ZnO nanorod arrays were fabricated in aqueous solutions under external voltages.The morphology and length of the nanorods could be readily controlled by varying such parameters as the voltage magnitude,growth time,solution concentration and substrate type.The external voltage,which made the adsorption of the Zn 2+ cation-containing complexes more possible,modified the growth behavior of the ZnO crystals and played a key role in guaranteeing the orderliness of the arrays.The increase in the nanorod length with the prolonged growth time gradually saturated due to the balance between the growth and the erosion.The ZnO nanorods respectively grown on the Zn and Si substrates differed considerably in both morphology and defect concentration.Field emission was extracted from arrays of nanorods with tapered ends.This field-assisted solution route for fabricating ZnO nanorods featured simplicity in manipulation,inexpensiveness in instrumentation,and effectiveness in controlling the morphology and length. ZnO nanorod arrays were fabricated in aqueous solutions under external voltages. The morphology and length of the nanorods could be modifying controlled by varying such parameters as the voltage magnitude, growth time, solution concentration and substrate type. External voltage, which made the adsorption of the Zn 2+ cation-containing complexes more possible, modified the growth behavior of the ZnO crystals and played a key role in guaranteeing the orderliness of the arrays. increase in the nanorod length with the prolonged growth time gradually saturated due to the balance between the growth and the erosion. ZnO nanorods respectively grown on the Zn and Si substrates differed substantially in both morphology and defect concentration. Field emission was extracted from arrays of nanorods with tapered ends. in manipulation, inexpensiveness in instrumentation, and effectiveness in controlling the morphology a nd length.