Passivation of InAs∕(GaIn)Sb short-period superlattice photodiodes with 10μm cutoff wavelength by epitaxial overgrowth with AlxGa1−xAsySb1−y

Abstract
An approach for the passivation of photodiodes based on compounds of the InAs ∕ GaSb ∕ AlSb materials family is presented. The passivation is realized by the overgrowth of patterned mesa devices with a quaternary Al x Ga 1 − x As y Sb 1 − y layer, lattice matched to the GaSb substrate. Proof of concept is demonstrated on infrared photodiodes based on InAs ∕ ( GaIn ) Sb superlattices with 10 μ m cutoff wavelength operating at 77 K where suppression of surfaceleakage currents is observed.