InAs/GaSb Superlattice Detectors Operating at Room Temperature

We have investigated mid-infrared detectors based on type-II transitions in InAs/GaSb strain layer superlattices (SLS). The SLS heterostructures were grown by solid source molecular beam epitaxy and were characterized by double crystal X-ray diffraction, transmission electron microscopy, photoluminescence and absorption measurements. The effect of aqueous ammonium sulfide passivation was investigated using picosecond excitation correlation (PEC) and variable array diode analysis (VADA). The surface recombination velocity was estimated to be 9.5times10⁵ cm/s for the unpassivated sample and 4.0times10⁵ cm/s for the passivated sample. NIP diodes were grown and fabricated with 300 periods of 8 ML InAs/8 ML GaSb SLS in the active region. Spectral response with lambda_cut-off~5mum was observed at room temperature with a Johnson noise limited D^* =4.6times10⁹ cm.Hz^1/2/W and a conversion quantum efficiency of 67% at V_b=-0.3 V. Scattering in the substrate was ignored for these measurements