The field of organic semiconductors has grown rapidly providing complementary options to inorganic semiconductors, such as flexibility and large-area application. Although organic transistors are slow compared to Si transistors, they have been of particular interest largely due to their ease of fabrication and compatibility with other electronic components; they form the building block of modern organic displays.
The dynamic coupling of charge carriers to the electronic polarization at the semiconductor-dielectric interface results in a renormalization of the transfer integral for the transport process. Ferroelectric dielectrics, permitting access to nearly an order of magnitude range of dielectric constants with temperature as the tuning parameter, offer a great platform to monitor the changes in interfacial transport in organic field-effect transistors (FETs) as the polarization strength is tuned. In this talk I will present our recent results on ferroelectric-based pentacene FETs. The weak temperature-dependence of the charge carrier mobility in the ferroelectric phase of the dielectric may be attributed to a polarization fluctuation driven transport. By comparing single dielectric layer FETs with stacked ferroelectric/inorganic dielectric FETs, the contribution from Fröhlich polarons is extracted. The temperature-dependent mobility of the polarons increases with the thickness of the ferroelectric layer. Using a strongly coupled polaron model, the hopping lengths were determined to vary between 2Å – 5Å.
