This research is concerned with studies of surfaces, particularly their structural, statistical mechanical and kinetic properties by employing Low-Energy Electron Diffraction and Scanning Tunneling Microscopy (STM). Prior results on strained silicon surfaces have shown dramatic and previously unexpected effects on the arrangement of surface steps as a function of strain for a silicon (100) surface. It is proposed to continue studies of the various consequences of the strain fields, including terrace width distributions, step-step interactions, step migration kinetics, step fluctuations and the temperature dependence of the step free energies. Quantitative studies of the double height step transition on silicon (100) surfaces will also be initiated. Exploratory studies of the initial stages of oxidation of silicon (100) surfaces will be begun. An investigation of the fundamentals of the reaction will be begun using both the spatial and spectroscopic resolution of the STM. This work may lead to the study of the interaction of vacancies with the various steps, the nucleation and growth of voids on terraces and vacancy diffusion. It is intended to extend the strain studies to isotropic strain rather than the uniaxial strain used to date. Lastly, recent studies of the sodium/silicon adsorption system using an atomic beam source will be extended to STM observations of the 3x2 and other incommensutate structures and also to the potassium/silicon system for comparison with the work of others.
