Low Density Metamorphic Quantum Dot structures with emission in the 1.3 - 1.55 µm window

We report on the molecular beam epitaxy growth of InAs/InGaAs metamorphic quantum dot structures for single-photon operation at long wavelengths. Low density of quantum dots has been achieved by depositing sub-critical coverages of InAs, while the redshift of emission was obtained by growing the nanostructures on relaxed InGaAs buffers. By optimizing the design and growth parameters, such as the InAs coverage, the post growth annealing time and the compositions of InGaAs confining layers, we were able to obtain structures with quantum dot densities of the order of the 108 cm-2 and emission in the whole range 1.3 - 1.55 ¼m at low temperature.