Minority Carrier Lifetime in Beryllium-Doped InAs/InAsSb Strained Layer Superlattices
STATE UNIV OF NEW YORK AT STONY BROOK
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Minority carrier lifetimes in undoped and Beryllium-doped Type-2 Ga-free, InAsInAsSb strained layer superlattices SLS with energy gaps as low as 0.165 eV were determined from photoluminescence kinetics. The minority carrier lifetime of 450 ns at 77 K in the undoped SLS confirms a high material quality. In similarly-grown structures that were p-doped to NA 6 1016 and 3 1017 cm exp -3, electron lifetimes of tn 45 ns and 8 ns were measured. The 6 1016 cm exp -3 doping level is a factor of 6 greater than the typical background doping level in long-wave infrared LWIR Ga-containing InAsGaSb SLS with similar bandgap and electron lifetime. This suggests that LWIR photodetectors with InAsInAsSb SLS absorbers can be designed with smaller minority carrier concentrations and diffusion dark current densities. A relatively slow decrease of the lifetime with doping suggests a minor role of Auger recombination in the studied Ga-free SLS at T 77 K with p-doping up to mid-1017 cm exp -3 level.
- Physical Chemistry
- Electrical and Electronic Equipment
- Optical Detection and Detectors
- Solid State Physics