The evolution of self-assembled InAs/GaAs(001) quantum dots grown by growth-interrupted molecular beam epitaxy

Self-assembled InAs quantum dots (QDs) grown on GaAs(001) by molecular beam epitaxy under continuous and growth-interruption modes exhibit two families of QDs, quasi-three-dimensional (quasi-3D; Q3D) and three-dimensional (3D) QDs, whose volume density evolution is quantitatively described by a classical 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 the conversion of Q3D to 3D QDs at a rate determined by the superstress and the participation of the wetting layer adatoms. The data analysis excludes Q3D QDs being extrinsic surface features due to inefficient cooling after growth.