Phase formation sequence and domain structure: A low-energy-electron- microscopy study of the Si(111)-(3 × 3) Ag surface

Changes in nucleation and phase formation sequence with temperature may strongly affect the morphology of the final phase. The Si(111)-(3 × 3) Ag structure develops directly from the clean (7×7) structure at lower temperatures (500-700 K). Preferred nucleation at step edges and (7×7) domain boundaries reduces the effective dimensionality of the substrate and explains anomalies in domain size scaling observed by Zuo and Wendelken. An intermediate three-domain (3×1) structure precedes the 3 structure at higher temperatures, leading to a complete change in 3 nucleation and growth, as well as final domain size distribution and total Ag coverage. © 1992 The American Physical Society.