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Oxide semiconductor alloys of x(LiGaO2)1/2-(1− x)ZnO were fabricated by the solid state reaction between β-LiGaO2 and ZnO and rf-magnetron sputtering. For the solid state reaction, the wurtzite-type single phases were obtained in the composition range of x⩽0.38. The formation range of the alloys was wider than that of the (Mg1− x Zn x )O system, because the β-LiGaO2 possesses a wurtzite-derived structure and approximately the same lattice constants with ZnO. The electrical resistivity and energy band gap of the 0.38(LiGaO2)1/2-0.62ZnO alloyed ceramic were 0.45 Ωcm and 3.7 eV, respectively, at room temperature. For the alloying by sputtering, the films consisting of the wurtzite-type single phase were obtained over the entire composition range of x(LiGaO2)1/2-(1− x)ZnO. The energy band gap was controllable in the range from 3.3 to 5.6 eV. For the as-deposited film fabricated using the 0.4(LiGaO2)1/2-0.6ZnO alloyed ceramic target, the energy band gap was 3.74 eV, and the electrical resistivity, carrier density and the Hall mobility at room temperature were 3.6 Ωcm, 3.4×1017 cm−3 and 5.6 cm2 V−1 s−1, respectively. [ABSTRACT FROM AUTHOR]

Abstract: The hydrothermal synthesis of anatase-type TiO2 films on Ti and Ti–Nb substrates was examined with a focus on crystallinity and surface morphology of the films. The substrates were chemically treated with H2O2/HCl or H2O2/HNO3 solution to prepare amorphous-like TiO2. The hydrothermal treatment of the resultant films was performed in an autoclave with deionized water or NH3 aqueous solution. The synthesized anatase-type TiO2 films showed high crystallinity and rectangular morphology. The (Ti, Nb)O2 film could be obtained by using Ti–Nb alloys as substrates. [Copyright &y& Elsevier]

We successfully fabricated core/shell-type composite QDs based on the ternary-CuInSe2. For the CuInSe2/ZnSe core/shell QDs, an enhanced photoluminescence (PL) emission intensity, such as 16% of the photoluminescence quantum yield (PLQY), and a blue-shift in the emission after the ZnSe coating, were observed. The increase in the PLQY was the result of an exchange of the surface capping ligand from the organic hexadecylamine to the inorganic ZnSe and the smoothing of the confining profile due to the alloying. The blue-shift was attributed to the shrinkage of the effective size of the core-CuInSe2 region due to the partial alloying of the core-CuInSe2 with the ZnSe-shell around their interfaces. For the inverted core/shell QDs, i.e., the nominally ZnSe/CuIn5Se8 core/shell QDs, they showed a red emission at 619 nm. The emission wavelength is the shortest among the previously reported QDs in Cu-In-Se system.

A novel synthesis route to organic-capped and colloidal ZnO quantum dots (QDs) has been developed. Specifically, zinc-di-t-butoxide and zinc-di-n-butoxide are hydrolyzed by very dilute water (400-600 mass ppm) in hydrophilic benzylamine and polymerized to ZnO by dehydration and/or a butanol elimination reaction. Growth of the ZnO QDs and exchange of the surface capping ligand from the hydroxyl groups and/or benzylamine to the oleylamine occur by heating the colloidal solution after addition of the oleylamine at 100-180°C. The final ZnO QDs with diameters in the range of 3-7 nm are highly dispersible in various organic solvents. The ZnO QDs exhibit the quantum size effect upon UV emission; it was controlled between 3.39 and 3.54 eV in the present study. The defect-related Vis emission decreased and the UV emission becomes dominant when zinc-di-n-butoxide with a 99.99% zinc purity is used as the starting material. The intensity of the photoluminescence UV emission is 1.5 times higher than that of the Vis emission., (Copyright © 2010 Elsevier Inc. All rights reserved.)