Nano-imprinting Make P (vdf - Trfe) Ferroelectric Micro-nano Graphics

Ferroelectric materials have a wide range of applications in transducers, ferroelectric memories for its good piezoelectric and ferroelectric properties. Poly(vinylidenefluoride-trifluoroethylene), P(VDF-TrFE), as one of the best organic ferroelectric polymers with spontaneous polarization close to10C/cm2and piezoelectric coefficient d/33～38pm/V at room temperature and meanwhile with excellent biocompatibility, is promising for potential applications in data storage, energy harvest and biotransducer. Different applications require fabrication of various complex micro/nanostructures. With the increasing demand of the miniaturization of these devices for smaller feature size, high density and enhanced performance, various techniques have been developed to pattern ferroelectric nanostructures such as self-assembly, electron beam lithography (EBL), focused ion beam (FIB) milling, X-ray lithography,UV lithography and dip-pen lithography. The self-assembly method suffers from poor control of feature size and regularity, which severely limits its applications. Although EBL, FIB milling, X-ray lithography and UV lithography are capable of patterning fine nanostructures, they are expensive, time-consuming and they are inclined to damage the surface of the ferroelectric materials, which will result in the damage of the ferroelectric properties of this material. Nanoimprinting, as an efficient way to fabricate nanostructures, has a good advantage over the several technologies mentioned aboveat this point. In this work, we apply nanoimprinting process for the ferroelectricP(VDF-TrFE)nano structures fabrication, and value the influence of the process on the piezo/ferroelectricity properties of this material.This paper first introduces several nanofabrication methods mentioned above, and then describes nanoimprinting technique,ferroelectric material PVDF and P(VDF-TrFE) and the piezoelectric and ferroelectric properties of these ferroelectric materials. And finally study the influence of temperature and time of the nanoimprinting process on thecrystallization of P(VDF-TrFE) thin film. But because nanoimprinting used in this paper isthe hot embossing, the temperature process is just prebaking, so we investigate the influence of prebaking temperature and time on the surface morphology and the crystallization of P(VDF-TrFE) thin film.One step and dual step nanoimprinting were used to fabricate P(VDF-TrFE) thin film nanostructures. Dual step nanoimprinting for complex nanostructure was paid more attention. We focused on how to optimize the fabricating process to get perfect complex nanostructure. And we also briefly introduce the application of the complex nanostructure of P(VDF-TrFE) in non-volatile memories, photonics, bionic structure and surface wetting.The surface morphology and ferroelectric properties of P(VDF-TrFE) thin film nanostructures have been characterized with atomic force microscopy(AFM) and piezoresponse force microscopy(PFM), respectively.Finally, we made a summary and prospect.Experiment results suggest that in different processing condition, this P(VDF-TrFE) thin film has different surface morphology and crystallization. For complex nanostructure made by dual step nanoimprinting, the second nanoimprinting process is quite similar to the first one, but not the same. It is quite important to control the imprinting pressure and temperature in order to get fine-qualified complex nanostructure. The imprinted P(VDF-TrFE) thin film still remains excellent piezoelectric and ferroelectric properties, which offers wide range of application of P(VDF-TrFE), such as multi-bit memories. And at the same time, nanoimprinting provides a simple way to fabricate complex nanostructure for wide range of application, such as bionics and surface wetting.