A New Efficient Synthesis of ZnS Thin Films Using Mist CVD Technique

Zinc Sulphide (ZnS) thin films have been successfully synthesized, using the Mist CVD method, as a buffer layer for photovoltaic applications. The films were deposited on glass substrates. The solution was prepared using Zinc Chloride and Thiourea as zinc and sulfur sources respectively. First, the effect of the solvent has been investigated and optimized, then we have studied the effect of the temperature on structural, morphological, and optical properties. The characterizations have been carried out using X-ray diffraction technique (XRD), UV-vis spectrophotometry, scanning electron microscopy (SEM), and atomic force microscopy (AFM). XRD results showed that ZnS films were crystallized in the zinc blende (ZB) structure with (111) orientation. Optical measurements have shown that all films exhibit, along the visible range, high transmittance and that the optical band gap depends on both solvent and temperature. The scanning electron microscopy shows that the nanostructures of ZnS are homogeneous mainly for 450°C using 25% distilled water and 75% methanol. The atomic force microscopy shows that the average linear (Ra) and surface (Sa) roughness, decreases as the distilled water rate decreases, with a high surface roughness (Sa=25.66 nm) for the temperature 450°C.