This work reports a process used to obtain CdS/CdTe thin film solar cells with high efficiencies between 14% and 14.6%. The procedure consists of sequentially depositing by RF sputtering and close space sublimation (CSS) of several layers onto a glass substrate, configured as glass/ITO/ZnO/CdS/CdTe/Cu/Mo. The CdTe layer was deposited by CSS at low substrate temperature (500 degrees C) under Ar-O-2 atmosphere and the activation process is performed with a mixture of Freon gas (HCF2Cl) and other gases. (C) 2011 Elsevier Ltd. All rights reserved.