Electrical Characterization of InAs/(GaIn)Sb infrared superlattice photodiodes for the 8 to 12 µm range

InAs/(GaIn)Sb superlattice photodiodes with a cutoff wavelength of 8.7 mu m show a dynamic impedance of R(0)A = 1.5 k omega cm2 at 77 K and a responsivity of 2 A/W, corresponding to a detectivity of D* = 1 x 10 (exp 12) cm (root of Hz/W). Diffusion limited performance is observed above 100 K. At lower temperatures the diodes are limited by generation-recombination currents. An analysis of the influence of different diode sidewall passivations on the surface contribution to the diode leakage current is presented. The out-of-plane electron mobility as well as the relative contributions of the electron and hole diffusion currents to the diode current were determined by a measurement of the magnetic field dependence of the reverse saturation current density of the diodes.