Raman Scattering of Solid and Liquid Clusters and Ultrathin Films

增强拉曼散射方法将用于原位研究沉积在表面上的团簇和超薄膜的超高真空。将获得有关声子态及其随团簇大小和温度的变化的信息。重点将放在非晶态或纳米晶态的半导体和半金属第IV族(C和Sn族)和V(Bi族和Sb)元素。拉曼散射也将应用于这组液体团簇，以获得从固态到液态相变的动力学信息。团簇和超薄膜的生长将采用溅射和激光辅助沉积方法。光电子能谱和高分辨率电子能量损失方法将提供有关电子和振动状态变化以及表面原子氢键作用的补充信息。%这项研究将集中在不同纳米结构的超薄膜和薄膜的近表面和体相性质上。重点将放在半导体或半金属团簇结构的研究上，在这些结构中，相对较少的原子数量和较大的表面积与体积比都可以实现材料性能的改进。固态团簇和液态团簇的性质都将被探究。这些材料的制备将采用各种超高真空沉积方法，包括磁控溅射、蒸发和激光辅助沉积。这些材料的物理性质和表征将采用一系列原位超高真空光谱方法。这将提供关于无序非晶和纳米晶固体的电子态和振动动力学的信息，并将探索键合和结构无序变化在超薄膜加工中的作用。另外还将获得团簇尺寸分布的非原位电子显微镜研究，并与合成方法相关。激光辅助沉积无定形碳和其他类似钻石的材料将涉及大学和行业的合作。

Enhanced Raman scattering methods will be used for in situ ultra- high vacuum studies of clusters and ultra-thin films deposited on surfaces. Information about the phonon states and their changes with cluster size and temperature will be obtained. Emphasis will be places on the semiconducting and semimetallic group IV (C and Sn) and V (Bi and Sb) elements in amorphous or nanocrystalline states. Raman scattering will also be applied to liquid clusters from this group to obtain dynamical information on the phase transformations from the solid to liquid state. Sputtering and laser assisted deposition methods will be employed for cluster and ultra-thin film growth. Photoemission and high resolution electron energy loss methods will provide complementary information on changes in electronic and vibrational states and the role of atomic hydrogen bonding on surfaces. %%% This research will focus on both near surface and bulk properties of ulrathin and thin films with different nanostructures. Emphasis will be placed on studies of semiconductor or semimetal cluster structures in which both the relatively small number of atoms and the large surface to volume ratio allow modified material properties to be achieved. Both solid as well as liquid state cluster properties will be explored. The preparation of these materials will employ a diverse range of ultrahigh vacuum deposition methods, including magnetron sputtering, evaporation and laser assisted deposition. The physical properties and characterization of these materials will employ a range of in situ ultrahigh vacuum spectroscopic methods. This will provide information on the electronic state and vibrational dynamics of disordered amorphous and nanocrystalline solids and will explore the role of bonding and structural disorder changes in the processing of ultrathin films. Additional ex situ transmission electron microscopy studies of cluster size distributions will be obtained and related to synthesis methods. Laser assisted deposition of amorphous carbon and other diamond-like materials will involve university-industry collaborations.