Giant Dielectric Constant Controlled by Maxwell-Wagner Dielectric Relaxation in Al2O3/TiO2 Nanolaminates Synthesized by Atomic Layer Deposition

Nanolaminate consisting of Al2O3 and TiO2 oxide sublayers were synthesized, using atomic layer deposition (ALD) to produce individual layers with atomic scale control. The main goal of this work is to produce robust high dielectric constant layers based on biocompatible materials, such as Al2O3 and TiO2, suitable to fabricate high-capacitance capacitors for microchip embedded energy storage capacitor for implantable biomedical devices. However, these capacitors based on Al2O3/TiO2 nanolaminates can provide powerful components for energy storage systems. The overall thickness of the nanolaminates was kept at 150 nm in order to avoid thickness effect when characterizing the impact of the individual layer thickness on the capacitor dielectric performance. The sublayer thicknesses were kept constant for the same multilayer structure, although they were changed from 50 nm to 0.2 nm for a series of different samples. Two electrical responses were measured and plots of modulus and impedance were produced for nanolaminates with sublayer thickness < 2 nm. Giant dielectric constant (K = 1000) was observed when the sublayer thickness is less than 0.5 nm. The dielectric constant of the Al2O3/TiO2 nanolaminates is orders of magnitude larger than that of Al2O3 (K=10) and TiO2 (K=70-80) dielectrics. Studies were performed to investigate the Maxwell-Wagner type dielectric relaxation as a function of sublayer thickness and temperature, and their contributions to the dielectric constant of the nanolaminates. The Al2O3/TiO2 nanolaminates provide a new paradigm in dielectric materials for a new generation of nanoelectronics, implantable biomedical devices and energy storage systems.

 

  • References:
  • W. Li, Z. Chen, R. N. Premnath, B. Kabius, and O. Auciello, “Controllable Giant Dielectric Constant in Al2O3/TiO2 Nanolaminates”, J. Appl. Phys. 110 (2011) 024106-1-8. “Giant Dialectric Constant Dominated by Maxwell-Wagner Relaxation in Al2O3/TiO2 Nanolaminates Synthesized by Atomic Layer Deposition,” W. Li, O. Auciello, R.N. Premnath, and B. Kabius Appl. Phys. Lett. 96 (2010) 162907/1-3.
  • POC: Orlando Auciello, This e-mail address is being protected from spambots. You need JavaScript enabled to view it. , 630-252-1685.