Exfoliation and Characterization of V₂Se₉ Atomic Crystals

Mass production of one-dimensional, V₂Se₉ crystals, was successfully synthesized using the solid-state reaction of vanadium and selenium. Through the mechanical exfoliation method, the bulk V₂Se₉ crystal was easily separated to nanoribbon structure and we have confirmed that as-grown V₂Se₉ crystals consist of innumerable single V₂Se₉ chains linked by van der Waals interaction. The exfoliated V₂Se₉ flakes can be controlled thickness by the repeated-peeling method. In addition, atomic thick nanoribbon structure of V₂Se₉ was also obtained on a 300 nm SiO₂/Si substrate. Scanning Kelvin probe microscopy analysis was used to explore the variation of work function depending on the thickness of V₂Se₉ flakes. We believe that these observations will be of great help in selecting suitable metal contacts for V₂Se₉ and that a V₂Se₉ crystal is expected to have an important role in future nano-electronic devices.