Long-Wave Type-II Superlattice Detectors with Unipolar Electron and Hole Barriers
Abstract
The performance of a long-wave infrared type-II InAs/GaSb superlattice photodetector with a 50% cut-off wavelength of approximately 8.7 micrometer 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 x 10(-5) A/cm2 at a reverse bias of -50 mV and a specific detectivity value of greater than 10(11) 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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 2012
- Accession Number
- ADA575643
Entities
People
- Ashok K. Sood
- Eric A. Decuir Jr.
- Gregory P. Meissner
- Nibir K. Dhar
- Nutan Gautam
- Priyalal S. Wijewarnasuriya
- Roger E. Welser
- Sanjay Krishna
Organizations
- United States Army Research Laboratory