Effects of Energetic Ion Irradiation on β-Ga2O3 Thin Films

Abstract

In the present work, effect of swift heavy ion (SHI) irradiation on structural and optical properties of β-Ga2O3 thin films was investigated. Different ion fluences (ϕ) of 120 MeV Ag9+ ions ranging from 1 × 1011 ions-cm−2 to 5 × 1012 ions-cm−2 were employed. The films were grown at room temperature (RT) using electron beam evaporation method and post-deposition annealing was done at 900 °C in oxygen atmosphere. X-ray diffraction (XRD) and UV–visible (UV-Vis) spectroscopy data confirmed the formation of polycrystalline β-Ga2O3 phase having a bandgap of ∼5.14 eV. An increase in the structural disorder, and decrease in the average crystallites size of β-Ga2O3 with increasing ϕ was also revealed by XRD. Ga2O3 thin films showed high transparency in the UV (upto 280 nm) and visible range with average transmittance of ∼80%. Rutherford backscattering spectrometry (RBS) revealed that the thin films were slightly O deficient. A low frequency vibration mode at 170 cm−1 arising from liberation and translation of tetrahedra-octahedra chains in β-Ga2O3 was observed through Raman spectroscopy. Scanning electron micrograph (SEM) images suggested that the films were fairly smooth.