Self-assembled structures of trimesic acid on the Ag/Si(1 1 1)-(√3 × √3)R30° surface

The room temperature growth and ordering of trimesic acid (TMA), 1,3,5-benzenetricarboxylic acid on the Ag/Si(1 1 1)-(√3 × √3)R30° surface has been investigated using scanning tunnelling microscopy (STM), and low energy electron diffraction (LEED). Molecules are found to adsorb at the step edges and defect sites. With increased coverage they diffuse freely to coalesce into ordered close-packed domains. An oblique unit cell is determined and a model proposed for these domains. A missing-molecule defect with short range ordering and a surface modulation with long range order within the domain structure were also investigated.