Characterisation of ferroelectric poly(vinylidene fluoride–trifluoroethylene) film prepared by Langmuir-Blodgett deposition

Ferroelectric polymer is a flexible memory material that is insensitive to environmental variations and lends itself to research in emerging optoelectronic applications. Using Langmuir-Blodgett (LB) deposition technology, the thickness of a ferroelectric film can be controlled in the nanometre range, offering a pathway to molecular electronics. In this reported work, ultrathin ferroelectric polymer films were fabricated through LB deposition technology and characterised by observing the surface morphology, crystallinity and polarisation-voltage relationships. Unlike previously reported ferroelectric LB films, this work has shown a maximum remanent polarisation (P_R) of 6 μC/cm² at 35 nm, which is compatible with the thick film prepared by the spin-coating method. In addition, the polarisation stability in terms of depolarisation was investigated, which showed that the engineering of the interface between the ferroelectric LB film and the substrate is an important, deterministic factor for reliable memory applications with high signal-to-noise ratios.