Carrier mobility of one-dimensional vanadium selenide (V₂Se₉) monolayer and nanoribbon systems: DFT study

Vanadium selenide (V2Se9) is a true one-dimensional (1D) crystal composed of atomic nanochains bonded by van der Waals (vdW) interactions. Recent experiments revealed the mechanical exfoliation of newly synthesized V2Se9. In this study, we predicted the electronic and transport properties of V2Se9 through computational analyses. We calculated the intrinsic carrier mobility of V2Se9 monolayers (MLs) and nanoribbons (NRs) using density functional theory and deformation potential theory. We found that the electron mobility of the two-dimensional (2D) (010)-plane ML of V2Se9 is highly anisotropic, reaching μ 2D, ze = 1327cm2 V-1 s-1 across the chain direction. The electron mobility of 1D NR systems in a (010)-plane ML of V2Se9 along the chain direction continuously increased as the thickness increased from 1-chain to 4-chain NR (width below 3 nm). Interestingly, the electron mobility of 1D 4-chain NR along the chain direction (μ1D,xe = 775 cm2 V-1 s-1) was higher than that of a 2D (010)-plane ML (μ 2D,xe = 567 cm2 V-1 s-1). These results demonstrate the potential of vdW-1D crystal V2Se9 as a new nanomaterial for ultranarrow (sub-3 nm width) optoelectronic devices with high electron mobility.