InGaAs/GaAsSb type-II quantum-well focal plane array with cutoff-wavelength of 2.5 μm

In the short wavelength infrared (SWIR) region, InGaAs/GaAsSb type-II quantum well absorption structures are proposed as an attractive material for realizing low dark current. Recently QVGA format (array size 320×256) focal plane array (FPA) with cutoff-wavelength of 2.35 μm was demonstrated for commercial use by our group. We succeeded in extending cut-off wavelength of FPA consisting of InGaAs/GaAsSb type-II quantum well up to 2.5 μm. The 250-pairs InGaAs/GaAsSb quantum well structure lattice matched to InP substrate was grown by metal organic vapor phase epitaxy (MOVPE). The p-n junction of each pixel was formed by selective zinc diffusion method. Dark current of pixel showed the diffusion current limited mode and slightly better than that of HgCdTe with a same cutoff-wavelength. We present the electrical and optical characteristics of InGaAs/GaAsSb type-II quantum well FPA with cutoff-wavelength of 2.5 μm.