Importance of Overcoming MOVPE Surface Evolution Instabilities for >1.3 μm Metamorphic Lasers on GaAs

We investigated and demonstrated a 1.3 mu m band laser grown by metalorganic vapor-phase epitaxy (MOVPE) on a specially engineered metamorphic parabolic-graded InxGa1-xAs buffer and epitaxial structure on a GaAs substrate. Bottom and upper cladding layers were built as a combination of AlInGaAs and InGaP alloys in a superlattice sequence. This was implemented to overcome (previously unreported) detrimental surface epitaxial dynamics and instabilities: when single alloys are utilized to achieve thick layers on metamorphic structures, surface instabilities induce defect generation. This has represented a historically limiting factor for metamorphic lasers by MOVPE. We describe a number of alternative strategies to achieve smooth surface morphology to obtain efficient compressively strained In0.4Ga0.6As quantum wells in the active layer. The resulting lasers exhibited low lasing threshold with a total slope efficiency of 0.34 W/A for a 500 mu m long-ridge waveguide device. The emission wavelength is extended as far as 1360 nm.

Automated summary

Researchers demonstrated a 1.3 μm band laser grown by MOVPE on a GaAs substrate with a specially engineered metamorphic parabolic-graded buffer to overcome surface epitaxial dynamics and instabilities. By using a combination of AlInGaAs and InGaP alloys for cladding layers, they achieved efficient compressively strained In0.4Ga0.6As quantum wells with low lasing threshold and high slope efficiency in the active layer.