Résumé
Significant progress has been recently achieved in the development of type-II superlattice barrier infrared detector, also called T2SL XBn structure. Indeed, T2SL quantum structure associated with XBn design enjoys important advantages such as low Auger recombination rate, tunable cut-off wavelength, or suppression of generation-recombination dark current. Consequently, the Ga-free InAs/InAsSb T2SL XBn structure is now a reliable candidate for the fabrication of high-performance focal plane arrays (FPA) in the MWIR (3-5μm) detection range. In this communication, we report on electro-optical characterizations of MWIR InAs/InAsSb T2SL XBn detectors, grown by molecular beam epitaxy (MBE) on GaSb substrate, showing cut-off wavelength at 5μm at 150K. Experimental measurements were made by time-resolved photoluminescence (TRPL), photoresponse, dark current-voltage (I-V) characteristics as a function of temperature, on devices having several barrier layer thicknesses. Lifetime values as great as 1.6μs (fig. 1), quantum efficiency as high as 53% and dark current density as low as 1.10-5 A/cm² were recorded at 150K. Such results are analyzed in order to understand the minority carrier transport mechanisms in this barrier detector structure.