Gate tuning of cellulose nanofibers-gated in-plane-gate IGZO transistors for humidity sensing

Abstract Electrolyte-gated transistors (EGTs) represent a highly intriguing device platform for intelligent bio- and chemical sensing. To enable effective humidity sensing with cellulose nanofibers-gated in-plane-gate indium gallium zinc oxide transistors. This work adopted three synergistic methods to tune the gate controllability: ion doping of the solid electrolyte, gate electrode restructuring, and application of pulsed gate voltages. Cellulose nanofibers gate electrolyte was doped with LiClO 4 to increase ionic conductivity and electric double layer capacitance. A C-shaped in-plane-gate design expanded the electrolyte region between the gate and channel, enabling a wider electric field distribution for improved gate control. With pulsed gate voltage operation, duty ratio adjustment revealed a sharply enhanced humidity response compared to quasi-static operation, achieving a higher current response ratio of 69.2 between 80% and 20% relative humidity. These results demonstrate that by combining material, structural, and signal engineering, the potential of in-plane-gate EGTs for humidity sensing is unlocked for humidity sensing applications.