Atomic layer adhesion of ferroelectric nanoparticles: a new approach to dielectric composites
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Atomic layer adhesion of ferroelectric nanoparticles: a new approach to dielectric composites Y. Espinal1,2
, S. Vijayan2
, S. P. Alpay2,3
, M. Aindow2,*
, and B. M. Hanrahan1
1
Army Research Laboratory, Adelphi, MD 20783, USA Department of Materials Science and Engineering, Institute of Materials Science, University of Connecticut, Storrs, CT 06269, USA 3 Department of Physics, University of Connecticut, Storrs, CT 06269, USA 2
Received: 24 March 2020
ABSTRACT
Accepted: 21 August 2020
A thin film dielectric composite has been produced consisting of lead-free barium titanate nanoparticles bound by the conformal atomic layer deposition of hafnia. The materials were examined crystallographically, topologically, and structurally using a variety of techniques including scanning electron microscopy and high-resolution transmission electron microscopy. Electrical measurements of capacitors using the composite material revealed dielectric constant variations of 200–1200 depending on the bias direction, corresponding to asymmetric leakage mechanisms and contributions from interface defects. Piezoresponse force microscopy indicated accessible polarization within the nanoparticles. This work illustrates an approach for conformally depositing a dielectrically tunable composite thin film with novel electrical properties.
Springer Science+Business
Media, LLC, part of Springer Nature 2020
Introduction Composite materials can be engineered to exhibit selectively desirable properties of each component while suppressing the undesirable ones. Ferroelectric (FE) materials are of interest for a variety of applications that include actuators [1, 2], transducers, infrared detectors, radars, energy storage, energy harvesting [3], and memory applications (non-volatile, polarization, or resistance switching based) [4–10]. Unfortunately, such materials are also
Handling Editor: David Cann.
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https://doi.org/10.1007/s10853-020-05145-w
susceptible to high leakage currents, typically high losses, and relatively low breakdown, which reduce significantly the specific coefficient of performance, or figure of merit, for a given application/system. Combining FE nanoparticles that have a large dielectric permittivity and a dielectric material with high dielectric strength could potentially provide a means to reduce loss and leakage, and to increase breakdown strength, while maintaining the important dielectric, piezoelectric, and pyroelectric properties inherent to FEs.
J Mater Sci
FE nanoparticles embedded in a dielectric polymer matrix have been shown to selectively enhance the dielectric permittivity of the resultant nanocomposites [11–13]. Zhang et al. [14] synthesized a flexible, three-dimensional ceramic/polymer composite that showed excellent piezoelectric and pyroelectric properties. Their findings represent progress on the path toward self-powered, wearable electronics. FE/ polymer composites have also demonstrated improved energy harvesting efficiency with power outp
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