Room temperature NO2 sensing performance of free-standing mesh-structure vanadium dioxide nanorods by a chemical vapour deposition method

The free-standing vanadium dioxide nanorods were successfully fabricated by chemical vapour deposition method. The effect of the deposition temperature on the microstructure of nanorods and room temperature NO2 sensing properties were studied. The morphology and crystal structure of as-grown nanorods were characterized by scanning electron microscopy, X-ray diffraction and RTS-8 four probe methods. The results show the free-standing mesh-structure and monoclinic crystalline structure of VO2 nanorods. Room temperature gas sensing measurements of sensors to NO2 with concentration span from 1 to 5 ppm were carried out. The results reveal that the sensors exhibit perfect reversibility with relatively high sensor response value up to 2.42 and fast response and recovery characteristics to NO2 in the n-type semiconducting state. Furthermore, NO2-sensing mechanisms of VO2 nanorods were further explained. These results are significant to the standpoint of VO2 applications in room temperature gas sensor. (C) 2016 Elsevier B.V. All rights reserved.