Electrical characterizations of asymmetric InAs/GaSb superlattice MWIR photodiodes

InAs/GaSb superlattice pin photodiodes, having an asymmetric period design, exhibited cut-off wavelength in the midwave infrared domain (MWIR) at 5 mu m at 77 K. Electrical characterizations including dark-current and capacitance-voltage measurements were performed on single detectors in the temperature range (77-300 K). The SL photodiode measurements revealed carrier concentrations of about 6 x 10(14) cm(-3) at 77 K, dark-current densities J = 4 x 10(-8) A/cm(2) at 77 K for V-bias = -50 mV and the measured R(0)A product is higher than 1.5 x 10(6) Omega cm(2) at 77 K. Comparison to classical pin diodes with symmetric period design show that the differential resistance area product is improved by more than one order of magnitude. This result obtained demonstrates the strong influence of the period on the electrical properties of SL MWIR photodiodes. (c) 2012 Elsevier B.V. All rights reserved.