Investigation of the physics of sensing in organic field effect transistor based sensors

In this study, we examine the physics governing the operation of chemical sensors based on field effect transistors, which use organic semiconductors as an active sensing medium. Short channel length devices can operate in the injection-limited regime and the sensing response in this regime is totally unlike the response in larger scale devices. In large geometry sensors, charge carrier trapping plays an important role in the sensor response. We describe in detail the various factors that influence charge trapping effects. Oriented dipoles from polar analytes can also influence sensor behavior and manifest as a current increase upon exposure to the analyte. (C) 2012 American Institute of Physics. [doi:10.1063/1.3686686]