To effectively passivate the technologically important GaAs ͑001͒ surfaces, in situ deposition of Al 2 O 3 was carried out with molecular beam epitaxy. The impacts of initial GaAs surface reconstruction and post-deposition annealing have been systematically investigated. The corresponding interfacial state density ͑D it ͒ were derived by applying the conductance method at 25 and 150°C on both p-type and n-type GaAs metal-oxide-semiconductor capacitors to establish the D it spectra in proximity of the critical midgap region. We show that significant reduction of D it near the midgap is achieved by applying an optimized thermal annealing on samples grown on a Ga-rich ͑4 ϫ 6͒ reconstructed surface.

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Hexagonal, single-crystalline, diamond nanoplatelets synthesized by microwave plasma (MP)CVD on Au-Ge alloy and nanocrystalline diamond (nc-diamond) film substrates, respectively, are reported. On the nc-diamond matrix, hexagonal diamond nanoplatelets can grow to a thickness of as little as approximately 10 nm. The effects of various processing parameters, such as methane concentration, microwave power, and gas pressure, on the growth of diamond nanoplatelets are explored. High-resolution transmission electron microscopy (HRTEM) reveals that the diamond nanoplatelets contain multi-parallel twins, and the side faces of the platelets exhibit {100}/{111} ridge-and-trough structure. Anisotropic growth of diamond nanoplatelet is believed to result from the side face structure of the twinned platelets and intensive plasma reaction.

The thermal decomposition of silver paste with the addition of a metallo-organic decomposition (MOD) compound generally requires a curing time of greater than 10 min and a curing temperature greater than 250 C, which does not meet the requirement for high-speed production in flexible substrates. In this study, attempts to modify the curing conditions of MOD silver pastes through the substitutions of silver flakes with silver(I) oxide (Ag 2 O) and silver(II) oxide (AgO) were performed. Differential thermal analysis (DTA), derivative thermogravimetric analysis (DTG), and X-ray diffraction (XRD) results indicated that the presence of residual silver oxide, which effectively catalyzes the evaporation of -terpineol and the decomposition of silver 2-ethylhexanoate, decreases the curing temperature and shortens the soaking time. The reduced silver and the remaining Ag 2 O enhance the connectivity and packing density of the silver flakes, and thus increase the electric conductivity of the films. For films prepared from pastes with 20 wt % Ag 2 O or AgO, resistivities of 14 Â 10 À6 and 19 Â 10 À6 mÁcm, respectively, were successfully achieved after being cured at 200 C for 5 min.

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In this study, the effects of the solvent and atmosphere on the thermal decomposition behaviors of silver 2-ethylhexanoate and -terpenol are investigated. Low-curing-temperature silver pastes made from Ag flakes, -terpineol and various amounts of silver 2-ethylhexanoate, were prepared and characterized. The microstructures and resistivities of cured films screen-printed from the pastes were examined. The results of thermal analysis in oxidizing and reducing atmospheres revealed that thermal decomposition is the dominating reaction during the heating process of silver 2-ethylhexanoate, even though the differential scanning calorimetry (DSC) result revealed an exothermic reaction for silver 2-ethylhexanoate heated in air due to oxidation. Thermal decomposition left almost pure Ag particles, which is beneficial for bridging between silver flake particles in the films. On the basis of the rheological behavior, microstructural evolution and electrical evaluation, it can be concluded that a low-curing-temperature silver paste with 5 wt % silver 2-ethylhexanoate addition is the best formulation, which possesses shear-thinning and thixotropic properties and a resistivity of 7:8 Â 10 À6 cm after being cured at 250 C, which is relatively close to the bulk resistivity of Ag.

Six low-temperature-curing silver pastes were prepared from silver flake, -terpineol and various metallo-organic decomposition (MOD) compounds. The thermal decomposition behaviors of the pastes were determined. The microstructures and resistivities of screen-printed films on alumina substrate after thermal treatment were characterized and discussed. Results indicated that 2-ethylhexanoate possesses the lowest decomposition temperature (190.3 C) among the MOD agents studied, and it forms silver particles to promote the linking of silver flake powders and thus reduces the resistivity to <13 mÁcm at a temperature as low as 200 C.