Electrical Characterization of ZnO Single Nanowire Device for Chemical Sensor Application

Vertically well-aligned high quality ZnO nanowires were grown on GaN epilayer on c-plane sapphire via a vapor-liquid-solid (VLS) process by introducing an Au thin film (3 nm) as a catalyst. ZnO single nanowire device was ingenuously fabricated by combining conventional optical lithography and high resolution electron beam lithography and its current–voltage characteristics were measured with doing the post process to acquire reproducible performance as a chemical gas sensor. And its temperature dependent current–voltage characteristics were measured to investigate temperature dependant electrical transport. The ZnO nanowire device showed slightly non-ohmic current–voltage characteristics which may be due to back-to-back configuration of the diodes with the insulating contact barriers and showed an relatively small activation energy of 0.2 eV. To test our device as a chemical sensor, the NO₂ gas response was reported at the elevated temperature.