Open AccessAdvantages of AlGaN-based deep-ultraviolet light-emitting diodes with an Al-composition graded quantum barrier
Author(s) -
Huabin Yu,
Zhongjie Ren,
Haochen Zhang,
Jiangnan Dai,
Chang Chen,
Shibing Long,
Haiding Sun
Publication year - 2019
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.27.0a1544
Subject(s) - light emitting diode , materials science , optoelectronics , quantum efficiency , diode , ultraviolet , quantum well , spontaneous emission , optics , quantum dot , electron , physics , laser , quantum mechanics
AlGaN-based deep-ultraviolet light-emitting diodes (DUV LEDs) still suffer from poor quantum efficiency and low optical power. In this work, we proposed a DUV LED structure that includes five unique Al x Ga 1-x N quantum barriers (QBs); Each QB has a linear-increment of Al composition by 0.03 along the growth direction, unlike those commonly used flat QBs in conventional LEDs. As a result, the electron and hole concentration in the active region was considerably increased, attributing to the success of the electron blocking effect and enhanced hole injection efficiency. Importantly, the optical power was remarkably improved by 65.83% at the injection current of 60 mA. After in-depth device optimization, we found that a relatively thinner graded QB layer could further boost the LED performance because of the increased carrier concentrations and enhanced electron and hole wave function overlap in the QW, triggering a much higher radiative recombination efficiency. Hence, the proposed graded QBs, which have a continuous increment of Al composition along the growth direction, provide us with an effective solution to boost light output power in the pursuit of high-performance DUV emitters.