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用探测在MgK_α和 AlK_α X光源激发下掠角发射的As 2p、GaZP、Ca3d和Ols光电子的办法,提高了XPS表面分析的灵敏度,从而研究了 GaAs(111)面在吸附氧过程中表面 Ga、As和O的变化情形.发现吸附一开始时氧同表面Ga原子成键,随后氧再同As原子成键.吸附引起As2p强度的减弱,而没有看到有Ga减少的现象.在400℃以下加热退火,可以使As-O键消失,但Ga-O 键依然存在,后者只有在550℃退火才会去除.经过氧吸附并550℃退火后,(2×2)LEED图样比吸附氧以前更为清晰,氧在表面的初始粘附系数减小,说明表面有序程度提高.从氧吸附并退火后表面As/Ga比的增大,推测是由于这一处理部分地消除了原先表面所存在的Ga岛.
The detection of As 2p, GaZP, Ca 3d and Ols photoelectrons emitted at a sweep angle of MgK_α and AlK_α X-ray sources enhanced the sensitivity of XPS surface analysis. The effects of GaAs (111) surface adsorption of Ga, As and O. It is found that the oxygen bonds with the surface Ga atom at the beginning of the adsorption, and then the oxygen bonds with the As atom again. The adsorption results in the weakened As2p without any decrease of Ga. As-O bonds disappear but the Ga-O bonds remain, and the latter is removed only by annealing at 550 ° C. After oxygen adsorption and annealing at 550 ° C., the (2 × 2) LEED pattern is prior to the adsorption of oxygen More clearly, the initial adhesion coefficient of oxygen on the surface decreases, indicating an increase in surface order.According to the increase of surface As / Ga ratio after oxygen adsorption and annealing, it is presumed that this process partially eliminates the original surface Island of existence.