Controlled selective growth of ZnO nanorod arrays and their field emission properties

Controlled, ordered arrays of ZnO nanorods having a high aspect ratio of similar to 30: 1 and diameter of similar to 50 nm were fabricated on silicon substrates by combining electron-beam lithography and simple solution growth techniques. This top-down and bottom-up hybrid approach resulted in excellent control of periodicity, location, and density of ZnO nanorod arrays on silicon substrates. The field emission measurements from the as-grown ZnO nanorod arrays showed a low turn-on field of similar to 2.85 V mu m(-1) and a high field-enhancement factor (beta) of similar to 1.68 x 10(3).