The Assessment for Sensitivity of a NO(2) Gas Sensor with ZnGa(2)O(4)/ZnO Core-Shell Nanowires—a Novel Approach

The application of novel core-shell nanowires composed of ZnGa(2)O(4)/ZnO to improve the sensitivity of NO(2) gas sensors is demonstrated in this study. The growth of ZnGa(2)O(4)/ZnO core-shell nanowires is performed by reactive evaporation on patterned ZnO:Ga/SiO(2)/Si templates at 600 °C. This is to form the homogeneous structure of the sensors investigated in this report to assess their sensitivity in terms of NO(2) detection. These novel NO(2) gas sensors were evaluated at working temperatures of 25 °C and at 250 °C, respectively. The result reveals the ZnGa(2)O(4)/ZnO core-shell nanowires present a good linear relationship (R(2) > 0.99) between sensitivity and NO(2) concentration at both working temperatures. These core-shell nanowire sensors also possess the highest response (<90 s) and recovery (<120 s) values with greater repeatability seen for NO(2) sensors at room temperature, unlike traditional sensors that only work effectively at much higher temperatures. The data in this study indicates the newly-developed ZnGa(2)O(4)/ZnO core-shell nanowire based sensors are highly promising for industrial applications.