Imaging and single dot spectroscopy of InP self-assembled quantum dots

Optical properties of InP self-assembled quantum dots (SADs) embedded in Ga 0.5In0.5P were studied under various conditions by means of the micro-spect roscopy. A strong optical anisotropy of the InP SADs was found in the macro -photoluminescence spectra and micro-photoluminescence (mu-PL) images showi ng two-fold symmetry, which reflects the anisotropic structure of the Ga0.5 In0.5P matrix. Successive red-shifts of the mu-PL peaks and a recovery of t he PL intensity with the increase of the temperature were clearly observed. The fluorescence intermittency from a single quantum dot was also investig ated. The on-off switching rate is drastically enhanced by a weak near-IR l aser beam irradiation. The influence of the matrix on the optical propertie s of the SADs is discussed. (C) 2000 Elsevier Science B.V. All rights reser ved.