With low energy electron irradiation in the 80–250keV range, we were able to create only those intrinsic defects related to the initial displacements of carbon atoms in the silicon carbide lattice. Radiation induced majority and minority carrier traps were analyzed using capacitance transient techniques. Four electron traps (EH1, Z1∕Z2, EH3, and EH7) and one hole trap (HS2) were detected in the measured temperature range. Their concentrations show linear increase with the irradiation dose, indicating that no divacancies or di-interstitials are generated. None of the observed defects was found to be an intrinsic defect–impurity complex. The energy dependence of the defect introduction rates and annealing behavior are presented and possible microscopic models for the defects are discussed. No further defects were detected for electron energies above the previously assigned threshold for the displacement of the silicon atom at 250keV.

CuO-CeO2 nanospheres with a porous structure were synthesized by an improved urea method involving first hydrothermal treatment to get Ce-Cu binary precursor and then the calcination of the precursor. The CuO-CeO2 nanospheres consist of spherical particles with diameters in the range of 300-400 nm. These nanospheres are actually composed of nanoparticles of ca. 10 nm, resulting in the formation of a mesoporous structure. Compared with conventional urea method, in which Ce-Cu binary precursor is commonly achieved in an oil bath at appropriate temperature, the Ce-Cu binary precursor obtained via the hydrothermal process could be more highly homogeneous and more highly interdispersed CuO-CeO2 thus was formed. In addition, the resulted porous CuO-CeO2 catalyst has a lower CO oxidation temperature of as low as 71 °C.

Strontium tungstate nanoparticles with diameters of 40-50 nm, nanopeanuts with diameters of 100-150 nm, and nanorods with a rough surface were controllably synthesized by a solvothermal-mediated microemulsion method. Various comparison experiments showed that several experimental parameters, such as the molar ratio (w) between water and CTAB and the concentration of reactants, played important roles for the morphological control of Sr(NO 3 ) 2 nanostructures. When the concentration of the Sr(NO 3 ) 2 aqueous solution was kept at 0.3 M, the morphology of the as-synthesized products elongated from nanospheres, to nanopeanuts, and to nanorods with the increase of the w value. A possible mechanism is proposed for the selective formation of the different morphologies. The SrWO 4 samples with different morphologies exhibited different photoluminescent properties. X-ray powder diffraction, transmission electron microscopy, selected area electron diffraction, and field-emission scanning electron microscopey were used to characterize these products.

Gallium nitride (GaN)-based vertical power Schottky barrier diode (SBD) has demonstrated outstanding features in high-frequency and high-power applications. This paper reviews recent progress on GaN-based vertical power SBDs, including the following sections. First, the benchmark for GaN vertical SBDs with different substrates (Si, sapphire, and GaN) are presented. Then, the latest progress in the edge terminal techniques are discussed. Finally, a typical fabrication flow of vertical GaN SBDs is also illustrated briefly.