Crystallographic Orientation-Aligned ZnO Nanorods Grown By A Tin Catalyst

Abstract

Well-aligned ZnO nanorods with identical crystallographic orientation have been synthesized using a vapor transport deposition process. Orientation-ordered nanorods grow normal to the c planes of the as-deposited micrometer-sized ZnO rods on a polycrystalline Al2O3 substrate, and each nanorod is along [0001] and enclosed by {21h1h0} facet surfaces. The nanorods remain in an identical crystal orientation with a homoepitaxial orientation relationship with the microrod. During the synthesis, reduced Sn from SnO2 powder added to the source materials functions as a catalyst, guiding the orientation-aligned growth of ZnO nanorods. By controlling the growth time at high temperature, uniform lengths of aligned nanorods have been received. This work demonstrates that metallic Sn could be a good candidate for catalyzing the growth of 1D nanostructures. Zinc oxide, a wide band gap (3.37 eV) semiconducting, piezoelectric, and photoconducting material, has a wide range of applications in solar cells,1 sensors,2-4 optoelectronic devices, and surface acoustic waveguides.5 Recently, 1D nanostructures of ZnO, including nanowires,6 nanobelts,7 and nanotubes,8 have been attracting vast interest in the field of nanotechnology. Hierarchy and aligned ZnO nanostructure