Growth and vacuum post-annealing effect on the properties of the new absorber CuSbS2 thin films

Post-growth treatments in vacuum atmosphere were performed on CuSbS2 films prepared by the single-source thermal evaporation method on glass substrates. The films were annealed in vacuum atmosphere for 2 h in temperature range 130-200 degrees C. The effect of this thermal treatment on the structural optical and, electrical properties of the films was studied. X-ray diffraction (XRD) patterns indicated that the films exhibited an amorphous structure for annealing temperature below 200 degrees C and a polycrystalline structure with CuSbS2 principal phase. For the films annealed at temperatures below 200 degrees C one direct optical transition in range 1.8-2 eV was found. For the films annealed at 200 degrees C, two optical direct transitions emerged at 1.3 and 1.79 eV corresponding to the CuSbS2 and Sb2S3 values respectively. The electrical measurements showed a conversion from low resistivities (3.10(-2)-9.10(-2)) Omega cm for the samples annealed at temperatures below 200 degrees C to relatively high resistivities (2 Omega cm) for the samples annealed at 200 degrees C. In all cases the samples exhibited p-Ztype conductivity. (C) 2008 Elsevier B.V. All rights reserved.