Hetero Epitaxial Growth of Layered Metal Chalcogenides

这是1992年RIA奖。提出了一种利用层状金属硫族化合物范德华表面制备异质界面体系的新思路。这将通过分子束外延的方法在彼此的顶部生长不同种类的层状金属硫族化合物来进行实验研究，这一过程被称为“范德华外延”。这种方法特别令人感兴趣的是能够在不考虑晶格匹配要求的情况下制造原子和电子突变异质界面。为了提高薄膜的质量，我们将详细研究外延的条件，并研究外延层的基本成核和生长。由于层堆叠顺序对过渡金属二硫族化合物性质的敏感性，我们将开发一种利用反射高能电子衍射振荡来确定生长薄膜的“多晶态”的技术。用这种方法制造的异质界面的独特性质将允许研究与金属和半导体之间电子转移相关的基本方面，从而探索肖特基器件结构的合理设计。最后，我们将研究在砷化镓上生长的半导体层状金属硫族化物，以期开发出新的材料体系。根据材料的特性选择不同的材料，构建复杂的层状异质结构的潜在灵活性将构成异质外延技术的重大突破。

This is a 1992 RIA Award. It is proposed to develop a new concept for fabricating hetero- interface systems using van der Waals surfaces of layered metal chalcogenide materials. This will be studied experimentally by growing different kinds of layered metal chalcogenides on top of each other by means of molecular beam epitaxy, a process that has been referred to as "van der Waals epitaxy". Of particular interest of this method is the ability to fabricate atomically and electronically abrupt hetero-interfaces without regard to their lattice matching requirement. The epitaxial conditions will be investigated in detail for improving the quality of the thin films, and the fundamental nucleation and growth of the epitaxial layers will be investigated. Due to the sensitivity of the layer stacking sequence to the properties of transition metal dichalcogenides, we will develop a technique to determine the "polytpism" of the growing thin film using Reflection High Energy Electron Diffraction oscillations. The unique nature of the hetero-interfaces fabricated by this method will allow the investigation of the fundamental aspects related to the electron transfer between metals and semiconductors, from which rational design of Schottky device structure will be explored. Finally the growth of selected semiconducting layered metal chalcogenide on GaAs will be investigated in a view toward the development of newer material systems. The potential flexibility for constructing complex layered heterostructures containing different materials selected for their specific material properties will constitute a substantial breakthrough in heteroepitaxy technology.