Growth and fabrication of InAs/GaSb type II superlattice mid-wavelength infrared photodetectors

We report our recent work on the growth and fabrication of InAs/GaSb type II superlattice photodiode detectors. The superlattice consists of 9 monolayer InAs/12 monolayer GaSb in each period. Lattice mismatch between the GaSb substrate and the superlattice is 1.5 x 10(-4). The full width at half maximum of the first-order satellite peak from X-ray diffraction is 28 arc sec. The P-I-N photodiodes in which the absorption regions (I regions) have 600 periods of superlattice show a 50% cutoff wavelength of 4.3 mu m. The current responsivity was measured at 0.48 A/W from blackbody radiation. The peak detectivity of 1.75 x 10(11) cmHz(1/2)/W and the quantum efficiency of 41% at 3.6 mu m were obtained.