Experimental Verification of NO_x Gas Dynamics and Kinetics on Carbon Nanotube Field Effect Transistor Gas Sensors

This paper proposes a framework for the description of NO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> gas sensing with carbon nanotube field effect transistors (CNFET). Using chemical reaction networks, we derive ordinary differential equation (ODE) models that well describe the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{NO}_{\mathrm{x}}$</tex>-CNT system. The proposed models are experimentally verified by fitting measured electrical output data of two different CNFET gas sensors during gas measurements with varying NO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> concentrations. The models achieve an improvement of up to 48% in the Normalized Root Mean Square Error (NRMSE) compared to the conventional Langmuir NO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> adsorption model. The determined chemical reaction rates are consistent with theoretical binding energies [1].