This award is to establish a new Materials Research Group at the University of Wisconsin at Madison. The topic of the research of this group is studies the fundamental mechanisms in growth and the resulting microstructure of thin films of semiconducting materials using chemical vapor deposition. The emphases of the research include: understanding of the interaction of the gas phase with the growing thin film through studies of the precursor gases and the gas phase chemistry, quantitative microscopic characterization of the kinetic and thermodynamic mechanisms involved in growth, ex- situ characterization of the structural, optical, and electronic nature of the resulting films, theoretical analysis and computational modeling of the gas phase chemistry and film structure, feedback from characterization and theory to growth chemistry, design of novel processing and materials on the basis of new understanding of the growth process. The group is developing a chemical vapor deposition system capable of growing electronic device-quality films, that also allows in-situ monitoring of the growth process. The initial materials being studied are silicon and silicon-germanium systems/multilayers. The later stages of the research involves studies of group III nitrides, which are wide band-gap semiconductors that show great promise for application in integrated electronic, optical, and optoelectronic devices. Characterization techniques being used include: photoreflectance, photoluminescence, reflection difference spectroscopy, mass spectroscopy, reflection high energy electron diffraction, scanning tunnelling microscopy, and low energy electron diffraction. Theoretical techniques include Monte Carlo simulations, rate equation calculations, and statistical mechanical methods. The strengths of the group are the balance of the complementary expertise of the investigators and the facilities available for this research. This research would not be possible without the collaboration of the investigators working in an interactive and integrated mode.
