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Highlights: [•] A bioactive coating was produced on porous Ti surface by an amendatory chemical method. [•] The structure of coating consisted of three layers: Ti substrate, intermediate layer and the outer surface. [•] The coating cross-sectional showed a compositional gradient from the intermediate layer toward the outer surface. [•] The coating exhibits a high ability to form apatite because of the hydroxyl functionalized surface with numerous Ca ions. [ABSTRACT FROM AUTHOR]

AlGaAs materials are used in a variety of cutting-edge devices and the band gap states after the surface oxidization is found with Fermi level pinning. With first-principle calculations, we explore the formation of gap states during the initial stage of native-oxide growth on Al 0.5 Ga 0.5 As (001) surface. The results indicate that oxygen adsorption at the bridge sites of Al (Ga)-As satisfies the bond saturation and doesn't lead to any effect on the surface gap states. The breaking of As-As dimer results in the defect states in band gap with Fermi level pining due to the replacement of oxygen. In the oxidization process, it is found that the As-As dimer is very easy to be broken. In addition, the defect states in band gap maybe disappear after the full oxidization of surface with the elimination of unsaturated As on surface. With these gap states, some absorption peaks are found to appear in the range of 0–1 eV in the absorption spectra. [ABSTRACT FROM AUTHOR]

Abstract: Vertically aligned ZnO nanowires (NWs) can be reconstructed on large scales by a solvent-evaporation-induced method. The morphologies of the nanowires are regulated by changing the concentration of the solution. Possible mechanism, which the compressive residual stresses and wires/wires self-attraction can be responsible for the surface reconstruction, is addressed. Furthermore, we compare the structural properties of ZnO nanowires before and after reconstructed. [ABSTRACT FROM AUTHOR]