| Electron beam lithography in ultra-high vacuum is combined with epitaxy of silver on Si(111) to generate crystalline metal nanowires of few atomic layers thickness and a width of less than 20 nm on an insulating support. The experiments are performed in a combined SEM-STM system for confocal and simultaneous operation of both microscopes at variable sample temperatures in the range 60-900K. Employing electron beam-induced selective thermal desorption, clean Si(111) windows are generated within a thin thermal surface oxide layer of 0.3-0.7 nm thickness. During deposition of Ag at a sample temperature of 130K small Ag islands nucleate in the Si windows as well as on the oxide areas. Subsequent annealing to room temperature or above leads to the formation of continuous flat epitaxial Ag islands constricted to the window areas. When the surface is annealed up to 700K the islands coalesce in the direction that is unconstricted by the oxide mask up to a length of some 100 nm while spherical non-percolated Ag clusters with diameters of several nanometers form on the oxide areas. |
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