Silver growth on [formula omitted] surfaces at low temperature

Abstract

Silver growth on the Si(111) 3 × 3 - Ag ( 3 - Ag) surface is investigated by RHEED. For Ag deposition on the 3 -Ag surface at 150 K, a 21 × 21 structure appears at a coverage of 0.2 monolayer (ML: 1 ML = 7.8 × 10 14/cm 2). Analyzing the RHEED rocking curves of this structure, we have concluded that Ag atoms are embedded at silicon trimer sites of the 3 -Ag surface. This surface is very similar to the structure of the 21 × 21 surface formed by 0.14 ML Au deposition. In further deposition another 3 structure reappears, and subsequently one-dimensional (1D) islands of Ag are formed along the [11̄0] direction. Besides 1D islands, 3D Ag crystals are also formed on the surface with orientations {100} Ag|{111} Si and {110} Ag|{111} Si. When annealed at room temperature the 1D islands are rearranged into small 3D islands. We discuss the origin of these 1D islands.