CuGaSe 2 solar cell cross section studied by Kelvin probe force microscopy in ultrahigh vacuum

Abstract

Kelvin probe force microscopy under ultrahigh vacuum conditions has been used to image the electronic structure of a Mo/CuGaSe2/CdS/ZnO thin film solar cell. Due to the high energy sensitivity together with a lateral resolution in the nanometer range we obtained detailed information about the various interfaces within the heterostructure. The absolute work function of the different materials was measured on a polished cross section. To obtain a flat and clean surface we optimized the sputtering process with Ar ions. The presence of an additional MoSe2 layer between the Mo backcontact and the CuGaSe2 absorber layer was observed.