Abstract :
An adjustment of a conduction band offset (CBO) of a window/absorber heterointerface is important for high efficiency Cu(In,Ga)Se2
(CIGS) solar cells. In this study, the heterointerface recombination was characterized by the reduction of the thickness of a CdS layer and
the adjustment of a CBO value by a Zn1 xMgxO (ZMO) layer. In ZnO/CdS/CIGS solar cells, open-circuit voltage (Voc) and shunt resistance
(Rsh) decreased with reducing the CdS thickness. In constant, significant reductions of Voc and Rsh were not observed in ZMO/
CdS/CIGS solar cells. With decreasing the CdS thickness, the CBO of (ZnO or ZMO)/CIGS become dominant for recombination. Also,
the dominant mechanisms of recombination of the CIGS solar cells are discussed by the estimation of an activation energy obtained from
temperature-dependent current–voltage measurements.
2008 Elsevier Ltd. All rights reserved.
