Electronic and Atomistic Effects in Nanostructures

本项目研究通过沉积、自组装和自组织制备的表面纳米级系统的电子结构、形态、稳定性和原子行为。感兴趣的系统包括沉积在硅和锗表面的银、铅和铋薄膜，这些薄膜是光滑的、阶梯状的或由纳米线阵列调制的。这些系统中的电子，受几何结构的限制或调制，可以组织成新的配置，包括量子阱态、共振和局域态；它们与原子晶格的相互作用可以导致原子组织、对称性和热力学行为的实质性变化。这些效应和现象对于“纳米科学与技术”这一流行的国家研究主题至关重要。在这些研究中使用的主要工具是角分辨光发射，在威斯康星州斯托顿的同步辐射中心进行，这是一个由国家科学基金会支持的国家用户设施。通过前沿研究，该项目为学生和博士后提供教育，并通过咨询、合作、分享经验和专业知识向社区提供服务。严格的学生训练，包括在国家设施工作，直接有助于工业，大学和国家实验室的人才需求。金属原子如Ag（银）、Pb（铅）和Bi（铋），在沉积到电子衬底材料如Si（硅）和Ge（锗）上后，可以形成光滑的薄膜或自组织成新颖的结构，包括簇、岛、金字塔阵列和其他纳米级几何形状。这些系统中的电子被迫适应几何形状，原子晶格结构对电子结构的改变起反应。因此，通常会出现新颖而有用的特性。这些纳米级现象的基本科学原理提出了智力挑战，并在纳米电子学、量子器件、涂层、催化剂、太阳能电池和电池技术等领域具有重要的技术意义。本项目利用同步辐射对这一课题进行基础研究。这项工作主要是在威斯康星州斯托顿的同步辐射中心进行的，这是一个由国家科学基金会支持的国家用户设施。通过前沿研究，该项目为学生和博士后提供教育，并通过咨询、合作、分享经验和专业知识向社区提供服务。严格的学生训练，包括在国家设施工作，直接有助于工业，大学和国家实验室的人才需求。

Technical abstract This project is a study of the electronic structure, morphology, stability, and atomistic behavior of selected surface-based nanoscale systems prepared by deposition, self-assembly, and self-organization. The systems of interest include films of Ag, Pb, and Bi deposited on surfaces of Si and Ge that are smooth, stepped, or modulated by nanowire arrays. Electrons in these systems, confined or modulated by the geometry, can organize into novel configurations including quantum well states, resonances, and localized states; their interactions with the atomic lattice can lead to substantial changes in atomic organization, symmetry, and thermodynamic behavior. These effects and phenomena are of central importance to "nanoscale science and technology," a prevailing national research theme. The primary tool used in these investigations is angle-resolved photoemission, performed at the Synchrotron Radiation Center in Stoughton, Wisconsin, which is a national user facility supported by the National Science Foundation. Through cutting-edge research, this project affords education to students and postdoctoral fellows and extends services to the community via consultation, collaboration, and sharing of experience and expertise. The rigorous student training including working at national facilities contributes directly to the personnel needs of industry, universities, and national laboratories. Non-technical abstract Metal atoms such as Ag (silver), Pb (lead), and Bi (bismuth), upon deposition onto electronic substrate materials such as Si (silicon) and Ge (germanium), can form smooth films or self-organize into novel configurations including arrays of clusters, islands, pyramids, and other geometrical shapes of nanoscale dimensions. Electrons in these systems are forced to adapt to the geometry, and the atomic lattice structure reacts to the electronic structure modification. Novel and useful properties often emerge as a result. The underlying scientific principles of these nanoscale phenomena present intellectual challenges and have important technological implications in areas such as nanoelectronics, quantum devices, coatings, catalysts, and solar cell and battery technologies. This project utilizes synchrotron radiation to perform fundamental studies on this topic. The work is primarily carried out at the Synchrotron Radiation Center in Stoughton, Wisconsin, a national user facility supported by the National Science Foundation. Through cutting-edge research, this project affords education to students and postdoctoral fellows and extends services to the community via consultation, collaboration, and sharing of experience and expertise. The rigorous student training including working at national facilities contributes directly to the personnel needs of industry, universities, and national laboratories.