Properties of ultrathin metallic films on Si(111) determined by high-resolution electron energy loss spectroscopy

Abstract

UV photoemission, low energy electron diffraction and high-resolution electron energy loss spectroscopy (EELS) have been used in situ to study the nature of 1–25 Å of Au and Pd deposited on Si(111) at temperatures of 20 and 300 K. New information is obtained regarding the formation, nature and microstructure of these metallic layers. We describe and apply a theoretical analysis of EELS which allows the determination of DC transport properties in these ultrathin layers. All metallic layers exhibit significantly higher resistivities than expected in comparison to bulk metal silicides or metallic glass phases, and can be attributed to diffuse scattering of conduction electrons at the interface. The interaction and behavior of atomic hydrogen with these films as detected by EELS is also described and found to convey additional information about their microstructure.