Review—Group III-Nitride-Based Ultraviolet Light-Emitting Diodes: Ways of Increasing External Quantum Efficiency. (1st January 2017)

• Record Type: Journal Article
• Authors: Park, Jae-Seong; Kim, Jong Kyu; Cho, Jaehee; Seong, Tae-Yeon
• Is Part Of: ECS journal of solid state science and technology. Volume 6:Number 4(2017)
• Page Start: Q42
• Page End: Q52
• Publication Date: 2017-01-01
• Subjects: AlGaN -- electrical efficiency -- external quantum efficiency -- internal quantum efficiency -- Ultraviolet light-emitting diode; Solid state chemistry -- Periodicals; Electronics -- Materials -- Periodicals; Electrochemistry -- Periodicals; 541.0421
• DOI: 10.1149/2.0111704jss
• Languages: English
• ISSNs: 2162-8777

Abstract

Abstract : There is a rapidly growing demand for highly efficient ultraviolet (UV) light sources for a wide variety of applications. In particular, state-of-the-art AlGaN deep UV light-emitting diodes (DUV LEDs) exhibit inadequately low external quantum efficiencies (EQEs). The low efficiencies are attributed to the inherent material properties of high-Al-content AlGaN including strained epitaxial layers, low carrier concentrations, and strong transverse magnetic (TM)-polarized light emission. Extensive efforts have been made to tackle these challenging issues and technological developments have been achieved and enabled the fabrication of reasonable EQE LEDs. In this review, recent advances in the growth of high-quality AlGaN epitaxial layers, transparent and reflective ohmic contacts, and light extraction for AlGaN-based UV LEDs are reviewed.