p-Type CuSbS2 thin films by thermal diffusion of copper into Sb2S3

We report the preparation of copper antimony sulfide (CuSbS2) thin films by heating Sb2S3/Cu multilayer in vacuum. Sb2S3 thin film was prepared from a chemical bath containing SbCl3 and Na2S2O3 salts at room temperature (27 °C) on well cleaned glass substrates. A copper thin film was deposited on Sb2S3 film by thermal evaporation and Sb2S3/Cu layers were subjected to annealing at different conditions. Structure, morphology, optical and electrical properties of the thin films formed by varying Cu layer thickness and heating conditions were analyzed using different characterization techniques. XRD analysis showed that the thin films formed at 300 and 380 °C consist of CuSbS2 with chalcostibite structure. These thin films showed p-type conductivity and the conductivity value increased with increase in copper content. The optical band gap of CuSbS2 was evaluated as nearly 1.5 eV.