Weinhardt, L.; Fuchs, O.; Peter, A.; Umbach, E.; Heske, C.; Reichardt, J.; Bär, M.; Lauermann, I.; Kötschau, I.; Grimm, A.; Sokoll, S.; Lux-Steiner, M.Ch.; Niesen, T.P.; Visbeck, S.; Karg, F.: Spectroscopic investigation of the deeply buried Cu(In,Ga)(S,Se)2/Mo interface in thin-film solar cells. Journal of Chemical Physics 124 (2006), p. 074705/1-5
10.1063/1.2168443
Abstract:
The Cu(In,Ga)(S,Se)2/Mo interface in thin film solar cells has been investigated by surface-sensitive photoelectron spectroscopy, bulk-sensitive X-ray emission spectroscopy, and atomic force microscopy. It is possible to access this deeply buried interface by using a suitable lift-off technique, which allows to investigate the back side of the absorber layer as well as the front side of the Mo back contact. We find a layer of Mo(S,Se)2 on the surface of the Mo back contact and a copper-poor stoichiometry at the back side of the Cu(In,Ga)(S,Se)2 absorber. Furthermore, we observe that the Na content at the Cu(In,Ga)(S,Se)2/Mo interface as well as at the inner grain boundaries in the back contact region is significantly lower than at the absorber front surface.