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

    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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