The influence of the buffer layer thickness and the thiourea concentration in chemical bath on the cell performance of ZnS(O,OH)/CIGS solar cells was investigated. It was found that a high efficiency CIGS solar cell could be achieved by increasing the thiourea concentration in the chemical bath deposition (CBD) solution even if a very thin ZnS(O,OH) buffer layer (10 nm) was used. As a result, the CBD deposition time could be shortened to one six as compared to that of thicker buffer layer thickness of 120 nm. The results are discussed in connection with the conduction band offset at the ZnS(O,OH)/CIGS interface. (C) 2013 Elsevier B.V. All rights reserved.