The goal of this research is to explore interfacial phenomena associated with the deposition of atoms, ions, and clusters on semiconductor surfaces. This work combines scanning tunneling microscopy with ab initio molecular dynamics simulations to correlate interfacial structures and properties with the dynamics of condensation ions and small clusters are deposited directly on the substrate using laser-assisted supersonic expansion. The experimental studies are unique because the energy, the trajectory, and the number of atoms in the cluster are controlled and because scanning tunneling microscopy is used to image the resultant surface and overlayer structure. The theoretical studies are unique because new computational techniques are implemented for determining the structure and interaction parameters of atoms and clusters on surfaces. These studies should allow analysis of growth conditions with quantum interatomic forces and testing of the predictions with surface analysis techniques. The proposed studies are important because the focus on properties of complex non-equilibrium systems where chemical and physical properties at the interface change over microscopic scales. Interface formation during non-equilibrium vacuum deposition is one of the challenging problems in the present day solid state sciences. Because the goal of this research is to correlate interface properties and interface structure, the successful realization of the proposed work will have significant impacts on the nano-fabrication of new electronic devices and the understanding of other surface related processes such as catalysis.
