KINETIC PROCESSES IN THE TRANSITION FROM AG(111) CRYSTALLITES TO (ROOT-3X-ROOT-3)R30-DEGREES DOMAINS FOR AG SI(111)-(7X7)/

Kinetic processes in the transition from metastable Ag(111) crystallit es to (root 3X root 3)R30 degrees domains in the initial growth of Ag on the Si(111)-(7X7) surface have been investigated using spot profile analysis low-energy electron diffraction. Upon annealing above 468 K, the number density M(t) of metastable Ag(111) crystallites (deposited at T-d similar to 333 K) is found to decrease exponentially with time t. Simultaneously, the average size of root 3 domains increases as R( t)similar to t(x), with the exponent x increasing with initially depos ited coverage and limited to a range of 1/3 less than or equal to x le ss than or equal to 2/5. A theoretical model for this structural trans ition is established to explain these observations, which is based on a kinetic process driven by the step-edge line tension of terraces in the Ag(111) crystallites. Also, a dissociation energy of an atom from the step edge of a Ag(111)crystallite is determined to be E(dis)simila r to 1.38 eV.