High-detectivity InAs _0.85 Sb _0.15 /InAs infra-red (1.8-4.8 μm) detectors

Abstract

We report the operation of broadband InAs0.85Sb0.15pn-junction photodetectors grown on InAs by liquid phase epitaxy. Despite the relatively large mismatch (≃1%) between the layers and the substrate the devices exhibit excellent zero bias detectivities (D*(70 K) = (1.5 × 1011 cm(Hz)1/2/W; D* (200 K) = 2 × 1010 cm(Hz)1/2/W at λ = 3.5 μm) and peak external quantum efficiencies of 40%.