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Proceedings Paper

A floating gate double quantum well far-infrared photoconductor
Author(s): Elizabeth Ledwosinska; Thomas Szkopek
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Paper Abstract

The design and characterization of a floating gate GaAs/AlGaAs double quantum well long-infrared photoconductor is reported, with record operating temperature and modulation bandwidth for a device of this type. The principle of device operation relies on the photoionization of one quantum well, which functions as a floating gate, to modulate the conductance of the underlying quantum well, which functions as a transistor channel. Photoionization under normal incidence illumination is facilitated by a metal grating. Responsivity of 80-160 A/W for 12-20 μm long-infrared radiation has been observed at a 10 K device temperature, and photoresponse is clearly discernable up to 30 K. The modulation bandwidth was measured to exceed 1 kHz. An NEP = 2×10-11 W/ square root Hz, and D* = 4×108 cm square root Hz/W were measured, as limited by quantum well conductance fluctuations. Device performance is in fair competition with conventional QWIPs and we also propose a method to increase input saturation power in a photodetector of this structure.

Paper Details

Date Published: 4 March 2010
PDF: 8 pages
Proc. SPIE 7601, Terahertz Technology and Applications III, 76010J (4 March 2010); doi: 10.1117/12.841198
Show Author Affiliations
Elizabeth Ledwosinska, McGill Univ. (Canada)
Thomas Szkopek, McGill Univ. (Canada)

Published in SPIE Proceedings Vol. 7601:
Terahertz Technology and Applications III
Laurence P. Sadwick; Creidhe M. M. O'Sullivan, Editor(s)

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