Investigation of dark current mechanisms on type-II InAs/GaSb superlattice very long wavelength infrared detectors

An analytical approach to isolating the contribution of surface leakage current from bulk dark current by simulating the current–voltage characteristic of InAs/GaSb superlattice detectors is presented in this paper. It is found that for all the mesa sizes used, the dark current is dominated by the surface component under low reverse bias, and the proportion of surface leakage current to total dark current increases with decreasing mesa size. The limiting dark current mechanisms and main parameters of the InAs/GaSb T2SL detectors were analyzed using a theoretical model including the contribution of surface leakage. We found that surface leakage currents provide a significant contribution, while the ohmic shunt current originating from threading dislocations is not significant.