Influence of Inter-Molar Concentration of Cu and Zn on the Various Properties of Sprayed Nanocrystalline Cu₂ZnSnS₄ Thin Films

Abstract

In this work, the quaternary nanostructured Cu2ZnSnS4 (CZTS) thin films were deposited on ITO glass substrates at a temperature of 300[Formula: see text]C by spray pyrolysis method and the influence of inter-molar concentration variations of copper and zinc on the structural, morphological and optical properties of grown samples was studied. The films were characterized by different sophisticated techniques including X-ray diffractometer (XRD), scanning electron microscopy (SEM), Raman spectroscopy and UV–Vis spectroscopy. The solitary presence of kesterite tetragonal phase with favored orientation along (112) plane is confirmed by XRD patterns and Raman spectroscopy. However, due to the variation in lattice parameters, a moderate shifting in (hkl) planes was observed. SEM micrographs and EDAX analysis showed the uniform morphology of the so-grown CZTS films covered with nanoplates of different sizes and the ionic compositional variation of the precursor solution matches with the elemental variation in the grown samples. A minor nonstoichiometry in chemical composition ratio [Formula: see text] from 0.74 to 1.24 was noticed in the films. Optical studies of CZTS films showed that these films possess optical band gap ranging from 1.45[Formula: see text]eV to 1.60[Formula: see text]eV.