Bound exciton dynamics in GaN grown by hydride vapor-phase epitaxy

Temperature-dependent time-resolved photoluminescence measurements were per formed on thick GaN layers grown by hydride vapor-phase epitaxy on Al2O3 su bstrates. Radiative lifetimes were determined for the neutral-donor-bound e xciton with position at 3.478 eV and for two neutral-acceptor-bound exciton s at 3.473 and 3.461 eV. We report a value of 3600 ps for the radiative lif etime of the acceptor-bound exciton transition at 3.461 eV. The dominant me chanism responsible for the nonradiative recombination of the bound exciton s is shown to be connected with dissociation of the bound excitons into fre e excitons. (C) 1999 American Institute of Physics. [S0003-6951(99)00752-4] .