AlGaAsSb-InGaAsSb-GaSb epitaxial heterostructures for uncooled infrared detectors

Abstract

Lattice matched n-type AlGaAsSb-InGaAsSb-GaSb heterostructures for uncooled infrared detectors, including separate absorption and multiplication avalanche photodiodes (SAM-APD), as well as low-voltage InGaAsSb APDs, were grown using inexpensive liquid phase epitaxy. Formation of the pn-junction was performed through diffusion of Zn from the vapor phase. Responsivity at /spl lambda/=2 /spl mu/m as high as 3.5 A/W was achieved in InGaAsSb APD biased at 8 V with the avalanche multiplication starting at 6 V. Our calculations have shown that the above parameters can result in a NEP value as low as 1/spl times/10/sup -12/ W or D* value as high as 2/spl times/10/sup 10/ cm/spl times/Hz/sup 1/2//W at room temperature for 400 /spl mu/m diameter (200 /spl mu/m diameter photoactive area) APDs.