Emission enhancement from nonpolar a-plane III-nitride nanopillar

Byung Jae Kim, Younghun Jung, Michael A. Mastro, Jennifer Hite, Neeraj Nepal, Charles R. Eddy, Jihyun Kim

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


A nonpolar a -plane GaN-based light emitting structure was patterned by self-assembled SiO2 nanosphere lithography and subsequent inductively coupled plasma (ICP) etch to define an array of nanopillar light emitters. The photoluminescence (PL) intensity was enhanced by ∼110% after the anisotropic ICP etch, compared with an unprocessed sample, which is attributed to a reduction in wave-guiding effects in the thin film. Additionally, the anisotropic ICP etch caused minimal wavelength shift in the dominant 3.34 eV near-bandedge radiative transition. A subsequent photoelectrochemical (PEC) etch process of the a -plane GaN nanopillars preferentially etched the underlying n -type layers, leaving a wider p -type cap. The n -type layers wet-etched by recession of the N-polar (000-1) plane (perpendicular to the a -plane growth axis) via formation of the distinctive pyramid-shaped facets. The PL intensity was enhanced by ∼168% after ICP and PEC etching although the peak emission occurred at a lower energy. The combination of nanosphere lithography and ICP was highly effective in improving the light extraction efficiency in a -plane nonpolar GaN-based light emitting diodes.

Original languageEnglish
Article number021004
JournalJournal of Vacuum Science and Technology B:Nanotechnology and Microelectronics
Issue number2
Publication statusPublished - 2011

Bibliographical note

Funding Information:
This research was supported by Future-based Technology Development Program (Nano Fields) through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (Grant No. 2010-0029328). The research at the U.S. Naval Research Laboratory was supported by the Office of the Naval Research.

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Process Chemistry and Technology
  • Surfaces, Coatings and Films
  • Electrical and Electronic Engineering
  • Materials Chemistry


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