| Abstract
| - We report on the orientation of nematic liquid crystals supported on highly regular, periodic, nanometer-scale structures formed from atomic steps on the surface of miscut silicon crystals thermally annealed inultrahigh vacuum (UHV). Prior to removal from UHV, the silicon templates were passivated by reactionwith methanol, acetone, or hydrogen and characterized by ultraviolet photoelectron spectroscopy usingsynchrotron radiation. In contrast to silicon substrates prepared in the past by wet chemical methods andsubstrates prepared by oblique deposition of metal and metal oxide films, the passivated templates preparedin UHV have highly regular single and bunched atomic steps that can be observed by scanning tunnelingmicroscopy. Three independent measurements of the orientation of nematic liquid crystals of 4-cyano-4‘-pentylbiphenyl (5CB) on these templates revealed the alignment of 5CB to be parallel to the atomic stepedges on samples with periodic single atomic steps (∼0.3 nm height, ∼15 nm width) as well as bunchedatomic steps (∼5 nm height, ∼70 nm width). Because the nanometer-scale structures of these surfaces arewell-defined and readily manipulated on spatial scales comparable to the sizes of a range of biologicalspecies, these surfaces may be useful as templates for the detection of the binding of biological speciesthrough changes in the orientation of liquid crystals.
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