Microwave- and conventional-hydrothermal synthesis of CuS, SnS and ZnS: Optical properties

Sulfides of Cu, Sn and Zn were synthesized by conventional-hydrothermal (C-H) and microwave hydrothermal (M-H) methods using thioacetamide as a sulfide source. The synthesized CuS, SnS and ZnS were characterized by powder X-ray diffraction (XRD), scanning electron microscopy and UV–vis diffuse reflectance spectra. The results suggest that M-H process led to very rapid crystallization of all the sulfides compared to the C-H process. Band gaps of the CuS, SnS and ZnS were determined to be 1.8, 1.3 and 3.6, respectively matching the theoretical anticipated band gaps of 2.0, 1.2 and 3.54, respectively suggesting that pure phases were obtained. The three sulfides are potentially useful for the composite solid-state synthesis of kesterite, a photovoltaic material.