Dual-gate organic thin film transistors as chemical sensors.

An organic/inorganic hybrid sensing device is proposed based on a dual-gate organic thin film transistor architecture using polythiophenes as semiconductors and AlOx as the top dielectric. When a polar molecule adsorbs on the top dielectric, the threshold voltage of the bottom gate transistor shifts leading to several orders of magnitude increase of the current at an appropriately chosen gate voltage. The devices are tested by exposing them to a saturated water atmosphere, which leads to a four orders of magnitude current increase within one minute. This sensor design maintains some advantages of organic semiconductors such as low-temperature processing and fabrication on flexible substrates. Finally, it can be operated at low voltages with the potential for extremely low-power operation. [ABSTRACT FROM AUTHOR]