A model for the formation of piezoelectric single-crystal nanorings and nanobows

Researchers at Georgia Tech synthesized nanobows and nanobelts by thermal evaporation of ZnO powder. The products were deposited onto a catalyst-free polycrystalline alumina substrate. The thickness-to-radius ratios of 53 nanorings and nanobows were measured using scanning electron microscopy. Results show that nanorings can form with either Zn- or O-terminated inner and outer surfaces, consistent with the electrostatic polar charge model that states bending in either direction is usually probable. Calculations based on the electrostatic polar charge model predicting the thickness/diameter ratios of nanorings formed by the bending of nanobelts show excellent agreement with the ratios measured for synthesized nanorings.