Temperature dependence of the optical properties of violet, blue and green InGaN/GaN single quantum well light-emitting diodes

摘要

Temperature dependence of the optical properties of InGaN/GaN single quantum well light-emitting diodes (LEDs) with different indium (In) contents is investigated by using the effective mass theory taking into account the band-gap shrinkage and lattice thermal expansion. The peak intensity of the spontaneous emission spectrum is decreased by 30.6%, 30.4%, and 30.3% for the violet, blue, and green LEDs in the temperature range 300 K-400 K, while the reductions of internal quantum efficiency (eta) with temperature are similar to 0.13, similar to 0.11, and similar to 0.1 respectively at the injection current density of 100 A cm(-2). Moreover, two different slopes for all the eta-T curves are observed: a lower absolute value of the slopes at T = 300-350 K; a larger absolute value of the slopes at T = 350-400 K. The numerical results also indicate that the efficiency droop effect with increasing the temperature becomes more serious, especially for the InGaN/GaN LED structures with the lower In-content.