Electron-hole complexes in individual semimagnetic quantum dots

We compare magneto-photoluminescence spectra of individual semimagnetic quantum dots (QDs) with different strengths of exchange interaction between a localized exciton and surrounding magnetic ions. The spectra of individual QDs with strong magnetic exchange interaction show a single line corresponding to a ground-state exciton. In QDs with weak interaction, exciton and biexciton spectra are identified, both showing a fine structure due to electron-hole exchange interaction. The anticrossing of dark and bright exciton states in low-symmetry QDs is demonstrated in magnetic fields in the Faraday geometry.