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Production and properties of molecule corrals in highly oriented pyrolytic graphite.

机译：高取向热解石墨中分子栏的生产和性质。

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The Introduction (Chapter 1) and Conclusion (Chapter 6) of this dissertation were prepared by Prof. Thomas P. Beebe, Jr., after the untimely death of Jennifer Dawn Alexander in 2002, in order to award her a posthumous Ph.D. degree. Chapters 2-5 are based on Jennifer's publications in the Journal of Physical Chemistry and Langmuir.;In Chapter 2, the surface chemistry of highly oriented pyrolytic graphite (HOPG) bombarded with energetic Cs+ ions was investigated. Defects in the HOPG created by the Cs+ ion bombardment act as nucleation sites for O2 oxidation at elevated temperatures, producing "molecule corral" pits. By varying the Cs+ dose density and bombardment energy, the pit density, yield, and depth can be accurately controlled.;In Chapter 3, gold and silicon nanostructures were produced by condensing the vacuum-evaporated elements onto nanometer-sized etch-pits on the HOPG surface. Annealing then results in the formation of metal and semiconductor nanostructures in pits on the graphite basal plane. By varying the ratio of the total amount of material evaporated to the diameter of the etch-pit templates, three distinct types of nanostructures were observed to form: rings, disks, and mesas.;In Chapter 4, surface defects on HOPG were controllably produced by bombardment with Cs+ ions. Defects thus created were oxidized at 650°C in air to produce nanometer-size monolayer and multilayer molecule corrals (pits). The controlled production of both monolayer and multilayer pits was realized and studied. The measured pit growth rates for multilayer pits are in good agreement with a new model of the pit growth rate acceleration by adjacent layers, and the separate contributions of surface diffusion and collision were extracted.;In Chapter 5, etch pits on HOPG were used to form gold nanostructures. Etch pit edges act as nucleation and growth sites for gold nanostructures and also fix gold nanostructures in place for study by scanning probe techniques. Hexagonal-shaped, flat-topped, and other gold nanostructures were formed in multilayer etch pits. Oxygen is found to adsorb molecularly onto surfaces of gold nanostructures at room temperature and atmospheric pressure. In contrast, no oxygen adsorption was observed on the surface of a Au(111) single crystal, thus demonstrating a significant cluster size effect.
机译：本论文的导论（第1章）和结论（第6章）是由小托马斯·P·比比（Thomas P. Beebe，Jr.）教授在詹妮弗·多恩·亚历山大（Jennifer Dawn Alexander）于2002年去世后准备的，以授予其死后博士学位。学位。第2-5章基于詹妮弗（Jennifer）在《物理化学杂志》和Langmuir上的发表。在第2章中，研究了被高能Cs +离子轰击的高取向热解石墨（HOPG）的表面化学。由Cs +离子轰击产生的HOPG缺陷在高温下充当O2氧化的成核位点，产生“分子库”凹坑。通过改变Cs +的剂量密度和轰击能量，可以精确地控制坑的密度，产率和深度。在第三章中，通过将真空蒸发的元素冷凝到纳米尺寸的蚀刻坑上，生产了金和硅的纳米结构。 HOPG表面。然后，退火导致在石墨基面上的凹坑中形成金属和半导体纳米结构。通过改变蒸发的材料总量与蚀刻坑模板直径的比值，可以观察到形成三种不同类型的纳米结构：环，盘和台面；在第四章中，可控地产生了HOPG上的表面缺陷。被Cs +离子轰击由此产生的缺陷在650°C的空气中被氧化，以产生纳米级的单层和多层分子围栏（凹坑）。实现并研究了单层和多层凹坑的受控生产。多层凹坑的测得的凹坑生长速率与相邻层的凹坑生长速率加速的新模型非常吻合，并且提取了表面扩散和碰撞的单独影响。形成金纳米结构。蚀刻坑边缘充当金纳米结构的成核和生长部位，并且还将金纳米结构固定在适当的位置，以通过扫描探针技术进行研究。在多层蚀刻坑中形成六边形，平顶和其他金纳米结构。发现氧在室温和大气压下可分子吸附在金纳米结构的表面上。相反，在Au（111）单晶的表面上没有观察到氧的吸附，因此显示出明显的团簇尺寸效应。

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