摘要
应用同步辐射光电子谱（ＳＲＰＥＳ）表征了一种新的ＣＨ３ＣＳＮＨ２／ＮＨ４ＯＨ溶液体系处理的ＧａＡｓ（１００）表面的成键特性和电子态．结果表明，经过处理的ＧａＡｓ（１００）表面，Ｓ既与Ａｓ成键也与Ｇａ成键，形成了Ｓ与ＧａＡｓ的新界面，这说明ＣＨ３ＣＳＮＨ２／ＮＨ４ＯＨ溶液处理的ＧａＡｓ（１００）表面具有明显的钝化作用．钝化表面退火处理后，发现ＡＳ的硫化物不稳定，分解或反应生成Ｇａ－Ｓ成分和元素态Ａｓ；室温下，Ｍｇ淀积硫钝化的ＧａＡｓ表面的实验结果表明，Ｍｇ置换ＧａＳ的Ｇａ成为金属Ｇａ偏析到表面，而硫以ＭｇＳ形成仍保留在界面，并且金属Ｍｇ淀积引起费米能级向价带顶（ＶＢＭ）移动约０．５ｅＶ，高覆盖度下，过量的金属Ｍｇ与其置换的偏析到表面金属Ｇａ反应形成ＭｇＧａ合金．
Abstract A new sulfur passivating mothed for GaAs,CH3CSNH2 treatment, has been devoloped.We have investigated the chemical bonds and electronic states of the GaAs surface by Synchrotron Radiation Photoelectron Spctroscopy (SRPES).The results show that the sulfides of Ga and As are formed on GaAs surface,and this treatment has an apparently passivating role.For the annealed S/GaAs system,the As sulfides are decomposed or further react with bulk GaAs into elemental As and GaS at RT.Mg deposition on passivation surface after annealing is also investigated.It is found that Ga atoms can be displaced from Ga-S bonds by Mg atoms,and diffuse into Mg overlayer, but sulfur atoms remain at interface.Band bending effect during Mg deposition, that is, the Ef movement is measured to be 0.5eV toward valence band maximium.
基金
国家自然科学资金
关键词
砷化镓
表面钝化
MgGa合金
同步辐射
表面处理
Interfaces (materials)
Passivation
Photoelectron spectroscopy
Surface properties
Synchrotron radiation
