Ge在Si(111)7×7表面的选择性吸附

THE PREFERENTIAL ADSORPTION OF Ge ON Si(111)7×7 SURFACE

利用超高真空扫描隧道显微镜研究了室温条件下Ge在Si( 111) 7× 7表面上初期吸附过程 .在Ge所形成团簇中存在一个临界核 .这些Ge团簇的吸附中心总是在三个增原子所围成的区域中 .它们的电子结构具有类似半导体的性质 ,即其局域态密度在远离费米面的能级处很大 ,而在费米面附近的能级处非常小 .

Ge preferential adsorption on Si(111) 7 x 7 surface at the initial stage has been investigated by ultra - high vacuum scanning tunneling microscopy (UHV - STM). We demonstrate that there is a critical nucleus for the adsorbed Ge clusters on Si(111) 7 x 7 surface. The center sites of the Ge clusters are located in the areas encircled by three adatoms. Moreover, on the Ge, clusters the local density of states near the Fermi level is drastically reduced, compared with that far from the Fermi level.