Band structure and optical absorption in InAs/GaSb quantum well

An analysis of band structure, wave function distribution and absorption of linearly polarized light along the [110] direction in InAs/GaSb quantum well grown along the [001] direction is performed by the eight-band K-P model and finite difference method. Our study shows that the band structure and wave function distribution could be regulated effectively by changing the thickness of InAs or GaSb layer. When the bottom of conduction subband and the top of the valence subband are in resonance, the hybridization of ground electron and light-hole state at the zone-center is very weak, and the overlap between the wave function of the ground and the first-excited electron state is considerable, according to the theory of wave function engineering, so the transition rate between the ground and the first-excited electron state at the zone-center is larger than that when the bottom of conduction subband and the top of the valence subband are not in resonance. This is very important for designing advanced optoelectronic devices such as far-infrared or mid-infrared cascade lasers and detecters based on InAs/GaSb quantum wells.