Monolithic integration of 940 nm AlGaAs distributed Bragg reflectors on bulk Ge substrates

High quality 940 nm AlxGa1-xAs n-type distributed Bragg reflectors (DBRs) were successfully monolithically grown on off-cut Ge (100) substrates. The Ge-DBRs have reflectivity spectra comparable to those grown on conventional bulk GaAs substrates and have smooth morphology and reasonable periodicity. These results strongly support VCSEL growth and fabrication on more scalable bulk Ge substrates for larger scale production of AlGaAs-based VCSELs.