Abstract
In-doped ZnO (IZO) nanoparticles have been prepared by sol-gel route and drying in ethanol under supercritical conditions. The morphological, microstructural and optical properties were investigated by transmission electron microscopy (TEM) analysis, X-ray powder diffraction (XRD) and UV-Vis-IR spectroscopy, respectively. Characterization data showed that both the pure ZnO and IZO nanoparticles have the hexagonal wurtzite structure, whereas the optical band gap decreases with the incorporation of indium dopant. Sensing devices consisting of a thick layer of IZO nanoparticles on interdigitated alumina substrates have been fabricated and their sensing characteristics were investigated. The sensor response and the high selectivity of the IZO nano-powders for carbon monoxide (CO) were reported.