Localization of excitons in the wetting layer accompanying self-assembled InAs/GaAs quantum dots

A wetting layer is a narrow, highly strained quantum well, which accompanies quantum dots grown by Stranski-Krastanov mode. Its importance for a full description of the quantum dots properties has recently been pointed out. It has been shown for example that excitons can be localized by potential fluctuations in the wetting layer. This is equivalent to the formation of 'natural' quantum dots in the WL. Excitonic emission from the single dots formed in the wetting layer accompanying the InAs/GaAs self-assembled quantum dots has been investigated in a high magnetic field (up to 23 T). Quadruplet splitting of the emission line has been observed. The attribution of the emission line to the recombination of negatively charged excitons is discussed. (author)