Engineering crystalline Au nanoparticles of anisotropic shape in epitaxially grown high-index SrTiO₃

We present a possible fabrication scheme of anisotropic nanoparticles grown in a crystal high-index material (SrTiO₃). Different ellipsoidal Au nano-antennas were formed by changing the Au seed layer thickness and subsequent embedding in SrTiO₃, prepared by pulsed laser deposition. Prior to the SrTiO₃ deposition, a temperature-induced dewetting process of the thin Au films results in different particle sizes and size distributions, which are the basis for anisotropic particle formation after embedding in a crystalline SrTiO₃ matrix. The dependence of the anisotropy on the Au seed layer thickness was investigated by X-ray diffraction (XRD) measurements. At this was noticed a stronger increase in size in c-axis direction than in a/b-axis direction for an increase of the Au seed layers. Additionally, the optical response of the particles was detected via the plasmon resonance shift in extinction and scattering spectra.