Elsevier

Materials Chemistry and Physics

Volume 82, Issue 3, 20 December 2003, Pages 997-1001
Materials Chemistry and Physics

Catalytic growth of ZnO nanotubes

https://doi.org/10.1016/j.matchemphys.2003.09.004Get rights and content

Abstract

ZnO nanotubes were synthesized on Au-coated silicon substrate by physical evaporation of the mixture of ZnO and graphite powders. The products were characterized by means of SEM, XRD, TEM and EDS. The as-prepared ZnO nanotube was a single crystal. A model for the VLS growth mechanism of ZnO nanotubes was presented.

Introduction

The discovery of carbon nanotubes by Iijima in 1991 has initiated intense experimental and theoretical interests in such tubular structure [1]. Up to now considerable efforts have been placed on the synthesis of different kinds of nanotubes, many other kinds of nanotubes such as sulfides, nitrides, and oxides have been reported. The formation of tubular nanostructure generally requires a layered or anisotropic crystal structure. Similar to the process for carbon nanotubes, WS2 [2], MoS2 [3], BN [4] nanotubes, which materials possess layer-like structural features, were synthesized by high temperature process. On the other hand, there are reports of nanotubes made from silica, alumina and metals that do not have a layered crystal; they are synthesized by using carbon nanotubes and porous membrane as template [5], [6]. However, these nanotubes are either amorphous, polycrystalline, or exist only in ultrahigh vacuum [7]. The growth of single crystal semiconductor nanotubes would be advantageous in potential nanoscale electronics, optoelectronics and biochemical-sensing applications.

ZnO is an important semiconductor material and has been investigated widely for its catalytic, electrical, optoelectronic and photochemical properties [8], [9]. Due to the size effect and quantum confinement effect, vast interests have been devoted to grow ZnO whiskers, nanowires and nanobelts in the past decade [10], [11], [12], [13], [14], [15], [16]. The room temperature ultraviolet laser in well aligned ZnO nanowires array has been demonstrated. Recently, ZnO nanotubes combined with Zn–ZnO nanocables were reported [17], [18]. Is it possible to synthesize ZnO nanotubes by the high temperature process like carbon nanotubes? In this paper ZnO nanotubes were synthesized on Au-coated silicon substrate by physical evaporation of the mixture of ZnO and graphite powders.

Section snippets

Experimental

ZnO powders mixed with graphite (molar ratio 1:1) were used as source materials. The reaction system consists of a horizontal tube furnace and quartz tube. The source materials were placed at the center of an alumina crucible, and the crucible was placed at the center of quartz tube mounted in a horizontal tube furnace. Silicon piece (Si [1 0 0]) coated with Au (about 3 nm) was placed 1–5 cm downstream from the center. The thickness of Au film was controlled by the evaporation time. The furnace was

Results and discussion

XRD results (shown in Fig. 1) demonstrated the product was ZnO, and all peaks could be indexed to a hexagonal structure. The morphology of as-prepared products were characterized by SEM and shown in Fig. 2. Two types of one-dimensional ZnO nanostructure were identified on the basis of morphology. As shown in Fig. 2(a), the product is observed as entangled and curved wire-like structures (denoted as Type I). Fig. 2(a1) (the inset in Fig. 2(a)) was a magnified view of Fig. 2(a). The length of

Conclusions

In summary, ZnO nanotubes were synthesized on Au-coated silicon substrate by physical evaporation of the mixture of ZnO and graphite powders. The as-prepared ZnO nanotube was a single crystal. The growth was controlled by VLS mechanism. A simple model for VLS growth mechanism was built up.

Acknowledgements

This work was supported by NSFC (20025102, 50028201, 20151001) and the state key project of fundamental research for nanomaterials and nanostructures.

References (22)

  • Y.W. Wang et al.

    J. Cryst. Growth

    (2002)
  • S. Iijima

    Nature

    (1991)
  • R. Tenne et al.

    Nature

    (1992)
  • Y. Feldman et al.

    Science

    (1995)
  • E.J.M. Hamilton et al.

    Science

    (1993)
  • C.R. Martin

    Science

    (1994)
  • P.M. Ajayan et al.

    Nature

    (1995)
  • Y. Kondo et al.

    Science

    (2000)
  • L. Vayssieres et al.

    Chem. Mater.

    (2001)
  • M.H. Huang et al.

    Science

    (2001)
  • M.H. Huang et al.

    Adv. Mater.

    (2001)
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