Photoluminescence of localized excitons in pulsed-laser-deposited GaN

Continuous-wave photoluminescence (PL) and time-resolved photoluminescence of gallium nitride layers grown by pulsed laser deposition are compared. Th e temperature dependence of the photoluminescence decay time and the PL-int egrated intensity allows a determination of radiative and nonradiative time constants of GaN. We find that luminescence peaks centered at 3.360 and 3. 305 eV at low temperature can be attributed to recombination of excitons lo calized at extended defects. The photoluminescence radiative lifetime at ro om temperature is on the order of tens of ns. (C) 1998 American Institute o f Physics. [S0003-6951(98)00549-X].