Abhängigkeit der piezoelektrischen Eigenschaften von Ferroelektreten von der Form, dem Elastizitätsmodul und der Aufladung von rechteckigen und konvexen Polymerröhrenarrays

• Applicant: Professor Dr.-Ing. Heinz von Seggern
• Subject Area: Electronic Semiconductors, Components and Circuits, Integrated Systems, Sensor Technology, Theoretical Electrical Engineering
• Term: from 2012 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 211266539

• Final Report Year: 2016

Final Report Abstract

A new approach for manufacturing from commercial FEP tubes of multi-channel piezoelectret arrays with tubular air cavities has been developed. By this approach a large number of flat arrays with regular tubular air cavities were produced from different FEP tubes. The overall thickness of investigated arrays was varied in between 350 μm and 600 µm while its dimensions are restricted to 30 mm × 40 mm. These dimensions, however, can easily be increased for production of large-scale units. To simulate the charging and discharging processes of above ferroelectrets an "internalvariable" continuum model was introduced for the first time. The model is capable to describe the poling dynamics of ferroelectrets, final distribution of potential across the devices with varied shape of air voids as well as the hysteresis behaviour of remanent charges and finally predict the maximal reachable charge density for selected array geometry. Moreover, the model allows the calculation of theoretical piezoelectric d33 coefficient, if the modulus of elasticity is known. The best arrays reveal the high and stable piezoelectric response with d33 coefficient up to 160 pC/N. In addition, the issues related to temporal stability, optimal charging conditions and stability of the piezoelectric characteristics at different pressures and frequencies were experimentally investigated.

Publications

• “Continuum modeling of charging process and piezoelectricity of ferroelectrets,” J. Appl. Phys. 2013, 114, 094103
  B.-X. Xu, H. von Seggern, S. Zhukov, and D. Gross
  
• “An internal-variable-based interface model for the charging process of ferroelectrets,” European Journal of Mechanics - A/Solids 2014, 48, pp. 97-111
  B.-X. Xu, H. von Seggern, S. Zhukov, and D. Gross
  
• “Polarization dynamics variation across the temperature- and composition-driven phase transitions in the lead-free Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 ferroelectrics,” J. Appl. Phys. 2015, 118, 134104
  S. Zhukov, M. Acosta, Yu. A. Genenko, and H. von Seggern
  
• “Effect of texturing on polarization switching dynamics in ferroelectric ceramics,” Appl. Phys. Lett. 2016, 108, 012907
  S. Zhukov, Yu. A. Genenko, J. Koruza, J. Schultheiß, and H. von Seggern, W. Sakamoto, H. Ichikawa, T. Murata, K. Hayashi, T. Yogo
  
• “Fatigue effect on polarization switching dynamics in polycrystalline bulk ferroelectrics,” J. Appl. Phys. 2016, 120, 064103
  Zhukov, J. Glaum, H. Kungl, E. Sapper, R. Dittmer, Y.A. Genenko, and H. von Seggern
  
• “Polarisation Dependence of Schottky Barrier Heights at Ferroelectric BaTiO3/RuO2 Interfaces: Influence of Substrate Orientation and Quality,” J. Phys. D: Appl. Phys. 2016, 49, 295304
  A. H. Hubmann, S. Li, S. Zhukov, H. von Seggern and A. Klein