title: The determining factor of a preferred orientation of GaN domains grown on m-plane sapphire substrates.
abstract: Epitaxial lateral overgrowth in tandem with the first-principles calculation was employed to investigate the determining factor of a preferred orientation of GaN on SiO2-patterned m-plane sapphire substrates. We found that the (1100)-orientation is favored over the (1103)-orientation in the region with a small filling factor of SiO2, while the latter orientation becomes preferred in the region with a large filling factor. This result suggests that the effective concentration determines the preferred orientation of GaN: the (1100)- and (1103)-orientations preferred at their low and high concentrations, respectively. Our computational study revealed that at a low coverage of Ga and N atoms, the local atomic arrangement resembles that on the (1103) surface, although the (1100) surface is more stable at their full coverage. Such a (1103)-like atomic configuration crosses over to the local structure resembling that on the (1100) surface as the coverage increases. Based on results, we determined that high effective concentration of Ga and N sources expedites the growth of the (1103)-orientation while keeping from transition to the (1100)-orientation. At low effective concentration, on the other hand, there is a sufficient time for the added Ga and N sources to rearrange the initial (1103)-like orientation to form the (1100)-orientation.
authors.affiliation: Department of Physics and Research Institute for Basic Sciences, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Korea.
authors.forename: Miyeon
authors.initials: M
authors.lastname: Jue
authors.affiliation: Department of Physics and Research Institute for Basic Sciences, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Korea.
authors.forename: Cheol-Woon
authors.initials: CW
authors.lastname: Kim
authors.affiliation: Department of Physics and Research Institute for Basic Sciences, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Korea.
authors.forename: Seoung-Hun
authors.initials: SH
authors.lastname: Kang
authors.affiliation: Department of Physics and Research Institute for Basic Sciences, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Korea.
authors.forename: Hansub
authors.initials: H
authors.lastname: Yoon
authors.affiliation: Department of Physics and Research Institute for Basic Sciences, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Korea.
authors.forename: Dongsoo
authors.initials: D
authors.lastname: Jang
authors.affiliation: Department of Physics and Research Institute for Basic Sciences, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Korea.
authors.forename: Young-Kyun
authors.initials: YK
authors.lastname: Kwon
authors.affiliation: Department of Physics and Research Institute for Basic Sciences, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Korea.
authors.forename: Chinkyo
authors.initials: C
authors.lastname: Kim