The ferroelectric properties of perpendicularly oriented, highly crystalline vinylidene fluoride (VDF) oligomer thin films were investigated by using a planar device configuration consisting of comblike Cr–Au electrodes with a 1 µm gap. In-plane polarization switching was induced by the rotation of the VDF oligomer. As the measurement temperature was increased from 295 to 380 K, the coercive field (Ec) decreased drastically from 124 to 7.7 MV/m. Furthermore, the thermal stability of our device significantly improved compared with that of conventional sandwiched devices utilizing VDF oligomer films with a parallel orientation.

No abstract

We fabricated a protective Parylene C layer coated with vinylidene fluoride (VDF) oligomer thin films to improve their thermal stability and investigated the temperature dependence of their pyroelectric properties. Following the heat resistance test (at 398 K for 500 h in the presence of air at atmospheric pressure), the deterioration of voltage sensitivity of the Parylene C coated sensor was approximately 20% (553 → 430 V W −1 ) and approximately 100% in the case of the sensor without Parylene C ( 551→ 0.86 V W −1 ). Parylene C coating prevented structural disturbances of VDF oligomer thin films and electrode cracking. Comparison of the VDF oligomer, Parylene-C-coated VDF oligomer, and Parylene-C-coated P (VDF-TrFE), demonstrated the superior thermal stability of the Parylene-C-coated VDF oligomeric pyroelectric sensor.