Growth and vacuum post-annealing effect on the properties of the new absorber CuSbS 2 thin films

Abstract

Post-growth treatments in vacuum atmosphere were performed on CuSbS 2 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 °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 °C and a polycrystalline structure with CuSbS 2 principal phase. For the films annealed at temperatures below 200 °C one direct optical transition in range 1.8–2 eV was found. For the films annealed at 200 °C, two optical direct transitions emerged at 1.3 and 1.79 eV corresponding to the CuSbS 2 and Sb 2S 3 values respectively. The electrical measurements showed a conversion from low resistivities (3.10 − 2 –9.10 − 2 ) Ω cm for the samples annealed at temperatures below 200 °C to relatively high resistivities (2 Ω cm) for the samples annealed at 200 °C. In all cases the samples exhibited p-Ztype conductivity.