Engineering of physical properties of spray-deposited nanocrystalline Sb2O3 thin films by phase transformation

Abstract

Nanostructured Sb2O3 thin films have been deposited onto glass substrates by using the chemical spray pyrolysis technique, and the effect of precursor solution volume on the physical properties was investigated for the first time. The prepared films were characterized in detail by using x-ray diffraction, field-emission scanning electron microscopy with energy dispersive x-ray analysis (FESEM-EDAX), UV-vis absorption and transmission spectroscopy, Raman spectroscopy analysis and electrical resistivity measurement. X-ray diffraction analysis shows that the senarmontite cubic phase is completely transferred to the valentinite orthorhombic phase as the precursor solution volume is increased. This phase transformation as a function of precursor volume is discussed in detail. The FESEM-EDAX analysis reconfirms the phase change showing well-defined nano-dimensional cubic hexagonal and orthorhombic octahedral morphologies with excellent stoichiometry. The optical property studies show that the bandgap energy of Sb2O3 varies from 3.43–3.98 eV as a function of precursor quantity. The as-grown Sb2O3 thin films are semiconducting in nature. The measured values of electrical resistivity and activation energy are found to be dependent on the spray solution volume. The electrical resistivity of deposited Sb2O3 thin films shows variation from 26.15 × 102–34.27 × 102 Ω cm and the activation energy of the films is in the order of 0.763–0.773 eV.