Growth mode of Pb films on vicinal Si(1 1 1)

Vicinal surfaces of silicon are good candidates as substrate for nanowires of metals by deposition on regular step arrays, since silicon surfaces may be prepared with very regular step arrays and silicon is insulating at low temperatures for conductance measurements of the wires. Using high resolution low-energy electron diffraction we have studied clean vicinal Si(7 7 9) and (5 5 7) surfaces and the deposition of metallic Pb films on these surfaces. We confirmed that both types of the clean vicinal surfaces are triple step surfaces. The triple step shows a separate superstructure, different from the superstructure on the (1 1 1) terraces. Pb films show a small inclination (<1°) towards the Si(1 1 1) plane due to the misfit between Pb and Si. Depending on the annealing temperatures Pb grows on the clean surface with one or two inclinations towards the Si(1 1 1) plane. The tendency of forming nanowires depends on the conditions of deposition and annealing.