InAs/GaSb量子阱的能带结构及光吸收

Band structure and optical absorption in InAs/GaSb quantum well

采用八能带K-P理论以及有限差分方法,研究了沿[001]方向生长的InAs/GaSb二类断带量子阱体系的能带结构、波函数分布和对[110]方向线性偏振光的吸收特性.研究发现,通过改变InAs或GaSb层的厚度,可有效调节该量子阱体系的能带结构及波函数分布.计算结果表明,当InAs/GaSb量子阱的导带底与价带顶处于共振状态时,导带基态与轻空穴基态杂化效应很小,且导带基态与第一激发态的波函数存在较大的重叠,导带基态与第一激发态之间在布里渊区中心处的跃迁概率明显大于导带底与价带顶处于非共振状态时的跃迁概率.研究结果对基于InAs/GaSb二类断带量子阱体系的中远红外波段的新型级联激光器、探测器等光电器件的设计具有重要意义.

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.