@misc{BaerSchubertMarsenetal., author = {B{\"a}r, Marcus and Schubert, Bj{\"o}rn-Arvid and Marsen, Bj{\"o}rn and Wilks, Regan G. and Pookpanratana, Sujitra and Blum, Monika and Krause, Stefan and Unold, Thomas and Yang, Wan Li and Weinhardt, Lothar and Heske, Clemens and Schock, Hans-Werner}, title = {Cliff-like conduction band offset and KCN-induced recombination barrier enhancement at the CdS/Cu2ZnSnS4 thin-film solar cell heterojunction}, abstract = {The electronic structure of the CdS/Cu2ZnSnS4 (CZTS) heterojunction was investigated by direct and inverse photoemission. The effects of a KCN etch of the CZTS absorber prior to CdS deposition on the band alignment at the respective interface were studied. We find a "cliff"-like conduction band offset at the CdS/CZTS interface independent of absorber pretreatment and a significant etch-induced enhancement of the energetic barrier for charge carrier recombination across the CdS/CZTS interface.}, language = {en} } @misc{BaerSchubertMarsenetal., author = {B{\"a}r, Marcus and Schubert, Bj{\"o}rn-Arvid and Marsen, Bj{\"o}rn and Krause, Stefan and Pookpanratana, Sujitra and Unold, Thomas and Weinhardt, Lothar and Heske, Clemens and Schock, Hans-Werner}, title = {Impact of KCN etching on the chemical and electronic surface structure of Cu2ZnSnS4 thin-film solar cell absorbers}, abstract = {The chemical and electronic surface structure of Cu2ZnSnS4 thin-film solar cell absorbers has been investigated by direct and inverse photoemission. Particular emphasis was placed on the impact of KCN etching, which significantly alters the surface composition and is best explained by a preferred etching of Cu and, to a lesser degree, Sn. As a consequence the surface band gap increased from (1.53 +/- 0.15) eV, which agrees with optically derived bulk band gap values, to (1.91 +/- 0.15) ev.}, language = {en} }