Synthesis and characterization of a plasmonic-semiconductor composite containing rationally designed, optically tunable gold nanorod dimers and anatase TiO₂

Herein we utilize on-wire lithography (OWL) to synthesize a composite plasmonic-semiconductor material composed of Au nanorod dimers embedded within anatase TiO₂ sheets. We demonstrate that, despite the harsh conditions necessary to synthesize crystalline TiO₂, the gapped nanostructures remain intact. Additionally, we show that the optical properties of these structures can be tailored via the geometric control afforded by the OWL process to produce structures with various gap sizes exhibiting different electric field intensities near the surface of the metal particles and that those fields penetrate into the semiconductor material. Finally, we show that this composite amplifies the electric field of incident light on it by a factor of 10³, which is more that 750 times greater than the isotropic materials typically used for these systems.