摘要
利用光电子能谱技术研究了室温下Ｃｅ膜表面的氧化，分析了在不同氧气暴露量下，稀土金属Ｃｅ氧化状态和样品功函数的变化。结果表明，在Ｏ２吸附的过程中，生成两种Ｃｅ的氧化物。在低的暴露量时，氧在Ｃｅ表面的吸附十分迅速，生成Ｃｅ２Ｏ３。同时，Ｃｅ２Ｏ０３中的Ｃｅ３ｄ和Ｏｌｓ谱峰随着氧气暴露量的增加向低结合能方向漂移。在高的暴露量下，氧在表面的吸附趋于缓慢，表面的Ｃｅ２Ｏ３被氧化成ＣｅＯ２。通过对样品加热，能使得四价的Ｃｅ重新转变回三价。功函数随着Ｏ２的暴露量增加先下降后上升。
Photoelectron spectroscopy has been used to study oxidation of Ce films at room temperature.The Ce oxidation state and work function changes were investigated at different oxygen exposures.The results show that there exist two kinds of Ce oxides during oxgyen adsorption.At low exposures,a fast oxgyen adsorption on Ce surface is related to the formation of Ce 2O 3 and the Ce3d and O1s core levels shift to lower binding energy with increasing oxygen exposure.At high exposures,a slow oxygen adsorption is due to the oxidation of Ce 2O 3 on the top layer,forming CeO 2.The dioxide can be converted into sesquioxide again by annealing.Work function change displays an initial decrease at low exposure,followed by an increase.
关键词
光电子能谱
动函数
氧化
铈膜
Photoelectron spectroscopy\ Work function\ Cerium Oxidation
