Reaction Pathway of Surface-Catalyzed Ammonia Decomposition and Nitrogen Incorporation in Epitaxial Growth of Gallium Nitride

Kieu My Bui, Jun Ichi Iwata, Yoshihiro Kangawa, Kenji Shiraishi, Yasuteru Shigeta, Atsushi Oshiyama

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

We report density functional calculations that clarify atom-scale mechanisms of vapor-phase epitaxial growth of GaN with gas sources of trimethylgallium and ammonia. We identify various stable adsorption structures of a Ga atom and NHx molecules (x = 0-3) on GaN(0001) surfaces and find that NH2 and NH units spontaneously intervene in Ga-Ga surface bonds on Ga-rich GaN(0001) surface. We then explore the reaction in which NH3 on the surface is decomposed and becomes an N-incorporated structure, -Ga-(NH)-Ga-, on the Ga-rich GaN(0001) and find that the reaction occurs with the energy barrier of 0.63 eV. Further exploration reveals that a reaction of H2 desorption occurs with the energy barrier of 2 eV, leaving the N atom incorporated in the Ga-N network. This barrier can be overcome when we consider the chemical potential of an H2 molecule in the gas phase at the growth temperature. This N incorporation on GaN is a new growth mechanism catalyzed by the growing surface.

Original languageEnglish
Pages (from-to)24665-24671
Number of pages7
JournalJournal of Physical Chemistry C
Volume122
Issue number43
DOIs
Publication statusPublished - Nov 1 2018

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

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