Nanostructured surfaces

Mechanisms of formation and electronic structure of 0D- and 2D- nanostructures of s- and d-metals
Karbivska L.I., Smolyak S.S., Karbivskii V.L.
Department of Nanostructures Physics, G.V. Kurdyumov Institute for Metal Physics, N.A.S. of Ukraine,
36 Academician Vernadsky Boulevard, Kyiv-03142, Ukraine
E-mail: karb@imp.kiev.ua

The formation mechanisms and electronic structure of metal nanostructures obtained by thermal deposition in ultrahigh vacuum without cooling the sample on atomically smooth surfaces of single crystals semiconductor Si, InSe and GaSe are studied. It is established that various nanostructures of s- and d-metals can be formed under such conditions, in particular, hexagonal-pyramidal, fractal, quantum wells and quantum dots, etc.
It is shown that the symmetry of the surface of the deposition interface, in particular, the symmetry of a single-crystal Si (111) 7×7 plane determines growth mechanism of hexagonal-pyramidal structures of s-metals. Self-ordered hexagonal-pyramidal nanostructures of s-metals are formed during high-vacuum thermal deposition only on the Si (111) 7×7 plane, while for the Si (110) plane monolayer only hexagonal formations are observed.
For the first time, single-layer flake-shape structures of s-metals were obtained. Point defects in single-layer lamellas are formed to minimize the energy. The methods of probe microscopy show the possibility of existence of free monolayer structures of noble metals, which requires further research. 
It is established that an atomically flat 3-4 ML Ag film cannot be obtained on the surface of Si (111) single crystal semiconductor by thermal deposition under ultrahigh vacuum at room temperature. Takes place the formation of multilayer 2D cluster structures, the heating of which at several hundred degrees Celsius leads to their stretching into an atomically smooth surface coating. The formation of the "blanket" effect is described by the mechanism of electronic cultivation.
The mechanism of ordering of zero-dimensional nickel nanostructures on the surfaces of single-crystal of silicon during vacuum thermal deposition is established. The symmetry of 3d-metals clusters arrangement on the Si (111) 7×7 surface repeats the symmetry of the substrate. The determining factor is the boundaries of twinning, which initiate a linear ordering.
Nanotribological parameters of subroughness Ra, Rq, Rzjis, Rz, Sratio for surface deposited nanostructures of s- and d-metals, and their dependence on technological parameters of drawing are established.
The small influence of the surface of InSe (0001) and GaSe (0001) on the geometry of nanostructures of s- and d-metals formed during thermal deposition in high vacuum without cooling the sample was established.
Research of processes of formation of nanostructures of s- and d-metals during the thermal deposition is actual not only from the fundamental point of view of principles of the organization of nanostructures, in particular, one-component metal, but also because of their possible practical application [1], in particular, in nanoelectronics.

1.	David F. Bocian, Werner G. Kuhr, Jonathan S. Lindsey, Rajeeve Balkrishna Dabke, Zhiming Liu. Formation of self-assembled monolayers of redox sams on silicon for molecular memory applications // Patent US 7,348,206 B2.-2008.