Mid-infrared intersubband electroluminescence in InAs/GaSb/AlSb type-II cascade structures

Mid-infrared intersubband light-emitting diodes based on InAs/GaSb/AlSb type-II cascade structure have been investigated. The observed emission energy is in good agreement with calculation based on the multi-band k·p theory. In contrast to interband cascade structures, dominant polarization of the emitted light is perpendicular to the quantum well layers. Structure dependence of intersubband electroluminescence is also presented.