Gas sensor mechanism based on Boltzmann statistics and transport theory: Assessing the impact of gas dynamics

Gas dynamics including gas flow, gas adsorption and desorption largely determine the electrical properties of gas sensors. Observing gas phase behavior through a gas sensor is important not only for the sensor itself, but also for nanofilm epitaxial applications. However, gas dynamics traditionally treated with the equilibrium Langmuir model cannot reflect the dynamic details of the gas phase from electrical observations and must rely on a complete theoretical model connecting gas dynamics and electrical transport. This also leads to the fact that the responsivity of all gas sensors does not consider the complete physical reaction and process and is not a truly standardized comparison parameter, making the responsivity comparison unreliable. In this work, a unified model of gas sensors based on Boltzmann transport and statistical theory is proposed to handle gas dynamics and electron transport connected by Langmuir boundary conditions. Jet flow effects are also considered. The theoretical results are consistent with experimental observations of SnO2 sensors for noble and oxidizing gases. This work extends the electrical response of the gas sensor to the field of gas dynamics, thus realizing the possibility of gas dynamics detection through the gas sensor.