Low voltage extrinsic switching of ferroelectric δ-PVDF ultra-thin films

Non-volatile memories operating at low voltage are indispensable for flexible micro-electronic applications. To that end, ferroelectric δ-PVDF films were investigated as a function of layer thickness down to 10 nm ultra-thin films. Capacitors were fabricated using PEDOT:PSS as non-reactive electrode. Full polarization reversal was obtained at an unprecedented voltage below 5 V. The remanent polarization of 7 μC/cm2 and coercive field of 120 MV/m are independent of layer thickness, demonstrating that ferroelectric switching in δ-PVDF is extrinsic, dominated by inhomogeneous nucleation and growth. The ease of processing of δ-PVDF allowed to determine a lower limit of the critical ferroelectric thickness.