Evolution of Patterned Gallium Arsenide (001) surface subjected to Molecular Beam Epitaxy Growth

We describe here a study of lateral length scale dependence of the transient evolution of surface corrugation during MBE growth of alternating layers of AlAs and GaAs with individual layer thickness of 50 nm (approximate configuration as used in the distributed Bragg reflectors of a VCSEL) or GaAs layers onto the patterned GaAs (001) substrates. By patterning the surface with arrays of cylindrical pits of varying diameter and spacing, we were able to study selectively the changes which occur as a function of lateral period over a range of corrugation amplitudes. The evolution in the surface morphology after various stages of growth was characterized in air with AFM. We show that there exists a critical length scale which separates regimes of amplification and decay of corrugation amplitude with further growth. We compare our observations with the predictions of existing continuum models