Plasmon Enhanced Internal Photoemission in Antenna-Spacer-Mirror Based Au/TiO2 Nanostructures
Journal article, 2015

Emission of photoexcited hot electrons from plasmonic metal nanostructures to semiconductors is key to a number of proposed nanophotonics technologies for Solar harvesting, water splitting, photocatalysis, and a variety of optical sensing and photodetector applications. Favorable materials and catalytic properties make systems based on gold and TiO2 particularly interesting, but the internal photo emission efficiency for visible light is low because of the wide bandgap of the semiconductor. We investigated the incident photon-to-electron conversion efficiency of thin TiO2 films decorated with Au nanodisk antennas in an electrochemical circuit and found that incorporation of a Au mirror beneath the semiconductor amplified the photoresponse for light with wavelength lambda = 500-950 nm by a factor 2-10 compared to identical structures lacking the mirror component. Classical electrodynamics simulations showed that the enhancement effect is caused by a favorable interplay between localized surface plasmon excitations and cavity modes that together amplify the light absorption in the Au/TiO2 interface. The experimentally determined internal quantum efficiency for hot electron transfer decreases monotonically with wavelength, similar to the probability for interband excitations with energy higher than the Schottky barrier obtained from a density functional theory band structure simulation of a thin Au/TiO2 slab.


Schottky barrier


surface plasmon

hot electrons


Yurui Fang

Chalmers, Applied Physics, Bionanophotonics

Yang Jiao

Chalmers, Applied Physics, Bionanophotonics

Kunli Xiong

Chalmers, Applied Physics, Bionanophotonics

Robin Ogier

Chalmers, Applied Physics, Bionanophotonics

Zhong-Jian Yang

Chalmers, Applied Physics, Bionanophotonics

Shiwu Gao

Chalmers, Applied Physics, Materials and Surface Theory

Andreas Dahlin

Chalmers, Applied Physics, Bionanophotonics

Mikael Käll

Chalmers, Applied Physics, Bionanophotonics

Nano Letters

1530-6984 (ISSN) 1530-6992 (eISSN)

Vol. 15 6 4059-4065

Subject Categories

Materials Engineering

Condensed Matter Physics





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