Interface morphology driven control of electrical properties of P(VDF–TrFE) and PMMA blend M–I–M capacitors

Abstract

In this manuscript, we report on the role of interfacial morphology between poly(methyl methacrylate) or PMMA and poly(vinylidenedifluoride–trifluoroethylene) or P(VDF–TrFE) thin films upon improvement in the ferroelectric and leakage characteristics of the P(VDF–TrFE)–PMMA devices. Whilst keeping the overall thickness of 200nm, PMMA is incorporated in different proportions along with P(VDF–TrFE) in three different configurations: in the form of blend, and two bilayer structures, one with PMMA films below P(VDF–TrFE) films and another with PMMA films on top of P(VDF–TrFE) films. In the blend form, addition of PMMA decreases the crystallinity of P(VDF–TrFE) resulting in deterioration of the ferroelectric properties of the blend before complete disappearance at 30% PMMA when the blend becomes amorphous. In the bilayer structures, whilst overall polarization of the bilayer structure decreased in comparison to a 200nm P(VDF–TrFE) only device, ferroelectric polarization of P(VDF–TrFE) in the bilayer was larger than P(VDF–TrFE) only device for the similar voltage drop. This is attributed to the development of morphology in the bilayer structure. Importantly, PMMA incorporation leads to nearly two orders of magnitude reduction in the electrical leakage rendering bilayer devices more suitable for device applications than P(VDF–TrFE) only device.