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Title: Impact of environmental conditions on the chemical surface properties of Cu(In,Ga)(S,Se){sub 2} thin-film solar cell absorbers

Environmentally driven aging effects play a crucial role in thin-film solar cells based on Cu(In,Ga)(S,Se){sub 2}, both for long-term stability and short air exposure during production. For a better understanding of such effects, Cu(In,Ga)(S,Se){sub 2} absorber surfaces were investigated by x-ray photoelectron and Auger electron spectroscopy after exposure to different environmental conditions. Identical absorbers were stored in a nitrogen atmosphere, in damp heat, and under ambient conditions for up to 14 days. We find varying degrees of diffusion of sulfur, copper, and sodium towards the surface, with potential impact on the electronic surface structure (band gap) and the properties of the interface to a buffer layer in a solar cell device. Furthermore, we observe an oxidation (in decreasing order) of indium, copper, and selenium (but no oxidation of sulfur). And finally, varying amounts of carbon- and oxygen-containing adsorbates are found. In particular, the findings suggest that, for ambient air exposure, sodium carbonate is formed at the surface.
Authors:
;  [1] ; ; ; ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [3] ;  [4] ;  [5] ;  [1] ;  [7]
  1. Experimental Physics VII, University of Würzburg, Am Hubland, 97074 Würzburg (Germany)
  2. AVANCIS GmbH and Co. KG, Otto-Hahn-Ring 6, 81739 Munich (Germany)
  3. Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology (KIT), Hermann-v.-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)
  4. (KIT), Hermann-v.-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)
  5. (UNLV), 4505 Maryland Parkway, Las Vegas, Nevada 89154-4003 (United States)
  6. (KIT), Engesserstr. 18/20, 76128 Karlsruhe (Germany)
  7. (KIT), Gemeinschaftslabor für Nanoanalytik, 76021 Karlsruhe (Germany)
Publication Date:
OSTI Identifier:
22275543
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 18; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE; AUGER ELECTRON SPECTROSCOPY; CARBON; COPPER; DIFFUSION; ELECTRONIC STRUCTURE; GALLIUM SULFIDES; INDIUM; INDIUM SELENIDES; INTERFACES; LAYERS; NITROGEN; OXIDATION; OXYGEN; SELENIUM; SODIUM; SODIUM CARBONATES; SULFUR; SURFACE PROPERTIES; SURFACES; THIN FILMS