Performance Optimization of GaAs-Based Vertical-Cavity Surface-Emitting Transistor-Lasers

We report on the optimization of p-n-p-type vertical-cavity surface-emitting transistor-lasers based on the fusion between an AlGaAs/GaAs heterojunction bipolar transistor and an InGaAs/GaAs vertical-cavity surface-emitting laser (VCSEL) using an epitaxial regrowth process. It is shown how a proper design of the base region can extend the transistor active range of operation well beyond lasing threshold, thereby resulting in typical transistor laser operational characteristics including milliwatt-range output power, milliampere-range base threshold current, record low-power dissipation under laser operation, and continuous-wave operation up to at least 60 °C. A pronounced breakdown in the collector current characteristics in the limit of high base current and/or emitter-collector voltage accompanied by a quenching of the optical output power is interpreted as being related to quantum well band filling.