Temperature-dependent properties of Co-evaporated CuS thin films

Covellite copper sulfide (CuS) thin films are deposited on soda-lime substrate using co-evaporation method at different substrate temperatures (150-300 °C). We investigated temperature-dependent properties such as structural, morphological, compositional, optical, and electrical properties of CuS thin films. The polycrystalline nature with orthorhombic structure of covellite CuS thin films is examined by X-ray diffraction (X-ray). The Raman analysis confirms the covellite CuS thin films without any other phases. Temperature dependence of morphology and elemental compositional of the films were carried out using scanning electron microscopy (SEM). The average grain size and surface roughness of the films examine using atomic force microscopy (AFM). The reduction in the direct energy band gap (2.49-2.32 eV) can be correlated to the quantum confinement. Hall results confirm that all the films are having p-type conductivity with lower resistivity in the range of 10⁻⁴ Ω cm. (author)