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

Controlled, ordered arrays of ZnO nanorods having a high aspect ratio of ∼30:1 and diameter of ∼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 ∼2.85 V νm^-1 and a high field-enhancement factor (β) of ∼1.68 × 10³.