Platelets and inorganic fullerenes on metal surfaces

实验研究了沉积在金属表面的层状半导体（MoS 2）n团簇的性质。与Si或GaAs相比，这些材料的可能优点是缺乏悬挂键、表面态和表面重构。簇可以是化学计量饱和的和化学惰性的，允许在环境条件下使用。电输运不会受到配体壳层的阻碍。首先在气相中研究（MeX 2）n团簇的几何和电子结构。主要的问题是：小富勒烯样结构存在或集群形成平面血小板？魔法数字真的存在吗？两种几何结构的HOMO-LUMO能隙的尺寸依赖性是什么？然后将质量选择的团簇离子软着陆在金属表面，用XPS、UPS、HREELS和STM研究了团簇-表面和团簇-团簇相互作用。平台形成具有可调节和良好限定的接触面积的金属-半导体纳米接触。可以使用XPS和UPS研究电荷转移和肖特基势垒高度。这种纳米接触的传输特性可以使用STM测量。实验工作伴随着相应的计算。

The properties of clusters of layered semiconductors like (MoS2)n deposited on metal surfaces are studied experimentally. The possible advantages of these materials compared to Si or GaAs are the lack of dangling bonds, surface states and surface reconstruction. The clusters may be stochiometrically saturated and chemically inert allowing use at ambient conditions. Electric transport will not be hampered by a shell of ligands. The geometric and electronic structure of (MeX2)n clusters will first be studied in the gas phase. The main questions are: Do small fullerene-like structures exist or do the clusters form planar platelets? Do magic numbers exist? What is the size dependence of the HOMO-LUMO gap for both geometries? Then the mass-selected cluster ions are softlanded on metal surfaces and the cluster-surface and cluster-cluster interactions are studied with XPS, UPS, HREELS and STM. Platelets form metal-semiconductor nanocontacts with an adjustable and well-defined contact area. Charge transfer and Schottky barrier heights can be studied using XPS and UPS. The transport properties of such nanocontacts can possibly be measured using STM. The experimental work is accompanied by corresponding calculations.