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Optical Engineering

Long-wave type-II superlattice detectors with unipolar electron and hole barriers
Author(s): Eric A. DeCuir; Gregory P. Meissner; Priyalal S. Wijewarnasuriya; Nutan Gautam; Sanjay Krishna; Nibir K. Dhar; Roger E. Welser; Ashok K. Sood
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Paper Abstract

The performance of a long-wave infrared type-II InAs/GaSb superlattice photodetector with a 50% cut-off wavelength of approximately 8.7 μm is presented. The ability to lower dark current densities over traditional P-type-Intrinsic-N-type diodes is offered by way of hetero-structure engineering of a pBiBn structure utilizing superlattice p-type (p) and n-type (n) contacts, an intrinsic (i) superlattice active (absorber) region, and unipolar superlattice electron and hole blocking (B) layers. The spectral response of this pBiBn detector structure was determined using a Fourier transform infrared spectrometer, and the quantum efficiency was determined using a 6250 nm narrow band filter and a 500 K blackbody source. A diode structure designed, grown, and fabricated in this study yielded a dark current density of 1.05×10-5 A/cm2 at a reverse bias of - 50 mV and a specific detectivity value of greater than 1011 Jones at 77 K. Theoretical fittings of the diode dark currents at 77 K were used in this study to help isolate the contributing current components observed in the empirical dark current data. A variable temperature study (80 to 300 K) of the dark current is presented for a diode demonstrating diffusion-limited dark current down to 77 K.

Paper Details

Date Published: 3 December 2012
PDF: 8 pages
Opt. Eng. 51(12) 124001 doi: 10.1117/1.OE.51.12.124001
Published in: Optical Engineering Volume 51, Issue 12
Show Author Affiliations
Eric A. DeCuir, U.S. Army Research Lab. (United States)
Gregory P. Meissner, U.S. Army Research Lab. (United States)
Priyalal S. Wijewarnasuriya, U.S. Army Research Lab. (United States)
Nutan Gautam, Ctr. for High Technology Materials (United States)
Sanjay Krishna, Ctr. for High Technology Materials (United States)
Nibir K. Dhar, Defense Advanced Research Projects Agency (United States)
Roger E. Welser, Magnolia Optical Technologies, Inc. (United States)
Ashok K. Sood, Magnolia Optical Technologies, Inc. (United States)

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