Photoexcitation cascade and multiple hot-carrier generation in graphene
Name
1210.1205.pdf
Size
423.54 KB
Format
Adobe PDF
Checksum (MD5)
09b3877432c9b51f198e356174788377
Author(s)
Tielrooij, K. J.
Song, J. C. W.
Jensen, S. A.
Centeno, A.
Pesquera, A.
Zurutuza Elorza, A.
Bonn, M.
Levitov, Leonid
Koppens, F. H. L.
Date Issued
February 2013
Journal
Nature Physics
Publisher
Springer Nature
Citation
Tielrooij, K. J. et al. “Photoexcitation Cascade and Multiple Hot-Carrier Generation in Graphene.” Nature Physics 9, n4 (February 2013): 248–252 © 2013 Macmillan Publishers Limited
Version
Author's final manuscript
Abstract
The conversion of light into free electron-hole pairs constitutes the key process in the fields of photodetection and photovoltaics. The efficiency of this process depends on the competition of different relaxation pathways and can be greatly enhanced when photoexcited carriers do not lose energy as heat, but instead transfer their excess energy into the production of additional electron-hole pairs through carrier-carrier scattering processes. Here we use optical pump-terahertz probe measurements to probe different pathways contributing to the ultrafast energy relaxation of photoexcited carriers. Our results indicate that carrier-carrier scattering is highly efficient, prevailing over optical-phonon emission in a wide range of photon wavelengths and leading to the production of secondary hot electrons originating from the conduction band. As hot electrons in graphene can drive currents, multiple hot-carrier generation makes graphene a promising material for highly efficient broadband extraction of light energy into electronic degrees of freedom, enabling high-efficiency optoelectronic applications.
MIT Department
Massachusetts Institute of Technology. Department of Physics
Terms of Use
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1038/NPHYS2564
