Physical properties and chemical reactivity of the buckled dimer on Si(100)

The chemical reactivity of the buckled dimer on Si(100) is reviewed from the viewpoint of physical properties of the substrate and the molecules, which have been obtained by several experimental techniques including valence and core-level photoelectron spectroscopy, high-resolution electron energy loss spectroscopy, scanning tunneling microscopy as well as theoretical calculations. The up dimer atom (S-u) of the buckled dimer on Si(100) is electron-rich and the down dimer atom (S-d) is electron-deficient. Thus, S-u is nucleophilic and S-d is electrophilic, and one can expect that the S-u acts as a Lewis base, and the S-d acts as a Lewis acid. This is a simple guiding principle and works well to understand and predict Si surface chemistry. Typical adsorption systems including trimethylamine, ammonia, water, BF3, ethylene and vinylbromide on Si(100)c(4 x 2) are discussed mainly based on our recent experimental investigation at the atomic-scale. (C) 2004 Elsevier Ltd. All rights reserved.