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Advances in Condensed Matter Physics
Volume 2014, Article ID 671210, 5 pages
http://dx.doi.org/10.1155/2014/671210
Research Article

Spatially Resolved Cathodoluminescence in the Vicinity of Defects in the High-Efficiency InGaN/GaN Blue Light Emitting Diodes

1Department of Electrical and Computer Engineering, Ajou University, Suwon 443-749, Republic of Korea
2Department of Energy Science, Sungkyunkwan University, Suwon 440-746, Republic of Korea

Received 24 May 2014; Revised 14 August 2014; Accepted 20 August 2014; Published 1 September 2014

Academic Editor: Mohindar S. Seehra

Copyright © 2014 Manh-Ha Doan and Jaejin Lee. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

In addition to the standard 447 nm blue emission from the InGaN/GaN multiple quantum wells, a high-energy shoulder is clearly observed in cathodoluminescence spectra of the high-efficiency InGaN/GaN blue light emitting diodes grown on sapphire substrates by metalorganic chemical vapor deposition. Monochromatic cathodoluminescence images of the samples measured at low temperature reveal a competition between the two emissions in the vicinity of the dislocations. The high-energy emission is dominant at the regions near the dislocation cores, while the blue emission is enhanced around the dislocation edges. The high-energy emission region is considered as a potential barrier that prevents the carriers for the blue emission from nonradiatively recombining at the dislocations.