ZnO nanowires and nanobelts: Structure switch by indium doping

Wire or belt-like ZnO one-dimensional nanostructures have been fabricated by various techniques in recent literature. We show that, in a steady-state vapor transport growth mode, the resulting ZnO product under similar growth conditions can be switched between [0001]-axial nanowires and < 1120 > - axial nanobelts simply by adding indium to the source. The former appear as ordered vertical arrays of pure ZnO while the latter are large aspect-ratio belts without spatial ordering. The growth mechanism is intensively discussed based on the examination of their early growth stages and analytical thermodynamic modeling. The calculation result agrees with the experiment observation, that in-situ indium doping influences the nucleation, and supports the dominating growth of a-axial nanobelts over c-axial nanowires.