Exciton diamagnetic shifts in self-formed closely stacked InAs/GaAs quantum dots

We evaluated the temperature dependence of exciton luminescence spectra and exciton diamagnetic shifts in self-formed closely stacked InAs/GaAs quantum dots and compared the results with those measured in the ${\mathrm{In}}_{0.18}$${\mathrm{Ga}}_{0.82}$As/GaAs quantum well. We found multiple-peak emission spectra and small, isotropic diamagnetic shifts in the quantum dots, which present a striking contrast to the quantum well. Based on the quantitative analyses of magneto-optical data, we conclude that the self-formed closely stacked InAs/GaAs quantum dot has an almost spherical quantum-confinement potential inside the stacked structure and that its luminescence is due to three-dimensionally confined excitons.