Electrical Characteristics of InGaN/AlGaN and InGaN/GaN MQW Near UV-LEDs

Electrical characteristics of In_0.05Ga_0.95N/Al_0.07Ga_0.93N and In_0.05Ga_0.95N/GaN multiple quantum well (MQW) ultraviolet light-emitting diodes (UV-LEDs) at 400nm wavelength are measured. It is found that for InGaN/AlGaN MQW LEDs, both ideality factor and parallel resistance are similar to those of InGaN/GaN MQW LEDs, while series resistance is two times larger. It is suggested that the Al_0.07Ga_0.93N barrier layer did not change crystal quality and electrical characteristic of p-n junction either, but brought larger series resistance. As a result, InGaN/AlGaN MQW LEDs suffer more serious thermal dissipation problem although they show higher light output efficiency.