Nanoscale growth of silver on prepatterned hydrogen-terminated Si(001) surfaces

Silver (Ag) growth on H-terminated Si(001) surfaces with prepatterns of sil icon (Si) dangling bonds has been studied at room temperature using a scann ing tunneling microscope (STM). The patterns were fabricated by extraction of hydrogen (H) atoms from a H-terminated Si(001)-(2X1) surface with a STM tip. The study covers four different patterns: growth on H-terminated Si(00 1) surfaces with (1) an isolated single dangling bond site, (2) a dangling bond wire (similar to 1 nm wide), (3) a dangling bond area (20x 20 nm(2)), and (4) a dangling bond array. Ag adatoms readily diffuse on the surface an d preferentially stick to patterns of dangling bonds. Ag adatoms are not sp ontaneously substituted fur H atoms around the Ag adsorption sites. The beh avior of Ag growth is different in each case. An isolated single dangling b ond site can be occupied by an isolated single Ag atom or a Ag cluster. The dangling bond wire is covered by an Ag island of 1 monolayer (ML) in heigh t. On the dangling bond area, Ag atoms preferentially stick to the edge of the area and a Ag island 1 ML, in height grows in the direction perpendicul ar to the dimer rows. The behavior of each growth pattern is explained by t he difference in binding energy of diffusing adatoms on H-terminated areas and Si dangling bond sites.