KF Post-deposition Treatment of Industrial Cu(In, Ga)(S, Se)2 Thin-film Surfaces: Modifying the Chemical and Electronic Structure
Document Type
Article
Publication Date
1-1-2017
Publication Title
Applied Physics Letters
Volume
111
Issue
7
Abstract
The chemical and electronic structures of industrial chalcopyrite photovoltaic absorbers after KF post-deposition treatment (KF-PDT) are investigated using electron spectroscopies to probe the occupied and unoccupied electronic states. In contrast to a variety of recent publications on the impact of KF-PDT, this study focuses on industrial Cu(In,Ga)(S,Se)2 absorbers that also contain sulfur at the surface. We find that the KF-PDT removes surface adsorbates and oxides and also observe a change in the S/Se ratio. Furthermore, the KF-PDT leads to a Cu reduction at the surface but to a much lower degree than the strongly Cu-depleted or even Cu-free surfaces reported for (non-industrial) sulfur-free Cu(In,Ga)Se2 absorbers. The valence band maximum at the surface is found at a lower energy compared to the untreated absorber, and the conduction band minimum is found at a higher energy, overall revealing a widening of the bandgap in the surface region. © 2017 Author(s).
File Format
File Size
1340 KB
Language
english
Repository Citation
Mezher, M.,
Mansfield, L. M.,
Horsley, K.,
Blum, M.,
Wieting, R.,
Weinhardt, L.,
Ramanathan, K.,
Heske, C.
(2017).
KF Post-deposition Treatment of Industrial Cu(In, Ga)(S, Se)2 Thin-film Surfaces: Modifying the Chemical and Electronic Structure.
Applied Physics Letters, 111(7),
http://dx.doi.org/10.1063/1.4998445