Interplay between emission wavelength and s-p splitting in MOCVD-grown InGaAs/GaAs quantum dots emitting above 1.3 μm

The electronic structure of strain-engineered single InGaAs/GaAs quantum dots emitting in the telecommunication O band is probed experimentally by photoluminescence excitation spectroscopy. The observed resonances can be attributed to p-shell states of individual quantum dots. The determined energy difference between the s-shell and the p-shell shows an inverse dependence on the emission energy. The experimental data are compared with the results of confined state calculations, where the impact of the size and composition in the investigated structures is simulated within the 8-band k·p model. On this basis, the experimental observation is attributed mainly to changes in the indium content within individual quantum dots, indicating a way of engineering and selecting a desired quantum dot whose electronic structure is the most suitable for a given nanophotonic application.