Performance analysis of tin-incorporated group-IV alloy based transistor laser

Steady state analysis of GeSn alloy based single quantum well mid-infrared transistor lasers (TL) is reported in this paper. A theoretical model for the device is developed by considering the active Ge0.85Sn0.15 well in the base of the transistor. The Model includes the effect of strain on the material gain and free carrier absorption in the active layer and optical confinement factor in various layers of the device. Laser rate equation and continuity equation for bulk minority carrier with 2-D carrier distribution in the active layer are solved to obtain the threshold base current density and other steady-state parameters of the device like photon density, current gain, etc. Results show that Sn composition in the active GeSn layer and some device parameters play important roles in the performance of the device. An estimated threshold base current density of 2.6 kA/cm2 with the current gain of 2722 is obtained for a particular composition of Sn into SiGeSn/GeSn alloy in the base.