| Popis: |
I have used density functional theory and classical molecular dynamics to study the chemistry of the native oxide layer on the Si(100) surface. Surface oxidation is accompanied by the development of tensile surface stress and by formation of Si species with a range of oxidation states. Total energy calculations of P and B substitution into the oxide layer and first principles molecular dynamics simulations of oxide growth on the doped surface both indicate a surface oxidation mechanism whereby impurities remain trapped at the Si/SiOx interface. A new two- and three-body classical potential is developed to simulate the hydroxylated, natively oxidised Si surface in contact with water solutions and biological molecules. The potential parameters are chosen to reproduce the structure, charge distribution, tensile stress and interactions with single water molecules of a natively oxidised Si surface previously obtained by ab initio simulations. I apply this classical potential to study the atomic-level processes that determine the mutual adhesion between hydrophilic Si wafers during room temperature bonding. Moreover, I have investigated the adhesion mechanisms of proteins such as collagen and human serum albumin, which mediate the interactions between cells and implanted Si-based devices. |
