Reporting a novel MOCVD growth scheme for the direct hetero-epitaxy of high-quality III-V alloys on SOI wafers, the researchers published their findings in the Optica journal under the title “Bufferless 1.5 µm III-V lasers grown on Si-photonics 220 nm silicon-on-insulator platforms”.
As well as detailing the epitaxy of different dislocation free III-V compound layers inside trapezoidal troughs on SOI, the researchers characterized the crystalline quality of these III-V materials through photoluminescence measurements and extensive use of transmission electron microscopy.
Based on numerical simulations, they then designed and fabricated both pure InP and InP/InGaAs air-cladded lasers on SOI, achieving room-temperature lasing in both the 900nm band and the 1500nm band under pulsed optical excitation.
Key to efficient light coupling into underlying Si-waveguides, the new growth scheme eliminates the need for thick III-V buffers to allow more efficient light coupling into the Si-waveguides. What’s more, the elimination of the thick buffers so far needed for III-V lasers on Si can significantly cut down the growth time and the production cost, the authors write. Using the new growth scheme, the researchers also claim that the epitaxial compounds could extend beyond conventional GaAs and InP and reach highly lattice-mismatched materials such as GaSb and InAs.