Scanning tunneling microscopy on Sn/Si(110) system

Surface superstructures on Sn/Si(110) system were investigated by scanning tunneling microscopy (STM). In addition to three superstructures reported previously, (4,3) X ((2) over bar,2), (3,0) X ((1) over bar,3) and (3,3) X ((2) over bar,1), new types of superstructures such as (2,0) X ((1) over bar,4) were clearly observed during transformation processes between these phases. It was found that the (4,3) X ((2) over bar,2) and (3,0) X ((1) over bar,3) consist of Sn trimers which arrange two- and one-dimensionally on the surface, respectively. The latter superstructure contains extra Sn atoms as monomers. The image of (3,3) X ((2) over bar,1) consists of cluster protrusions that contain four or more Sn atoms arranged two-dimensionally. It was also found that the (2,0) X ((1) over bar,4) superstructure consists of Sn dimes rows along the [(1) over bar 10] direction. Transition processes between the phases is discussed, based on the structural models proposed in the present study. (C) 1998 Elsevier Science B.V. All rights reserved.