The study of self-assembled nanostructures by Atomic Force Microscopy
O. BUTE, E. Placidi, F. Arciprete, F. Patella, M. Fanfoni, A. Balzarotti, V. Cimpoca

Abstract. The aim of this article is to present a detailed Atomic Force Microscopy study of InAs/GaAs (001) self-assembled quantum dots grown by Molecular Beam Epitaxy during its complete evolution cycle (transition from 2D islands to 3D islands). We have performed a statistical analysis regarding the volume and density of QD, identifying the existence of two separated distributions ( for quasi-3D dots and 3D dots). We have observed that the density number value of quasi-3D QDs decreases from
1.1 X 1010 cm-2 to 4.3 X 109 cm-2 for a coverage between 1.57 ML and 1.61 ML, while for 3D QDs it increases by a factor of 10 (from 2.1 X 1010 cm-2 to 2.3 X 1010 cm-2) so as the 3D QDs become the prevailed structures. We can assume as critical coverage, 1.59 ML.