Strain-compensated InGaAsSb/AlGaAsSb mid-infrared quantum-well lasers

The use of strain-compensated InGaAsSb/AlGaAsSb quantum wells for the fabrication of type I mid-infrared laser devices grown on GaSb substrates by molecular-beam epitaxy is reported. The creation of a tensile strain in the Al0.25Ga0.75AsySb1−y barriers by the incorporation of an arsenic fraction greater than 2% allows to reduce the average strain in the active region and increase the valence band offset to improve hole confinement in the wells. A 2.82 μm emission wavelength in pulsed mode along with a 660 A/cm2 threshold current density are obtained at room temperature for a type I InGaAsSb/AlGaAsSb double-quantum-well laser diode. By further increasing the indium and arsenic compositions into the wells and barriers, respectively, pulsed lasing at a wavelength of 2.89 μm at room temperature has also been achieved.