Site-controlled growth and field emission properties of ZnO nanorod arrays

ZnO nanorod arrays with different structures were grown on Si substrates at different temperatures by using a chemical vapor transport process. The growth sites and population of ZnO nanorods were controlled by the primarily grown micropyramids. The density and size of these nanorods were greatly affected by the growth temperature. A growth mechanism is proposed which attributes the overgrowth of ZnO nanorods to the orientation adhesion and to the difference in the saturation pressure at different temperatures. The field emission (FE) measurements show that the high density arrays of small nanorods exhibit excellent FE properties.