Preferential Nucleation and Self-Limiting Growth of Cu Nanoclusters

J. Phys. Chem. B 2002, 106, 6419-6430

6419

Preferential Nucleation and Self-Limiting Growth of Cu Nanoclusters on S(4 × 4)/W(111) Qifei Wu,† Wenhua Chen,‡ and Theodore E. Madey*,†,‡ Department of Chemistry, Department of Physics and Astronomy, and Laboratory for Surface Modification, Rutgers, The State UniVersity of New Jersey, Piscataway, New Jersey 08854 ReceiVed: NoVember 12, 2001; In Final Form: February 1, 2002

The interaction of Cu with the highly ordered S(4 × 4)/W(111) surface has been studied by means of Auger electron spectroscopy (AES), low-energy electron diffraction (LEED), and scanning tunneling microscopy (STM) at room temperature. The substrate is a sulfur-induced nanoscale reconstruction of W(111) with (4 × 4) periodicity characterized by broad, planar terraces (∼30 nm in width). We find that fractional monolayers of vapor-deposited Cu grow homogeneously as clusters on the S(4 × 4)/W(111) surface over a wide coverage range. At low Cu coverages (