ABSTRACT
Research on nanosized particles started around 1930 with the discovery of that CdSe and CdS inclusions in silicate glasses cause a color change [ 1 ]. Recently, more than 50 years after the first experiments, the formation of a CdSe three-dimensional semiconductor quantum dot superlattice was reported [2]. During the years many investigations on small particles fabricated in different
ways have been performed, but it was not until the first observation of photoluminescence from a single quantum dot that the research area attracted any general attention [3]. The single dots were created by a laser-induced local interdiffusion of a GaAs/AlGaAs single quantum-well structure. The problem with inhomogenous broadening due to a variation in quantum dot-size could now be mastered. Two years later, single-dot photoluminescence of InAs quantum dots (QDs) obtained by self-organized growth on GaAs was reported [4] , The growth was performed in the Stranski-Krastanov (SK) growth mode [5] , where the first layer or layers remain smooth and clusters form on top because of the accumulation of elastic strain energy in the layer(s) due to a fairly large lattice mismatch (2% to 7%) between film and substrate. This type of growth provides a simple way to obtain QDs on a variety semiconductor surfaces. These early reports stimulated several research-groups to explore new phenomena in solid state physics and material science induced by the quasi zero-dimensional confinement of SK-grown QDs.
