Surface facetting induced by adsorbates

The presence of adsorbates can modify the morphology of the underlying substrate. The modifications are the results of a subtle thermodynamic balance between intermolecular and molecular-substrate interactions together with the surface relaxation energy. The information on how the substrate structures are influenced by the adsorbates, and therefore, the physical and chemical properties of the resulting interface is fundamentally important. In this review, we examine facetting of transition metals induced by either atomic species or organic molecules. First we focus on facetting induced by atomic species and small molecules under high pressure or UHV conditions. Following that, organic molecules containing several electronegative elements, such as amino acids, benzoic acid and aminobenzoic acid, are examined. These organic molecules can induce large scale facets with great similarity on fcc crystal surfaces. Learning from the correlation between the facetting induced by these molecules and those of atomic species, we try to rationalise the molecular mechanism for the formation of adsorbate induced facets. (C) 2003 Elsevier Ltd. All rights reserved.