title: Controllable synthesis and optical properties of novel ZnO cone arrays via vapor transport at low temperature.
abstract: Novel ZnO cone arrays with controllable morphologies have been synthesized on silicon (100) substrates by thermal evaporation of metal Zn powder at a low temperature of 570 degrees C without a metal catalyst. Clear structure evolutions were observed using scanning electron microscopy: well-aligned ZnO nanocones, double-cones with growing head cones attached by stem cones, and cones with straight hexagonal pillar were obtained as the distance between the source and the substrates was increased. X-ray diffraction shows that all cone arrays grow along the c-axis. Raman and photoluminescence spectra reveal that the optical properties of the buffer layer between the ZnO cone arrays and the silicon substrates are better than those of the ZnO cone arrays due to high concentration of Zn in the heads of the ZnO cone arrays and higher growth temperature of the buffer layer. The growth of ZnO arrays reveals that the cone arrays are synthesized through a self-catalyzed vapor-liquid-solid (VLS) process.
authors.affiliation: Hefei National Laboratory for Physical Sciences at Microscale, and Department of Physics, University of Science and Technology of China, Hefei 230026, China.
authors.forename: Xinhai
authors.initials: X
authors.lastname: Han
authors.forename: Guanzhong
authors.initials: G
authors.lastname: Wang
authors.forename: Jiansheng
authors.initials: J
authors.lastname: Jie
authors.forename: Wallace C H
authors.initials: WC
authors.lastname: Choy
authors.forename: Yi
authors.initials: Y
authors.lastname: Luo
authors.forename: T I
authors.initials: TI
authors.lastname: Yuk
authors.forename: J G
authors.initials: JG
authors.lastname: Hou