CdS layers grown by chemical bath deposition (CBD) are treated in different ways to improve the performance of CdS/CdTe solar cells. It has been found that the open circuit voltage of the CdS/CdTe solar cell increases when the CBD CdS is annealed with CdCl(2) before the deposition of CdTe by close spaced sublimation (CSS). A thin CBD CdS (similar to 80 nm) with bi-layer structure can significantly improve the short circuit current of the CdS/CdTe solar cells. (C) 2010 Elsevier B.V. All rights reserved.