"XBn" barrier photodetectors for high sensitivity and high operating temperature infrared sensors

Philip Klipstein

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

230 Scopus citations


A barrier photodetector is a device in which the light is absorbed in a narrow bandgap semiconductor layer whose bands remain essentially flat or accumulated at the operating bias so that all carrier depletion is excluded. In a conventional photodiode below a threshold temperature T0, typically 130-150K for MWIR devices, the dark current is due to Generation-Recombination (G-R) centres in the depletion layer. In a barrier detector, the absence of depletion in the narrow bandgap semiconductor ensures that the G-R contribution to the dark current is negligible. The dark current in the barrier detector is thus dominated by the diffusion component, both above and below T0. Therefore, at a given temperature below T0, a barrier detector will exhibit a lower dark current than a conventional photodiode with the same cut-off wavelength. Alternatively, for a given dark current, a barrier detector will operate at a higher temperature than a conventional photodiode, provided that this temperature is below T0. Device architectures are presented for barrier detectors with photon absorbing layers based on InAs 1-xSbx alloys and type-II InAs/GaSb superlattices (T2SL). The thermionic and tunneling components of the dark current are analyzed and shown to be negligible for typical device parameters. An operating temperature of ∼150K is estimated for a MWIR barrier detector with f/3 optics and a cut-off wavelength of 4.2μ.

Original languageEnglish
Title of host publicationInfrared Technology and Applications XXXIV
StatePublished - 2008
Externally publishedYes
EventInfrared Technology and Applications XXXIV - Orlando, FL, United States
Duration: 17 Mar 200820 Mar 2008

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


ConferenceInfrared Technology and Applications XXXIV
Country/TerritoryUnited States
CityOrlando, FL


  • Dark current
  • Diffusion current
  • Focal plane array
  • Generation-recombination current
  • High operating temperature
  • Indium arsenide antimonide
  • Infrared detector
  • Shockley-read-hall
  • Type II superlattice


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