Date of this Version
JOURNAL OF APPLIED PHYSICS 121, 194103 (2017)
Organic ferroelectric materials, including the well-known poly(vinylidene fluoride) and its copolymers, have been extensively studied and used for a variety of applications. In contrast, the VDF oligomer has not been thoroughly investigated and is not widely used, if used at all. One key advantage the oligomer has over the polymer is that it can be thermally evaporated in vacuum, allowing for the growth of complex heterostructures while maintaining interfacial cleanliness. Here, we report on the ferroelectric properties of high-quality VDF oligomer thin films over relatively large areas on the order of mm2. The operating temperature is identified via differential scanning calorimetry and pyroelectric measurements. Pyroelectric measurements also reveal a stable remanent polarization for these films which persists over very long time scales, an important result for nonvolatile data storage. Temperature dependent pyroelectric and capacitance measurements provide compelling evidence for the phase transition in these films. Capacitance-voltage and currentvoltage measurements are used to confirm ferroelectricity, quantify the dielectric loss, and calculate the spontaneous polarization. Finally, piezoresponse force microscopy is used to demonstrate large area, low-voltage ferroelectric domain reading/writing in VDF oligomer thin films. This work enables new channels for VDF oligomer applications and research.