Large-scale patterning of zwitterionic molecules on a Si(111)-7 × 7 surface.

The formation of a large scale pattern on Si(111)-7 × 7 reconstruction is still a challenge. We report herein a new solution to achieve this type of nanostructuration by using of zwitterionic molecules. The formation of a large-scale pattern is successfully obtained due to the perfect match between the molecular geometry and the surface topology and to electrostatic interactions between molecules and surface. The adsorption is described by high-resolution scanning tunneling microscopy (STM) images and supported by density functional theory and STM calculations.