KF Post-deposition Treatment of Industrial Cu(In, Ga)(S, Se)2 Thin-film Surfaces: Modifying the Chemical and Electronic Structure

Authors

Michelle Mezher, University of Nevada, Las VegasFollow
Lorelle M. Mansfield, National Renewable Energy LaboratoryFollow
Kimberly Horsley, University of Nevada, Las VegasFollow
Monika Blum, University of Nevada, Las VegasFollow
Robert Wieting, STION
Lothar Weinhardt, University of Nevada, Las VegasFollow
Kannan Ramanathan, STIONFollow
Clemens Heske, University of Nevada, Las VegasFollow

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).

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