Rusu, M.; Glatzel, Th.; Neisser, A.; Kaufmann, C.A.; Sadewasser, S.; Lux-Steiner, M.Ch.: Formation of the physical vapor deposited CdS/Cu(In,Ga)Se2 interface in highly efficient thin film solar cells. Applied Physics Letters 88 (2006), p. 143510/1-3
10.1063/1.2190768
Abstract:
We report on the buffer/absorber interface formation in highly-efficient (14.5%, AM1.5) ZnO/CdS/Cu(In,Ga)Se2 solar cells with a physical vapor deposited CdS-buffer. For Se-decapped Cu(In,Ga)Se2 (CIGSe) absorbers we observe sulfur passivation of the CIGSe grain boundaries during CdS growth and at the interface a thermally stimulated formation of a region with a higher band gap than that of the absorber bulk, determining the height of the potential barrier at the CdS/CIGSe interface. For air-exposed CIGSe samples the grain boundary passivation is impeded by a native oxide/adsorbate layer at the CIGSe surface determining the thermal stability of the potential barrier height.