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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 16, Iss. 24 — Nov. 24, 2008
  • pp: 19695–19705

Impact of the contact metallization on the performance of photoconductive THz antennas

N. Vieweg, M. Mikulics, M. Scheller, K. Ezdi, R. Wilk, H.-W. Hübers, and M. Koch  »View Author Affiliations

Optics Express, Vol. 16, Issue 24, pp. 19695-19705 (2008)

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Both AuGe based alloys and Ti/Au metal layer stacks are widely used as ohmic metal contacts for photoconductive THz antennas made of low temperature grown GaAs. Here, we present the first systematic comparison between these two metallization types. A series of antennas of both kinds is excited by femtosecond laser pulses and by the emission from two diode lasers, i.e. we test the structures as pulsed THz emitters and as photomixers. In both cases, coherent and incoherent detection schemes are employed. We find that the power emitted from the antennas with AuGe metallization is 50% higher than that of antennas with a Ti/Au metal layer. From a comparison with a photomixer model we conclude that the higher output power results from a lower contact resistance of the AuGe contacts leading to an increased current flow. However, Ti/Au contacts have a higher thermal stability which might be advantageous if high system stability is called for.

© 2008 Optical Society of America

OCIS Codes
(130.4815) Integrated optics : Optical switching devices
(300.6495) Spectroscopy : Spectroscopy, teraherz

ToC Category:

Original Manuscript: October 6, 2008
Revised Manuscript: November 11, 2008
Manuscript Accepted: November 11, 2008
Published: November 13, 2008

N. Vieweg, M. Mikulics, M. Scheller, K. Ezdi, R. Wilk, H.W. Hübers, and M. Koch, "Impact of the contact metallization on the performance of photoconductive THz antennas," Opt. Express 16, 19695-19705 (2008)

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