Public Research Seminar by Microelectronics Thrust, Function Hub, HKUST (GZ) - Robust High Temperature Operation of InAs Quantum Dot Lasers Grown on (001) Si

Epitaxially grown quantum dot (QD) lasers are emerging as an economical approach to obtain on-chip light sources. Thanks to the three-dimensional confinement of carriers, QDs show greatly improved tolerance to defects and promise other advantages such as low transparency current density, high temperature tolerance, isolator-free operation, and enhanced four-wave-mixing. These material properties distinguish them from traditional III–V/Si quantum wells (QWs) and have spawned intense interest to explore a full set of photonic integration using epitaxial growth technology. My focus of this seminar would be on the breakthroughs in long lifetime at elevated temperatures. Threading dislocations are significantly reduced to the level of 1×106 cm-2 via a novel asymmetric step-graded filter. Misfit dislocations are efficiently blocked from the QD region through well-engineered trapping layers. A record-breaking extrapolated lifetime of more than a million hours has been achieved at 80 °C, forecasting that device reliability is now entering the realm of commercial relevance and a monolithically integrated light source is finally on the horizon. Potential issues with the low defect structure on the manufacturability of the large scale wafers will be briefly discussed as well.