title: Growth mechanism, photoluminescence, and field-emission properties of ZnO nanoneedle arrays.
abstract: ZnO nanoneedle arrays have been grown on a large scale with a chemical vapor deposition method at 680 degrees C. Zn powder and O(2) gas are employed as source materials, and catalyst-free Si plates are used as substrates. Energy-dispersive X-ray and X-ray diffraction analyses show that the nanoneedles are almost pure ZnO and preferentially aligned in the c-axis direction of the wurtzite structure. The growth mechanism of ZnO nanoneedle arrays is discussed with the thermodynamic theory and concluded to be the result of the co-effect of the surface tension and diffusion. Photoluminescence spectrum of the as-grown products shows a strong emission band centering at about 484 nm, which originates from oxygen vacancies. Field-emission examination exhibits that the ZnO nanoneedle arrays have a turn-on voltage at about 5.3 V/microm.
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Graduate School of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100080, P. R. China.
authors.forename: Zengxing
authors.initials: Z
authors.lastname: Zhang
authors.forename: Huajun
authors.initials: H
authors.lastname: Yuan
authors.forename: Jianjun
authors.initials: J
authors.lastname: Zhou
authors.forename: Dongfang
authors.initials: D
authors.lastname: Liu
authors.forename: Shudong
authors.initials: S
authors.lastname: Luo
authors.forename: Yanming
authors.initials: Y
authors.lastname: Miao
authors.forename: Yan
authors.initials: Y
authors.lastname: Gao
authors.forename: Jianxiong
authors.initials: J
authors.lastname: Wang
authors.forename: Lifeng
authors.initials: L
authors.lastname: Liu
authors.forename: Li
authors.initials: L
authors.lastname: Song
authors.forename: Yanjuan
authors.initials: Y
authors.lastname: Xiang
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Zhao
authors.forename: Weiya
authors.initials: W
authors.lastname: Zhou
authors.forename: Sishen
authors.initials: S
authors.lastname: Xie