SrAl4O7 (SA2) phosphor powders were synthesized by using a modified Pechini process. Varying amounts of boron was incorporated into the SA2 lattice to investigate the effects on crystal structure and optical properties. X-ray spectra showed that boron addition enhances phase purity of the powder at a calcination temperature of 1000 °C, whereas the formation of a new S4A7 phase was induced when a calcination temperature of 1100 °C was used. The afterglow duration was extended to longer than 5 hours when boron was present in 4-11 mol%. To elucidate the enhanced optical properties, interband trap characteristics were studied by thermoluminescence and photoluminescence.

Amorphous ZITO films were deposited by dc magnetron sputtering onto glass substrates from ceramic oxide targets containing Zn:In:Sn cation ratios of 1:2:1 and 1:2:1.5. The microstructure, carrier density, mobility, and resistivity of as-deposited and annealed samples were evaluated using x-ray diffraction and Hall effect measurements. The as-deposited films were amorphous and remained so after annealing at 200°C in air for up to five hours. Transmissivity of the films exceeded 80% in the visible spectral region. The minimum resistivity value (7.6×10−4 Ω-cm) was obtained from thin films deposited using the 1:2:1 composition target and a substrate temperature of 300°C.

We have experimentally demonstrated that the interface between ITO and Si or Si0.85Ge0.15 is metastable, with silicon reducing ITO to form an amorphous oxide layer and In metal. A 400nm-thick ITO layer was deposited on two types of substrates: p-type, <100> silicon wafers and a silicon wafer with a 400nm-thick layer of Si0.85Ge0.15 grown by CVD. Annealing of the ITO/Si system resulted in the growth of a 5nm-thick planar, interfacial SiO2 layer and the formation of In metal in the ITO above the SiO2 layer. In contrast, annealing of the ITO/Si0.85Ge0.15 system produced an interfacial Si0.85Ge0.15O2 layer that was non-uniform in thickness and which had a non-planar surface morphology. As-deposited and annealed samples were characterized by HREM, EDS, and C-V measurements. Thermodynamic and kinetic arguments predicted both of the different reaction paths that were observed in the two systems.

Single crystal films of n-type 3C-SiC were hydrothermally processed at pressures ranging from 10 to 70 MPa at 550°C. To study the effects of initial thin film microstructure on hydrothermal processing, two different samples of CVD-grown SiC were studied: one, 200 nm thick, contained low angle boundaries and a high density of planar defects; the other, 3500 nm thick, was planar and contained relatively few defects. Raman Spectroscopy, X-Ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) were used to study the chemistry and microstructure of the SiC material both before and after hydrothermal treatment. This study reveals that low temperature (T=550°C) oxidation of single crystal epitaxial SiC is possible but that the resulting oxide film microstructure is strongly dependent on the initial film microstructure and oxidation is greatly enhanced along low angle grain boundaries and on planar defects.

We have developed a novel solid-state method for forming interfacial silicon dioxide by a two step process of rf sputtering tin-doped indium oxide (ITO), a transparent conductor, onto Si substrates followed by annealing at 800°C in flowing ultra-high purity nitrogen. TEM, XRD, FTIR, and C-V measurements were used to characterize the microstructure and morphology of as-deposited and annealed samples. The silicon dioxide layer grows interfacially between Si and In2O3 and, for a 5 nm thick oxide, is planar on a 2–4 monolayer scale over hundreds of nm. The kinetics of the solid-state interfacial oxidation reaction were studied and a model has been developed.