Optical and electrical step-recovery study of minority-carrier transport in an InGaN/GaN quantum-well light-emitting diode grown on sapphire

摘要

Forward-to-reverse bias step-recovery experiments were performed on an InGaN/GaN single-quantum-well light-emitting diode grown on sapphire. With the quantum well sampling the minority-carrier hole density at a single position, the optical emission displayed a two-stage decay. Using a solution to the diffusion equation to self-consistently describe both the optical and electrical recovery data, we estimated values for the hole lifetime (758+/-44 ns), diffusion length (588+/-45 nm), and mobility (0.18+/-0.02 cm(2)/V s) in GaN grown on sapphire. This low value of the minority-carrier mobility may reflect trap-modulated transport, and the lifetime is suggestive of slow capture and emission processes occurring through deep levels. (C) 2004 American Institute of Physics.