NO2 sensors made from In2O3 nanowires functionalized with Ag

초록

In2O3 nanowires functionalized with Ag were prepared by thermal evaporation of a mixture of In2O3 and graphite powders followed by sputter deposition of Ag and thermal annealing. The sensors were fabricated using the Ag-functionalized In2O3 nanowires. Scanning electron microscopy showed that In2O3 nanowires with diameters in a range from a few tens to a few hundreds with diameters of a few tens of nanometers. Transmission electron microscopy and X-ray diffraction showed that the nanowires were body-centered cubic-structured polycrystalline In2O3. On the other hand, the nanoparticles were amorphous. The multiple-networked In2O3 nanowire sensors showed a response of 0.79% at 25 ppm NO2 at 100℃ whereas the Ag-functionalized In2O3 nanowire sensors showed a response of 61.37% under the same conditions. Ag-functionalization decreased the recovery time for the In2O3 nanowires regardless of NO2 concentration despite the response time being decreased or increased slightly depending on the NO2 concentration. In addition the enhancement of the sensing properties of the In2O3 nanowires by functionalization with Ag is discussed.