Minority carrier diffusion length for electrons in an extended SWIR InAs/AlSb type-II superlattice photodiode

We fabricated and characterized InAs/AlSb Type II superlattice photodetectors for the short wave infrared region with lambda(cutoff) close to 2.5 mu m. Using C-V and quantum efficiency measurements, we extracted the carrier diffusion lengths, L-diff, and at 220 K and 300 K, they were 0.94 mu m and 1.9 mu m, respectively. In addition, I-V and detectivity measurements were carried out. The quantum efficiencies at lambda = 2.18 mu m, -50 mV, 300 K, and 200 K were 29% and 16% and the detectivities were above 10(10) and 2 X 10(11) cm Hz(1/2)/Watt, respectively. At a bias of -50 mV, the dark current densities at 300 K and 200 K were 4 mA/cm(2) and 2.3 X 10(-6) A/cm(2) and the resistance-areas were 16 Omega cm(2) and 38 k Omega cm(2), respectively. Published by AIP Publishing.