Selective growth of vertical and horizontal ZnO nanowires for device applications

We report on the growth of ZnO nanowire (NW) arrays on selected areas by using a vapor phase deposition technique. For vertically aligned ZnO NW growth, we used ZnO thin films as seed layers. We confined the NW growth area by patterning SiO₂ thin films, which suppressed the NW formation on the surface. To fabricate horizontal NW devices, we used Au nano-particles as a catalyst, resulting in laterally grown NWs with random directions. Two neighboring metal electrodes, bridged by horizontal NWs, showed reproducible transport properties. We noted that the morphology and the optical properties of the vertical and the horizontal NWs were different. This suggests that our growth direction control is accompanied by distinct growth behaviors.