Optical Properties of High Energy Tin (Sn 5+ ) Ion Irradiated Metal-Organic Chemical Vapor Deposition Grown GaN on Sapphire

Unintentionally doped n-type GaN(0001) epitaxial layers grown by metal-organic chemical vapor deposition (MOCVD) on sapphire substrates have been irradiated with 75 MeV Tin (Sn 5+ ) ion. Effect of different ion fluences at 10 11 , 10 12 and 10 13 cm -2 were studied by means of time correlated single photon counting (TCSPC), UV-visible optical spectroscopy and photoluminescence (PL) measurements at room temperature. The exponential decay of minority carrier life times was observed between 1910 and 1110 ps (pico-second) with increasing ion doses upto 10 13 cm -2 . High-energy irradiation with different ion fluences of GaN epitaxial layers creates midgap states in the material. Change in the absorption edges between 3.41 and 2.95 eV were observed by UV-absorption coefficient (α 2 ) method on increasing fluences rate. Band-edge and yellow emissions were recorded for all GaN samples by transient steady state PL measurement at room temperature.