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.

Theory of spontaneous emission of quantum dots in the linear regime

“…The real geometry of self-assembled In(Ga)As quantum dots grown on GaAs substrates is rather complicated. For example, Kiravittaya et al [27] reported two types of QD shapes: pyramids elongated along the [1][2][3][4][5][6][7][8][9][10] directions bounded by [137] facets, and domes with a multi-faceted shape. However, we approximate the specific In 0.5 Ga 0.5 As self-assembled quantum dot with a lens-shaped potential (figure 1).…”

“…Photoluminescence (PL) is a powerful tool for the understanding of the QDs characteristics and it has been intensively studied in recent years both experimentally [2][3][4][5] and theoretically [6][7][8][9][10].…”