Different morphologies of ZnO nanorods and their sensing property

Different morphologies of one-dimensional (1D) ZnO nanocrystals were successfully synthesized by hydrothermal process with cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS) and polyethylene glycol (PEG) assisted. The morphology and structure of crystals were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis. Gas sensors have been fabricated using the 1D ZnO crystals to examine the responses to NO2 and CO gases over a range of operating temperature from 150 to 450 °C. The effect of surfactant and calcination condition, as well as morphologies obtained by different synthesized methods on sensing property were systematically investigated. The response of NO2 was greatly enhanced from 239.5 to 470.0 by the addition of 5% cadmium element as dopant during CTAB-assisted low temperature hydrothermal process. The effect of Cd loading on the gas sensing property and the sensing mechanism were discussed.