Thin film zinc oxide gas sensor fabricated using near-field electrospray

Near-field electrospray was used to deposit zinc acetate precursor particles over comb electrodes. These particles were heated and oxidized to form a zinc oxide (ZnO) semiconductor at 500 °C. The resulting ZnO thin film on the comb electrode was incorporated into a gas sensor, which was examined using a custom built measurement system. The current that was measured through the electrodes was used to calculate the resistance of the ZnO between the fingers of the comb electrode. The resistance decreased as the sensor was exposed to the target gas of ethanol, while the sensing response (R0/Rg) increased at higher concentrations of target gas. The ZnO sensor displayed high sensitivity because of the small diameters and high specific surface area of the electrospray particles. The ZnO sensors show great promise for use as micro/nano gas sensors as they exhibit high sensitivity, repeatability and stability.