Reducing the critical thickness of epitaxial Ag film on the Si(111) substrate by introducing a monolayer Al buffer layer

Abstract

We report a method to prepare atomically smooth Ag film, with thickness as small as 2 monolayers (ML) and a well-defined interface on the Si(111) substrate, by introducing a monolayer Al(111) 1×1 buffer layer. Scanning tunneling microscopy, low-energy electron diffraction, and x-ray photoelectron emission diffraction were employed to in situ study the film and interface structures. Compared with the growth of Ag on a clean Si(111) 7×7 surface, the buffer layer lowers the critical thickness from 6 to 2 ML. The effect is explained based on an enhanced charge spillage at the interface.