InAs/AlSb quantum-cascade light-emitting devices in the 3–5 μm wavelength region

Midinfrared (3.7–5.3 μm) electroluminescent devices based on a quantum-cascade (QC) design have been demonstrated using InAs/AlSb heterostructures, grown on GaSb substrates. The very high conduction band discontinuity (>2 eV) of this material system allows the design of QC devices at very short wavelengths. Well-resolved luminescence peaks were observed up to 300 K, with a full-width-at-half-maximum to peak wavelength ratio (Δλ/λ) of the order of 8%. The emission wavelengths are in good agreement with the results of our model. The emitted optical power is lower than that predicted, due to a nonoptimized electron injection into the active region.