Electrical and structural properties of nano-imprinted ferroelectric polymers
(2014)
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- Authors
- Supervisors
- Jonas, Alain
- Abstract
- Organic electronics have become an active research topic in recent years since they have the potential to supplement the existing silicon based technologies. Here, we studied nano-imprinted ferroelectric polymers that can be used to fabricate cheap, flexible, and low voltage nonvolatile memory devices. Crystallizing ferroelectric polymers in the cavities of nano-imprinting molds was found to dramatically enhance the ferroelectric performance of copolymers like those based on vinylidene fluoride and trifluoroethylene, P(VDF-TrFE). The exact reason for this effect was however not fully elucidated. This work consequently focuses on making progress into these issues. In this thesis, we have fabricated nano-imprinting molds by electron beam lithography, and used them to produce confined nanoobjects of different shape, height, and lateral dimensions by nano-imprint lithography. The structural properties of the resulting nano-patterns were studied using infrared spectroscopy (IR) and atomic force microscopy (AFM), whereas the local ferroelectric properties were monitored by piezoresponse force microscopy (PFM); the latter technique was studied in more details, being an important tool for our work. We observe that nano-processing conditions like imprinting temperature, the size and shape of mold cavities, and the presence or not of a thin residual layer between the pillars are very critical in determining both the structural and electrical properties of P(VDF-TrFE) of the resulting nanostructures. In addition, we show that the thermal stability is well preserved for fully confined nanodots with dimensions and height in the range of few tens of nanometer only. Our findings indicate the complexity of the effect of nano-confinement on the structure and properties of P(VDF-TrFE), and provide useful practical insights for the realization of high density non-volatile ferroelectric memories.
- Affiliations
Citations
Kassa, H. G. (2014). Electrical and structural properties of nano-imprinted ferroelectric polymers. https://hdl.handle.net/2078.5/49767