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.