Non-volatile Ferroelectric Poly(vinylidene fluoride-co-trifluoroethylene) Memory Based on a Single-Crystalline Tri-isopropylsilylethynyl Pentacene Field-Effect Transistor

Abstract

A new type of nonvolatile ferroelectric poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) memory based on an organic thin-film transistor (OTFT) with a single crystal of tri-isopropylsilylethynyl pentacene (TIPS-PEN) as the active layer is developed. A bottom-gate OTFT is fabricated with a thin P(VDF-TrFE) film gate insulator on which a one-dimensional ribbon-type TIPS-PEN single crystal, grown via a solvent-exchange method, is positioned between the Au source and drain electrodes. Post-thermal treatment optimizes the interface between the flat, single-crystalline ab plane of TIPS-PEN and the polycrystalline P(VDF-TrFE) surface with characteristic needle-like crystalline lamellae. As a consequence, the memory device exhibits a substantially stable source-drain current modulation with an ON/OFF ratio hysteresis greater than 10(3), which is superior to a ferroelectric P(VDF-TrFE) OTFT that has a vacuum-evaporated pentacene layer. Data retention longer than 5 x 10(4) s is additionally achieved in ambient conditions by incorporating an interlayer between the gate electrode and P(VDF-TrFE) thin film. The device is environmentally stable for more than 40 days without additional passivation. The deposition of a seed solution of TIPS-PEN on the chemically micropatterned surface allows fabrication arrays of TIPS-PEN single crystals that can be potentially useful for integrated arrays of ferroelectric TFT memory.