Electronic and structural properties of polycrystalline CdTe films which were grown at the atmosphere of vacuum, AL Ar/O-2 mixture, by close space sublimation were studied. The effects of O-2 and CdCl2 on the CdTe films were investigated from the energy band and electronic properties perspective. Based on the electrical transport measurement from 300 K to 125 K, the height of grain boundary barrier was calculated from the mobility and was found to be increased with the increasing partial pressure of O-2 in CdTe deposition process. XPS spectra showed that the O-Te interaction causes the band bending downward, resulting in the increased barrier at grain boundary. XPS spectra also showed that post annealing with CdCl2 enhanced the p-doping in CdTe intensively and improved the quantum efficiency of CdS/CdTe solar cells. (C) 2015 Elsevier B.V. All rights reserved.