Zinc oxide nanobelts by RF sputtering for ethanol sensor

Zinc oxide nanobelts were RF sputtered onto a copper tube. Their nanostructure has been confirmed by FE-SEM and Raman spectroscopy. The copper tube coated with these ZnO nanobelts was then employed as an ethanol gas sensor. To characterize the sensor, experiments with ethanol at concentration levels of 50–2000 ppm and at operating temperatures ranging from 200 to 290 °C were performed. The sensitivity and response time of the sensorʹs resistance for several ethanol concentrations and operating temperatures was determined. The relationship between the sensorʹs sensitivity and ethanol concentration level suggests that the adsorbed oxygen species at the sensorʹs surface is O2−.