Pseudo-Inverter Based on Silicon-on-Insulator for Highly Sensitive NO₂ and NH₃ Gas Detection

This study investigates the application of silicon-on-insulator (SOI) substrate-based pseudo-inverter (Ψ-inverter) and pseudo-MOS (Ψ-MOS) for NO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>2</roman></sub> and NH<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>3</roman></sub> gas detection. Experimental results demonstrate that Ψ-inverter, characterized by high internal gain, consistently exhibits superior sensitivity compared to the Ψ-MOS device across various channel thicknesses for both target gases. At 1-ppm concentration, Ψ-inverter achieved remarkable sensitivities of 1248% and 83.9% for NO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>2</roman></sub> and NH<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>3</roman></sub>, respectively, surpassing Ψ-MOS sensitivity by factors of 102.5 and 19.7. In addition, Ψ-inverter configuration offers the advantage of direct voltage signal output, facilitating practical implementation.