An atomistic insight into reactions and free-energy profiles of NH3 and Ga on GaN surfaces during the epitaxial growth

Mauro Boero, Kieu My Bui, Kenji Shiraishi, Kana Ishisone, Yoshihiro Kangawa, Atsushi Oshiyama

研究成果: ジャーナルへの寄稿学術誌査読

抄録

Precursor molecules (NH3 and Ga compounds) along with carrier gas (H2 or N2) used to grow GaN structures bring a large amount of hydrogen atoms which affect the growing mechanism of GaN. This has a non-negligible effect of the chemistry and diffusivity of precursors and dissociation products. To encompass the experimentally difficulty in of unraveling such a complicated reaction mechanism, we resort to first principles molecular dynamics modeling, providing an atomistic insight into two major issues. The first one is the evolution of H atoms after the adsorption and dissociation of NH3 on the growing GaN surface. The second issue is to shed light on the role of passivating hydrogen at growth conditions for a typical GaN Ga-rich (0001) surface. In the first case, reaction pathways alternative to the product of molecular hydrogen (H2) can be realized, depending on the initial conditions and morphology of the surface, resulting in an adsorption of H atoms, thus contributing to its hydrogenation. In the second one, instead, we show how the presence of passivating H atoms at the surface, corresponding to a relatively high degree of hydrogenation, contribute to limit the diffusivity of Ga adatoms at the typical growth temperatures.

本文言語英語
論文番号153935
ジャーナルApplied Surface Science
599
DOI
出版ステータス出版済み - 10月 15 2022
外部発表はい

!!!All Science Journal Classification (ASJC) codes

  • 化学 (全般)
  • 凝縮系物理学
  • 物理学および天文学(全般)
  • 表面および界面
  • 表面、皮膜および薄膜

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