Design and Simulation of a Mid-infrared Quantum Cascade Laser Based on Ge-Si Superlattices

摘要

This paper presents a novel valance intersubband laser based on Si-based Si-Ge super-lattices grown on a relaxed Sio.sGeo 5 buffer layer. Effective mass theory is used to calculate the in-plane valence subband dispersion of Si-Ge superlattices within 6x6 Kane model. Analysis of the in-plane energy dispersion shows that the light-hole effective mass is inverted at off zone center region. The laser structure can be designed with a simple quantum cascade scheme. Our calculation shows that with the electrical pump, it is possible to achieve population inversion between the two subbands at local k space where the light-hole effective mass is inverted. Optical gain of the order lOO/cm can be achieved with a pumping current density 10 kA/cm2.