Crystallographic investigation of Au nanoparticles embedded in a SrTiO$_3$ thin film for plasmonics applications by means of synchrotron radiation

TL;DR

This study uses synchrotron radiation to analyze the crystallographic orientations of self-organized Au nanoparticles embedded in SrTiO3, revealing preferred alignments and their dependence on film thickness, relevant for plasmonics applications.

Contribution

It provides detailed crystallographic orientation data of Au nanoparticles in SrTiO3 using synchrotron X-ray diffraction, a novel insight for plasmonic material design.

Findings

Au nanoparticles preferentially align with (111) orientation along the substrate normal.

Two in-plane orientations are identified for each main orientation.

The in-plane orientation populations depend on the initial gold film thickness.

Abstract

Self-organized monocrystalline Au nanoparticles with potential applications in plasmonics are grown in a SrTiO$_3$ matrix by a novel two-step deposition process. The crystalline preferred orientation of these Au nanoparticles is investigated by synchrotron hard x-ray diffraction. Nanoparticles preferentially align with the (111) direction along the substrate normal (001), whereas two in-plane orientations are found with $[110]_{SrTiO_3} \: || \: [110]_{Au}$ and $[100]_{SrTiO_3} \: || \: [110]_{Au}$. Additionally, a smaller diffraction signal from nanoparticles with the (001) direction parallel to the substrate normal (001) is observed; once again, two in-plane orientations are found, with $[100]_{SrTiO_3} \: || \: [100]_{Au}$ and $[100]_{SrTiO_3} \: || \: [110]_{Au}$. The populations of the two in-plane orientations are found to depend on the thickness of the gold film deposited in the first step of the growth.