High-resolution LEED profile analysis and diffusion barrier estimation for submonolayer homoepitaxy of Ag/Ag(100)

We present a high-resolution low-energy electron diffraction study of two-dimensional island distributions formed by depositing 0.3 ML of Ag on Ag(100). The substrate temperature ranged between 170 and 295 K. From the ring structure or "splitting" of the diffraction profiles, we determine the behavior of the spatial correlation length characterizing the island distribution. The precise relationship between this correlation length and the mean island separation is also determined via an analysis of kinematic diffraction from island distributions in a realistic model of nucleation and growth. Resulting estimates of this separation are consistent with those based on results from a previous scanning tunneling microscopy study at 295 K. From the Arrhenius behavior of the correlation length, we estimate a terrace diffusion barrier for Ag on AE(100) of 0.40 +/- 0.04 eV, with a vibrational prefactor of about 3 X 10(13) s(-1).