This article presents the InAs/GaSb type-II superlattice interband cascade photodetector low-frequency noise analysis. Presented noise measurements were conducted in temperature range 77-300 K and in frequency range 1-10 kHz. The spectral characteristics of the detector noise at various voltages are analyzed. The measured power spectral density is compared to the theoretical prediction. This comparison suggests that noise estimates based on the dark current may not always be valid and the noise source is difficult to be extract. We showed two samples, one of which was characterized by a large leakage currents contribution being directly translated into increased noise.
Measurements of low-frequency noise of type-II superlattice detectors designed for mid-IR wavelengths are used to determine noise limitations, calculate the real detectivity, and study 1/f noise-current correlations in these devices. No 1/f noise connected to the diffusion current is found as opposed to the generation-recombination, shunt, and tunneling currents. The contribution from the shunt current to 1/f noise can be so large that shunt-originated noise dominates in the high-temperature region, in which current is limited by the generation-recombination and diffusion components. It is also demonstrated that devices made of type-II superlattice contain traps generating random processes with thermally activated kinetics, and the activation energies of these traps are determined.