SnS/CdS heterojunction is a promising system for the fabrication of thin film solar cells. In our work, thin film SnS/CdS heterojunction was prepared by evaporating US and SnS films. The photovoltaic properties of the heterojunction were investigated with posttreatment of the window material treatment by CdCl2 for grain size enlargement. I-V characteristics in dark and at light were taken and figures of merit were evaluated. The efficiency with and without window layer treatment were about 0.08% and 0.05%, respectively, under 100 mW/cm(2) intensity. To the best of our knowledge so far there has been no report on vacuum-evaporated SnS-based heterojunction with window material treatment by CdCl2. (C) 2008 Elsevier B.V. All rights reserved.