Insulators and device geometry in polymer field effect transistors

In order to increase the stability and practicality of polymer field effect transistor (FET) devices, different manufacturing parameters are investigated, including choice of material, processing solvent, and device geometry. It is found that the performance of the devices is closely related to the choice of gate insulator material, the applied sample configuration and the order of layer deposition. Thermally cross-linked polymers are investigated as insulator materials. For a top gate configuration the key parameter is the choice of insulator material (and solvent) while for the bottom gate configuration, device performance is largely dependent on interfacial properties, which may be controlled for example by surface treatment. This study shows that care must be taken in designing and applying the gate insulator layer of a FET.