Interband tunneling in InAs/GaSb type-II cascade structure

GaSb-based interband and intersubband type-II cascade lasers are promising for mid- and far-infrared applications. For intersubband lasing scheme an efficient electron extraction from the lowest lasing level is a necessary requirement to achieve the intersubband inverse population, and, hence, lower threshold and higher CW operating temperature. In type-I cascade structures, electron transition into adjacent quantum well, accompanied by LO-phonon emission, is the most effective depopulation mechanism, whereas for type-II design the interband tunneling process is the primary path for electron escape, especially in interband lasing scheme with lower lasing states located in the GaSb layer. In the work we study the interband tunneling depopulation in the intersubband InAs/GaSb/InAs (A/B/A) laser heterostructure.