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Proceedings Paper

Ultra-high optical responsivity of semiconducting asymmetric nano-channel diodes for photon detection
Author(s): Y. Akbas; T. Plecenik; P. Ďurina; A. Plecenik; A. Jukna; G. Wicks; Roman Sobolewski
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Paper Abstract

The asymmetric nano-channel diode (ANCD) is the 2-dimensional electron gas (2DEG) semiconductor nanodevice that, unlike a conventional diode, relies on the device nanostructure and field-controlled transport in a ballistic nanometerwidth channel instead of barriers to develop its asymmetric, diode-like current-voltage (I-V) characteristics. We focus on ANCD optoelectronic properties, and demonstrate that the devices can act as very sensitive, single-photon-level, visiblelight photodetectors. Our test structures consist of 2-μm-long and ~230-nm-wide channels and were fabricated using electron-beam lithography on a GaAs/AlGaAs heterostructure with a 2DEG layer, followed by reactive ion etching. The I-V curves were collected by measuring the transport current under the voltage-source biasing condition, both in the dark and under light illumination. The experiments were conducted inside a cryostat, in a temperature range from 300 K to 78 K. As an optical excitation, we used a 800-nm-wavelength, generated by a commercial Ti:sapphire laser operated either at a quasi-continuous–wave mode or as a source of 100-fs-wide pulses. The impact of the light illumination was very clear, and at low temperatures we observed a significant photocurrent Iph ~ 0.25 μA at temperature 78 K for the incident optical power as low as 1 nW, with a limited dark-current background. The magnitude of the device optical responsivity increased linearly with the decrease of the optical power, reaching for 1-nW optical excitation the value as high as ~400 A/W at room temperature and >800 A/W at 78K. The physics of the photoresponse gain mechanism in the ANCD arises from a vast disparity between the sub-picosecond transit time of photo-excited electrons travelling in the 2DEG nanochannel and the up to microsecond lifetime of photo-excited holes pushed towards the device substrate.

Paper Details

Date Published: 15 May 2017
PDF: 6 pages
Proc. SPIE 10229, Photon Counting Applications 2017, 102290N (15 May 2017); doi: 10.1117/12.2270908
Show Author Affiliations
Y. Akbas, Univ. of Rochester (United States)
T. Plecenik, Comenius Univ. in Bratislava (Slovakia)
P. Ďurina, Comenius Univ. in Bratislava (Slovakia)
A. Plecenik, Comenius Univ. in Bratislava (Slovakia)
A. Jukna, Univ. of Rochester (United States)
Vilnius Gediminas Technical Univ. (Lithuania)
G. Wicks, Univ. of Rochester (United States)
Roman Sobolewski, Univ. of Rochester (United States)

Published in SPIE Proceedings Vol. 10229:
Photon Counting Applications 2017
Ivan Prochazka; Roman Sobolewski; Ralph B. James, Editor(s)

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