nBn extended short-wavelength infrared focal plane array

Arash Dehzangi, Abbas Haddadi, Romain Chevallier, Yiyun Zhang, Manijeh Razeghi*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


An extended short-wavelength nBn InAs/GaSb/AlSb type-II superlattice-based infrared focal plane array imager was demonstrated. A newly developed InAs0.10Sb0.90∕GaSb superlattice design was used as the large-bandgap electron barrier in this photodetector. The large band gap electron-barrier design in this nBn photodetector architecture leads to the device having lower dark current densities. A new bi-layer etch-stop scheme using a combination of InAs0.91Sb0.09 bulk and AlAs0.1Sb0.9∕GaSb superlattice layers was introduced to allow complete substrate removal and a shorter wavelength cut-on. Test pixels exhibit 100% cutoff wavelengths of ~2.30 and ~2.48 μm at 150 and 300 K, respectively. The devices achieve saturated quantum efficiency values of 59.7% and 63.8% at 150 and 300 K, respectively, under backside illumination and without any antireflection coating. At 150 K, photodetectors exhibit dark current density of 8.75 × 10−8 A∕cm2 under −400 mV applied bias, providing specific detectivity of 2.82 × 1012 cm · Hz12∕W at 1.78 μm. At 300 K, the dark current density reaches 4.75 × 10−2 A∕cm2 under −200 mV bias, providing a specific detectivity of 8.55 × 109 cm · Hz12∕W 1.78 μm.

Original languageEnglish (US)
Pages (from-to)591-594
Number of pages4
JournalOptics Letters
Issue number3
StatePublished - Feb 1 2018

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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