Open Access Nano Express

Tapered ZnO Whiskers: {hkil}-Specific Mosaic Twinning VLS Growth from a Partially Molten Bottom Source

Bang-Hao Huang1, Pouyan Shen1 and Shuei-Yuan Chen2*

Author Affiliations

1 Department of Materials and Optoelectronic Science, Institute of Materials Science and Engineering, National Sun Yat-sen University, Kaohsiung, Taiwan, ROC

2 Department of Mechanical and Automation Engineering, I-Shou University, Kaohsiung, Taiwan, ROC

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Nanoscale Research Letters 2009, 4:503-512  doi:10.1007/s11671-009-9273-2

Published: 25 February 2009

Abstract

Zn particulates overlaid with wurtzite (W)-type ZnO condensates having nearly orthogonal and facets were found to self-catalyze unusual tapered W-ZnO whiskers upon isothermal atmospheric annealing, i.e., thermal oxidation, at 600 °C. Analytical electron microscopic observations indicated that such whiskers formed tapered slabs having mosaic and twinned domains. The tapered whiskers can be rationalized by an alternative vapor–liquid–solid growth, i.e., {hkil}-specific coalescence twinning growth from the ZnO condensates taking advantage of a partially molten bottom source of Zn and the adsorption of atoms at the whisker tips and ledges under the influence of capillarity effect. The tapered whiskers having strong photoluminescence at 391 nm and with a considerable flexibility could have potential applications.

Keywords:
ZnO; Whiskers; Pulsed laser ablation; VLS; Photoluminescence