Applied Physics Letters · 1995 · 90 citations · 0 references
Natural SciencesMaterials EngineeringMaterials ScienceOptical MaterialsOptoelectronicsSemiconductor MaterialsInfrared Optical MaterialsOptical Properties Of SemiconductorsOptical Properties Of SolidsSemiconducting MaterialsSemiconductor LasersSemiconductor PhysicsAntimonide SemiconductorsBand GapContinuous OperationLaser MaterialsOptical Band GapStimulated EmissionSuperlattice MaterialsSuperlattices
Effective band gaps of type-II superlattices (SLs) can cover a wide infrared wavelength range, even beyond the narrowest band gap of any natural antimonide semiconductor alloys. This letter reports the first InAs/InAsxSb1−x type-II SL lasers with cw, optically pumped operation up to 95 K. The stimulated emission results from spatially indirect transitions of relatively extended electron states in the InAs/InAsxSb1−x SL conduction band to the hole states that are localized in the InAsx Sb1−x layers. The lasing wavelength is around 3.3–3.4 μm. Equivalent threshold current densities are estimated to be 3.3 and 56 A/cm2 at sample temperatures of 5 and 95 K, respectively. The characteristic temperature (T0) is approximately 32 K. These results demonstrate that the InAs/InAsxSb1−x type-II SL clad by AlAs0.16Sb0.84 ordered-alloy layers is a promising material system for midwave infrared semiconductor lasers.