Optical and electrical properties of 80 MeV Si8+ ions irradiated Ga-doped zinc stannate films

Abstract

We studied the effects of 80 MeV Si\(^{8+}\) ions on the structural characteristics, surface morphology, optical and electrical properties of 200 nm thick Ga-doped zinc stannate films, fabricated using the pulsed laser deposition technique. The analysis of the glancing incidence X-ray diffraction patterns reveal that the pristine crystalline films became amorphous after Si\(^{8+}\) ion irradiation, and the surface images from atomic force microscopy display an enhancement in surface roughness with increasing ion fluences. The optical studies show a decrease in the bandgap from 3.62 to 3.42 with irradiation and quenching of the luminescent defects deep in the bandgap. The resistivity of the films decreased with Ga-doping and swift heavy ion (SHI) irradiation. These modifications in the physical properties due to irradiation are understood based on irradiation induced amorphization and thermal spike model. It was found that Ga-doping and SHI irradiation produce similar effects on the electrical and optical properties of the zinc stannate films. These amorphous films may provide a better alternative to the crystalline zinc stannate films, which have potential applications as transparent conducting oxide.