Fabrication and lasing characteristics of GaN nanopillars

Ming Hua Lo*, Yuh Jen Cheng, Hao-Chung Kuo, Shing Chung Wang

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

3 Scopus citations

Abstract

We report the fabrication of GaN nanopillars and their laser action characteristics under optical pumping measurement. The nanopillars were fabricated from a GaN epitaxial wafer by self-assembled Ni nanomasked etching, followed by epitaxial regrowth to form crystalline facets on the etched nanopillars. The regrowth process is intended to reduce surface defects created during ICP-RIE etching. The density of etched GaN nanopillars is about 8.5×108/cm2 and the diameter and height of GaN nanopillars are about 250 nm and 650 nm, respectively. The as grown GaN nanopillars exhibit a random distribution with hexagonal pillar geometry. The sample is optically excited by frequency tripled Nd:YAG pulsed laser. The Gaussian waist of pumping spot is 1.8 um. At low pumping intensity, the emission has a broad spontaneous emission spectrum with maximum at 363 nm. As pump intensity increases, a narrow peak at 363 nm emerges quickly from the broad spontaneous emission back ground. The lasing action occurs at threshold pump power density of 122 MW/cm2. The emission linewidth decreases with pumping power across threshold and reaches a lowest value of about 0.38 nm above threshold. The excitation-power-dependent spectra show that the lasing wavelength has a slight blue shift as pump power increases. We remark that this is due the band filling of the increasing excited carrier density.

Original languageEnglish
Title of host publicationGallium Nitride Materials and Devices VI
DOIs
StatePublished - 13 May 2011
EventGallium Nitride Materials and Devices VI - San Francisco, CA, United States
Duration: 24 Jan 201127 Jan 2011

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume7939
ISSN (Print)0277-786X

Conference

ConferenceGallium Nitride Materials and Devices VI
CountryUnited States
CitySan Francisco, CA
Period24/01/1127/01/11

Keywords

  • excitonic emission
  • GaN laser
  • GaN nanopillar

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