TiO2分子在GaN（0001）表面吸附的理论研究

摘要

The adsorption of molecule TiO2 on GaN（0001） surface is theoretically explored by using a plane wave ultrasoft pseudo-potential method based on the density functional theory.The bonding processing of TiO2molecule on the surface of GaN（0001）,the adsorption energy,and the adsorption orientation are investigated.The results indicate that Ti atom is adsorbed on fcc site or on hcp site,and two O atoms are combined with two Ga atoms on the GaN surface after adsorption.The chemical bonding of Ga—O shows a covalent feature,and the chemical bonding energy is achieved to be 7.932—7.943 eV.The O—O line directions lie along the GaN [110] directions,in accordance with experimental reports of（100） [001] TiO2//（0001） [110] GaN.From ab initio dynamics calculation,the adsorption process can be divided into physical adsorption,chemical adsorption and superficial stable state,and the stable adsorption site is in accordance with the optimized results.%采用基于密度泛函理论的平面波超软赝势法,计算了TiO2分子在GaN（0001）表面的吸附成键过程、吸附能量和吸附位置.计算结果表明不同初始位置的TiO2分子吸附后,Ti在fcc或hcp位置,两个O原子分别与表面两个Ga原子成键,Ga—O化学键表现出共价键特征,化学结合能达到7.932—7.943eV,O—O连线与GaN[110]方向平行,与实验观测（100）[001]TiO2//（0001）[110]GaN一致.通过动力学过程计算分析,TiO2分子吸附过程经历了物理吸附、化学吸附与稳定态形成的过程,稳定吸附结构和优化结果一致.