Structure of the Bi/Si(111) Surface by Field-Ion Scanning Tunneling Microscopy

Abstract

A combination of LEED and FI-STM has been used to characterize the Bi/Si(111) system. Two distinct phases of the √3×√3 structure formed on the Si(111) surface are imaged for the first time by STM and are studied as a function of coverage. Trimers of Bi atoms are clearly resolved at 1 ML whereas single Bi atom adsorption are documented at 1/3 ML. The atomic geometry of these structures and the development of two phases as a function of coverage are discussed.