Initial research efforts will focus in two area: (1) Selective Chemical Vapor Deposition (CVD): One of their objectives here is to determine how "functionalizing" surfaces such as Si with H, OH, and halides will alter the barriers to film nucleation. Experimentally, they will probe the barriers to adsorption and nucleation by scattering a seeded supersonic molecular beam of precursor molecules from the functionalized surface at various well-defined translational energies. At incident energies where the barrier height is exceeded, the dissociatively adsorbed surface intermediates will be trapped by maintaining the substrate at cryogenic temperatures. Vibrational spectroscopy (by electron energy loss) will be employed to identify the adsorbed fragments. The gas phase products, film composition, and the degree of epitaxy during deposition will be monitored by mass spectroscopy, Auger electron spectroscopy, and low-energy electron diffraction, respectively. In addition, they will apply scanning tunneling microscopy to study film nucleation at an atomic level during CVD. (2) Heterogeneous Catalytic Polymerization: Initially, studies will focus on olefin polymerization. The polymer chemistry will be modelled by attaching alkyl groups to modified Ti and Zr surfaces. Precursors such as aluminum alkyls and alkyl iodides will be utilized to generate the surface alkyls. The olefin insertion chemistry will be probed by scattering olefin molecular beams from active catalysts deposited onto a quartz crystal microbalance designed to measure the polymerization rate. These studies will permit them to determine the effects of olefin translational energy on the polymerization rate.
