High operating temperature nBn detector with monolithically integrated microlens

We demonstrate an InAsSb nBn detector monolithically integrated with a microlens fabricated on the back side of the detector. The increase in the optical collection area of the detector resulted in a five-fold enhancement of the responsivity to R-p = 5.5 A/W. The responsivity increases further to R-p = 8.5 A/W with an antireflection coating. These 4.5 lm cut-off wavelength antireflection coated detectors with microlenses exhibited a detectivity of D*(lambda) = 2.7 x 10 10 cmHz(0.5)/W at T = 250 K, which can be reached easily with a single-stage thermoelectric cooler or with a passive radiator in the space environment. This represents a 25K increase in the operating temperature of these devices compared to the uncoated detectors without an integrated microlens. Published by AIP Publishing.