Solvent-dependent electrical characteristics and mechanical stability of flexible organic ferroelectric field-effect transistors

Flexible organic ferroelectric field-effect transistors (Fe-FETs) have attracted attention for next-generation memory applications. A fundamental understanding of the electrical properties and mechanical stability of transistors is a prerequisite to realizing practical flexible electronics. Here, we demonstrate the solvent-dependent electrical characteristics and mechanical stability of flexible Fe-FETs. Poly(vinylidene fluoride-trifluoro-ethylene) (P(VDF-TrFE)) based Fe-FETs were fabricated by using dimethylformamide (DMF) and methyl ethyl ketone (MEK) solvents on a polyimide substrate. P(VDF-TrFE) from DMF formed a smoother surface than a surface from MEK; the surface property greatly affected the electrical properties and mechanical stability of the devices. Larger hysteresis and higher mobility were obtained from Fe-FET using DMF compared to those characteristics from using MEK. Furthermore, Fe-FET using DMF showed lower degradation of on-current and mobility under repetitive mechanical stress than an MEK-based Fe-FET, due to its excellent semiconductor-insulator interface. These results will guide appropriate solvent selection and contribute to the improvement of flexible Fe-FET electrical properties and mechanical stability in the next generation of memory devices.