Dark current simulation of InAs/GaSb ii type super-lattice nBn detectors with equivalent material method

The type-II InAs/GaSb superlattices have been recognized as popular materials for the third-generation infrared focal plane detectors. In recent years, the performances of the type ii superlattice infrared focal plane have been improved dramatically. High operating temperature can be achieved by using the monopolar barrier structure of InAs/GaSb type ii superlattice material system. In this paper, the nBn type (also known as Bariodes) mid-wavelength infrared detector based on InAs/GaSb type ii superlattice is studied. As the device has no depletion layer, the recombination and trap assisted tunneling effects are inhibited, and the dark currents are effectively reduced. Based on the equivalent material method, the relationship between the dark current and the doping concentration, thickness and composition of the barrier layer and absorption layer was analyzed in detail, and the optimal working condition was pointed out.