Low-Operating-Voltage Operation and Improvement in Sensitivity With Passivated OFET Sensors for Determining Total Dose Radiation

Using high-k material in a gate dielectric stack, low-operating-voltage organic semiconducting material sensors for determining total dose radiation are proposed. To improve the stability of organic semiconducting layer in the atmospheric conditions, a thin silicon nitride layer deposited by hot-wire CVD process was used as a passivation layer. Furthermore, in order to achieve higher sensitivity, a parallel connection of organic field-effect transistors (OFETs) is explored in this letter. These sensors are exposed to ionizing radiation using a cobalt-60 radiation source for different total dose values. A three-times improvement in sensitivity was observed in the off current with a three-OFET array.