Crystallographic Orientation-Aligned ZnO Nanorods Grown by a Tin Catalyst

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 {21̄1̄0} 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.