Enhanced Internal Quantum Efficiency of Bandgap-Engineered Green W-Shaped Quantum Well Light-Emitting Diode

Muhammad Usman,Dong-Guang Zheng,Urooj Mushtaq,Muhammad Rafiq,Nazeer Muhammad,Dong-Pyo Han

doi:10.3390/app9010077

Abstract

To improve the internal quantum efficiency of green light-emitting diodes, we present the numerical design and analysis of bandgap-engineered W-shaped quantum well. The numerical results suggest significant improvement in the internal quantum efficiency of the proposed W-LED. The improvement is associated with significantly improved hole confinement due to the localization of indium in the active region, leading to improved radiative recombination rate. In addition, the proposed device shows reduced defect-assisted Shockley-Read-Hall (SRH) recombination rate as well as Auger recombination rate. Moreover, the efficiency rolloff in the proposed device is associated with increased built-in electromechanical field.

Highlights

Enhancing the internal quantum efficiency (IQE) of GaInN-based light-emitting diodes (LEDs) has been discussed in the literature for potential solid-state lighting applications [1,2,3]
Strong band-bending in W-LED is observed because of the increased electrostatic field, owing to the indium fluctuation i.e., 34%–28%–34%, which hinders carrier transport in the W-LED apart from the indium localization [28,29,31,32,45,47,48]
The enhancement in the light output power and the efficiency are associated with the improved radiative recombination rate and reduced defect-assisted internal quantum efficiency are associated with the improved radiative recombination rate and SRH, and the Auger recombination rates contribute in the proposed device

Summary

Introduction

Enhancing the internal quantum efficiency (IQE) of GaInN-based light-emitting diodes (LEDs) has been discussed in the literature for potential solid-state lighting applications [1,2,3]. There are multiple reports to improve the IQE of LEDs mainly by using nonpolar substrates [4,5] and bandgap engineering [6,7,8,9]. In comparison to the conventional rectangular quantum wells, it has been shown using triangular, staggered, dip-shaped, and trapezoidal wells that the electron-hole wavefunction overlap is significantly improved in the quantum wells (QWs), which leads to improved optoelectronic output of the device [11,25,26,27]. Most of the reported work on bandgap engineering is based on

Methods

Results

Conclusion