Ⅶ族元素在Si(111)和Ge(111)表面上的吸附

本文用原子集团模型和电荷自洽的EHT方法研究了Ⅶ族元素在Si(111)和Ge(111)表面上的化学吸附。利用能量极小的原则确定了各元素的化学吸附构型。对于Cl,在这两个表面均是顶位吸附。对于Ⅰ,都呈三度空位吸附。对Br,顶位及三度空位吸附均能发生,但是在Si(111)表面顶位吸附要优于三度空位,而在Ge(111)表面则三度空位吸附优于顶位。最后对Ⅶ族元素原子在这两种表面的吸附行为作了讨论,并与实验作了比较。 关键词：

THE GROUP Ⅶ ELEMENTS CHEMISORPTION ON Si(111) AND Ge (111) SURFACES

In the present paper, the cluster model and the charge self-consistent EHT method are used to study the chemisorptions of group VII elements on both Si (111) 1×1 and Ge(111)1×1 surfaces. The chemisorbed sites are determined by minimizing the total energy. For Cl, the absorption takes place on the atop sites for both Si (111) and Ge (111) surfaces. For I, the result shows that the threefold hollow sites of both surfaces are more preferable. For Br, both the atop and the threefold hollow sites seem to be possible on both surfaces. However, for Br/Si(lll)l×1 the atop site is more stable, whereas for Br/Ge (111)1×1 the threefold hollow site is more stable. Finally, the trend of the chemisorptions of the group VII atoms on the two surfaces are discussed and comparison with the recent SEXAFS results presented.