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

Mikulics, M.; Grützmacher, D.; Adam, R.; Serafini, J.; Sobolewski, R.; Zhang, J.

doi:10.1063/1.4737442

Journal Article

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

Mikulics, M.FZJ* ; Zhang, J. ; Serafini, J. ; Adam, R. ; Grützmacher, D.FZJ* ; Sobolewski, R.

2012
American Institute of Physics Melville, NY

Applied physics letters 101, 031111 (2012) [10.1063/1.4737442]

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Please use a persistent id in citations: http://hdl.handle.net/2128/7572 doi:10.1063/1.4737442

Abstract: 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 similar to 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 similar to 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 similar to 7300 cm(2)/V.s, extremely low dark currents, and similar to 7% intrinsic detection efficiency, which, together with their experimentally measured photoresponse repetition time of similar to 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. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4737442]

Keyword(s): J

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Physics, Applied

Note: The authors thank P. Song and M. Samuels for their assistance in some experiments. This work was supported in part by NSF Grant No. ECCS-0901701 (Rochester). J.Z. and J.S. acknowledge support from the Frank Horton Graduate Fellowship Program at the University of Rochester's Laboratory for Laser Energetics, funded by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC52-08NA28302 and the New York State Energy Research and Development Authority. The support of NSF and DOE does not constitute their endorsement of the views expressed in this article.

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