Investigation of α-Sn Dependence of Band Structure and Optical Emission in Si/Si_yGe_1-x-ySn_x/Si Quantum Well Laser

In this work, we report a theoretical investigation of the influence of α-Sn concentration on the optical laser-gain emission in Si/Ge_1−x−ySi_ySn_x/Si quantum wells (QWs). 14- and 24-band k.p Hamiltonian have been introduced to calculate subband and band structures of QWs and bulk α-Sn respectively. The unknown Luttinger like parameters describing the p-type conduction bands (CBs) of the bulk α-Sn have been obtained via the 24-band k.p model. The impact of the semi-metal α-Sn on the subband structure and optical laser-gain emission are calculated with the insertion of the strain given from the compound Si_xGe_1-x-ySn_y. It has been shown that the α-Sn changes the electronic band structure and as a result the optical laser-gain emission increases and decreases with a very small concentrations of α-Sn. We can predict that Si/Ge_1−x−ySi_ySn_x/Si QWs should be realized with a very small concentrations of α-Sn in most applications involving optical laser-gain emission.