Web Release Date: February 22,
Influence of Temperature on Evolution of Coaxial ZnO/Al2O3 One-Dimensional Heterostructures: From Core-Shell Nanowires to Spinel Nanotubes and Porous Nanowires
and
Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany, and IMTEK, Faculty of Applied Science, Albert-Ludwigs-University Freiburg, Georges-Köhler-Allee, 79110 Freiburg, Germany
Received: November 16, 2007
In Final Form: January 4, 2008
Abstract:
In this paper, we present the influence of temperature on the Kirkendall effect-related evolution of coaxial
ZnO/Al2O3 one-dimensional heterostructures based on a solid-state reaction. Controllable fabrication of spinel
ZnAl2O4-based nanotubes and porous nanowires can step-by-step be achieved from ZnO/Al2O3 core-shell
nanowires with a change in the reaction temperature. In particular, we demonstrate that the formation of
completely hollow nanotubes in this system is not strictly limited to a fixed stoichiometry of ZnO/Al2O3
required for the spinel-forming reaction when an annealing temperature of 800 
C is employed. Combined
with atomic layer deposition, the wall thickness of the formed nanotubes can be further precisely tailored and
defined. Our finding provides an effective route to fabricate spinel nanotubes as well as nanotube arrays on
a large scale.
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