Crystallization and ferroelectric properties of the amorphous precursor films of Poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) blended with Pb(Zr,Ti)O₃

Abstract

Precursor films based on poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) and P(VDF-TrFE) blended with Pb(Zr,Ti)O₃ (PZT) were spin-coated on Si substrates and subsequently annealed at 150, 170, or 190°C. X-ray diffraction studies showed that the crystallization from the amorphous precursor films to the γ phase starts at higher annealing temperatures without involving the formation of other polymorphs when the P(VDF-TrFE) is blended with PZT, and the PZT content increases, resulting in an amorphous phase and/or crystalline γ phase. Nevertheless, a larger memory window width and much higher accumulation capacitance are induced by the blended PZT within the low operating voltage ranges from −0.5 to 2.0 V and from −2.0 to 6.0 V for 76.7 and 96.7 wt % PZT blending, respectively. Furthermore, these improvements in the hysteretic characteristics in the capacitance–voltage measurements are also directly correlated with the degree of P(VDF-TrFE) crystallization and the presence of PZT. This approach enables viable routes toward the commercialization of nonvolatile ferroelectric memory devices and their market extension to potential applications as functional devices.