High-Performances AlGaN-based DUV-LED via Under-Level Multiple Quantum Well Configuration

TL;DR

This paper presents a novel under-level MQW design for AlGaN-based DUV-LEDs that significantly improves efficiency and light output by mitigating polarization effects and carrier confinement issues.

Contribution

The study introduces an under-level MQW configuration for DUV-LEDs, demonstrating substantial efficiency enhancements over traditional above-level structures.

Findings

Quantum efficiencies increased nine-fold

Luminescence intensity improved ten-fold

Light output power increased five-fold

Abstract

Low internal and external quantum efficiencies in high Aluminium content AlGaN-based deep-ultraviolet light-emitting diode (DUV-LED) occurred due to strong polarization effects, spontaneous and piezoelectric polarization, at the interface between two materials. It also leads to a low carrier confinement and Quantum Confined Stark Effect (QCSE), contributing to the efficiency droop of the DUV-LED. This work demonstrates an under-level MQW configuration implemented in a DUV-LED with a 257 nm emission wavelength. Three DUV-LED structures, above-, same- and under-level MQW were investigated, covering important optoelectronics properties such as energy band diagram, carrier concentrations, radiative recombination rates and electric field distribution. It is found that the quantum efficiencies, luminescence intensity and light output power of the under-level configuration has been enhanced by nine-, ten- and five-folds, relative to the above-level MQW configuration.