(Invited) DLTS Studies of Defects in n-GaN

We have studied electron and hole traps in Si-doped n-GaN grown by metal organic chemical vapor deposition on n+-GaN, sapphire, SiC and Si substrates. DLTS using bias pulses, MCTS using above-band-gap light pulses and ODLTS using below-band-gap light pulses have been employed for fabricated Schottky diodes. The energy levels and capture cross sections of four electron traps and three hole traps are reported. A variation of dominant traps in concentration between wafers and among diodes on each wafer is observed, which is discussed based on the dependence of trap concentrations on the growth conditions.