Interfacial Charge Distribution-Dependent Modulation of Luminescence Characteristics of InGaN ∕ GaN Multiquantum-Barrier Heterosystems

Abstract

We have investigated the unique correlations between the excitonic characteristics and the interfacial charge distribution of multiple quantum well (MQW) light-emitting diodes (LEDs) over a broad range of temperatures. From the intensity–current–voltage characteristics of MQW LEDs, we observed a remarkable reduction and modulation in the distribution of the leakage charge over the light-emitting layer when adopting the multiquantum-barrier (MQB) structure. For nonunity ideality factors, which we extracted from current–voltage analyses, we found that it was the temperature that determined the carrier transport mechanism in the heterodevices. Furthermore, carrier tunneling processes, determined from the extent of charge accumulation, led to more-anomalous values of the pseudotemperature and characteristic energy , which resulted from an abnormal deterioration of the luminescence intensities for a low effective density of states (DOS). We found that low-indium-content MQB devices exhibited inherently low values of over a broad range of temperatures. These values were associated with a low characteristic energy, a low charge population of the multilayer interface states, and a more-effective DOS. The signal intensity in the temperature-dependent electroluminescence spectrum deteriorated considerably at temperatures below , consistent with the presence of a greater number of charges at a higher value of .