High-performance InAs/GaSb superlattice photodiodes for the very long wavelength infrared range

We report on the demonstration of high-performance p-i-n photodiodes based on type-II InAs/GaSb superlattices with 50% cut-off wavelength lambda (c)=1 6 mum operating at 80 K. Material is grown by molecular beam epitaxy on GaS b substrates with excellent crystal quality as evidenced by x-ray diffracti on and atomic force microscopy. The processed devices show a current respon sivity of 3.5 A/W at 80 K leading to a detectivity of similar to1.51x10(10) cmHz(1/2)/W. The quantum efficiency of these devices is about 35% which is comparable to HgCdTe detectors with a similar active layer thickness. (C) 2001 American Institute of Physics.