3 December 2012 Long-wave type-II superlattice detectors with unipolar electron and hole barriers
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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.
© 2012 Society of Photo-Optical Instrumentation Engineers (SPIE)
Eric A. DeCuir, Gregory P. Meissner, Priyalal S. Wijewarnasuriya, Nutan Gautam, Sanjay Krishna, Nibir K. Dhar, Roger E. Welser, Ashok K. Sood, "Long-wave type-II superlattice detectors with unipolar electron and hole barriers," Optical Engineering 51(12), 124001 (3 December 2012). https://doi.org/10.1117/1.OE.51.12.124001 . Submission:

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