Self-assembled ErAs nanoislands for enhanced terahertz detection.

ORAL

Abstract

Traditionally, THz detectors based on photoconductive (PC) antennas have utilized low-temperature grown GaAs (LT-GaAs) and radiation-damaged silicon-on-sapphire (RD-SOS) due to their fast carrier trapping times. However, the development of self-assembled ErAs nanoislands embedded in a GaAs matrix offers a particularly useful alternative for THz PC devices based on the ability to independently tune photo-excited carrier lifetimes, trap density, and dark resistance. In this work, we demonstrate enhanced THz detection using self-assembled ErAs:GaAs nanoisland structures. Three nearly identical THz PC antenna detectors are fabricated; one each on the LT-GaAs, RD-SOS, and ErAs:GaAs substrates. Their performance in a typical THz time-domain spectroscopy system is compared in terms of optical efficiency, bandwidth, and saturation behavior. Carrier lifetimes in all three substrates are also compared via pump-probe techniques.

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Authors

  • John O'Hara

  • Rohit Prasankumar

    • Los Alamos National Laboratory

  • Josh Zide

  • Arthur Gossard

    • Materials Department, University of California, Santa Barbara
    • University of California, Santa Barbara
    • University of California-Santa Barbara

  • Antoinette Taylor

    • Los Alamos National Laboratory
    • MST-CINT, Los Alamos National Laboratory

  • Richard Averitt

    • Los Alamos National Laboratory
    • Los Alamos National Lab