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Proceedings Paper

Distinguishing between plasmon-induced and photo-excited carriers in a device geometry (Presentation Recording)

Paper Abstract

The use of surface plasmons, charge density oscillations of conduction electrons of metallic nanostructures, could drastically alter how sunlight is converted into electricity or fuels by increasing the efficiency of light-harvesting devices through enhanced light-matter interactions. Surface plasmons can decay directly into energetic electron-hole pairs, or “hot” carriers, which can be used for photocurrent generation or photocatalysis. However, little has been understood about the fundamental mechanisms behind plasmonic carrier generation. Here we use metallic nano-wire based hot carrier devices on a wide-bandgap semiconductor substrate to show that plasmonic hot carrier generation is proportional to field intensity enhancement instead of bulk material absorption. We also show that interband carrier generation results in less energetic carriers than plasmon-induced generation, and a plasmon is required to inject electrons over a large energy barrier. Finite Difference Time Domain (FDTD) method is used for theoretical calculations, which match well with experimental results. This work points to a clear route to increasing the efficiency of plasmonic hot carrier devices and drastically simplifies the theoretical framework for understanding the mechanisms of hot carrier generation.

Paper Details

Date Published: 5 October 2015
PDF: 1 pages
Proc. SPIE 9547, Plasmonics: Metallic Nanostructures and Their Optical Properties XIII, 95471T (5 October 2015); doi: 10.1117/12.2188519
Show Author Affiliations
Hangqi Zhao, Rice Univ. (United States)
Bob Y. Zheng, Rice Univ. (United States)
Alejandro Manjavacas, Rice Univ. (United States)
Michael J. McClain, Rice Univ. (United States)
Peter Nordlander, Rice Univ. (United States)
Naomi J. Halas, Rice Univ. (United States)

Published in SPIE Proceedings Vol. 9547:
Plasmonics: Metallic Nanostructures and Their Optical Properties XIII
Allan D. Boardman; Din Ping Tsai, Editor(s)

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