Anomalous temperature dependence of electroluminescence intensity in InGaN single quantum well diodes

Temperature dependence of electroluminescence (EL) spectral intensity of the super-bright green InGaN single quantum well (SQW) light emitting diodes (LEDs), fabricated by Nichia Chemical Industry Ltd., has been studied over a wide temperature range (T = 15-300K) and as a function of injection current level. It is found that, when T is decreased slightly to 140 K, the EL intensity efficiently increases probably due to reduced non-radiative recombination processes and/or increased carrier capture by the localized radiative recombination centers. However, by decreasing T, further, down to 15 K, it drastically decreases due to the reduced carrier capture and population, accompanying the disappearance of injection current dependent line shape changes (blue-shift) caused by band filling of the localized recombination centers, These results indicate that the efficient carrier capture by SQW is crucial to enhance the radiative recombination of injected carriers in the presence of the high dislocation density. (C) 2001 Elsevier Science B.V. All rights reserved.