FRG: Quantum Engineering of Metallic Nanostructures

本计画探讨量子限制对金属/半导体薄膜及奈米结构磊晶成长之影响。该方法是一种理论/实验相结合的合作活动的研究人员在美国。TX/Austin和ORNL，旨在更好地理解和利用“电子增长”概念。到目前为止，“电子生长”模型的主要发现是量子限制，电荷溢出和界面诱导的电子密度os-cillations之间的竞争可以使一个平坦的金属薄膜临界，神奇，边缘稳定，或完全不稳定的形态粗糙化。对于GaAs和其他III-V族半导体衬底上的Ag，电子生长机制导致存在用于形成原子级平坦膜的临界厚度。理论研究还表明，其他金属/半导体系统的魔厚度的存在，以及振荡的金属-非金属转变的可能性。 该项目的理论和实验范围将包括纵向和横向的量子效应以及热力学和动力学因素之间的相互作用。我们的目标是更深入地了解薄膜生长的电子机制的途径，并实现低维结构的可控形成。我们也将探讨利用与量子态和电荷量子化相关的电子能量学来影响量子点阵列的几何有序性和尺寸选择的可能性。我们将在实验上研究各种系统中临界/魔厚度和振荡金属-非金属转变的理论预测。该项目涉及材料科学领域的基础研究问题，具有高技术相关性。研究中获得的基本知识和理解有望为下一代电子/光子材料做出贡献。 该计划的一个重要特点是通过在一个基本和技术重要领域对学生进行培训，将研究和教育结合起来。该项目由DMR/EM和DMR/MET方案共同支持。

This project addresses effects of quantum confinement on epitaxial growth of metal/semiconductor thin films and nanostructures. The approach is a combined theory/experiment collaborative activity among researchers at U. Tx/Austin and ORNL, and is aimed at greater understanding and utilization of an "electronic growth" concept. To date, the main findings of the "electronic growth" model are that a competition between quantum confinement, charge spilling, and interface-induced electron density os-cillations can make a flat ultrathin metal film critically, magically, marginally stable, or totally unstable against morphological roughening. For Ag on GaAs and other III-V semiconductor substrates, the electronic growth mechanism leads to the existence of a critical thickness for the formation of an atomically flat film. Theoretical studies also showed the existence of magic thicknesses for other metal/semiconductor systems, and the possibility of oscillatory metal-nonmetal transitions. The theo-retical and experimental scope of this project will include quantum effects in both the vertical and lat-eral directions and the interplay between thermodynamic and kinetic factors. The goal is to gain a deeper understanding of the pathways of the electronic mechanism for film growth, and to achieve controlled formation of lower-dimensional structures. The possibility of using electronic energetics as-sociated with quantum states and charge quantization to influence geometric ordering and size selec-tion of quantum dot arrays will also be explored. Theoretical predictions of critical/magic thicknesses and oscillatory metal-nonmetal transitions in a variety of systems will be studied experimentally.%%% The project addresses basic research issues in a topical area of materials science with high technologi-cal relevance. The basic knowledge and understanding gained from the research is expected to contrib-ute to next generation electronic/photonic materials. An important feature of the program is the inte-gration of research and education through the training of students in a fundamentally and technologi-cally significant area. The project is co-supported by the DMR/EM and DMR/MET programs.