Cu-Doped ZnO Nanoneedles and Nanonails: Morphological Evolution and Physical Properties

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• 作者：Zhou Zhang ; Jia Bao Yi ; Jun Ding ; Lai Mun Wong ; Hwee Leng Seng ; Shi Jie Wang ; Jun Guang Tao ; Gong Ping Li ; Guo Zhong Xing ; Tze Chien Sum ; Cheng Hon Alfred Huan ; Tom Wu
• 刊名：Journal of Physical Chemistry C
• 出版年：2008
• 出版时间：July 3, 2008
• 年：2008
• 卷：112
• 期：26
• 页码：9579 - 9585
• 全文大小：2392K
• 年卷期：v.112,no.26(July 3, 2008)
• ISSN：1932-7455

文摘

Controlling novel morphologies and developing effective doping strategies are two important tasks for advancing ZnO-based nanomaterials. We have grown vertically aligned Cu-doped ZnO nanonails and nanoneedles and observed a continuous evolution between various morphologies. Selecting source compositions and regulating vapor and gas pressures modify the Ehrlich−Schwoebel energy barrier for the surface diffusion and determine the morphologies. X-ray diffraction study indicates a decrease in the lattice parameter after the Cu doping. Photoluminescence measurements taken on both doped and undoped samples show that, in the Cu-doped ZnO nanostructures, the band-edge UV emission and the broad green emission are red-shifted by ~7 and 20 nm, respectively. X-ray photoelectron spectroscopy study revealed a higher level of oxygen vacancies in nanoneedles, which was found to enhance the green emission. Room-temperature ferromagnetism was also observed in Cu-doped ZnO nanomaterials. On the basis of the strong correlations between structures and properties, we demonstrate that the morphologies and the optical and magnetic characteristics can be tailored to a large degree in transition-metal-doped ZnO nanostructures.