Performance improvement of light-emitting diodes with W-shaped InGaN/GaN multiple quantum wells

Abstract

Using APSYS simulation program, we investigate the optical performance of InGaN/GaN multiple quantum well (MQW) blue light-emitting diodes (LEDs) with a W-shaped well structure with respect to optical output power and internal quantum efficiency with variation in injection current. The concept of W-shaped quantum well is proposed to lower the polarization field and to obtain better overlapping between the peaks of electron and hole concentrations. Our proposed LED with W-shaped quantum wells exhibits 91% improvement in output power as compared to a rectangular quantum well LED. Furthermore, our proposed LED shows 20% efficiency drooping in contrast to 49% with a conventional LED at an input current = 120 mA. Moreover, we analyze our results with the help of band diagram, electron and hole concentrations, and also radiative recombination rate in the wells obtained from numerical simulation program.