Advanced Recovery and High-Sensitive Properties of Memristor-Based Gas Sensor Devices Operated at Room Temperature

Fast recovery, high sensitivity, high selectivity, and room temperature (RT) sensing characteristics of NO gas sensors are essential for environmental monitoring, artificial intelligence, and inflammatory diagnosis of asthma patients. However, the conventional semiconductor-type gas sensors have poor sensing characteristics that need to be solved, such as slow recovery speeds (>360 s), low sensitivity (3.8), and high operating temperatures (>300 °C). We propose here a memristor-based NO gas sensor as a gasistor (gas sensor + memory resistor) with SnO₂, Ta₂O₅, and HfO₂ films, which successfully demonstrated the feasibility of fast reaction/recovery (<1 s/90 ns) and high sensitivities such as 11.66 and 5.22 in Ta₂O₅ and HfO₂ gasistors for NO gas, at RT. Furthermore, so as to reinforce the selectivity in multigas ambient, we suggest a parallel circuit using three kinds of gasistors having different sensitivities for NO, O₂, and C₂H₆ gases, which results in an improvement of selectivity for the selected gas at RT.