High performance type-II InAs/GaSb superlattice photodiodes

H. Mohseni*, Y. Wei, M. Razeghi

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review

22 Scopus citations


We report on the demonstration of high performance p-i-n photodiodes based on type-II InAs/GaSb superlattices operating in the very long wavelength infrared (VLWIR) range at 80 K. Material is grown by molecular beam epitaxy on GaSb substrates with excellent crystal quality as evidenced by x-ray diffraction and atomic force microscopy. The processed devices with a 50% cutoff wavelength of λc=22 μm show a peak current responsivity about 5.5 A/W at 80 K. The use of binary layers in the superlattice has significantly enhanced the uniformity and reproducibility of the energy gap. The 90% to 10% cut-off energy width of these devices is on the order of 2kT which is about four times smaller compared to the devices based on InAs/Ga1-xInxSb superlattices. Similar photovoltaic devices with cut-off wavelengths up to 25 μm have been measured at 80 K. Our experimental results shows excellent uniformity over a three inch wafer area, indicating the possibility of VLWIR focal plane arrays based on type-II superlattices.

Original languageEnglish (US)
Pages (from-to)191-199
Number of pages9
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - 2001
EventPhotodetectors: Materials and Devices VI - San Jose, CA, United States
Duration: Jan 22 2001Jan 24 2001


  • HgCdTe
  • Infrared detector
  • Long wavelength
  • Quantum well
  • Superlattice
  • Type-II

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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