Performance enhancement of GaN/AlGaN multi-quantum-well ultraviolet light-emitting diodes by a novel p-type electron blocking layer with graded inverted V-shaped structure

To enhance the operational efficiency of GaN/AlGaN multi-quantum-well (MQWs) ultraviolet light-emitting diodes (UV-LEDs) and alleviate the adverse impacts of polarization electric fields, measures need to be taken to improve their performance. This study designed three different structures of p-type electron blocking layers (EBLs) by Silvaco ATLAS software and investigated the effects of the three different structures of p-type EBLs on the electroluminescence (EL) spectra, carrier concentration in the active region, optical output power and radiation recombination efficiency of GaN/AlGaN MQWs UV-LEDs. The simulation results demonstrate the effectiveness of the novel graded inverted V-shaped structure of EBL, which we designed to reduce band bending at the interface between the final quantum barrier and p-type EBL. As well as better prevent the leakage of electrons from the active region, that is, to increase the limitation of electrons and hole injection, increase the concentration of carriers in the MQWs and make the LED of this structure have better photoelectric performance. The emission peak of the LED is 351 nm when the injected current is 200 mA, the full width at half maximum is roughly 9.1 nm and the output power is 450 mW, using this structure, the optical output power can be boosted by 29.3%. The proposed research is based on a GaN/AlGaN MQWs LED structure, but this research can be extended to various combinations of semiconductor structures.