纤锌矿晶体结构
材料科学
悬空债券
从头算
吸附
氧气
氮化物
单独一对
化学物理
X射线光电子能谱
双层
结晶学
图层(电子)
物理化学
纳米技术
化学工程
锌
分子
硅
化学
光电子学
冶金
工程类
有机化学
生物化学
膜
作者
Zhi Fang,Enhui Wang,Yafeng Chen,Xinmei Hou,Kuo‐Chih Chou,Weiyou Yang,Junhong Chen,Minghui Shang
标识
DOI:10.1021/acsami.8b08242
摘要
With superior electrical and thermal properties, aluminum nitride (AlN) exhibits wide application. However, AlN is rather oxygen-sensitive and tends to be oxidized at high temperature. The surface oxidation of AlN remains a major challenge, while the underlying physics of AlN surface oxidation is still elusive. Here, First-principles calculations were performed to study wurtzite AlN(0001) surface oxidation process. The adsorption energy of oxygen was calculated to be site-dependent on the surface with varying O coverage. Calculation indicates that oxygen atoms are preferentially adsorbed at the hollow site (H3) of the AlN(0001) surface regardless of the O coverage. N2 is determined as the dominant gas product. The procedure of N3– removal and the formation of N vacancies (VN) take place step by step. VN plays an accelerating role in the oxidation of AlN, and O2– prefers to occupy the site of VN via consuming the Al p lone-pair electrons and passivating the dangling bond states of Al. An O–Al–O layer is formed when the first Al–N bilayer is fully oxidized, which could be regarded as a precursor of γ-Al2O3. On the basis of our atomic-level simulation, a possible phase transformation mechanism from γ-Al2O3 to α-Al2O3 was further proposed.
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