STM Analysis of Growth Process and Electronic Properties of microcluster.

微团簇生长过程和电子特性的 STM 分析。

基本信息

批准号：
02640248
负责人：
NISHITANI Ryusuke
金额：
$ 1.15万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

项目摘要

In order to analyze electronic and atomic structures of a microcluster with a given number of atoms, we have constructed a system for the preparation of mass-selected microclusters, and an scanning tunneling niicroscope for an ultra-high vacuum system(UHV-STM). The cluster-preparation system consists of zi liigii-current ion gun and a high-resolution mass spectrometer. Our STM is based on a model by Deniuth, and is computcr-cojitrolled with a home-i-nade feed back circuit. The control software is written using Turbo C++ V. 1. In addition to tiic construction of these instruments, we have made STM analyses of the microclusters and fine particles in air, which are prepared by three different methods : (1)thermal vaporization, (2)laser vaporization, and(3)electrochemical reaction. The growth process of gold particles on the graphite surface has been analyzed by STM in air. We have observed cap-shaped microclusters of about 2 nm in diameter in an atomic resolution which serve as nuclei for the gold-film formation. The gold fine-particles are formed at the nucleation sites after the formation of the nuclei. The particles aggregate into larger particles and/or islands of gold films through coalescence between smaller particles. The morphology of particles and islands is dependent on the temperature of the substrate, which is related with the degree of coalescence between particles. The particles on the graphite surface prepared by laser vaporization are also analyzed by STM in air. The degree of formation of nuclei by laser vaporization is 10' times as high as that by thermal vaporization. This fact is associated with higher energy of laservaporized ions, which is analyzed by the time- and space-resolved optical-measurements of fluorescence radiated from vaporized particles. The electrodeposition process is studied by electrochemical STM. We have obtained in-situ STM images during growth and coalescence of particles at liquid-graphite interface.

为了分析具有给定数量原子的微簇的电子和原子结构，我们已经构建了一个用于制备质量选择的微量群体的系统，以及用于超高真空系统（UHV-STM）的扫描隧道niicroscope。群集准备系统由Zi Liigii-Current Ion Gun和高分辨率质谱仪组成。我们的STM基于Deniuth的模型，并且由I-Nade Feed Back Circie将计算机计算。控制软件是使用Turbo C ++ V编写的。1。除了进行这些仪器的直接构造外，我们还对空气中的微量群体和细颗粒进行了STM分析，这些方法还通过三种不同的方法制备：（1）热蒸发，（2）激光蒸发，以及（3）电化学反应。 STM在空气中分析了石墨表面上金颗粒的生长过程。我们已经观察到在原子分辨率中直径约为2 nm的帽形微量簇，该分辨率是金膜形成的核。金细粒子在成核形成后在成核位点形成。颗粒通过较小颗粒之间的合并聚集成较大的颗粒和/或黄金膜的岛屿。颗粒和岛屿的形态取决于底物的温度，这与颗粒之间的合并程度有关。 STM在空气中还分析了由激光蒸发制备的石墨表面上的颗粒。激光蒸发的核形成程度与热蒸发一样高10'倍。这一事实与较高的Laserervodricion离子的能量有关，这是通过从蒸发颗粒辐射出的荧光的时间和空间分辨的光学测量来分析的。通过电化学STM研究了电沉积过程。我们在液态 - 石材界面的颗粒生长和合并期间获得了原位STM图像。