Probing the highly efficient room temperature ammonia gas sensing properties of a luminescent ZnO nanowire array prepared via an AAO-assisted template route.

Here, we report the facile synthesis of a highly ordered luminescent ZnO nanowire array using a low temperature anodic aluminium oxide (AAO) template route which can be economically produced in large scale quantity. The as-synthesized nanowires have diameters ranging from 60 to 70 nm and length ∼11 µm. The photoluminescence spectrum reveals that the AAO/ZnO assembly has a strong green emission peak at 490 nm upon excitation at a wavelength of 406 nm. Furthermore, the ZnO nanowire array-based gas sensor has been fabricated by a simple micromechanical technique and its NH3 gas sensing properties have been explored thoroughly. The fabricated gas sensor exhibits excellent sensitivity and fast response to NH3 gas at room temperature. Moreover, for 50 ppm NH3 concentration, the observed value of sensitivity is around 68%, while the response and recovery times are 28 and 29 seconds, respectively. The present synthesis technique to produce a highly ordered ZnO nanowire array and a fabricated gas sensor has great potential to push the low cost gas sensing nanotechnology.