Author/Authors :
M Hanke، نويسنده , , D Grigoriev، نويسنده , , M Schmidbauer، نويسنده , , P Sch?fer، نويسنده , , R K?hler، نويسنده , , U.W. Pohl، نويسنده , , R.L Sellin، نويسنده , , D Bimberg، نويسنده , , N.D. Zakharov، نويسنده , , P Werner، نويسنده ,
Abstract :
We report on structural investigations on multi-fold stacks of In0.6Ga0.4As quantum dots (QDs) embedded within a GaAs matrix. The structures have been grown by means of metalorganic chemical vapor deposition. Cross-sectional transmission electron micrographs prove a pronounced vertical QD correlation, while plan-view images do not show any lateral ordering. Grazing incidence diffraction within various crystallographic zones clearly reveal a QD shape with a four-fold symmetry. Comparing dynamical scattering simulations, which base on finite element calculations for the strain field show that the shape of the QDs can be described by a prism with a flat top on a thin wetting layer. The mean lateral dot distance evaluated from diffuse X-ray scattering agrees well with the QD density estimated from TEM plan-view images.
