Analysis of untreated cross sections of Cu(In,Ga)Se2 thin-film solar cells with varying Ga content using Kelvin probe force microscopy

The potential distribution of the Cu(In,Ga)Se-2/CdS/ZnO layer structure on untreated cross sections of Cu(In,Ga)Se-2 thin-film solar cells are analyzed by Kelvin probe force microscopy under ambient conditions. The potential differences between the Cu(In,Ga)Se-2 absorber and the ZnO window layer are systematically investigated, providing direct evidence for a Fermi energy shifting in Cu(In,Ga)Se-2 absorbers with different Ga content. (C) 2011 American Institute of Physics. [doi:10.1063/1.3607954]