Calculating the Effect of AlGaN Dielectric Layers in a Polarization Tunnel Junction on the Performance of AlGaN-Based Deep-Ultraviolet Light-Emitting Diodes

Abstract

In this work, AlGaN-based deep-ultraviolet (DUV) light-emitting diodes (LEDs) with AlGaN as the dielectric layers in p+-Al0.55Ga0.45N/AlGaN/n+-Al0.55Ga0.45N polarization tunnel junctions (PTJs) were modeled to promote carrier tunneling, suppress current crowding, avoid optical absorption, and further enhance the performance of LEDs. AlGaN with different Al contents in PTJs were optimized by APSYS software to investigate the effect of a polarization-induced electric field (Ep) on hole tunneling in the PTJ. The results indicated that Al0.7Ga0.3N as a dielectric layer can realize a higher hole concentration and a higher radiative recombination rate in Multiple Quantum Wells (MQWs) than Al0.4Ga0.6N as the dielectric layer. In addition, Al0.7Ga0.3N as the dielectric layer has relatively high resistance, which can increase lateral current spreading and enhance the uniformity of the top emitting light of LEDs. However, the relatively high resistance of Al0.7Ga0.3N as the dielectric layer resulted in an increase in the forward voltage, so much higher biased voltage was required to enhance the hole tunneling efficiency of PTJ. Through the adoption of PTJs with Al0.7Ga0.3N as the dielectric layers, enhanced internal quantum efficiency (IQE) and optical output power will be possible.

Recent Progress in III‐Nitride Tunnel Junction Light‐Emitting Diodes

“…MOCVD gives good scalability, whereas the hydrogen-rich environment in MOCVD reactor is problematic and postgrowth The charged state densities of d) the space charges and e) the fixed space charges at the interfaces in TJs for structures A, B, and C at 0 V. Reproduced under the terms of the CC BY 3.0 license. [59] Copyright 2021, The Authors. Published by MDPI.…”

“…The intensity of E t is degraded by E p in high‐Al‐content AlGaN interlayer and enhanced by E p in the p + /n + ‐type layers, as shown in Figure 4c–e, which could lead to a more homogeneous lateral distribution of hole concentrations and radiative recombination along the horizontal direction in LEDs. [ 59 ] However, an increase in the Al content of AlGaN interlayer results in higher TJ resistance. Table 1 presents a variety of TJ structures reported in the literature, as well as their growth methods and specific resistances.…”

“…Figure 4. a-c) Distributions of the electric fields.The charged state densities of d) the space charges and e) the fixed space charges at the interfaces in TJs for structures A, B, and C at 0 V. Reproduced under the terms of the CC BY 3.0 license [59]. Copyright 2021, The Authors.…”

Series-Biased Micro-LED Array for Lighting, Detection, and Optical Communication

“…Owing to its low power consumption, fast response time, and remarkable luminous efficiency, micro-LED arrays based on gallium nitride (GaN) have emerged as a focal point of interest among researchers, particularly in the fields of high-speed visible light communication and cutting-edge lighting technologies [1][2][3][4][5]. These micro-LED arrays, each incorporating numerous micro-LEDs on a single chip, have the potential to improve optical communication.…”

Advantages of AlGaN Tunnel Junction in N-Polar 284 nm Ultraviolet-B Light Emitting Diode

“…27 Among numerous approaches being investigated, the III-nitride research community has been paying close attention to the use of N-polar AlGaN alloys as the fundamental components for UVB LEDs. [28][29][30] As opposed to metal-polar (Ga-polar) III-nitrides, Npolar III-nitride films have drawn interest because of their distinctive advantages which include reduced efficiency droop in the use of LEDs. 31,32 The N-polar device exhibits remarkably suppressed efficiency droop; the droop value decreases from 43.1% to 11.2%, showing the superior electrons blocking capability of the N-polar devise.…”