Temperature-dependent electroluminescenceintensity in green and blue (In,Ga)N multiple-quantum-well diodes

摘要

Electroluminescence (EL) intensity has been investigated ofgreen and blue (In,Ga)N multiple-quantum-well diodes grown on the c-plane sapphire over a wide temperature range and as a function of current between 0.01 and 10 mA. The EL intensity of the green diode with the p-(Al,Ga)N electron blocking layer does not show low-temperature quenching, especially atlow injection levels, previously observed for the blue (In,Ga)N quantum-well diodes. This finding rules out possibilities that the freeze-out of holes at deep Mg acceptor levels and the failure of hole injections through the p-(Al,Ga)N layer are directly responsible for the EL quenching at temperatures below 100 K. Variations of the EL efficiency with current level suggest that capture/escape efficiencies of injected carriers by the wells play an important role for the determination of EL external quantum efficiency.