High-performance extended SWIR photodetectors using strain compensated InGaAs/GaAsSb type-II quantum wells

We have successfully fabricated extended SWIR photodetectors with the cutoff wavelength of 2.5 μm by using InGaAs (-0.3 %)/GaAsSb(+0.3 %) strain compensated type-II quantum wells as an absorption layer. The 250-pair InGaAs/GaAsSb quantum wells were grown on an InP substrate by metal organic vapor phase epitaxy. The p-n junction was formed in the absorption layer by selective zinc diffusion. Dark current was low and showed diffusion current limited mode. Quantum efficiency in the wavelength region between 2.0 μm and 2.5 μm which corresponds to the type-II absorption became twice as high as that of the normal lattice-matched InGaAs/GaAsSb type-II quantum wells.