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Abstract: Anatase TiO2 hollow microspheres with a high percentage of exposed {001} facets have been successfully synthesized by a one-step hydrothermal strategy in the presence of hydrogen peroxide and hydrofluoric acid solution. It is found that both HF and H2O2 play an essential role in the formation of TiO2 hollow polyhedron TiO2 microspheres with exposed {001} facets. A plausible mechanism for formation of the TiO2 hollow spheres with exposed {001} facets by dissolution–recrystallization and Ostwald ripening is proposed based on the experimental observations. The products exhibited enhanced photocatalytic activities for degradation of methylene blue dye present in aqueous solution under ultraviolet light irradiation at ambient temperature. [Copyright &y& Elsevier]

Abstract: Unintentionally doped high-Al-content Al0.45Ga0.55N/GaN high electron mobility transistor (HEMT) structures with and without AlN interfacial layer were grown by metal–organic chemical vapor deposition (MOCVD) on two-inch sapphire substrates. The effects of AlN interfacial layer on the electrical properties were investigated. At 300K, high two-dimensional electron gas (2DEG) density of 1.66×1013 cm−2 and high electron mobility of 1346cm2 V−1 s−1 were obtained for the high Al content HEMT structure with a 1nm AlN interfacial layer, consistent with the low average sheet resistance of 287Ω/sq. The comparison of HEMT wafers with and without AlN interfacial layer shows that high Al content AlGaN/AlN/GaN heterostructures are potential in improving the electrical properties of HEMT structures and the device performances. [Copyright &y& Elsevier]

Abstract: The spectroscopy of the adsorbed silane coupling agent on micro-sized silica particles was observed by 1H solid state NMR (SSNMR) under fast magic angle spinning (MAS). We found that this is a fast and effective way to characterize the structure and dynamics of the thin layer of coupling agent on the surface of micro-sized silica. Compared with conventional 29Si NMR spectroscopy and other methods, the present proton solid state NMR is a promising method to characterize the adsorbed layer on micro-sized silica. [Copyright &y& Elsevier]