초록 |
Organic field-effect transistors (OFETs) need to be reliably operatable at low voltages for prolonged periods of time. In order to achieve low operating voltages, many research groups have focused on high gate-capacitance structures, which can be produced by increasing the dielectric constant and/or decreasing the film thickness. The high-k materials that usually include ionic impurities or polar functionalities can cause irreversible hysteresis and bias stress behavior. In contrast, ferroelectric poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE) has tunable crystal structures and high dielectric constant. Here, PVDF-TrFE blend films were used as gate dielectrics for vacuum-processed OFETs. Surface properties of the PVDF-TrFE blend films could be optimized via controlling the crystalline behavior, without any drastic drop in the overall dielectric constant. Then, pentacene OFETs were fabricated and characterized. |