Design and modeling of InAs/GaSb type II superlattice based dual-band infrared detectors

The objective of this paper is to provide a credible analysis for predicting the spectral responsivity of InAs/GaSb/AlSb type-II superlattice (T2SL) based dual-band infrared photodetectors. An overview of the T2SL based design criteria is given and new dual-band detector architecture with a model dual-band detector structure designed to detect light in the mid-wave infrared (MWIR) and long-wave infrared (LWIR) ranges is presented. The absorption coefficient is modeled empirically and the quantum efficiency spectra are calculated using a numerical model and Hovel’s analytical expressions. The spectral cross-talk due to the response of the LWIR channel to residual MWIR light is also investigated. It is shown that the significance of this cross-talk primarily depends on the temperature of the target (scene) being detected. For MWIR/MWIR (two bands in the MWIR range) dual-band detectors, the spectral cross-talk becomes significant irrespective of the target temperature. Eliminating the spectral cross-talk in T2SL dual-band detectors presently remains a challenge.