Atomic resolution images of H-terminated Si(111) surfaces in aqueous solutions

The first atomic images of the hydrogen terminated Si(111) surface have been acquired in aqueous sulfuric acid solutions. The observed interatomic distance with threefold symmetry is ∼3.8 Å, indicating that the ideal Si(111):H-1×1 surface can be prepared by chemical etching in NH4F solutions. It is demonstrated that in situ scanning tunneling microscopy is an extremely important method for revealing chemical processes with atomic resolution in the chemical etching of semiconductors in solutions.