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首页> 外文会议>Symposium on Compound Semiconductor Surface Passivation and Novel Device Processing held April 5-7, 1999, San Francisco, California,U.S.A. >Theory of the sulphur-passivated InP(001) surface
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Theory of the sulphur-passivated InP(001) surface

机译：硫钝化InP（001）表面的理论

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We present a detailed and comprehensive theoretical investigation of the sulphur-passivated (001) surface of InP. First, the ground-state structure is determined using density-functional methods, including full relaxation of the surface. The lowest-energy structure at 0 K is a striking (2x2) reconstruction with the S atoms displaced from the bridge sites to form short and long dimers, belonging to two distinct sublayers. This surface structure is used to calculate the backscattering Raman spectrum; the two peaks arising from surface-layer vibrations predicted by our calculations are observed. Next, our first-principles calculations are extended to the study of a number of other states of the surface that can arise upon annealing. For this purpose, we construct and relax several higher-energy states of the surface, and calculate the corresponding core-level photoemission psectra. A remarkable sequence of structures is found to unfold from the fully S-covered ground state as they become energeticaly accessible. The surface S atoms exchange with bulk P atoms, forming new (and strong) S-P bonds while dissociating pre-existing S-S dimers. The predicted core-level spectra are found to be entirely consistent with the experimental measurements; our calculations indicate that the annealed (at about 700 K) surface is a (2x2) structure containing two S and two P atoms per unit cell. Finally, we have used to predicted stable surface structures to calculate the photoemission and inverse photoemission psectra. They are found to agree well with experment if the surface is assumed to consist of a mixture of the above ground-state and annealed structures.
机译：我们对InP的硫钝化（001）表面进行了详细而全面的理论研究。首先，使用密度泛函方法（包括表面完全松弛）确定基态结构。 0 K处的最低能级结构是惊人的（2x2）重构，其中S原子从桥的位点移位而形成短和长的二聚体，属于两个不同的子层。这种表面结构用于计算反向散射拉曼光谱。观察到由我们的计算预测的表面层振动产生的两个峰。接下来，我们的第一性原理计算被扩展到研究在退火时可能出现的表面的许多其他状态。为此，我们构造并放松了表面的几个高能态，并计算了相应的核心能级光发射谱。人们发现，在充满能量的情况下，从完全被S覆盖的基态中可以展开出一系列惊人的结构。表面的S原子与大量的P原子交换，形成新的（且牢固的）S-P键，同时解离先前存在的S-S二聚体。发现预测的核心能级谱与实验测量值完全一致。我们的计算表明，退火后的表面（约700 K）是一个（2x2）结构，每个晶胞包含两个S和两个P原子。最后，我们已经使用预测稳定的表面结构来计算光发射和反向光发射谱。如果假定表面由上述基态和退火结构的混合物组成，则它们与实验非常吻合。

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