Insight into the step flow growth of gallium nitride based on density functional theory
Insight into the step flow growth of gallium nitride based on density functional theory
复制标题
基于密度泛函理论洞察氮化镓阶梯流生长
DOI：
10.1016/j.apsusc.2022.155840
复制
发表时间：
2023
影响因子：
6.7
通讯作者：
Oshiyama Atsushi
中科院分区：
文献类型：
--
作者：
My Bui Kieu;Shiraishi Kenji;Oshiyama Atsushi
我们报道了基于密度泛函理论的第一性原理计算，阐明了在由Ga吸附原子和Ga-H结构基元组成的混合GaN（0001）表面上外延生长的机制。我们发现，源气体分子NH3分解的Ga吸附原子网站上的NH单元和由此产生的NH单元扩散在一个新发现的协调一致的方式，其中Ga吸附原子协助在NH扩散通过湮灭附近的悬挂键。我们还确定了H-覆盖的台阶边的结构，并得到它们的形成能。我们发现合理的反应途径附近的台阶边缘，其中NH单元和Ga吸附原子被纳入外延膜，形成新的单元的GaN。所获得的最终结构肯定是GaN外延生长的阶梯流动机制的表现。
We report the first-principles calculations based on the density-functional theory that elucidate the mechanism of the epitaxial growth on the mixed GaN (0001) surface which consists of the Ga-adatom and the Ga-H structural motifs. We find that the source-gas molecule NH3is decomposed on the Ga-adatom site to an NH unit and the resulting NH unit diffuses in a newly found concerted way in which the Ga adatom assists in the NH diffusion by annihilating dangling bonds nearby. We also identify the structures of the H-covered step edges and obtain their formation energies. We find plausible reaction pathways near the step edges in which the NH units and Ga adatoms are incorporated in the epitaxial films, forming new units of GaN. The obtained final structures are certainly the manifestation of the step-flow mechanism of the epitaxial growth of GaN.