TY - JOUR
T1 - First-principle study of ammonia decomposition and nitrogen incorporation on the GaN surface in metal organic vapor phase epitaxy
AU - Bui, Kieu My
AU - Iwata, Jun Ichi
AU - Kangawa, Yoshihiro
AU - Shiraishi, Kenji
AU - Shigeta, Yasuteru
AU - Oshiyama, Atsushi
N1 - Funding Information:
This work was partly supported by MEXT through its projects, ‘‘Social and Scientific Priority Issue: Creation of New Functional Devices and High-Performance Materials to Support Next-Generation Industries by post-K Computer” and ‘‘Program for Research and Development of Next-Generation Semiconductors to Realize an Energy-Saving Society”. Computations were performed mainly at the Supercomputer Center at the Institute for Solid State Physics, The University of Tokyo, The Research Center for Computational Science, National Institutes of Natural Sciences, and the Center for Computational Science, University of Tsukuba.
Publisher Copyright:
© 2018 Elsevier B.V.
PY - 2019/2/1
Y1 - 2019/2/1
N2 - Based on the density functional theory (DFT), we theoretically investigate the growth mechanism of GaN (0001) using the Metal-Organic Vapor-Phase Epitaxy (MOVPE). We first identify the structure of the growing Ga rich GaN (0001) surface, then study the adsorption of NHx (x = 0–3) on such surface. We find that NH2 and NH units spontaneously intervene in the Ga-Ga weak bonds on the Ga-rich GaN (0001) surface. A reaction pathway of decomposition of NH3 on Ga rich surface is revealed. During reaction, N is found to incorporate in the weak Ga-Ga bond and form – Ga – (NH) – Ga – structure. The activation barrier of NH3 is surprisingly small, just 0.63 eV. We also explore the decomposition of NH2 to N to form Ga-N network and find the plausible reaction pathway with the energy barrier of 2 eV. Taking into account the chemical potential of an H2 molecule in the gas phase at the growth temperature, we find that this reaction can be overcome. This NH3 decomposition mechanism and the N incorporation on GaN is a new growth mechanism catalyzed by the growing surface.
AB - Based on the density functional theory (DFT), we theoretically investigate the growth mechanism of GaN (0001) using the Metal-Organic Vapor-Phase Epitaxy (MOVPE). We first identify the structure of the growing Ga rich GaN (0001) surface, then study the adsorption of NHx (x = 0–3) on such surface. We find that NH2 and NH units spontaneously intervene in the Ga-Ga weak bonds on the Ga-rich GaN (0001) surface. A reaction pathway of decomposition of NH3 on Ga rich surface is revealed. During reaction, N is found to incorporate in the weak Ga-Ga bond and form – Ga – (NH) – Ga – structure. The activation barrier of NH3 is surprisingly small, just 0.63 eV. We also explore the decomposition of NH2 to N to form Ga-N network and find the plausible reaction pathway with the energy barrier of 2 eV. Taking into account the chemical potential of an H2 molecule in the gas phase at the growth temperature, we find that this reaction can be overcome. This NH3 decomposition mechanism and the N incorporation on GaN is a new growth mechanism catalyzed by the growing surface.
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U2 - 10.1016/j.jcrysgro.2018.11.031
DO - 10.1016/j.jcrysgro.2018.11.031
M3 - Article
AN - SCOPUS:85058367959
SN - 0022-0248
VL - 507
SP - 421
EP - 424
JO - Journal of Crystal Growth
JF - Journal of Crystal Growth
ER -