Ab initio total energy study of ZnO adsorption on a sapphire (0001) surface
Ab initio total energy study of ZnO adsorption on a sapphire (0001) surface
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DOI：
10.1103/physrevb.70.045413
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发表时间：
2004-07
影响因子：
3.7
通讯作者：
Yang Chun;Li Yan-rong;Li Jin-shan
中科院分区：
文献类型：
--
作者：
Yang Chun;Li Yan-rong;Li Jin-shan
采用基于密度泛函理论的平面波超软赝势法，对蓝宝石（0001）表面和ZnO的吸附进行了理论计算。通过比较Al和O在表面弛豫前后的PDOS，我们展示了蓝宝石（0001）不同的表面状态，并分析了Al和O对表面化学键的影响。进一步研究了ZnO分子在表面的成键过程、吸附能和成键取向、表面结构的变化以及表面化学键的特征。结果表明：ZnO吸附后，第一层Al-O的表面向内弛豫减弱，甚至消除；化学键能。其化学键与相邻表面Al-O键之间存在30°的偏转角；锌的稳定化学吸附位点与表面o六方对称偏转约30°。通过对吸附前后的原子序数、态密度和成键电子密度的分析，发现ZnO与表面形成的化学键具有强离子键的特征，而两者之间的化学键具有共价键的特征，这种化学键主要来自Zn 4s和o2p的杂化，部分来自Zn 3d和o2p的杂化。从而有利于在ZnO薄膜生长初期形成四面体配位。因此有利于纤锌矿结构的形成。
The sapphire (0001) surface and the adsorption of ZnO are theoretically calculated by using a plane wave ultrasoft pseudo-potential method based on density functional theory. By comparing the PDOS of the Al and the O before and after the surface relaxation, we demonstrate different sapphire (0001) surface states, and changes in surface chemical bonding resulting from Al and O are analyzed. The bonding processing of a ZnO molecule on the surface of, adsorption energy and bonding orientation, and change in surface structure as well as the characters of surface chemical bonding are further investigated. We conclude that the surface inward relaxation in the first layer Al-O is weakened, even eliminated after the surface adsorption of the ZnO; chemical bonding energy achieved. There is a deflected angle of 30° between the chemical bonding of theand the adjacent surface Al-O bonding; the stable chemical adsorption site of Zn is just about 30° deflected from the O-hexagonal symmetry of thesurface. Through analysis of the atomic populations, density of state, and bonding electronic density before and after the adsorption, it is revealed that the chemical bonding formed by theof the ZnO and the surfaceis characterized by strong ionic bonding, while the bond of theand the surfacehas a covalent character, which mainly comes from the hybridization of the Zn 4s and the O 2p and partially from the hybridization of the Zn 3d and the O 2p, so as to facilitate the forming of tetrahedral coordination in the initial stage of the ZnO films growth. Hence it is favorable for the formation of the wurtzite structure.