Classification of metastabilities in the electrical characteristics of ZnO/CdS/Cu(In,Ga)Se2 solar cells

Abstract We experimentally distinguish between three types of metastable electrical behavior in Cu(In,Ga)Se 2 -based heterojunction thin-film solar cells. A metastable increase of net acceptor concentration in the bulk of the Cu(In,Ga)Se 2 absorber material is induced by illumination with red light, an increase of net positive charge at the interfacial region is induced by blue light, and a reversible creation of negative charges occurres by the application of reverse bias at temperatures above 340 K. We discuss the physical origin of these metastabilities.