Growth and Characterization of Vertically Aligned Nonpolar [11̅00] Orientation ZnO Nanostructures on (100) γ-LiAlO 2 Substrate

In this work, we demonstrate the capability of controlling the crystallographic orientation of ZnO nanostructure arrays grown along nonpolar [1 (1) over bar 00] orientation. The Au catalyst was used to initiate and guide the growth of ZnO nanostructures on (100) gamma-LiAlO2 substrate. The morphology, structure, and optical properties of the as-synthesized ZnO nanostructures were characterized by field emission scanning electron microscopy, X-ray diffraction, field emission transmission electron microscope, monochromatic cathodoluminescence image, and photoluminescence spectroscopy. The ZnO nanostructure arrays exhibited special shape and were aligned vertically on the (100) gamma-LiAlO2 substrate. A cooperative of Au-catalyzed VLS vertebral column growth along [1 (1) over bar 00] orientation, zinc-self-catalyzed VLS growth along [0001], and ZnO VS lateral expansion growth process was proposed for the special ZnO nanostructures.