Thermal Oxidation CuO Nanowire Gas Sensor for Ozone Detection Applications

In this study, cupric oxide nanowires (CuO NWs) on patterned interdigitated electrodes (PIEs) used as ozone (O3) gas sensors, were successfully fabricated using thermal oxidation and the microelectromechanical systems (MEMS) technique. After the thermal oxidation process, CuO NWs with different heights and densities were fabricated using a pure copper seed layer with a thickness ranging from 0.5 μm to 2 μm. In this experiment, a low temperature, low concentration, and repeatable CuO NWs gas sensor was fabricated, which can detect O3 gas at a low concentration of 50 ppb and low temperature of 100°C with a high sensor response (40%). The concentration response of this gas sensor shows an increasing linear trend, with an increase of O3 concentration in the range of 50 ppb - 300 ppb. Additionally, the results indicated that this CuO NWs gas sensor is more selective for O3 than CO, CO2, C2H5OH, C3H6O, NO2, or NH3. While CuO has been less studied in O3 detection compared with other semiconducting metal oxide materials, CuO NWs show potential applications in gas sensing devices for low-temperature and low-concentration O3 environmental monitoring.