Synthesis and characterization of ZnO nanorings with ZnO nanowires array aligned at the inner surface without catalyst

ZnO nanorings with nanowires array aligned at the inner surface were first synthesized by evaporating ZnO powder in methanol/argon atmosphere at 1140 °C without the assistance of any catalyst. The products were characterized by X-ray diffraction, scanning electron microscopy equipped with energy spectrum and transmission electron microscopy. Nanorings with a diameter of approximate 3 μm were fabricated with self-assembled bent nanocombs at the side of inner surface. The results revealed that the mechanism of ZnO nanorings with nanowires array aligned at the inner surface can be addressed by two unique features of the polar surfaces simultaneously, i.e. polar charge induced by minimizing energy and different chemical activities between different ionic-terminated surfaces.