Optical and structural properties of CuSbS 2 thin films grown by thermal evaporation method

Abstract

Structural, optical and electrical properties of CuSbS 2 thin films grown by thermal evaporation have been studied relating the effects of substrate heating conditions of these properties. The CuSbS 2 thin films were carried out at substrate temperatures in the temperature range 100–200 °C. The structure and composition were characterized by XRD, SEM and EDX. X-ray diffraction revealed that the films are (111) oriented upon substrate temperature 170 °C and amorphous for the substrate temperatures below 170 °C. No secondary phases are observed for all the films. The optical absorption coefficients and band gaps of the films were estimated by optical transmission and reflection measurements at room temperature. Strong absorption coefficients in the range 10 5–10 6 cm − 1 at 500 nm were found. The direct gaps Eg lie between 0.91–1.89 eV range. It is observed that there is a decrease in optical band gap Eg with increasing the substrate temperature. Resistivity of 0.03–0.96 Ω cm, in dependence on substrate temperature was characterized. The all unheated films exhibit p-type conductivity. The characteristics reported here also offer perspective for CuSbS 2 as an absorber material in solar cells applications.