The importance of overcoming MOVPE surface evolution instabilities for >1.3 $\mu$m metamorphic lasers on GaAs

• Main Authors: Mura, Enrica E, Gocalinska, Agnieszka M, O'Brien, Megan, Loi, Ruggero, Juska, Gediminas, Moroni, Stefano T, O'Callaghan, James, Arredondo, Miryam, Corbett, Brian, Pelucchi, Emanuele
• Format: Journal Article
• Language: English
• Published: 15.03.2021
• Subjects: Physics - Applied Physics
• DOI: 10.48550/arxiv.2103.08267

We investigated and demonstrated a 1.3 $\mu$m-band laser grown by metalorganic vapour phase epitaxy (MOVPE) on a specially engineered metamorphic parabolic graded In$_x$Ga$_{1-x}$As 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 utilised 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 In$_{0.4}$Ga$_{0.6}$As quantum wells in the active layer. The resulting lasers exhibited low lasing threshold with 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.