Microscopic Mechanisms of Chemical Reactions on Semiconductor Surface

1. 利用低能电子衍射、高分辨电子能损失谱和热脱附谱研究了金刚石表面C（100）的结构、电子态、振动态和化学反应性。特别是首次在C（100）上观察到Diels-Alder反应。推广目前的工作，可以预测任何其他具有适当对称性的共轭二烯都可以与C（100）表面发生反应。(1)利用高分辨率电子能量损失谱研究了Si(100)（2x1）表面的声子。观察到与表面二聚体运动有关的损耗。特别是，首次观察到与二聚体屈曲相关的二聚体摇摆模式导致的20 meV损失。观察到瑞利声子与体声子的投影态密度共振。并将实验结果与晶格动力学计算结果进行了比较。(2)利用扫描隧道显微镜研究了氧- si (111)7x7表面在10 ~ 300 K范围内的相互作用。对不稳定反应中间体的行为有了新的认识。

1. Study on the diamond surfaceThe structure, electronic states, vibrational states and chemical reactivity of the C(100) surface have been studied by low-energy electron diffraction, high resolution electron energy loss spectroscopy and thermal desorption spectroscopy. In particular, the Diels-Alder reaction was observed to occur on C(100) for the first time. Extending the present works, it can be predicted that any other conjugated dienes with suitable symmmetry react with the C(100) surface.2. Study on the silicon surface(1) The surface phonons of the Si(100)(2x1) surface have been studied by the use of high resolution electron energy loss spectroscopy. Losses related to the surface dimer motions are observed. In particular, the 20 meV loss attributed to the dimer-rocking mode asociated with the dimer buckling was observed for the first time. The Rayleigh phonons are observed in resonance with the projected density of states of bulk phonons. Comparison between the experimental results and lattice dynamical calculations were made.(2) The oxygen-Si(111)7x7 surface interactions were studied, by the use of scanning tunneling microscopy, in the temperature region between 10 and 300 K. New informations were obtained on the behaviors of unstable reaction intermediates.