A Sonochemical Approach to the Fabrication of Laterally Aligned ZnO Nanorod Field Emitter Arrays on a Planar Substrate

A simple and novel sonochemical route has been demonstrated to produce the lateral growth of zinc oxide (ZnO) nanorod arrays on a quartz wafer without the use of metal catalysts. Highly crystalline ZnO nanorods grew laterally on the edge of a Zn thin film seed layer, with preferential growth along the [0001] direction. The average diameter and length of the ZnO nanorods, grown laterally from the edge of the Zn thin film, were 156 and 933 nm, respectively. The vertical growth of ZnO nanorods on the top surface of the seed layer was suppressed by a Si thin film growth barrier. The lateral ZnO nanorod arrays showed excellent field emission properties, 60 mA/cm² at 6.5 V/μm, with a low turn-on field in the range of 3.9-4.0 V/μm. Because of the compatibility of this process with current standard semiconductor microfabrication technologies, this sonochemical approach constitutes a practical technique for the design of state-of-the-art nanodevices based on laterally grown ZnO nanorod arrays on planar substrates.