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 integrated 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 conditions, the density and dimension of the Au nanopillars can be tuned effectively, leading to highly tailorable optical properties including tunable localized surface plasmon resonance (LSPR) peak and hyperbolic dispersion shift in the visible and near-infrared regimes. The work highlights the feasibility of integrating epitaxial hybrid oxide–metal plasmonic metamaterials on Si toward future complex Si-based integrated photonics.

Integration of highly anisotropic multiferroic BaTiO3–Fe nanocomposite thin films on Si towards device applications

“…40,41 Fascinating optical properties in pure BTO and BTO nanocomposite thin lms have previously been reported, including large Pockel's coefficients and hyperbolic dispersion. 27,28,34,42 Since the microstructural characterization and magnetic properties revealed highly anisotropic features arising from the Fe nanopillars, the optical properties of the BTO-Fe thin lms integrated on Si were also investigated in this study. Angular-dependent reectance (R%) measurements were performed at various incident angles (e.g., 30 , 40 , 50 , 60 and 70 ) using a spectroscopic ellipsometer.…”

“…This shi is a phenomenon which has also been observed in other oxide-metal nanocomposite thin lms. 27,28 The permittivity values of the BTO-Fe lms grown on various buffer congurations were also explored using the ellipsometric Psi (J) and Delta (D) data from incident light angles of 55 , 65 , and 75 . In-plane and out-of-plane real permittivity values were derived separately using a uniaxial anisotropy model and are plotted in Fig.…”

“…Recent advancements using the VAN platform beyond the conventional oxide-oxide systems have presented great potential in the growth of self-assembled metal nanopillars in an oxide matrix, such as plasmonic Au nanopillars in a BTO matrix, magnetic Co pillars in BaZrO 3 , and others. [27][28][29][30] It is noted that most of the VAN demonstrations have been focused on single crystal oxide substrates with limited success of oxide-oxide VAN growth on Si substrates, 31,32 and even fewer reports of oxidemetal VANs on Si. 28 In this work, a multiferroic BaTiO 3 -Fe (BTO-Fe) VAN system is demonstrated on buffered Si substrates using pulsed laser deposition.…”

“…[27][28][29][30] It is noted that most of the VAN demonstrations have been focused on single crystal oxide substrates with limited success of oxide-oxide VAN growth on Si substrates, 31,32 and even fewer reports of oxidemetal VANs on Si. 28 In this work, a multiferroic BaTiO 3 -Fe (BTO-Fe) VAN system is demonstrated on buffered Si substrates using pulsed laser deposition. The crystallinity and the physical properties are tuned for BTO-Fe lms grown on two different buffer congurations: an STO/TiN bilayer buffer and a single layer TiN buffer.…”

Metamaterials-Enabled Sensing for Human-Machine Interfacing

“…Such local maxima in the corresponding spectra or signals of metamaterials can be used as the eigenvalues or indications to improve the sensing accuracy and selectivity to enable the super-resolution detection of ambient environment, even with extremely small amounts of analytes [52,53]. For example, most EM metamaterials involve metallic nanostructures because metal nanostructures enable the occurrence of the localized surface plasmon resonance (LSPR) phenomenon, which is the collective but nonpropagating oscillations of surface electrons in the metal nanostructures [54][55][56][57][58][59][60][61][62]. LSPR can lead to the significant EM enhancement, altering the light-matter interaction with different absorption, reflection, and transmission properties, resulting in different characterization techniques like plasmon-enhanced fluorescence, surface-enhanced infrared absorption spectroscopy, and surface-enhanced Raman scattering [63].…”