Time-resolved photoluminescence spectroscopy in GaN-based semiconductors with micron spatial resolution

Recombination dynamics in GaN-based layers have been studied by means of ph otoluminescence spectroscopy having spectral and spatial resolution. It was found that PL lifetime (tau(PL)) Of the epitaxially laterally overgrown Ga N (ELO-GaN), which consists of the regions with high (window) and low (wing ) threading dislocation density (DD), was dominated by the nonradiative rec ombination process at room temperature (RT), and that the tau(PL). measured at wing region (DD = 10(6) cm(-2)) was 86 ps which is slightly larger than the value (70 ps) at window region (DD = 10(8) cm(-2)). These indicate tha t threading dislocations limit hardly the emission efficiency even with the se DD-levels, and that the device performance is mainly limited by other ty pes of nonradiative recombination centers. (C) 2000 Elsevier Science B.V. A ll rights reserved.