  Self-assembled InAs quantum dots (QDs) grown on GaAs(001) surface by
molecular beam epitaxy under continuous and growth-interruption modes exhibit
two families of QDs, quasi-3D (Q3D) and 3D QDs, whose volume density evolution
is quantitatively described by a rate-equation kinetic model. The volume
density of small Q3D QDs decreases exponentially with time during the
interruption, while the single-dot mean volume of the large QDs increases by
Ostwald ripening. The kinetics of growth involves conversion of quasi-3D to 3D
QDs at a rate determined by superstress and participation of the wetting layer
adatoms. The data analysis excludes that quasi-3D QDs are extrinsic surface
features due to inefficient cooling after growth.
