Structure-dependent surface conductance at the initial stages in metal epitaxy on Si(111) surfaces

Abstract

Combination of reflection high energy electron diffraction and in-situ measurements of surface conductance and Hall effect enables one to correlate atomic structures of surfaces and their macroscopic electrical properties. For initial deposition of Au and Cs onto clean Si(111)-7 × 7 and Au-induced superstructure (5 × 2, 6 × 6, √3 × √3) surfaces, the differences between them in terms of Fermi level pinning and band bending were revealed. Inversion layers were created at the Au-covered surfaces and changed into depletion layers on metal adsorption onto them, resulting in steep decrease in surface conductance, while the clean surface was much less sensitive in terms of band bending change on metal adsorption because of Fermi level pinning. The band bending of each surface is also supported by photoemission data.