Radiative recombination of charged excitons and multiexcitons in CdSe quantum dots

We report semi-empirical pseudopotential calculations of emission spectra of charged excitons and biexcitons in CdSe nanocrystals. We find that the main emission peak of charged multiexcitons-originating from the recombination of an electron in an s-like state with a hole in an s-like state-is blueshifted with respect to the neutral monoexciton. In the case of the negatively charged biexciton, we observe additional emission peaks of lower intensity at higher energy, which we attribute to the recombination of an electron in a p state with a hole in a p state.