Interplay between thermodynamics and kinetics in the capping of InAs/GaAs(001) quantum dots.
A microscopic picture for the GaAs overgrowth of self-organized quantum dots is developed. Scanning tunneling microscopy measurements reveal two capping regimes: the first being characterized by a dot shrinking and a backward pyramid-to-dome shape transition. This regime is governed by fast dynamics resulting in island morphologies close to thermodynamic equilibrium. The second regime is marked by a true overgrowth and is controlled by kinetically limited surface diffusion processes. A simple model is developed to describe the observed structural changes which are rationalized in terms of energetic minimization driven by lattice mismatch and alloying.
Costantini
G
G
Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany.
Rastelli
A
A
Manzano
C
C
Acosta-Diaz
P
P
Songmuang
R
R
Katsaros
G
G
Schmidt
O G
OG
Kern
K
K