Low-voltage programmable/erasable high performance flexible organic transistor nonvolatile memory based on a tetratetracontane passivated ferroelectric terpolymer

Abstract

Abstract Future flexible electronic systems require memory devices combining low power consumption and mechanical bendability. However, high programming/erasing (P/E) voltages, which are universally required to switch the storage states in previously reported ferroelectric organic field-effect transistor (Fe-OFET) nonvolatile memories (NVMs), severely prevent their practical applications. In this work, we develop a novel route to achieve a low-voltage programmable/erasable flexible Fe-OFET NVM. Ferroelectric terpolymer poly(vinylidene-fluoride-trifluoroethylene-chlorotrifluoroethylene) [P(VDF-TrFE-CTFE)], rather than the conventional ferroelectric copolymer poly(vinylidene-fluoride-trifluoroethylene) [P(VDF-TrFE)], is used as the gate dielectric. The low coercive field of P(VDF-TrFE-CTFE) is the main contribution to the low-voltage operation in the Fe-OFET NVM, even with a relative thick ferroelectric gate dielectric layer. By depositing a long-chain alkane molecule Tetratetracontane (TTC) as the passivation layer on the surface of P(VDF-TrFE-CTFE) film, the layer-by-layer growth mode of semiconductor pentacene is obtained, which results in a large crystalline grain and good interface morphology at the channel/dielectric. Therefore, the mobility of Fe-OFET NVMs is greatly improved. As a result, a high performance flexible Fe-OFET NVM is achieved, with a low P/E voltage of ±15 V, high mobility up to 0.5 cm2 V−1 s−1, reliable P/E endurance property over 1000 cycles, stable data storage retention capability over 6000 s, and excellent mechanical bending durability without visible degradation after 2000 repetitive tensile bending cycles at a small curvature radius of 4.0 mm.