Multi-domain gate-engineered pentacene OFET for hydrogen detection: design, modeling, and simulation

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This research work addresses key challenges in organic field-effect transistor (OFET)-based gas sensors by proposing a compact differential hydrogen ( H 2 ) sensor based on a pentacene OFET with a bottom gate extended in both in-plane and out-of-plane (IP-OP) directions. The IP-OP extended architecture enhances hydrogen sensitivity while reducing footprint and environmental susceptibility, and the differential configuration suppresses common-mode effects, improving robustness against environmental fluctuations. Platinum-coated vias in a 10 μ m-thick parylene-C layer selectively expose the gate while protecting the pentacene channel from environmental effects. The proposed sensor is designed, analytically modeled, and validated using previously reported experimental results. The effects of incoming H 2 gas pressure on charge transfer, the highest occupied molecular orbital and the lowest unoccupied molecular orbital energy levels, and the corresponding drain current characteristics are analyzed, and a Verilog-A model of the sensor is developed for circuit-level integration and differential amplifier performance evaluation. A 16% change in the platinum (Pt) gate work function over 0 to 0.5 torr hydrogen pressure ( P H 2 ) shifts the P-OFET threshold voltage ( V TH ) from − 0.16 V to − 1.5 V. The drain current varies from − 1.35 mA at zero P H 2 to − 0.66 mA at P H 2 = 0.5 torr, with a relative change greater than 50% at V GS = V DS = − 3