Study of Effect of Substrate Temperature on Structure, Morphology and optical Properties of Spray Deposited Cu2ZnSnS4 Nano Thin films.

Abstract

Cu₂ZnSnS₄ (CZTS) films for different substrate temperatures were deposited by using simple chemical spray technique. Analytical reagent Grade; Copper chloride (CuCl₂), Zinc chloride (ZnCl₂), Tin chloride (SnCl₄.5H₂O) and thiourea (SC(NH₂)₂) were used as  Cu⁺,  Zn⁺, and  Sn⁺ and  ion sources respectively. A set of five CZTS films was deposited using five different substrate temperatures (175, 200, 250, 275, and 300 ).  The structure, Morphology, Elemental analysis and optical properties of these films were studied using X-ray diffratometer (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Analysis (EDX) and UV-Visible spectroscopy techniques respectively. The XRD spectra showed that all films are polycrystalline and exhibit kesterite tetragonal crystal structure with preferential orientation along (112) direction. The crstallinity was found increased with substrate temperature. The calculated crystallite size was increased with increase in substrate temperature. The surface morphology of CZTS films was improved with increase in substrate temperature. The film sample deposited for 275   represent excellent spherical granules CZTS crystals of increasing size from 640 nm to 1.8 μm arranged in regular fashion with some void spaces. The purity of the composition was investigated using Elemental analysis of the deposited films. The optical band gap was estimated using Tauc plots. The band gap obtained was to be in the range of 1.4 to 1.6 eV.