Self-organized 1D nanostructures on the beta-SiC(100) surface: silicon atomic lines and dimer vacancy chains

We investigate the self-formation of Si atomic lines and dimer vacancy chai ns on the beta-SiC(100) surface by atom resolved scanning tunneling microsc opy (STM). We show that, using a rigorous protocol in surface preparation, it is possible to build very long, very straight and defect-free Si atomic lines. These lines are derived from the dimer rows of the beta-SiC(100) 3x2 surface reconstruction by selective Si removal resulting, at the initial s tep, in very long dimer line vacancies. Using the capability of the scannin g tunneling microscope to probe simultaneously both filled and empty electr onic states, we confirm that these atomic lines are composed of Si-Si dimer s perpendicular to the line direction. These Si atomic lines are derived fr om the beta-SiC(100) 3 x 2 surface dimer rows by surface thermal dismantlin g including, at the initial step, Si removal "dimer row by dimer row" leavi ng very long dimer line vacancies. On the 3 x 2 surface, the Si-Si dimers a re asymmetric in marked contrast with the dimers forming the Si atomic line s that are symmetric. Such a behavior is understood in terms of decreased l ateral interaction between atomic lines when the spacing between them is in creased. These highly stable atomic Lines reveal a novel aspect of SiC in i ts ability to also be a very suitable material in nanotechnologies and micr o/nano-electronics of the future. (C) 2000 Elsevier Science B.V. All rights reserved.