Design of Pentacene Thin-Film Transistor Based Hydrogen Gas Sensor with High-K Dielectric Materials for High Sensitivity

Abstract

Electrical properties of an organic field-effect transistor were modelled in top gate top contact (TGTC) geometry and H2 gas sensors were designed for increased sensitivity based on the structure. Safety concerns related to hydrogen usage must be addressed; these hazardous characteristics include a wide flammable range (4%–75%) that results in a rapid burning velocity, a low minimum ignition energy (0.017 mJ), a high heat of combustion (143 kJ g−1), and the high diffusivity of hydrogen gas (0.61 cm2 s−1 in the air). These characteristics make it impossible to control hydrogen combustion after a specific time. All simulations were performed in the Silvaco TCAD ATLAS tool. We analysed the driving principle of gas sensors and introduced gas sensing properties in OFET using platinum metal at the gate electrode for H2 gas detection. IOFF, ION, and VTH are sensitivity parameters that alter when the metalwork function of the gate changes with respect to the gas present on it. The designed sensor was analysed for different dielectric materials. Results demonstrate that the increase in sensitivity for OFET-based H2 sensors is 73.4%, 80.7%, 90.5%, and 95.6% when the work function changes by 50, 100, 150, and 200 meV for Pt gate electrodes with an increase in dielectric value of insulating layer from SiO2 (3.9) to La2O3 (27). Results were compared with the In1-xGaxAs CGNWFET-based H2 sensor as the work function varies at 200 meV,the sensitivity enhancement with OFET-based H2 sensors is 8.09%.