Ge/Ag(111): SURFACE ALLOY OF A SEMICONDUCTOR ON A METAL

Abstract

We present one of the first experimental studies of the formation of an ordered surface alloy of a semiconductor, Ge, and a metal, Ag, with bulk tendency to phase separation. The kinetics of growth at room temperature as well as the surface segregation of Ge have been investigated for the (111) orientation using Auger Electron Spectroscopy (AES) and Low Electron Energy Diffraction (LEED). The growth mode of Ge on Ag(111) is layer-by-layer like up to at least two layers. An unexpected ordered surface alloy forming a [Formula: see text] superstructure is observed during the growth at 1/3 germanium monolayer, followed by a p(7× 7) superstructure at one-monolayer coverage. The surface Ge segregation studied via both dissolution and segregation kinetics shows the particular stability of the ordered [Formula: see text] surface alloy.