InGaAs应变减少层对InAs量子点发光波长红移的影响

用有限元法对InAs/GaAs量子点材料的应变分布进行了研究,特别强调了三元化合物In0.2Ga0.8As应变减少层对各个应变分量的影响。在应变减少层作用下沿着平行生长方向和垂直于生长方向的应变分量增强;对电子结构有重要影响的静水应变和双轴应变分量也得到了增强。采用八带k.p理论,研究了在有应变减少层的条件下,应变对带边的影响,计算结果表明,与没有应变减少层相比,应变导致带隙变窄,定性解释了实验观察到的发光波长红移现象。通过调整相关参数,可以采用应变减少层技术实现光纤通信系统用的长波长发射激光器。

Investigation of InGaAs Strain Reducing Layer on the Redshift of PL Wavelength for InAs Quantum Dots

A systematical investigation about the strain distributions around the InAs/GaAs quantum dots using the finite element method is presented. A special attention is paid to the influence of In0.2Ga0.8As strain reducing layer. The numerical results show that the horizontal and vertical strains components are reinforced in the InAs quantum dot due to the strain reducing layer. The hydrostatic strain and biaxial strain, which are significant to the electronic structure, are also increased in the quantum dot. In the framework of eight-band k·p theory, we studied the band edge modification in the presence of strain reducing layer. Results demonstrate that the strain reducing layer yield the decreasing of band gap, I. E. ,the redshift phenomenon observed in experiment. Our calculated results show that the degree of the redshift will increase with increasing the thickness of the strain reducing layer. The calculated results can explain the experiment results in literature, and further confirmed that the long wavelength emission used for optical fiber communications are realizable by adjusting the dependent parameters.