Mid-Infrared Emission in Ge/Ge 1-x Sn x /Ge Quantum Well Modeled Within 14-Band k.p Model.

Band structure and gain in a Ge/Ge_1-xSn_x/Ge quantum well are described theoretically using a 14-band k.p model. It has been shown that the quantum well width and the α-Sn concentration considerably modify the conduction and valence subband structure, and, as a result, the optical gain changes with the insertion of a very small concentration of α-Sn. In particular, we have determined the necessary injection carrier density Nj and the critical α-Sn concentration for elevated high gain lasing. It is found that for Nj = 1.5 × 10¹⁸ cm⁻³, we achieved a maximum peak gain for α-Sn concentration of the order 0.155. We can predict that Ge/Ge_1-xSn_x/Ge QWs should be manufactured with an α-Sn concentration less than 0.155 in devices for optoelectronics applications such as telecommunication and light emitting laser diodes. [ABSTRACT FROM AUTHOR]