Structure of thin SiO2 films grown on Mo(112)

Abstract

Ultra-thin SiO2 films were prepared by evaporating Si onto a Mo(112) surface followed by oxidation and annealing up to 1200 K. The surface structure and film quality were investigated by low-energy electron diffraction (LEED), Auger spectroscopy (AES), and high-resolution electron energy loss spectroscopy (HREELS). A well-ordered, monolayer Mo(112)-c(2×2)-SiO 2 structure was characterized by HREELS and shown to exhibit unique phonon features compared to bulk SiO2. The phonon features are assigned to Si-O-Mo rather than Si-O-Si species, and the surface structure determined to be Mo(112)-c(2×2)-ESiO4 where each of the four oxygen atoms bonds to the substrate Mo atoms.