Highly-ordered arrays of the identical-size nanoclusters (i.e., magic-cluster 2D crystals) have been successfully fabricated with Group-III adsorbates on Si surfaces. In the case of In/Si(100), the perfectly-ordered 4×3 can be formed. It has been found that each 4×3-In pyramid-like cluster formed by 6 In and 7 Si atoms can be modified by further In deposition, namely, central Si atom in the cluster can be replaced by two In atoms, thus forming In8Si6 cluster. This modification of the magic-cluster composition leading to the changeover of its electronic properties (i.e., cluster doping) has been demonstrated [1]. It has been found that dynamic behavior of the doped cluster in In/Si(100) system opens a prospect for using the cluster as an atomic-scale memory cell [2].
We demonstrate that adding the second adsorbate (In) to the well known Si(111)α-√3×√3-Au structure alters the domain wall structure. Upon annealing at 600°C, the domain-walls are eliminated and highly-ordered almost defect-free homogeneous Si(111)√3×√3-(Au,In) develops. Plausible mechanism of stabilization of the domain-wall-free surface is the stress relieving caused by In adsorption, which in turn affects electronic properties of the surface phase [3].
The following temperature-induced reversible structural phase transitions have recently been found in the surface phases developed on the Si(111), Si(100) and Ge(100) surfaces: √7×√3 → √7×√7 at 240 K in the In/Si(111) system [4], 2×1 → (6,1)×(0,6) at 100 K in the Tl/Si(100) system [5] and 2×1 → c(12×14) at 120 K in the Tl/Ge(100) system [6]. Possible mechanisms of these phase transitions will be discussed.
Formation of ordered nanostructures on the various modified Si surfaces will also be discussed.
[1] V.G. Kotlyar et al., Phys. Rev. Lett. 91, 026104 (2003).
[2] A.A. Saranin et al., Phys. Rev. B 74, 125304 (2006).
[3] D.V. Gruznev et al., Phys. Rev. B 73, 115335 (2006).
[4] A.A. Saranin et al., Phys. Rev. B 71, 165307 (2005).
[5] A.A. Saranin et al., Surf. Sci. 601, 595 (2007).
[6] A.A. Saranin et al., Phys. Rev. B 74, 035436 (2006).
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