AVS 49th International Symposium
    Nanometer Structures Thursday Sessions
       Session NS-ThA

Paper NS-ThA10
Fabrication of Low-dimensional Nanostructured Substrates

Thursday, November 7, 2002, 5:00 pm, Room C-207

Session: Nanowires
Presenter: M. Yoshimura, Toyota Technological Institute, Japan
Authors: M. Yoshimura, Toyota Technological Institute, Japan
K. Ojima, NIMS, Japan
K. Ueda, Toyota Technological Institute, Japan
Correspondent: Click to Email
A clean Si(110) surface is reconstructed into so-called "16x2" superstructure, where pentagonal silicon clusters (hereafter, "pentagons") form one-dimensional up-and-down terrace structure with monatomic layer (0.2 nm) in height and about 5 nm in periodicity. This structure is expected to be a novel template for low-dimensional nanostructures. Since high step-density in this surface is due to relaxation of surface stress caused by formation of pentagons, it is possible to control the terrace width by modifying surface stress intentionally. Recently we succeeded in increasing terrace width by about 50% in Sn/Si(110) system. In this surface, Sn atoms form trimers, which are inserted into the pentagons. Then the spacing between pentagons is increased, giving lower surface stress and lower density of steps. Thus the arrangement of pentagons dominates surface structure in Si(110). However, the atomistic processes of rearrangement have not yet been clear. Here we first demonstrate the control of dimensionality of Si(110)-16x2 surface, namely, single or double domain, by using tilted wafers. We found that the epitaxial growth of metals on these surfaces was completely different from each other. Secondly, we examined adsorption of other metals on Si(110) to see how the pentagons change their positions and how the surface stress is relaxed. In contrast to Sn/Si(110), the up-and-down terraces immediately annihilate on Ag/Si(110) system. Lastly we compare the case of Ge(110), which forms a similar 16x2 structure, and discuss the mechanism of stress relaxation in (110) surface based on above results.