Growth morphology of vicinal hillocks on the (101) face of KH(sub 2)PO(sub 4): Evidence of surface diffusion

摘要

The growth morphologies of vicinal hillocks on KH(sub 2)PO(sub 4) (101) surfaces have been investigated using atomic force microscopy. Both 2D and spiral dislocation growth hillocks are observed on the same crystal surface at supersaturations of (approximately)5%. Growth occurs on monomolecular 5 (Angstrom) steps both by step-flow and through layer-by-layer growth. The distribution of islands on the terraces demonstrate that surface diffusion is an important factor during growth. Terraces that are less than the diffusion length do not contain any islands. This, together with the length scale of the inter island spacing and the denuded zones provide an estimate of the diffusion length. In situ experiments at very low supersaturation ((approximately)0.l%) show that growth is a discontinuous process due to step pinning. In addition, in situ images allow for the direct determination of the fundamental growth parameters (alpha), the step edge energy, and (beta), the kinetic coefficient.