Effects of Energetic Ion Irradiation on β-Ga<sub>2</sub>O<sub>3</sub> Thin Films
Saurabh Yadav, Shubhra Dash, Asit Patra, G.R. Umapathy, Sunil Ojha, Shiv P. Patel, Rakesh Kumar Singh, Y. S. Katharria
Abstract
In the present work, effect of swift heavy ion (SHI) irradiation on structural and optical properties of β -Ga 2 O 3 thin films was investigated. Different ion fluences ( ϕ ) of 120 MeV Ag 9+ ions ranging from 1 × 10 11 ions-cm −2 to 5 × 10 12 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 -Ga 2 O 3 phase having a bandgap of ∼5.14 eV. An increase in the structural disorder, and decrease in the average crystallites size of β -Ga 2 O 3 with increasing ϕ was also revealed by XRD. Ga 2 O 3 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 -Ga 2 O 3 was observed through Raman spectroscopy. Scanning electron micrograph (SEM) images suggested that the films were fairly smooth.