The possibility of fabrication of atomically accurate low-dimensional stepped structures with promising properties based on Si(hhm) vicinal surfaces was demonstrated in Ref.[1].
We report STM and LEED studies of atomic and electronic structures of clean and Gd-decorated stepped Si(hhm) surfaces. Single crystalline Si(557) and Si(556) samples (n-type, P-doped, 25Ω×cm at 300K) were used in the studies. The experiments were conducted in UHV (p<1×10-10Torr) spectrometer LAS-3000 (RIBER) equipped with low energy electron diffraction, Auger electron spectroscopy and room temperature STM GPI-300. Atomically ordered atomic structures on clean vicinal Si(557), Si(556) surfaces were prepared by high temperature direct current annealing. The results of STM studies showed that periodicity of the step array for clean Si(557)-(7×7) is determined by the annealing procedure. As a consequence, annealing at various temperature regimes induced a formation of regular atomically ordered arrays with different step periodicity. The atomically resolved STM images reveal different atomic structures of the triple steps on Si(557) surfaces with different step periodicities.
Gd atomic structures on the Si(557)-(7×7), Si(556)-(7×7) surfaces were fabricated by deposition of submonolayer Gd coverages and annealing of the samples at temperatures around 600°C. Atomically resolved STM images of ordered Gd structures on the steps and terraces of the Si(557) and Si(556) surfaces were measured with clean and Gd covered tungsten tips.
This work was supported by the Russian Academy of Sciences (programs "Effect of Atomic, Crystal, and Electronic Structure on the Properties of Condensed Matters" and "New Materials"), NT-MDT (Zelenograd), the Ministry of Education and Science of the Russian Federation.
[1] A.Kirakosian, R.Bennewitz, J.N.Crain, Th.Fauster, J.-L.Lin, D.Y.Petrovykh, and F.J.Himpsel. Appl. Phys. Lett. 79 (2001) 1608. |