MBE growth of room-temperature InAsSb mid-infrared detectors

Some key growth issues for InAsSb mid-infrared detectors are presented. We investigate the influence of growth temperature and Sb/As flux ratio on InAsSb alloy composition and on carrier lifetime. The Sb mole fraction in InAs1-xSbx depends linearly on the Sb flux using either As-2 or As-4 (0.02 less than or equal to x less than or equal to 0.16). However, the Sb incorporation rate is significantly lower using As-2 flux. The carrier lifetime in thick InAsSb layers closely lattice-matched to GaSb is measured by time-resolved photoconductivity. The values obtained vary from 15 to 200 ns depending on growth conditions. The main result is that the carrier lifetime increases as the growth temperature deer-eases and seems to be limited by Shockley-Read recombinations. Finally, an InAs0.91Sb0.09 p i-n photovoltaic detector is grown and operates at room temperature. A detectivity of 1.5 x 10(9) cm root Hz/W at 3.39 mum and 250 It is measured. We show that the quality of the active region material ensures a sufficiently low generation-recombination current. (C) 2001 Elsevier Science B.V. All rights reserved.