We demonstrated high performance long wavelength InAs/GaAs0.09Sb0.91 type-II superlattices infrared photo-detectors grown on InAs substrates. Superlattices photodiodes with InAs layer thickness from 14 to 24 ML showed 50% cutoff wavelength from 6 to 12.5 μm while the lattice-mismatch was kept smaller than 4.0 × 10−4 without any additional interface layers for strain balance. Quantum efficiency spectra showed oscillating characteristics which were attributed to the plasma effect in the highly doped InAs buffer layers. The absorption coefficient of 1800 cm−1 and diffusion length of 10 μm of minority carriers in the SLs on InAs have been obtained through simulation. A photodiode exhibited a 12.5 μm cutoff wavelength with a peak detectivity of 7.4 × 1010 cm Hz1/2 W−1 and 2.6 × 1011 cm Hz1/2 W−1 at 76 K and 52 K, respectively.
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