Temperature dependence of metal film growth via low‐energy electron diffraction intensity oscillations: Pt/Pd(100)

A commercial, conventional low‐energy electron diffraction apparatus is used to monitor Bragg intensity oscillations during the growth of Pt on Pd(100). The effect of substrate temperature between 80 and 400 K is investigated. Between 80 and 300 K, two to three Bragg oscillations are observed. The oscillation amplitude damps out quickly as film coverage increases at fixed temperature, but damp out less quickly at the higher substrate temperatures. Above ∼350 K, reconstruction of the Pt overlayer interferes with the oscillations. These data indicate that a kinetic barrier, most probably the barrier to surface diffusion,inhibits the system from achieving macroscopic equilibrium, and that the true equilibrium growth mode for this system is layer‐by‐layer. A new, analytical procedure is used to determine the coverage distribution within the layers from the Bragg intensities during growth. Bragg oscillations are predicted to occur at low substrate temperatures where surface diffusion is minimal and deposition is essentially random, but restricted to the fourfold hollow adsorption sites.