Nanoclusters and Nanoribbons*

We studied the epitaxial growth of VSi₂ on Si(111). The films were grown under UHV conditions using e-beam deposition of V on Si(111) substrates and subsequent annealing to temperatures ranging between 600-1100 °C. The films were investigated using in-situ scanning tunneling microscopy (STM), ex-situ atomic force microscopy (AFM), and ex-situ scanning electron microscopy (SEM).

At V coverages much larger than 1 monolayer (ML), we found that VSi₂ prefers to grow into 3 types of islands: hexagonal flat clusters, pyramidal hut clusters, and faceted hut clusters. All of which have low aspect ratios. At V coverages around 1 ML, however, we found that VSi₂ forms elongated nanoclusters with high aspect ratios and arrays of nanoribbons. In this presentation, we will explore: (1) the role of strain in the growth of these structures; (2) an STM methodology we developed to simultaneously map the topography, work function, and LDOS; and (3) the electronic structure of VSi₂ nanoribbons.