Langmuir–Blodgett Fabrication of Nanosheet-Based Dielectric Films without an Interfacial Dead Layer

概要

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Langmuir–Blodgett (LB) deposition was employed to fabricate high-$\kappa$ dielectric nanofilms of titania nanosheets. The LB-based layer-by-layer approach using an atomically flat SrRuO3 substrate is effective for the fabrication of atomically uniform and highly dense nanofilms. These films exhibited both high dielectric constant ($\kappa\sim 123$) and low leakage current density ($J< 10^{-7}$ A cm-2) for thicknesses down to 5 nm, while eliminating the size-effect problems encountered in current high-$\kappa$ films. From analyses of interfacial structures by transmission electron microscopy and hard X-ray photoelectron spectroscopy, we have clarified that the films are composed of a well-ordered lamellar structure without an interfacial dead layer. According to first-principles calculations, a highly polarizable nature of titania nanosheets can bring improved dielectric properties, yielding high-$\kappa$ values even in an ultrathin geometry (${<}10$ nm).
Published by the Japan Society of Applied Physics through the Institute of Pure and Applied Physicsの論文
2008-09-25