Electronic and structural properties of Interdiffused Self-Assembled Quantum Dots from Magneto-Photoluminescence

A set of self-assembled InAs/GaAs quantum dot (QD) samples annealed at various temperatures for 30 s was studied using magneto-photoluminescence up to 28 T. Blueshifts increasing with annealing temperature, due to Ga-As interchange at the QD-barrier interface, are correlated with a reduction in inhomogeneous broadening and a reduction in inter-sublevel spacing. These new sample properties allow us to obtain clear crossing patterns closely matched with Fock-Darwin diagrams where the field applied perpendicular to the QD plane lifts the state degeneracies. In the limit that in-plane electron and hole wavefunction extension is the same, the splitting of the p-shell with magnetic field is inversely proportional to the in-plane exciton reduced mass. We use this to obtain the evolution of the latter with intermixing, and compare with predictions of single-particle k*p calculations.NRC publication: Ye