Integration of Hybrid Plasmonic Au-BaTiO3 Metamaterial on Silicon Substrates.

Abstract

Silicon integration of nanoscale metamaterials is a crucial step toward low-cost and scalable optical-based integrated circuits. Here, a self-assembled epitaxial Au-BaTiO3 (Au-BTO) hybrid metamaterial with highly anisotropic optical properties has been demonstrated on Si substrates. A thin buffer layer stack (<20 nm) of TiN and SrTiO3 (STO) was applied on Si substrates to ensure the epitaxial growth of the Au-BTO hybrid films. Detailed phase composition and microstructural analyses show excellent crystallinity and epitaxial quality of the Au-BTO films. By varying the film growth condition, the density and dimension of the Au nanopillars can be tuned effectively, which leads to highly tailorable optical properties including tunable localized surface plasmon resonance (LSPR) peak and hyperbolic dispersion shift in the visible and near-infrared regime. The work highlights the feasibility of integrating epitaxial hybrid oxide-metal plasmonic metamaterials on Si towards future complex Si-based integrated photonics.