Optical and Electrical Study of InAs/GaSb Type II Strained Layer Superlattice for Mid-wave Infrared Detector

This paper reports the results of modeling of optical and electrical characteristics of InAs/GaSb type II strained layer superlattice (SLS) for the mid-wave infrared detection with n-on-p polarity. The band gap calculation of the SLS was conducted as a function of the InAs and GaSb thickness, using a modified Kronig-Penny model. The cut off wavelength of the fabricated diode was ~ 6 μm (~ 0.2 eV) at 120 K. The product of zero-bias resistance and area (R0A) as a function of an applied bias was investigated in detail to analyze the dark current mechanisms. The thermal diffusion and generation-recombination current were dominant factors under low positive bias. However, as the reverse bias voltage increased, the trap assisted component became one of the dominant dark current factors.