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 ( $\Psi $ -inverter) and pseudo-MOS ( $\Psi $ -MOS) for NO2 and NH3 gas detection. Experimental results demonstrate that $\Psi $ -inverter, characterized by high internal gain, consistently exhibits superior sensitivity compared to the $\Psi $ -MOS device across various channel thicknesses for both target gases. At 1-ppm concentration, $\Psi $ -inverter achieved remarkable sensitivities of 1248% and 83.9% for NO2 and NH3, respectively, surpassing $\Psi $ -MOS sensitivity by factors of 102.5 and 19.7. In addition, $\Psi $ -inverter configuration offers the advantage of direct voltage signal output, facilitating practical implementation.