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

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±44ns), diffusion length (588±45nm), and mobility (0.18±0.02cm2∕Vs) 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.