Horizontal growth and <i>in situ</i> assembly of oriented zinc oxide nanowires

Abstract

The positioning and directed assembly of semiconductor nanowires (NWs) is of considerable current interest for “bottom-up” approaches to the engineering of intricate structures from nanoscale building blocks. We report a horizontal growth mode for ZnO NWs on the (112¯0) sapphire surface in which NWs grow in the [11¯00]sap direction. This growth mode strictly depends on the size and spacing of the Au nanodroplet catalysts and competes with the vertical growth of the NWs. An approach is presented which promotes the horizontal growth, in situ alignment, and predictable positioning of ZnO NWs. This strategy allows for the large scale assembly of NWs, width control, and production of quantum wires.