Low-temperature electroluminescent behaviors of InGaN/GaN based nanorod light emitting diode arrays

Liang Yi Chen, Chun Hsiang Chang, Ying Yuan Huang, Jian Jang Huang

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

For InGaN/GaN based nanorod devices using top-down etching process, the optical output power is affected by non-radiative recombination due to sidewall defects (which decrease light output efficiency) and mitigated quantum confined Stark effect (QCSE) due to strain relaxation (which increases internal quantum efficiency). Therefore, the exploration of low-temperature optical behaviors of nanorod light emitting diodes (LEDs) will help identify the correlation between those two factors. In this work, low-temperature EL spectra of InGaN/GaN nanorod arrays was explored and compared with those of planar LEDs. The nanorod LED exhibits a much higher optical output percentage increase when the temperature decreases. The increase is mainly attributed to the increased carriers and a better spatial overlap of electrons and holes in the quantum wells for radiative recombination. Next, while the nanorod array shows nearly constant peak energy with increasing injection currents at the temperature of 300K, the blue shift has been observed at 190K. The results suggest that with more carriers in the quantum wells, carrier screening and band filling still prevail in the partially strain relaxed nanorods. Moreover, when the temperature drops to 77K, the blue shift of both nanorod and planar devices disappears and the optical output power decreases since there are few carriers in the quantum wells for radiative recombination.

Original languageEnglish
Title of host publicationEleventh International Conference on Solid State Lighting
DOIs
Publication statusPublished - 2011
Event11th International Conference on Solid State Lighting - San Diego, CA, United States
Duration: 2011 Aug 222011 Aug 24

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume8123
ISSN (Print)0277-786X

Conference

Conference11th International Conference on Solid State Lighting
Country/TerritoryUnited States
CitySan Diego, CA
Period11-08-2211-08-24

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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