Non-contact atomic force microscopy study of the Sn/Si(1 1 1) mosaic phase

We have analyzed the height dependence of the Si and Sn atoms on the 1/6 monolayer (ML) Sn/Si(1 1 1)-(H3 H3)R308 surface, also known as Sn/Si(1 1 1) mosaic phase, by means of non-contact atomic force microscopy (NC-AFM) technique. By preparing samples in which the Sn/Si(1 1 1) mosaic phase and the Si(1 1 1)-(7 7) surfaces coexist, and taking account of the proportion of bright and dim contrast atoms when comparing NC-AFM images of both surfaces, we have been able to discriminate between the two atom species forming the mosaic phase. Additionally, we have found a pronounced variation of the height of the Si adatoms with the number of first neighboring Sn adatoms in the Sn/Si(1 1 1) mosaic phase.