Transition of Activation Energy Induced by the Polarization of Au Nanoparticles in Organic Field-Effect Transistors at Low Temperatures

The molecular packing of the organic semiconductors significantly influences charge transport in organic field-effect transistors (OFETs). In addition, a pronounced impact of the dielectric layer is observed on the charge conduction within the few monolayers above the semiconductor–dielectric interfaces. This study highlighted the hysteresis and charge transport behavior of a nanocomposite dielectric-based OFET across a broad range of measurement temperatures spanning from 50 to 350 K. The influence of the dielectric layer blooms at around 100 K measurement temperature, where a prominent crossover in hysteresis has taken place in both the dual sweep transfer curves and C–V curves. The activation energy shifts from low to high due to hysteresis reversal at 100 K. Carrier mobility supports hopping-assisted charge transport. Experimental evidence shows that polarization of gold nanoparticles due to the gate field affects charge conduction at cryogenic temperatures, while trap states dominate polarization at elevated temperatures.