Buffer design for nitrogen polarity GaN on sapphire ( 0 0 0 1 ) by RF-MBE and application to the nanostructure formation using KOH etching

Ryuji Katayama, Kentaro Onabe

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)

Abstract

GaN films were grown by radiofrequency plasma-assisted molecular beam epitaxy on a variety of sapphire ( 0 0 0 1 ) substrates with different buffer layer and/or preparation processes, to show the controllability of lattice-polarity selection as well as their applicability to the nanostructure fabrication. Film polarities, which have been checked by reflection high-energy electron diffraction reconstructions and etched morphologies in KOH aqueous solution, were very sensitive to these preparation processes. Ga-polarity GaN could be obtained by an introduction of a high-temperature nitridation and an AlN interlayer deposition, and the N-polarity film with a flat surface and large grains could be grown on a low-temperature-nitrided sapphire in combination with a use of nitrogen-flux modulation sequence, while other pretreatment resulted in the mixed polarities. The resultant morphology of N-polarity GaN after KOH etching clearly reflects crystallographic orientation and the highly anisotropic-etching behavior show the usefulness of the low-temperature-nitrided sapphire for obtaining large-domain N-polarity GaN and the feasibility of nanostructure fabrication without the use of an expensive dry-etching process.

Original languageEnglish
Pages (from-to)245-248
Number of pages4
JournalPhysica E: Low-Dimensional Systems and Nanostructures
Volume32
Issue number1-2 SPEC. ISS.
DOIs
Publication statusPublished - 2006 May 1

Keywords

  • GaN
  • KOH etching
  • Polarity
  • RF-MBE

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics

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