Microphotoluminescence studies of single quantum dots. II. Magnetic-field experiments

We perform microphotoluminescence measurements on a series of single GaAs/${\mathrm{Al}}_{\mathrm{x}}$ ${\mathrm{Ga}}_{1\mathrm{-}\mathrm{x}}$As quantum dots of various lateral confinement in magnetic fields up to 5 T. A diamagnetic shift and a Zeemann spin splitting of the luminescence lines depending on the size of the structure is observed. The characteristic diamagnetic shift demonstrates the excitonic origin of the luminescence. The spin splitting increases with the exciton energy.