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Growth of High-Density Zinc Oxide Nanorods on Porous Silicon by Thermal Evaporation
Faculty of Electrical Engineering, Universiti Teknologi Malaysia, Skudai 81310, Johor, Malaysia
School of Electrical System Engineering, Universiti Malaysia Perlis, Kuala Perlis 02000, Perlis, Malaysia
Department of Electrical Engineering, Nagaoka University of Technology, Kamitomioka-machi, Nagaoka, Niigata 940-2137, Japan
Faculty of Electrical Engineering, Universiti Teknologi MARA, Shah Alam 40450, Selangor, Malaysia
Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia, Jalan Semarak, Kuala Lumpur 54100, Malaysia
* Author to whom correspondence should be addressed.
Received: 29 October 2012; in revised form: 28 November 2012 / Accepted: 6 December 2012 / Published: 13 December 2012
Abstract: The formation of high-density zinc oxide (ZnO) nanorods on porous silicon (PS) substrates at growth temperatures of 600–1000 °C by a simple thermal evaporation of zinc (Zn) powder in the presence of oxygen (O2) gas was systematically investigated. The high-density growth of ZnO nanorods with (0002) orientation over a large area was attributed to the rough surface of PS, which provides appropriate planes to promote deposition of Zn or ZnOx seeds as nucleation sites for the subsequent growth of ZnO nanorods. The geometrical morphologies of ZnO nanorods are determined by the ZnOx seed structures, i.e., cluster or layer structures. The flower-like hexagonal-faceted ZnO nanorods grown at 600 °C seem to be generated from the sparsely distributed ZnOx nanoclusters. Vertically aligned hexagonal-faceted ZnO nanorods grown at 800 °C may be inferred from the formation of dense arrays of ZnOx clusters. The formation of disordered ZnO nanorods formed at 1000 °C may due to the formation of a ZnOx seed layer. The growth mechanism involved has been described by a combination of self-catalyzed vapor-liquid-solid (VLS) and vapor-solid (VS) mechanism. The results suggest that for a more precise study on the growth of ZnO nanostructures involving the introduction of seeds, the initial seed structures must be taken into account given their significant effects.
Keywords: zinc oxide; nanorods; porous silicon; thermal evaporation; vapor-liquid-solid
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MDPI and ACS Style
Rusli, N.I.; Tanikawa, M.; Mahmood, M.R.; Yasui, K.; Hashim, A.M. Growth of High-Density Zinc Oxide Nanorods on Porous Silicon by Thermal Evaporation. Materials 2012, 5, 2817-2832.
Rusli NI, Tanikawa M, Mahmood MR, Yasui K, Hashim AM. Growth of High-Density Zinc Oxide Nanorods on Porous Silicon by Thermal Evaporation. Materials. 2012; 5(12):2817-2832.
Rusli, Nurul I.; Tanikawa, Masahiro; Mahmood, Mohamad R.; Yasui, Kanji; Hashim, Abdul M. 2012. "Growth of High-Density Zinc Oxide Nanorods on Porous Silicon by Thermal Evaporation." Materials 5, no. 12: 2817-2832.