Type IIInAs/GaSb superlattice photovoltaic detectors with cutoff wavelength approaching 32 μm

We report the most recent advance in the area of type II InAs/GaSb superlattice photovoltaic detectors that have cutoff wavelengths beyond 25 mum, with some at nearly 32 mum. The photodiodes with a heterosuperlattice junction showed Johnson noise limited peak detectivity of 1.05x10(10) cm Hz(1/2)/W at 15 mum under zero bias, and peak responsivity of 3 A/W under -40 mV reverse bias at 34 K illuminated by similar to300 K background with a 2pi field-of-view. The maximum operating temperature of these detectors ranges from 50 to 65 K. No detectable change in the blackbody response has been observed after 5-6 thermal cyclings, with temperature varying between 15 and 296 K in vacuum. (C) 2002 American Institute of Physics.