Single-crystalline ZnO nanowires on zinc substrate by a simple hydrothermal synthesis method

A simple synthesis route to long ZnO nanowires with high aspect ratio of up to ∼ 1000 on zinc substrate in the NaOH aqueous solution was reported, without the assistance of any catalyst, templates or high temperature. We studied the key influencing factors including the reaction time and the solution concentration. With the increase of reaction time from 12 h to 24 h, the average length of ZnO nanowires would increase correspondingly. Through this synthesis route, we can obtain a mass of products and the method is both convenient and reproducible. The as-grown ZnO nanowires are single crystalline with a wurtzite structure.