Investigation of structural and optical properties of ZnTiO3 thin films irradiated with 50 MeV oxygen ions

This paper aims to investigate the effects of high-energy ion irradiation on the structural, morphological, optical, and luminescent characteristics of ZnTiO3 (ZTO) films. ZTO films were grown on silicon and quartz substrates via RF magnetron sputtering in pure argon ambiance and annealed at 800 degrees C for crystallization. The annealed (pristine) samples were irradiated with 50 MeV oxygen ions at three distinct fluences: 1 x 1012, 5 x 1012, and 1 x 1013 ions/cm2. X-ray diffraction (XRD) data demonstrates that the intensity of highly oriented (311) peak first increases with fluence up to 5 x 1012 and then decreases at 1 x 1013 ions/cm2. The root mean square roughness (RMS) increases initially from 8.22 (pristine) to 9.10 nm (1 x 1012 ions/cm2) and decreases to 8.25 nm for 1 x 1013 ions/cm2 fluence. Transmittance spectra indicate an enhancement in the transmission of irradiated films. The calculated band gap of pristine and irradiated films lies in the range of 3.93-3.84 eV. X-ray photoelectron spectroscopy (XPS) analysis reveals a reduction in oxygen vacancies up to a fluence of 5 x 1012 and then rises at 1 x 1013 ions/cm2. The enhancement of peak intensity is observed in photoluminescence (PL) spectra on increasing the ion fluence due to a reduction in the non-radiative recombination centers.