Influence of Precursor Concentration on Sprayed In2O3 Thin Films

Abstract

Indium oxide (In₂O₃) thin films have been deposited on borosilicate substrate by spray pyrolysis technique using indium acetate as a precursor solution. The influence of precursor concentration was studied in the range of 0.025-0.15 M with substrate temperature 450 ºC. The deposited films were characterized by using X-ray diffraction, scanning electron microscope with EDAX, atomic force microscope, UV-visible spectrophotometer and photoluminescence. The XRD analysis indicated that the films were highly preferential grain orientation along (222) plane with cubic crystal structure. The surface morphology, grain size and roughness of the films were observed by SEM and AFM. The UV-visible spectroscopy revealed that the films had high transmittance in the visible region above >75 % and the optical band gap values were found to be in the range of 3.48-3.68 eV. The optical constants such as refractive index (n), extinction coefficient (k) and real and imaginary parts of dielectric constants (e) were evaluated from transmittance and reflectance data. The photoluminescence was studied at room temperature with a 325 nm as excitation wavelength.