Long-wavelength infrared detectors based on strained InAs--Ga/sub 1-//sub x/In/sub x/Sb type-II superlattices

Journal Article · Wed Mar 01 04:00:00 EST 1989 · J. Vac. Sci. Technol., A; (United States)

DOI:https://doi.org/10.1116/1.576201· OSTI ID:6771031

Mailhiot, C; Smith, D L

We demonstrate that infrared detectors made from strained type-II superlattices consisting of III--V semiconductors can have favorable properties for long-wavelength (lambda/sub c/ >10 ..mu..m) detection applications. We specifically consider InAs--Ga/sub 1-//sub x/ In/sub x/ Sb strained-layer superlattices with xapprox. =0.4 . This is a type-II superlattice where the conduction-band minimum of InAs is lower in energy than the valence-band maximum of Ga/sub 1-//sub x/ In/sub x/ Sb. Electrons are localized in the InAs layers while holes are localized in the Ga/sub 1-//sub x/ In/sub x/ Sb layers. Generally, in a type-II superlattice such as InAs--GaSb, large absorption coefficients cannot be achieved at the small values of band gap necessary for long-wavelength detection because the localization of electrons and holes in adjacent layers leads to small optical matrix elements. Therefore, small band gaps and large optical matrix elements appear to be two mutually exclusive requirements in the InAs--GaSb superlattice. Here, we show that it is possible to obtain large optical absorption coefficients at the values of band gap required for long-wavelength detection by taking advantage of internal lattice-mismatch induced strains present in InAs--Ga/sub 1-//sub x/ In/sub x/ Sb superlattices.

• Research Organization: Xerox Webster Research Center, Webster, New York 14580
• OSTI ID: 6771031
• Journal Information: J. Vac. Sci. Technol., A; (United States), Journal Name: J. Vac. Sci. Technol., A; (United States) Vol. 7:2; ISSN JVTAD
• Country of Publication: United States
• Language: English

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ARSENIC COMPOUNDS
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CHARGE CARRIERS
ELECTRO-OPTICAL EFFECTS
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