skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: High power ultraviolet light emitting diodes based on GaN/AlGaN quantum wells produced by molecular beam epitaxy

Abstract

In this paper, we report on the growth by molecular beam epitaxy and fabrication of high power nitride-based ultraviolet light emitting diodes emitting in the spectral range between 340 and 350 nm. The devices were grown on (0001) sapphire substrates via plasma-assisted molecular beam epitaxy. The growth of the light emitting diode (LED) structures was preceded by detailed materials studies of the bottom n-AlGaN contact layer, as well as the GaN/AlGaN multiple quantum well (MQW) active region. Specifically, kinetic conditions were identified for the growth of the thick n-AlGaN films to be both smooth and to have fewer defects at the surface. Transmission-electron microscopy studies on identical GaN/AlGaN MQWs showed good quality and well-defined interfaces between wells and barriers. Large area mesa devices (800x800 {mu}m{sup 2}) were fabricated and were designed for backside light extraction. The LEDs were flip-chip bonded onto a Si submount for better heat sinking. For devices emitting at 340 nm, the measured differential on-series resistance is 3 {omega} with electroluminescence spectrum full width at half maximum of 18 nm. The output power under dc bias saturates at 0.5 mW, while under pulsed operation it saturates at approximately 700 mA to a value of 3 mW, suggestingmore » that thermal heating limits the efficiency of these devices. The output power of the investigated devices was found to be equivalent with those produced by the metal-organic chemical vapor deposition and hydride vapor-phase epitaxy methods. The devices emitting at 350 nm were investigated under dc operation and the output power saturates at 4.5 mW under 200 mA drive current.« less

Authors:
; ; ; ; ; ;  [1]
  1. Department of Electrical and Computer Engineering, Boston University, Boston, Massachusetts 02215 and Center of Photonics Research, Boston University, Boston, Massachusetts 02215 (United States)
Publication Date:
OSTI Identifier:
20884894
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 100; Journal Issue: 10; Other Information: DOI: 10.1063/1.2388127; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALUMINIUM NITRIDES; CHEMICAL VAPOR DEPOSITION; CRYSTAL GROWTH; ELECTRIC CONDUCTIVITY; ELECTROLUMINESCENCE; FABRICATION; GALLIUM NITRIDES; LAYERS; LIGHT EMITTING DIODES; MOLECULAR BEAM EPITAXY; QUANTUM WELLS; SAPPHIRE; SEMICONDUCTOR MATERIALS; SILICON; SUBSTRATES; THIN FILMS; TRANSMISSION ELECTRON MICROSCOPY; ULTRAVIOLET RADIATION; VAPOR PHASE EPITAXY

Citation Formats

Cabalu, J S, Bhattacharyya, A, Thomidis, C, Friel, I, Moustakas, T D, Collins, C J, Komninou, Ph, U.S. Army Research Laboratory, Adelphi, Maryland 20783, and Physics Department, Aristotle University, 54124 Thessaloniki. High power ultraviolet light emitting diodes based on GaN/AlGaN quantum wells produced by molecular beam epitaxy. United States: N. p., 2006. Web. doi:10.1063/1.2388127.
Cabalu, J S, Bhattacharyya, A, Thomidis, C, Friel, I, Moustakas, T D, Collins, C J, Komninou, Ph, U.S. Army Research Laboratory, Adelphi, Maryland 20783, & Physics Department, Aristotle University, 54124 Thessaloniki. High power ultraviolet light emitting diodes based on GaN/AlGaN quantum wells produced by molecular beam epitaxy. United States. doi:10.1063/1.2388127.
Cabalu, J S, Bhattacharyya, A, Thomidis, C, Friel, I, Moustakas, T D, Collins, C J, Komninou, Ph, U.S. Army Research Laboratory, Adelphi, Maryland 20783, and Physics Department, Aristotle University, 54124 Thessaloniki. Wed . "High power ultraviolet light emitting diodes based on GaN/AlGaN quantum wells produced by molecular beam epitaxy". United States. doi:10.1063/1.2388127.
@article{osti_20884894,
title = {High power ultraviolet light emitting diodes based on GaN/AlGaN quantum wells produced by molecular beam epitaxy},
author = {Cabalu, J S and Bhattacharyya, A and Thomidis, C and Friel, I and Moustakas, T D and Collins, C J and Komninou, Ph and U.S. Army Research Laboratory, Adelphi, Maryland 20783 and Physics Department, Aristotle University, 54124 Thessaloniki},
abstractNote = {In this paper, we report on the growth by molecular beam epitaxy and fabrication of high power nitride-based ultraviolet light emitting diodes emitting in the spectral range between 340 and 350 nm. The devices were grown on (0001) sapphire substrates via plasma-assisted molecular beam epitaxy. The growth of the light emitting diode (LED) structures was preceded by detailed materials studies of the bottom n-AlGaN contact layer, as well as the GaN/AlGaN multiple quantum well (MQW) active region. Specifically, kinetic conditions were identified for the growth of the thick n-AlGaN films to be both smooth and to have fewer defects at the surface. Transmission-electron microscopy studies on identical GaN/AlGaN MQWs showed good quality and well-defined interfaces between wells and barriers. Large area mesa devices (800x800 {mu}m{sup 2}) were fabricated and were designed for backside light extraction. The LEDs were flip-chip bonded onto a Si submount for better heat sinking. For devices emitting at 340 nm, the measured differential on-series resistance is 3 {omega} with electroluminescence spectrum full width at half maximum of 18 nm. The output power under dc bias saturates at 0.5 mW, while under pulsed operation it saturates at approximately 700 mA to a value of 3 mW, suggesting that thermal heating limits the efficiency of these devices. The output power of the investigated devices was found to be equivalent with those produced by the metal-organic chemical vapor deposition and hydride vapor-phase epitaxy methods. The devices emitting at 350 nm were investigated under dc operation and the output power saturates at 4.5 mW under 200 mA drive current.},
doi = {10.1063/1.2388127},
journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 10,
volume = 100,
place = {United States},
year = {2006},
month = {11}
}