MBE growth of GaInAsSb/AlGaAsSb double heterostructures for diode lasers emitting beyond 2μm

This paper reports on molecular beam epitaxy used to grow GaInAsSb/AlGaAsSb double heterostructures, lattices matched to GaSb substrates, for diode laser emission at 2.3 μm. Double-crystal x-ray diffraction measurements were used to determine alloy lattice constants, and photoluminescence and infrared absorption spectroscopies were used to determine the bandgaps of the GaInAsSb layers. Alloy compositions measured by Auger electron spectroscopy were consistent with measured lattice constants and bandgaps. Diode lasers fabricated from the double heterostructures were operated in the pulsed mode at room temperature with threshold current densities as low as 1.5 kA cm-2, differential quantum efficiencies as high as 50 percent, and output power as high as 900 mW per facet