Structural, Elemental, Morphological and Optical Spectroscopic Studies on High Quality <111> Grown Nanocrystalline ZnTe Thin Films: An Effect of Thickness

摘要

Zinc telluride (ZnTe) is an excellent material and has good semiconducting properties for optoelectronic device applications. In this paper we report the study on thickness dependent structural, morphological and optical properties of thermally evaporated ZnTe thin films preferentially grown along <111>. The structural parameters were determined by using the powder X-ray diffraction data. The crystallite size were calculated by Scherer formula and found to be 9.7, 14.26, 15.7 nm for 100, 200 and 300 nm thicknesses, respectively. The lattice strain and dislocation densities were also calculated. Elemental composition in all the films was studied by energy dispersive X-ray spectroscopy. Scanning electron microscopic studies were carried to check the uniformity, morphology and grain size of the thin films at different places. The UV-VIS-NIR spectroscopic study was carried out for all the thin films and absorption coefficient, transmission, optical band gap were calculated. Optical band gap was found to be decreases with thicknesses of the thin films as the crystallite size was found to be increases with thickness.