Ge(112)-(4×1)-In表面重构的原子结构

ATOMIC STRUCTURE OF THE Ge(112)-(4×1)-In RECONSTRUCTION

用扫描隧道显微镜 (STM)研究了亚单层In原子引起的Ge(112 ) (4× 1) In表面重构 .结合随偏压极性不同而显著不同的STM图象和相应的“原子图象” ,为这个重构提出了一个原子结构模型 ,供进一步研究参考 .其中 ,In原子的吸附位置与它在Si(112 )表面的吸附位置一致 ,但与Al原子和Ga原子在Si(112 )表面的吸附位置不同 .

We have studied the Ge(112) (4×1) In reconstruction with scanning tunneling microscopy (STM). Based on our bias dependent STM images and the characteristic electronic structure of stable submonolayer group Ⅲ metal/group Ⅳ semiconductor interfaces, we propose an atomic model of this reconstruction for further investigation. The adsorption sites of In atoms are the same as In atoms' adsorption sites in the Si(112) (7×1) In reconstruction, but are different from the adsorption sites of Al and Ga atoms on the Si(112) surface. We suggest that this difference in adsorption sites is mainly due to the longer covalent bond length of In atoms. We further propose that, due to the smaller misfit, Al and Ga atoms may form longer nano wires along the step edges on the Ge(112) surface.