The Pentagonal Nature of Self-Assembled Silicon Chains and Magic Clusters on Ag(110).

The atomic structures of self-assembled silicon nanoribbons and magic clusters on Ag(110) substrate have been studied by high-resolution noncontact atomic force microscopy (nc-AFM) and tip-enhanced Raman spectroscopy (TERS). Pentagon-ring structures in Si nanoribbons and clusters have been directly visualized. Moreover, the vibrational fingerprints of individual Si nanoribbon and cluster retrieved by subnanometer resolution TERS confirm the pentagonal nature of both Si nanoribbons and clusters. This work demonstrates that Si pentagon can be an important element in building silicon nanostructures, which may find important applications for future nanoelectronic devices based on silicon.