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.

为了分析给定原子数的微团簇的电子和原子结构，我们构建了质量选择微团簇制备系统和超高真空系统扫描隧道显微镜（UHV-STM）。团簇制备系统由电流离子枪和高分辨率质谱仪组成。我们的 STM 基于 Deniuth 的模型，并通过 home-i-nade 反馈电路进行计算机控制。控制软件使用Turbo C++ V编写。 1. 除了这些仪器的tiic构建之外，我们还对空气中的微团簇和细颗粒进行了STM分析，这些微团簇和细颗粒是通过三种不同的方法制备的：（1）热汽化，（ 2）激光汽化，以及（3）电化学反应。通过STM在空气中分析了金颗粒在石墨表面的生长过程。我们在原子分辨率下观察到直径约 2 nm 的帽状微团簇，它们充当金膜形成的核。成核后，在成核部位形成金微粒。颗粒通过较小颗粒之间的聚结聚集成较大颗粒和/或金膜岛。颗粒和岛的形态取决于基材的温度，而基材的温度又与颗粒之间的聚结程度有关。通过激光汽化制备的石墨表面的颗粒也可以在空气中通过 STM 进行分析。激光汽化的成核程度是热汽化的10倍。这一事实与激光汽化离子的较高能量有关，这是通过对汽化粒子辐射的荧光进行时间和空间分辨光学测量来分析的。通过电化学STM研究了电沉积过程。我们获得了液体-石墨界面颗粒生长和聚结过程中的原位 STM 图像。