Geometry and Polarization Effects in Designing Metallic-Semiconductor Nanostructures for Plasmonic Hot Carrier Collection

Abstract

Hot carrier collection assisted with surface plasmon integrated with metallic-semiconductor nanostructures directs a way for direct photoelectric conversion, which could be utilized for a photochemical reaction or photovoltaic energy conversion. Modeling plasmon-assisted thermal carrier generation, transport, and injection across the Schottky barrier helps us to acknowledge design considerations for these devices. Here, the effects of the nanostructure’s geometry and light polarization on hot electron collection are emphasized by analyzing a simple structure of rectangular gold nanorod and a sophisticated 2D Au/TiO2 nanocavity arrays designed by our group. The high electric field intensity inside the metallic nanostructure at the plasmon frequency enhances the hot electron generation shown here. The momentum distribution of hot electrons is determined by the nanostructure’s geometry and light polarization, which mostly affects collection efficiency. The structural and optical design is known to elevate the internal electric field from ordinary to the metal-semiconductor pathway that assists in producing hot carriers that accumulate adequate motion through the Schottky barrier, which further increases the effectiveness of the device.