Island Formation of Adspecies and LEED
If the temperature of the surface is sufficiently low, an attractive interaction among adatoms or admolecules which are bound at sites of specific symmetry on the surface will give rise to the formation of ordered islands of the adsorbate. These islands are characterized by a local density greater than the overall density of the adsorbate on the surface. This local density is related to the two-dimensional periodicity within the ordered islands. Evidence for the formation of ordered islands has been observed quite frequently with LEED [10.1–5]. Both the thermodynamic and kinetic (e.g. adsorption, desorption, and surface diffusion) properties of an overlayer that contains islands are determined by the degree of order and the size and relative positioning of the islands [10.61 This information can be obtained using LEED since the shape (angular profile) of the diffracted electron beams is determined by the size and distribution of ordered regions of scatterers on the surface [10.7–15].
KeywordsSmall Island Width Ratio Beam Profile Island Size Island Formation
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