Singularities in the magneto-photoluminescence spectra from isolated quantum dots

Abstract

We have optically investigated quantum dots containing a few electrons each. In zero magnetic field, the photoluminescence (PL) should reflect the occupied density of states of such artificial atoms. However, the few-electron response to recombination of one of these electrons with a localized hole appears to be enhanced as the energy of the electrons approaches the highest occupied state. This phenomenon resembles the Fermi-edge singularity observed in the PL spectra from n-type two- and one-dimensional electron systems. Like in the case of doped n-type quantum wires, this singularity is seen to dominate the PL spectrum of the quantum dots at a low magnetic field with a sharp fall in intensity at a specific magnetic field.