Effect of swift heavy ions of silver and oxygen on GaN

Gallium nitride semiconductors are in the focus of current research. Investigative studies have been carried out to understand the effect of swift heavy ions on metal organic chemical vapour deposition (MOCVD) grown GaN epilayers. Silver (Ag8+) and oxygen (O7+) ions at energy of 100 MeV and fluence of 1 × 1013 ions cm−2 were used in this study. Irradiated samples were characterized by atomic force microscopy (AFM), photoluminescence (PL) and UV–Visible optical absorption. Surface defects were observed from AFM images, which indicate increase in defects after Ag8+ ion irradiation when compared to as-grown GaN. However, with O7+ ion irradiation there is decrease in the surface defects and smoothening of the surface. The PL studies show that O7+ ion irradiation gives rise to red shift and the optical absorption studies provide evidence for the change in the band gap after ion irradiation.