Surface science of silicon dangling bonds, condensed molecular films and nanostructured materials

点击翻译按钮获取中文摘要

Understanding the chemical processes occurring on surfaces is fundamentally important to many areas of science and technology including environmental science, materials research, molecular electronics and nanotechnology. The proposed work seeks to study the surface chemistry and physics on increasingly more complex substrates, from single-crystal Si surfaces, to condensed polycrystalline and amorphous molecular thin films, to nanostructured materials. Our study will focus on adsorbates with biochemical interest, and to follow the evolution of the structures and electronic properties of their intermediates upon adsorption and interactions with heat, low-energy electrons and ions. Using specialized tools such as pulsed laser deposition and molecular beam epitaxy, we will also develop new classes of functional nanomaterials, which would not only provide important test beds for investigating fundamental processes on complex surfaces, but also serve as basic platforms for developing new applications in the emerging field of nanotechnology. Three specific programs are proposed: (a) Organosilicon surface chemistry involving the Si dangling bonds: Special emphasis will be placed on studying the surface biochemistry of organic acids containing multiple functional groups, evolution of organic semiconductor oligomers, surface reactions of DNA nucleobase groups, and processes induced by low-energy electrons/ions. (b) Ice surface chemistry: Adsorption of simple amino acids and DNA nucleobase groups on ice may hold the key to life formation in the primordial world. Following the surface chemistry leading to the formation of peptide bonds on ice as a function of temperature would be of great interest. (c) Nanostructured materials: The development of novel metallic core-shell nanoparticles has provided much of the recent commercial applications in catalysis and electronics. Magnetic nanoparticles offer new prospects for field-directed growth, self-assembly and patterning in an external magnetic field. Fabricating half-metallic ferromagnetic nano-films (including CrO2, Sr2FeMoO6, Fe3O4, and metal-doped ZnO) provides the basic material platforms for spintronics, photovoltaics and photonics.