Functionalization of silicon(111) surfaces to create layers containing coordination complexes and metallic nanostructures.

摘要

The evolution of microelectronics into nanoelectronics and the need for the future development of logic circuits require a continual miniaturization of the feature elements of conventional electronic circuitry. Such miniaturization, however, will eventually create severe physical and chemical limitations for existing silicon based technology. We are interested in the ultimate miniaturization of logic circuits by utilizing single molecules as electronic switches or storage elements in molecular-based electronics. Our approach towards building electronic devices involves incorporating molecules as the active features in the hydride silicon/molecular approach. In our work, we seek to functionalize Si(111) surfaces with monolayers of redox-active materials, such as polypyridyl ruthenium (II) complexes, which display different charged states at distinct voltages. Via hydrosilylation, characteristic of organosilane chemistry, the desired functionalization is achieved by the treatment of a hydride-passivated Si(111) surface with a redox-active material containing an alkene functionality. A diverse range of chemically modified Si(111) surfaces can be obtained using receptive monolayers. 4-Vinylpyridine was selected as the archetypical molecular material for our approach and analysis, with the vinyl functionality participating in the hydrosilylation reaction and the pyridyl head group affording an active and selective interface for the attachment of redox-active materials via ligand substitution reactions. In this research, materials were characterized using 1D- and 2D-NMR, FTIR and UV-visible spectroscopy, and TEM, while modified surfaces were characterized using ATR-FTIR, AFM, XPS and RBS.