Patterned growth and field emission of ZnO nanowires

A simple and reliable method has been developed for the controlled patterned growth of ZnO nanowire arrays with different sizes on silicon substrates. A patterned Au catalyst film was prepared on the silicon wafer by a combination of r.f. magnetron sputtering and photolithographic patterning processes, and the patterned ZnO nanowires with different diameters were synthesized via vapor phase transport. Scanning electron microscopy (SEM) showed that the diameters of the nanowires were scattered in a range of 100–400 nm and the length up to 8 μm. The measurement of field emission (FE) revealed that the as-synthesized patterned ZnO nanowire arrays have a low turn-on field of 2.4 V/μm at the current density of 0.1 μA/cm2. This approach opens the possibility of creating micropatterns, one-dimensional nanostructures for application as FE-based flat panel displays, sensor arrays, and optoelectronic devices.