Influence of Annealing Temperature on the Structural and Optical Properties of Tellurium-Doped ZnO Thin Films for Optoelectronic Applications

Abstract

The structural, morphological and optical properties of Te-doped ZnO thin films prepared on microscopic glass substrates using the sol-gel technique were investigated. Zinc acetate dihydrate and tellurium tetrachloride as starting precursors, 2-methoxy ethanol as solvent were used to prepare the gel solution. Deposited films were post-annealed at different temperatures and characterized by X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and UV-VIS Spectrophotometer for studying structural, surface morphological and optical properties. Energy dispersive analysis by X-ray (EDAX) shows the incorporation of Te content into ZnO. XRD spectrum confirmed that the deposited Te-doped ZnO films are hexagonal. The crystallinity of films was found to be increased with an increase in post-annealing temperature. The optical band gap of Te-doped ZnO annealed films was found to be increased from 3.225 to 3.281 eV. Photoluminescence (PL) intensity of ultraviolet and blue emission measurements of the thin films was obtained in the spectral range from 350 to 600 nm.