title: Patterning of self-assembled monolayers based on differences in molecular conductance.
abstract: Scanning tunneling microscopy (STM) is used for replacement patterning of self-assembled monolayers (SAMs) of thiols on a sub-10 nm scale. Contrasting other schemes of scanning probe patterning of SAMs, the exchange of molecules relies on differences in conductance and, thus, occurs under tunneling conditions where the resolution of the tip is maintained. Exchange takes place at the boundary between different thiols but only when the tip moves from areas of lower to higher conductance. In combination with SAMs which exhibit excellent structural quality, patterns with a contour definition of +/- 1 molecule, lines as thin as 2.5 nm and islands with an area of less than 20 nm2 are straightforwardly produced. It is suggested that the shear force exerted onto the molecules with the lower conductance triggers displacement of the one with higher conductance.
authors.affiliation: EaStCHEM School of Chemistry, University of St Andrews, St Andrews KY16 9ST, UK.
authors.forename: Cai
authors.initials: C
authors.lastname: Shen
authors.forename: Manfred
authors.initials: M
authors.lastname: Buck
mesh_terms: D003460:Crystallization / Q000379:methods*; D004553:Electric Conductivity; D004563:Electrochemistry / Q000379:methods*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008567:Membranes, Artificial; D016252:Microscopy, Scanning Tunneling / Q000379:methods*; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D013499:Surface Properties
chemical_list: D046911:Macromolecular Substances; D008567:Membranes, Artificial