Temperature dependence of electroluminescence intensity of green and blue InGaN single-quantum-well light-emitting diodes

Temperature dependence of electroluminescence (EL) spectral intensity of th e super-bright green and blue InGaN single-quantum-well (SQW) light-emittin g diodes has been studied over a wide temperature range (T=15-300 K) under a weak injection current of 0.1 mA. It is found that when T is slightly dec reased to 140 K, the EL intensity efficiently increases, as usually seen du e to the improved quantum efficiency. However, with further decrease of T d own to 15 K, it drastically decreases due to reduced carrier capture by SQW and trapping by nonradiative recombination centers. This unusual temperatu re-dependent evolution of the EL intensity shows a striking difference betw een green and blue SQW diodes owing to the different potential depths of th e InGaN well. The importance of efficient carrier capture processes by loca lized tail states within the SQW is thus pointed out for enhancement of rad iative recombination of injected carriers in the presence of the high-densi ty dislocations. (C) 2001 American Institute of Physics.