Scanning-tunneling-microscope observation of 2×1 structure on a homoepitaxially grown Si(111) surface

Abstract

We have used scanning tunneling microscopy to study molecular-beam epitaxial growth on Si(111)7×7 surface. On the homoepitaxially grown surface at 500 °C, we find the small domains of non-DAS (dimer adatom stacking fault) rowlike ordered structures, the periodic rows of which run along the [011¯] and [1¯10] directions. The atomic configuration of these structures seems to be consistent with Pandey’s π-bonded chain model for Si(111)2×1 structure. We discuss two kinds of π-bonded chains, and the boundaries along the atomic rows between the 2×1 and DAS domains.