Structural optimization of indium oxide thin film for gamma dosimetry applications

Abstract

Structural optimization of Indium oxide (INO) thin films was carried out with different deposition parameters for gamma sensing applications. Indium oxide films had been deposited on glass substrates by spray pyrolysis technique for three different concentrations of precursor solution and two different substrate temperatures. XRD spectra confirm the polycrystallinity and cubic structure of INO with a dependency of preferred orientation on both substrate temperature and thickness of the thin film. Raman analysis was done to study the structural information and to obtain the phonon modes present in the thin films. Phonon modes corresponding to cubic In2O3 were detected in Raman spectra. The morphological study revealed the change of grain shape with the preferred orientation. EDAX spectra validate the presence of Indium and Oxygen in the film. 0.1 M sample deposited at 4500C showed higher transmittance of about 75%. Direct and indirect bandgap energy were estimated for which it increased with an increment in substrate temperature and also decreased with an increment in molar concentration. Urbach energy shows an inverse relation with bandgap energy. PL spectra exhibit blue emissions implying the presence of oxygen vacancies or lattice defects along with Near band edge (NBE) emission. The presence of In and O was quantified, and chemical states were identified using XPS measurements. Electrical measurements ensure the good conductivity of prepared films. Thermoluminescence studies were carried out to confirm the suitability of the prepared film for dosimetry applications.