The dependence of excitonic characteristics on the interface charge distribution with multiquantum barrier

Abstract

Unique correlations between the excitonic characteristics and hetero-interface charge distribution of InGaN/GaN multiple quantum well light-emitting diodes (LEDs) were investigated over a broad range of temperatures. The dependence of non-unity ideality factors extracted from the current-voltage analysis on temperature determines the carrier-transport mechanisms in the heterodevices. Furthermore, the carrier tunneling processes via the extent of the charge population consequently cause anomaly more pseudo-temperature (To) and further characteristic energy (Eo), result in the abnormal deterioration of the luminescence intensities with small effective density of state. With respect to conventional GaN barrier devices, low-indium MQB devices inherently exhibit a small To over a variety of temperature ranges. The small To associated with a small characteristic energy and charge population of the multilayer interface states is obtained for each sample at the higher temperature regime. Accordingly, the high-indium MQB ensemble manifests a relatively higher characteristic energy than does the low-indium MQB ensemble. The characteristic energy Eo for the LEDs with InxGa1-xN/GaN multiquantum barriers were found to be decreased as increased In composition of InxGa1-xN/GaN MQBs. Correspondingly, the temperature-dependent electroluminescence observations suggest that the characteristic energy Eo anomaly caused the spectral intensity to deteriorate.