Improvement of light-extraction efficiency of deep-UV LEDs using transparent p-AlGaN contact layer

Author

Maeda, Noboru ; Hirayama, Hiroshi

Author_Institution

RIKEN, Wako, Japan

fYear

2013

fDate

June 30 2013-July 4 2013

Firstpage

1

Lastpage

2

Abstract

We demonstrated deep-ultraviolet light-emitting diodes (DUV-LEDs) with emission wavelengths at around 285 nm using transparent p-AlGaN contact layer and reflective p-type electrode. The reflectivity of p-type electrode was increased from 30% to approximately 70% by introducing Ni(1nm)/Al metal layers. The external quantum efficiency (EQE) of the 288 nm LED was increased from 1.9% to 2.5% by replacing conventional p-GaN contact layer by transparent p-AlGaN contact layer. The increase of light extraction efficiency (LEE) was estimated to be by 1.5 times. We finally achieved EQE of 5% in DUV-LED by improving both of LEE and electron injection efficiency (EIE). The EQE of DUV-LED would be much increased by optimizing the device structure and by combining with other approaches.

Keywords

III-V semiconductors; aluminium compounds; gallium compounds; light emitting diodes; transparency; wide band gap semiconductors; AlGaN; deep-UV LED; deep-ultraviolet light-emitting diodes; electron injection efficiency; external quantum efficiency; light extraction efficiency; light-extraction efficiency; reflective p-type electrode; reflectivity; transparent contact layer; wavelength 288 nm; Aluminum gallium nitride; Electrodes; Gold; III-V semiconductor materials; Light emitting diodes; Nickel; Substrates; AlGaN DUV LED; light-extraction efficiency; p-AlGaN contact layer;

fLanguage

English

Publisher

ieee

Conference_Titel

Lasers and Electro-Optics Pacific Rim (CLEO-PR), 2013 Conference on

Conference_Location

Kyoto

Type

conf

DOI

10.1109/CLEOPR.2013.6600209

Filename

6600209