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Molecular beam epitaxy of InP-based alloys for long-wavelength vertical cavity lasers

In this article we describe the growth, design, and characterization of a 1310nm lattice-matched vertical cavity laser which take advantage of an AlGaAsSb distributed Bragg reflector and AlInGaAs active regions. The molecular beam epitaxial growth for this structure was particularly challenging due to the various III–V alloys used; in particular, the interfaces between them were observed to be a significant source of macroscopic defects and roughness. The AlGaAsSb–InP interface was seen to control the yield and overall quality of device structures, and so was the focus of the crystal growth optimization. InP heat- and current-spreading layers were utilized to offset the thermal and electrical limitations of the AlGaAsSb mirrors; we optimized the defect density and roughness of these epilayers by studying their dependence on growth temperature and P overpressure. Vertical cavity lasers grown using these optimized approaches and incorporating a thin, selectively etched tunnel-junction aperture were fabricat...