Nanoplasmonic Terahertz Photoconductive Switch on GaAs

Barmak Heshmat †, Hamid Pahlevaninezhad †,Yuanjie, Pang †, Mostafa Masnadi-Shirazi ‡, Ryan Burton Lewis ‡§, Thomas Tiedje †, Reuven Gordon *†, and Thomas Edward Darcie †

^† Department of Electrical and Computer Engineering,University of Victoria, V8P 5C2, Victoria, BC Canada

^‡ Department of Electrical and Computer Engineering,University of British Columbia, V6T 1Z4, Vancouver, BC, Canada

^§ Department of Physics and Astronomy, University of British Columbia, V6T 1Z1, Vancouver, BC, Canada

Nano Lett., Article ASAP

DOI: 10.1021/nl303314a

Publication Date (Web): November 21, 2012

Copyright © 2012 American Chemical Society

Low-temperature (LT) grown GaAs has a subpicosecond carrier response time that makes it favorable for terahertz photoconductive (PC) switching. However, this is obtained at the price of lower mobility and lower thermal conductivity than GaAs. Here we demonstrate subpicosecond carrier sweep-out and over an order of magnitude higher sensitivity in detection from a GaAs-based PC switch by using a nanoplasmonic structure. As compared to a conventional GaAs PC switch, we observe 40 times the peak-to-peak response from the nanoplasmonic structure on GaAs. The response is double that of a commercial, antireflection coated LT-GaAs PC switch.