Abstract
We report the molecular beam epitaxy growth of a new laser structure on n-type (1 0 0) InAs substrate, which was designed for emission near 3 μm at 80 K and 3.3 μm at room temperature. This structure employs the InAsSb/InAs/InAsSb/InAlAsSb type-II “W” configuration in the active region, broad InAlAsSb waveguides, and AlAsSb cladding layers. Lattice-matching of In0.88Al0.12As1−xSbx quaternary alloy was obtained at a low temperature (420°C) by controlling the Sb2/(Sb2+As2) BEP ratio using high V/III flux ratios, while the growth of AlAs0.16Sb0.84 was performed at higher temperatures (480°C and 525°C) using a quasi stoichiometric growth method, based on the control of Al, As and Sb incorporation rates with a V/III ratio close to one. Laser diodes fabricated from these structures showed laser emission near 2.95 μm at 80 K with a threshold current density of 150 A/cm2. The devices operated in pulsed mode up to 155 K. Ridge lasers exhibited continuous wave operation at 80 K with an optical power efficiency of 62.5 mW/A/facet.