Chemically synthesized one-dimensional zinc oxide nanorods for ethanol sensing

One-dimensional (1D), single-phase (0 0 2) crystalline zinc oxide (ZnO) nanorod (NR) based conductometric sensors have been developed and investigated toward ethanol (C2H5OH) vapor. The ZnO NRs were chemically deposited onto conductometric transducer of alumina substrates employing a simple hydrothermal method. To facilitate the nucleation of ZnO NRs for oriented growth from the substrate, a seed layer of ZnO nanoparticles was pre-deposited employing filtered cathodic vacuum arc (FCVA) deposition technique onto the substrate containing pre-patterned interdigital electrodes (IDTs). Micro-characterization studies revealed that the NRs have a single crystal 1D structure with an average diameter of 30-50 nm. The developed sensors were exposed toward ethanol of different concentrations at temperature up to 330 °C. An optimum sensor operational temperature was found between 280 and 310 °C. At this temperature range, high sensitivity, fast response and fast recovery in conjunction with a stable baseline occur. The long-term stability test of the developed sensors confirmed that they are highly stable with only less than 3% variation of the dynamic performances (baseline resistance, sensitivity, response and recovery time).