics, Condensed Matter

Abstract

This paper presents a spectroscopic analysis of the interface between a CuIn1-xGaxS2 (CIGS2) absorber and a CdS buffer layer on stainless steel foil by Auger electron spectroscopy (AES), inverse photoemission spectroscopy (IPES) and photoelectron spectroscopy (PES) such as X-ray photoelectron spectroscopy (XPS), and ultraviolet photoelectron spectroscopy (UPS). By combining these spectroscopic techniques, detailed information about the electronic and chemical properties of the CIGS2 surface and the CdS/CIGS2 interface can be obtained. The gallium concentration in CIGS2 films was found to increase continuously towards the Mo back contact. XPS analysis showed the presence of KCO3 on the surface of CdS, deposited on etched and un-oxidized samples indicating diffusion of potassium. No potassium was observed on oxidized as well as samples having thicker CdS (50 nm) indicating the effectiveness of oxidation and chemical bath deposition (CBD) process in cleaning the sample surface effectively. In addition, investigation of the electronic level alignment at the interface has been carried out by combining PES and IDES. Conduction band offset of -0.45 (+/- 0.15) eV and a valence band offset of -1.06 (+/- 0.15) eV were measured. These unfavorable conditions limit efficiency of CIGS2 thin film solar cells. (c) 2005 Elsevier Ltd. All rights reserved.

Journal Title

Journal of Physics and Chemistry of Solids

Volume

66

Issue/Number

11

Publication Date

1-1-2005

Document Type

Article; Proceedings Paper

Language

English

First Page

1872

Last Page

1875

WOS Identifier

WOS:000234288700007

ISSN

0022-3697

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