Dynamic transformation in the morphology of Pd-deposited Si(111) with thermal treatment using UHV STM

Abstract

From the dynamic transformation in the morphology of Pd-deposited Si(111) surfaces with thermal treatment, observed by ultrahigh vacuum scanning tunneling microscopy (UHV-STM), the surface reactions of Pd on the Si(111) surface were clarified for the first time with appropriate models on a sound basis. At a low coverage below one monolayer (ML), 2D islands composed of Pd 2Si single crystals were clearly observed to be formed via a surface thermal reaction. At high coverages (> 2ML), following the growth of the epitaxial Pd 2Si film a (3√3 × 3√3)R30° superstructure appeared over the Pd 2Si surface at 300°C. This specific structure was demonstrated to be due to Si segregation.