Rapid Evaluation of Electron Mobilities at Semiconductor-Insulator Interfaces in an Ambient Atmosphere by a...

Intrinsic mobility of electrons at the interfaces between crystalline organic semiconductors and insulating dielectric polymer films was rapidly evaluated in an ambient atmosphere by TRMC@Interfaces, a noncontact and nondestructive method based on dielectric loss spectroscopy of microwaves. By just preparing simple metal-insulator-semiconductor devices, local-scale motions of charge carriers injected into the interface by pulses of gate bias voltage were monitored through reflected microwave changes, resulting in the evaluation of local-scale charge carrier mobilities together with the value of trap density at the interface. The evaluated high electron mobilities of 12 cm² V^-1 s^-1 for N,N'-bis(cyclohexyl)naphthalene-1,4,5,8-bis(dicarboximide) (DCy-NDI) and 15 cm² V^-1 s^-1 for N,N'-dioctylperylene-1,4,5,8-bis(dicarboximide) (DC -PDI) are the benchmarks for organic semiconducting materials that are comparable with the highest ones reported from the field-effect transistor devices. The present TRMC@Interfaces was found to serve as a rapid screening technique to examine the intrinsic performance of organic semiconducting materials as well as a useful tool enabling the precise discussion on the relationship among their local-scale charge carrier mobility, thin-film morphology, and packing structure.