Nanostructured barium titanate composites for embedded radio frequency applications

Abstract

We describe a vapor-phase codeposition method to fabricate a ceramic-in-polymer composite system comprising ferroelectric barium titanate nanoparticles in a highly polarizable polyaniline-polyurethane copolymer host. As-deposited composites exhibited a capacitance density of 15nF∕cm2 and a resonance frequency close to 100MHz with a loss tangent of 0.8. Annealing nanocomposites at 135°C resulted in slightly reduced but frequency-independent capacitance density (∼10nF∕cm2) with a loss tangent of 0.1 and resonance frequency at 200MHz. The interplay of polarization modes is discussed in relation to capacitor performance. The fabricated capacitors have potential for applications in embedded technology in the radio frequency.

Low Cost, Tailored Nanocomposites: Properties and Applications

“…high specific capacitance together with stable capacitor functions) are needed for high-frequency (> 1 MHz) portable electronic systems for various functional applications. These include energy storage, ultrasensitive transducers, embedded capacitors as well as nanoelectromechanical systems (NEMS) [11]. Conventional ferroelectric materials exhibit dielectric relaxation as a result of alterations of the elastic and electric behavior and the movement of the domain walls at frequencies exceeding 1 MHz [12].…”

“…While high specific capacitance (i.e. capacitance density) can be obtained from these materials, dielectric relaxation limits their stable capacitor performance in the high-frequency [11].…”

“…(d) Magnitude of impedance for the annealed PANI/PU-BT nanocomposite. The inset shows the circuit model of the capacitor with a testing area of 1 mm 2[11].…”

Effective dielectric constant of two phase systems: Application to mixed conducting systems

“…[5][6][7] These extensions in the modeling and systematic experimental investigation of mixed conducting two phase systems with percolation can provide useful information for various practical applications. [8][9][10][11] Such investigations of two phase systems were performed earlier in our laboratory using suspensions of metal-oxide powders in organic solvents (slurries) by impedance spectroscopy techniques. [12][13][14] Measurements using slurries have some obvious advantages for a broader-range investigation in comparison with other types of two phase systems such as polymer-ceramic composites.…”

Photoemission Spectroscopy and Atomic Force Microscopy Investigation of Vapor-Phase Codeposited Silver/Poly(3-hexylthiophene) Composites

“…The nanoengineering of hybrid polymer−metal − , −metal oxide , −semiconductors , , −polymers , , and −fullerenes as thin films is a fast developing field of nanotechnology. These new composite materials show promise for a variety of applications in novel organic optoelectronics such as solid-state electronics , , electroluminescent devices and photovoltaics − , and photodetectors .…”