Mobility Improvement in N-Type Organic FET with Hetero-Layered Structure

Abstract

The field-effect mobility in n-type fullerene field-effect transistors was improved by the hetero-layered structure including the interfacial layer of organic semiconductor between the insulator and channel semiconductor. Various types of hole transporting material were employed for the interfacial layer. The device showed high electron mobility exceeding 1 cm 2 =Vs that was better than that for the substrates with conventional surface treatments, for example, hexamethyldisilazane (HMDS) and octadecyltrichlorosilane (OTS). These results suggest that the electron-donating character of the hole transporting materials leads to filling the electron traps at the insulator interface.

Charge Trapping and Storage by Composite P3HT/PC60BM Nanoparticles Investigated by Fluorescence-Voltage/Single Particle Spectroscopy

“…Thus, an excess of electrons is built up near the NPs and NP/dielectric interfaces (Figure d). Previous literature reports have extensively documented that electrons can be deeply trapped at organic/dielectric interfaces, or even in the bulk of the dielectric, and that PC 60 BM is a deep electron trap as well. , In these cases, anticlockwise hysteresis in capacitance–voltage data was typically observed. , In addition, when comparing the forward sweep curve obtained at 4.0 V/s, particularly from −10 to 0 V (forward sweep), with the corresponding fast scan curves obtained at 40 V/s, a negative shift is evident for the slow scan curve in the data reported herein. Similar observations have been reported previously for capacitance–voltage measurements on polymer–dielectric two-terminal and three-terminal devices. , Several reports have also been made where capacitance–voltage measurements were completed on P3HT and P3HT/PC 60 BM two-terminal and three-terminal devices under illumination. − Strong hysteresis was observed in all of the reports and was attributed to a build-up of free carriers due to photoinduced charge transfer from P3HT to PC 60 BM or spontaneous exciton dissociation in the absence of PC 60 BM, that results in trapping of electrons at the organic/dielectric interface.…”