直接带隙Ge耦合双量子阱中的光吸收系数

在有效质量近似下,详细研究了直接带隙Ge/Ge Si耦合双量子阱中带间光跃迁吸收系数和阈值能量随量子阱结构参数的变化情况.结果表明:随着量子阱阱宽增大,带间光跃迁吸收强度会逐渐减弱,阈值能量减小,吸收曲线向低能方向移动,出现了红移现象.增强耦合量子阱间的耦合效应使得带间光吸收强度显著提升.此外,与非对称耦合量子阱相比,耦合效应对对称耦合量子阱中光吸收系数的影响更为显著.

Absorption coefficient in direct-gap Ge double coupled quantum wells

Within the framework of the effective-mass approximation, we study the dependences of the interband optical absorption coefficient and threshold energy on the structure parameters of the direct-gap Ge/GeSi double coupled quantum wells. It is found that when the well width is increased, the intensity of the interband optical absorption is reduced. Moreover, the threshold energy is decreased and the absorption peak is moved towards the lower energy. Red shift is observed. The intensity of the interband optical absorption increases considerably with the increasing of the coupling effects between the quantum wells. Furthermore, in comparison to the asymmetry double quantum wells, the coupling effects on the optical absorption coefficient are more significant in the symmetric double coupled quantum wells.