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Identification of individual surface adsorbates

识别各个表面吸附物

基本信息

批准号：
14340087
负责人：
UEHARA Yoichi
金额：
$ 9.98万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

We have successfully demonstrated that individual adsorbates on solid surfaces can be identified with scanning tunneling microscope (STM) light emission spectroscopy. STM has proven to be a very powerful tool for visualizing surface nano-structures with atomic spatial resolution. While an atom or a molecule adsorbed on a surface can be visualized by STM, their species cannot be identified from the STM image alone. Methods for identifying individual adsorbates are highly desirable in many fields of surface science and nanotechnology. When electrons are injected into a sample surface from the tip of a STM, visible light is emitted. Since the cross-section of the electron beam emitted by the STM tip is on the order of the atomic size, the tunneling electrons are selectively injected into the area with the corresponding size. Hence when the tip is located over an adsorbate imaged by the conventional STM operation, the excited optical spectrum (i.e., STM light emission spectrum) will reflect its properties. The purpose of the present project was to demonstrate that surface adsorbates can be identified by STM light emission spectra. For this purpose we have measured the STM light emission spectra of various combinations of adsorbates and substrates ; oxygen atoms on Cu(110), Ni(110) and Ag(110), hydrogen atoms on Ni(110), CO molecules on Cu(110), Pt(110), and Ni(110), and Rhodamine 6G molecules on highly ordered pyrolytic graphite (HOPG). We found that the optical spectra of these adsorbates are different from those of the corresponding substrates. This result clearly indicates that identification of surface adsorbates becomes possible by STM light emission measurements.

我们已经成功证明，可以使用扫描隧道显微镜 (STM) 光发射光谱来识别固体表面上的单个吸附物。 STM 已被证明是一种非常强大的工具，可以以原子空间分辨率可视化表面纳米结构。虽然吸附在表面上的原子或分子可以通过 STM 可视化，但仅通过 STM 图像无法识别它们的种类。在表面科学和纳米技术的许多领域中，非常需要用于识别单个吸附物的方法。当电子从 STM 尖端注入样品表面时，会发出可见光。由于STM尖端发射的电子束截面为原子尺寸量级，因此隧道电子被选择性地注入相应尺寸的区域。因此，当尖端位于通过传统 STM 操作成像的吸附物上方时，激发光谱（即 STM 光发射光谱）将反映其特性。本项目的目的是证明表面吸附物可以通过 STM 光发射光谱进行识别。为此，我们测量了吸附物和底物的各种组合的 STM 发射光谱； Cu(110)、Ni(110) 和 Ag(110) 上的氧原子，Ni(110) 上的氢原子，Cu(110)、Pt(110) 和 Ni(110) 上的 CO 分子，以及高度有序热解石墨 (HOPG) 上的罗丹明 6G 分子。我们发现这些吸附物的光谱与相应底物的光谱不同。该结果清楚地表明通过 STM 光发射测量可以识别表面吸附物。