A continuum description of self-assembly of quantum dots based on the physics of surface steps
Brown University, US
In the past couple of years, experiments have revealed several novel and unexpected features during the growth of strained SiGe/Si quantum dots which are addressed in this talk. We present a unified theoretical description that explains several key observations including the nucleationless growth of shallow stepped mounds, transformation of these mounds into (105) faceted quantum dots in both high and low-misfit films and kinetics of self-similar island coarsening. Our continuum model is informed by the physics of surface steps, particularly their interactions and the dependence of their formation energy on strain. By means of atomistic simulations, we propose a novel rebonded step structure that explains the stability of stepped (001) surfaces and (105) facets under compressive strain. Information gained from these calculations is incorporated into a 3D continuum model to simulate kinetics of island formation, growth, coalescence and coarsening.
NSTI Nanotech 2003 Conference Technical Program Abstract