Subpicosecond electron-hole recombination time and terahertz-bandwidth photoresponse in freestanding GaAs epitaxial mesoscopic structures

Journal Article · Wed Jul 18 04:00:00 EDT 2012 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4737442· OSTI ID:1095080

Mikulics, Martin ^[1]; Zhang, Jie ^[2]; Serafini, John ^[3]; Adam, Roman ^[4]; Grützmacher, Detlev ^[5]; Sobolewski, Roman ^[6]

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1. Peter Grünberg Institut PGI-9, Forschungszentrum Jülich 1 , D-52425 Jülich, Germany and , D-52425 Jülich, Germany; Jülich-Aachen Research Alliance (JARA)—Fundamentals of Future Information Technology 1 , D-52425 Jülich, Germany and , D-52425 Jülich, Germany; Laboratory for Laser Energetics, University of Rochester, Rochester, NY
2. Department of Electrical and Computer Engineering and Laboratory for Laser Energetics, University of Rochester 2 , Rochester, New York 14627-0231, USA
3. Department of Physics and Astronomy and Laboratory for Laser Energetics, University of Rochester 3 , Rochester, New York 14627-0231, USA
4. Peter Grünberg Institut PGI-6, Forschungszentrum Jülich 4 , D-52425 Jülich, Germany
5. Peter Grünberg Institut PGI-9, Forschungszentrum Jülich 1 , D-52425 Jülich, Germany and , D-52425 Jülich, Germany; Jülich-Aachen Research Alliance (JARA)—Fundamentals of Future Information Technology 1 , D-52425 Jülich, Germany and , D-52425 Jülich, Germany
6. Department of Electrical and Computer Engineering and Laboratory for Laser Energetics, University of Rochester 2 , Rochester, New York 14627-0231, USA; Department of Physics and Astronomy and Laboratory for Laser Energetics, University of Rochester 3 , Rochester, New York 14627-0231, USA

We present the ultrafast (THz-bandwidth) photoresponse from GaAs single-crystal mesoscopic structures, such as freestanding whiskers and platelets fabricated by the top-down technique, transferred onto a substrate of choice, and incorporated into a coplanar strip line. We recorded electrical transients as short as ~600 fs from an individual whisker photodetector. Analysis of the frequency spectrum of the photoresponse electrical signal showed that, intrinsically, our device was characterized by an ~150-fs carrier lifetime and an overall 320-fs response. The corresponding 3-dB frequency bandwidth was 1.3 THz—the highest bandwidth ever reported for a GaAs-based photodetector. Simultaneously, as high-quality, epitaxially grown crystals, our GaAs structures exhibited mobility values as high as ~7300 cm²/V·s, extremely low dark currents, and ~7% intrinsic detection efficiency, which, together with their experimentally measured photoresponse repetition time of ~1 ps, makes them uniquely suitable for terahertz-frequency optoelectronic applications, ranging from ultrafast photon detectors and counters to THz-bandwidth optical-to-electrical transducers and photomixers.

• Research Organization: Univ. of Rochester, NY (United States). Lab. for Laser Energetics
• Sponsoring Organization: USDOE
• DOE Contract Number: FC52-08NA28302
• OSTI ID: 1095080
• Report Number(s): DOE/NA/28302-1077
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 3 Vol. 101; ISSN 0003-6951
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English

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36 MATERIALS SCIENCE