Influence of Cu doping on structure, morphology and optical characteristics of SnO2 thin films prepared by chemical bath deposition technique

Abstract

This paper reports various properties of four Cu-doped SnO2 thin films (hereafter called CuSnO-TFs) synthesized on glass substrate at temperature 80 °C via the standard chemical bath deposition method. The as-deposited films were annealed at 400 °C for 1 h. The as-prepared samples were characterized at room temperature using different analytical tools to determine the effects of varying Cu doping contents (0–3 wt%) on their structures, morphologies, and optical characteristics. The XRD analyses of the studied CuSnO-TFs showed their body-centered tetragonal structures in rutile phase with high purity and good polycrystallinity. The average crystallite size was increased from 17.6 to 34.52 nm with the increase of Cu contents from 0 to 3%, respectively. The SEM images of the grown films revealed agglomerated morphologies with the nucleation of spherical clusters or granules. Both visible transmittance and optical band gap energies of the films were decreased with the increase of Cu levels. In addition, the values of the refractive index, extinction coefficient, and dielectric constant of the deposited films were gradually increased and shifted towards higher wavelengths with the increase of Cu doping proportion. It was shown that by tuning the Cu contents overall properties of the proposed SnO2 thin films can be customized which are desired for diverse functional applications.