铯对GaAs（100）表面氧化的催化作用

Cs-Promoted Oxidation on GaAs（100） Surface

摘要: 我们用XPS、UPS及功函数的测量研究了氧在Cs复盖的及清洁的GaAs（100）表面的吸附行为．实验结果证明，在0.6ML的Cs复盖度下，碱金属Cs可以使衬底的氧化大大增强．在氧吸附初期（＜1L），氧优先吸附在碱金属复盖层以下或碱金属原子之间的As原子位置上．随氧的暴露量的增加，氧吸附在Ga和As的位置上．此时，Ca和As独立地被氧化形成Ga₂O₃和As₂O₃。

Abstract: The adsorption behavior of oxygen on Cs-covered and clean GaAs（100） surface are studied with XPS, UPS and work function measurement. The experimental results show that the drastic enhancement of the oxidation of substrate has been observed on Cs covered GaAs（100） surface with deposition of 0.6ML. The oxygen may be located on As atoms beneath or between alkali metal atoms. With increasing the amount of exposure, the oxygen may be located on both Ga and As atoms and Ga and As could be oxided by forming Ga₂O₃ and As₂O₃.