The Electronic Nose: The Effect of Metal Oxide Modifications to Well-Aligned ZnO Nanowire Arrays for Highly Sensitive and Selective Gas Detection

摘要

To mimic biological olfactory receptor arrays, a three dimensional (3D) "electronic nose" was fabricated by using well-aligned ZnO nanowire arrays modified with different metal oxides. Metal oxide nanowire arrays share 3D structures similar to mammalian olfactory receptor arrays, with thousands of vertically aligned nanowires providing a high reception area which can significantly enhance the sensors' sensitivity. Meanwhile, with different material decorations, each array of nanowires can produce a distinguishable response for each separate analyte, which would provide a promising way to improve the selectivity. We have successfully fabricated gas sensors based on SnO_2, In_2O_3, and WO_3 coatings which have discriminated five gases which are NO_2, H_2S, H_2, NH_3, and CO. The sensitivity to NO_2 and H_2S has reached down to the ppb level.