Solvent-Dependent Electrical Characteristics and Mechanical Stability of Flexible Organic Ferroelectric Field-Effect Transistors

Abstract

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.

Resistance switching and conduction mechanism on ferroelectric copolymer thin film device

“…There is no need to undergo harsh electric and magnetic field treatments, and the high-crystallinity fully anti-ferroelectric phases can be obtained directly from the solution by annealing at low temperature [8]. In the past few years, P(VDF-TrFE) has been applied in various memories, including ferroelectric resistive memory [4,9,10], ferroelectric capacitors [11,12], ferroelectric tunnelling junction (FTJs) [13][14][15][16][17], ferroelectric diodes [18][19][20][21][22][23][24], ferroelectric field effect transistors (FeFET) [25][26][27][28][29]. In FTJs, ferroelectric film is only a few nanometres so that electrons can pass through the ferroelectric through the quantum tunnelling effect.…”