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High-k Dielectric Nanocomposites

Jackie Li (City University of New York)

Prager Medal Symposium in honor of George Weng: Micromechanics, Composites and Multifunctional Materials

Wed 1:30 - 2:50

MacMillan 117

High-k dielectric in general refers to a material with a dielectric constant k higher than that of SiO2. With miniaturization of electronic devices, seeking a high-k nanodielectric becomes more urgent and important. In this talk, we present a novel approach to preparing three different types of doped barium titanate (BT) nanocrystal formulations that can be deposited in conjunction with polymers in order to prepare a thin film nanodielectric composite that exhibits highly desirable capacitor characteristics. Characterization is performed by XRD, Raman Spectroscopy, SEM and HRTEM. A comprehensive analysis of the dielectric performance compared with pure BaTiO3 nanocrystal films reveals improvements in capacitance (permittivity), lower loss and dramatically improved ESR, all to a high frequency range (>10 MHz). As a baseline, a proposed model combines Debye type of dissipation, soft mode theory and the influence of conductivity on the dielectric properties of single domain crystalline BaTiO3 is established to study dielectric frequency spectrum. Combining with various homogenization approaches, the effective dielectric properties of nanodielectric composites are obtained in terms of concentration of the nanodielectrics and frequency. This complete study through synthesis, characterization and modeling provides fundamental knowledge for designing optimized dielectric systems with better performance for energy storage applications.