Time-resolved photoluminescence spectroscopy of GaN excitonic transitions

It had been used to study the dynamics of the free and donor-bound exciton transitions in GaN epitaxial layers grown by metal-organic chemical vapor deposition (MOCVD). Luminescence spectra, recombination lifetimes of these transitions as well as their temperature dependencies had been measured, from which the radiative recombination lifetimes of about 0.12 ns for the neutral donor bound excitons and of about 0.4ns for the free excitons had been obtained. The observed high radiative recombination rates of these transitions imply superior optical properties of GaN, which promise many important optical device applications including efficient and fast UV-blue lasers based on GaN.