Ga-migration on a Ga-rich and As-stabilized surfaces: Ga-droplet and GaAs- nanostructure formation

This study investigates the Ga migration behavior in the droplet formation process on GaAs (100), (111)A, and (111)B surfaces. A Ga migration model, consisting of intrinsic and thermally induced Ga migration on Ga-rich surface, is proposed. This model can explain the Ga migration on Ga-rich surface at low temperature compared to the conventional growth mode of GaAs epitaxy. The Ga migration length is greatest for (111)B, followed by (100) and (111)A surfaces at temperature ranging from 50 to 500 °C. The Ga diffusion from a droplet also discuss under As-stabilized conditions. The Ga diffusion direction and length strongly depend on the surface orientation and surface stoichiometry.