High performance InAs/Ga1-xInxSb superlattice infrared photodiodes

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Abstract
The optical and electrical properties of infrared photodiodesdiodes based on InAs/(GaIn)Sb superlatticesgrown by molecular beam epitaxy were investigated. The diodes, with a cut-off wavelength around 8 μ m show a current responsivity of 2 A/W. By proper adjustment of the p-doping level above the n-background concentration the depletion width exceeds a critical size of about 60 nm, leading to the suppression of band-to-band tunnelingcurrents. Above that critical width the dynamic impedance R 0 A at 77 K reaches values above 1 k Ω cm 2 leading to a Johnson-noise-limited detectivity in excess of 1×10 12 cm √ Hz/W.