Scanning tunneling spectroscopy of oxygen adsorbates on the GaAs(110) surface
Scanning tunneling spectroscopy of oxygen adsorbates on the GaAs(110) surface
复制标题
GaAs(110)表面氧吸附物的扫描隧道光谱
DOI：
--
复制
发表时间：
1988
期刊：
影响因子：
--
通讯作者：
R. Feenstra
中科院分区：
文献类型：
--
作者：
J. Stroscio;R. Feenstra
用扫描隧道显微镜(STM)测量了氧吸附在GaAs(110)表面的隧道电流与外加电压的空间分辨关系。观察到了不同长度尺度的效应，它们来自系统中的两个电荷来源：带负电的吸附体和带正电的空间电荷层。空间电荷层在n型材料上产生能带弯曲，这被观察到分别隧穿出价带和导带的起始点的移位。我们用表面空间电荷层的隧穿电流的理论计算来分析这些位移。在氧吸附在n型材料上的正上方，在价带边的顶部附近观察到隧道效应的增强，而在导带的底部附近观察到相应的减弱。这种局域行为被认为是由带电的库仑势产生的表面态密度的变化引起的。
Spatially resolved measurements of the tunneling current versus applied voltage are obtained for oxygen adsorbed on the GaAs(110) surface, using a scanning tunneling microscopy (STM). Effects with different length scales are observed, arising from two sources of charge in the system: negatively charged adsorbates and a positively charged space charge layer. The space charge layer produces band bending on n‐type material, which is observed as a shift in the onsets for tunneling out of and into the valence and conduction bands, respectively. We analyze these shifts using theoretical calculations of the tunneling current through surface space charge layers. Directly above an oxygen adsorbate on n‐type material, an enhancement in tunneling is observed near the top of the valence band edge, while a corresponding decrease is observed near the bottom of the conduction band. This local behavior is identified as arising from changes is the surface density‐of‐states produced by the Coulomb potential of the charged ...