Photoluminescence and photoluminescence excitation studies in 80 MeV Ni ion irradiated MOCVD grown GaN

We report damage creation and annihilation under energetic ion bombardment at a fixed fluence. MOCVD grown GaN thin films were irradiated with 80 MeV Ni ions at a fluence of 1 × 1013 ions/cm2. Irradiated GaN thin films were subjected to rapid thermal annealing for 60 s in nitrogen atmosphere to anneal out the defects. The effects of defects on luminescence were explored with photoluminescence measurements. Room temperature photoluminescence spectra from pristine sample revealed presence of band to band transition besides unwanted yellow luminescence. Irradiated GaN does not show any band to band transition but there is a strong peak at 450 nm which is attributed to ion induced defect blue luminescence. However, irradiated and subsequently annealed samples show improved band to band transitions and a significant decrease in yellow luminescence intensity due to annihilation of defects which were created during irradiation. Irradiation induced effects on yellow and blue emissions are discussed.

► MOCVD grown GaN samples are irradiated with 80 MeV Ni ions at room temperature.
► PL and PLE studies have been carried out for band to band, BL and YL emissions.
► Ni ions irradiated GaN shows BL band at 450 nm besides YL band.
► Radiation annealed Ga vacancies have quenching effect on YL intensity.
► We speculated that BL and YL are associated with N and Ga vacancies, respectively.