Organic field effect transistors with bulk low doping

Organic Field Effect Transistors (OFETs), while showing a lot of promise, currently suffer from a number of limitations. Organic doping can help to overcome these limitations. It opens up a number of new possibilities by offering a way to define majority charge carriers, control the charge carrier density, threshold voltage etc. precisely and produce devices with better performance, stability, and reproducibility. The doping techniques explored in OFETs thus far have been in the range of a few wt.%, which has limited the use of doping to contact doping or a thin doped layer at the gate dielectric interface. Furthermore, the high doping concentrations used place serious limitations on the doping efficiency that can be achieved. Here we demonstrate the successful use of low doping in the 100ppm range throughout the bulk of the organic semiconductor layer of an OFET with the use of a rotating shutter.