Surface characterization of epitaxial Cu-rich CuInSe2 absorbers
Evandro M. Lanzoni, Conrad Spindler, Omar Ramirez, Michele Melchiorre, Susanne Siebentritt, Alex Redinger
University of Luxembourg, Luxembourg, Luxembourg

In this work, we investigated the electrical properties of epitaxial Cu-rich CuInSe2 by frequency modulation Kelvin probe force microscopy (FM-KPFM) in ultra-high vacuum. We observed a work function dependence according to the surface orientation of the Cu-rich CIS crystal. Additionally, we analyze the sample surface after the conventional procedure of KCN etching. Our results show the possibility to increase the efficiency of epitaxial Cu-rich CuInSe2 by growing the materials in the appropriated surface orientation where the variations in work function are reduced.