FLUX DEPENDENCE OF THE AG/SI(111) GROWTH

We have studied the initial stages ((1 divided-by 2) ML) of the growth of Ag on Si(111) as a function of temperature T and deposition rate F to identify the operating diffusion mechanism. The specular beam intensity at 150 K shows short-lived oscillations which depend on the total amount of Ag deposited, irrespectively of the deposition rate, and suggest the absence of thermal diffusion at this low temperature. Growth studies at higher temperatures T greater-than-or-equal-to 473 K, monitoring the formation of the square-root 3 x square-root 3 R30-degrees structure as a function of deposition rate, measure a non-thermal component R0 > 50 angstrom to the diffusion length. The temperature dependence of the square-root 3 growth is used to measure an activation energy E(d) = (0.24 +/- 0.05) eV.