Oblique-angle deposition of self-assembled zigzag-shaped Au nanostructures in La0.7Sr0.3MnO3–Au vertically aligned nanocomposite thin films

Abstract

Hyperbolic metamaterials (HMMs) provide a unique tailorable material platform to manipulate light–matter interactions, which traditional single-phase materials cannot achieve easily. Typical HMMs possess a periodic array of metallic nanopillars embedded within a dielectric matrix material. As a new class of HMMs, vertically aligned nanocomposites (VANs) demonstrate uniformly distributed, vertically aligned metallic nanopillars in an oxide matrix via a self-assembly deposition process. Herein, by combining oblique-angle deposition (OAD) and multilayer VAN growth, zigzag-shaped metallic nanopillars within an oxide matrix have been demonstrated. Specifically, by changing the oblique angle in each layer during multilayer Au–La_0.7Sr_0.3MnO₃ VAN growth, zigzag-shaped Au nanopillars are embedded within the La_0.7Sr_0.3MnO₃ matrix. Interestingly, by varying the inclination angles of the substrate and utilizing the shadowing effect during OAD, tailorable Au nanostructures and tunable anisotropic optical properties have been demonstrated. This new OAD–VAN combined deposition method presents great potential for the design and processing of very complex 3D HMMs for future integrated photonic devices.