# Nucleation and growth of Ag islands on the (root 3 x root 3)R30 degrees phase of Ag on Si(111)

Title | Nucleation and growth of Ag islands on the (root 3 x root 3)R30 degrees phase of Ag on Si(111) |

Publication Type | Journal Article |

Year of Publication | 2011 |

Authors | Belianinov A, Unal B, Ho KM, Wang CZ, Evans JW, Tringides MC, Thiel PA |

Journal Title | Journal of Physics-Condensed Matter |

Volume | 23 |

Pages | 265002 |

Date Published | 07/06 |

ISBN Number | 0953-8984 |

Accession Number | ISI:000291658700003 |

Keywords | 3x root 3-ag, competing processes, controlling energies, epitaxial-growth, LOW-TEMPERATURES, restructuring process, root-3-ag surface, scanning-tunneling-microscopy, si(111)-root-3x-root-3-ag surface, small-cluster mobility |

Abstract | We use scanning tunneling microscopy to measure densities and characteristics of Ag islands that form on the (root 3 x root 3) R30 degrees-Ag phase on Si(111), as a function of deposition temperature. Nucleation theory predicts that the logarithm of island density varies linearly with inverse deposition temperature. The data show two linear regimes. At 50-125 K, islands are relatively small, and island density decreases only slightly with increasing temperature. At 180-250 K, islands are larger and polycrystalline, and island density decreases strongly with increasing temperature. At 300 K, Ag atoms can travel for distances of the order of 1 mu m. Assuming that Ag diffusion occurs via thermally activated motion of single atoms between adjacent sites, the data can be explained as follows. At 50-125 K, the island density does not follow conventional Arrhenius scaling due to limited mobility and a consequent breakdown of the steady-state condition for the adatom density. At similar to 115-125 K, a transition to conventional Arrhenius scaling with critical nucleus size (i = 1) begins, and at 180-250 K, i > 1 prevails. The transition points indicate a diffusion barrier of 0.20-0.23 eV and a pairwise Ag-Ag bond strength of 0.14 eV. These energy values lead to an estimate of i approximate to 3-4 in the regime 180-250 K, where island density varies strongly with temperature. |

URL | <Go to ISI>://000291658700003 |

DOI | 10.1088/0953-8984/23/26/265002 |

Alternate Journal | J Phys-Condens MatJ Phys-Condens Mat |