Impact of substrate temperature on physical properties of nebulizer spray deposited (222) oriented indium oxide thin films

Thin films of indium oxide (In₂O₃) compound on micro glass substrate were synthesized using the Nebulized Spray Pyrolysis (NSP) process at various substrate temperatures from 300 to 550 °C in steps of 50 °C. X-ray diffraction studies exposed the film's polycrystalline nature, with a cubic structure and a preferred orientation along the (222) plane. The optical spectra of these films have been measured in the 300–1100 nm wavelength range. Band gap values of more than 3.45 eV with direct allowed nature, Urbach energy values, and skin depth were observed for all the films. The surface composition of the elements was examined with the EDAX spectrum. Scanning electron microscope (SEM) pictures exhibited flower-like grains. By Hall effect measurement, the electrical parameters were examined which established that the films prepared at 500 °C substrate temperature possess a minimum resistivity of 1.05 × 10² Ω-cm with mobility of 155 cm²/Vs. The room-temperature photoluminescence spectra showed that all samples had four emission bands, including a prominent peak in the UV region at 361 nm.