Families of islands in InAs/InP self-assembled quantum dots:: a census obtained from magneto-photoluminescence

The low temperature photoluminescence properties of InAs/InP self-assembled quantum dots are investigated in magnetic fields up to 17 T. The zero field spectrum exhibits a number of inhomogeneously broadened peaks similar to the highly excited spectrum of InAs/GaAs quantum dots in which emission from excited states can be observed. However, for InAs/InP dots, application of a magnetic field in the Faraday configuration reveals only weak diamagnetic shifts, thus proving that the transitions originate from zero angular momentum states consistent with ground state emission from distinct families of islands present in the sample. The diamagnetic shift is observed to increase as the thickness of the island family increases. Calculations performed assuming a flat disc geometry show that the latter effect can be accounted for by the change in carrier effective mass as the dot thickness increases.