Voltage-dependent scanning tunneling microscopy images of the Ge(111)-c(2×8) surface
Voltage-dependent scanning tunneling microscopy images of the Ge(111)-c(2×8) surface
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Ge(111)-c(2×8)表面的电压依赖扫描隧道显微镜图像
DOI：
10.1116/1.581222
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
R. F. Willis
中科院分区：
文献类型：
--
作者：
Geunseop Lee;H. Mai;I. Chizhov;R. F. Willis
我们呈现了Ge（111）-c（2×8）表面的扫描隧道显微镜图像，其中清洁和含杂质部分都表现出显着的电压依赖性变化。空态图像中只观察到吸附原子，而填充态图像中同时出现吸附原子和其余原子，但随着偏压的变化而改变对比度。用低至0.5V的电压拍摄的填充态图像证实了在静止原子带和费米能级之间存在表面态，并且它不是悬挂键状的，即，发现其缔合电荷分布在吸附原子和其余原子上。含杂质表面的电压依赖性图像显示杂质周围的离域特征。这些离域特征是首次在III-V族半导体表面以外的表面上观察到的。这是由于杂质相对于清洁部分带电，导致杂质附近的能带弯曲。
We present scanning tunneling microscopy images of the Ge(111)-c(2×8) surface where both clean and impurity-containing portions exhibit significant voltage-dependent variations. While only adatoms are observed in empty state images, both adatoms and rest atoms simultaneously appear in filled state images but changing contrast with varying bias voltage. The filled state image taken with a voltage as low as 0.5 V confirms that a surface state exists between rest-atom bands and the Fermi level and it is not dangling-bond-like, i.e., its associated charge is found to be distributed over both adatoms and rest atoms. The voltage-dependent images of the impurity-containing surface show delocalized features around the impurity. These delocalized features are observed for the first time on the surface other than III–V semiconductor surfaces. It is attributed to the charged impurity relative to the clean part, causing the band bending near the impurity.