Spontaneous long-wavelength interlevel emission in quantum-dot laser structures

Spontaneous emission has been observed for the first time as a result of interband transitions of holes and electrons between size-quantization levels in vertically coupled quantum dots and also as a result of transitions from quantum-well states to a quantum-dot level. The spectral range of the emission was in the far-infrared (λ≅10–20 μm). The long-wavelength emission was only recorded simultaneously with short-wavelength interband emission (λ≅0.94 μm) in InGaAs/AlGaAs quantum-dot laser structures at above-threshold currents.