V₂O₅: A 2D van der Waals Oxide with Strong In-Plane Electrical and Optical Anisotropy

Abstract

VO with a layered van der Waals (vdW) structure has been widely studied because of the material's potential in applications such as battery electrodes. In this work, microelectronic devices were fabricated to study the electrical and optical properties of mechanically exfoliated multilayered VO flakes. Raman spectroscopy was used to determine the crystal structure axes of the nanoflakes and revealed that the intensities of the Raman modes depend strongly on the relative orientation between the crystal axes and the polarization directions of incident/scattered light. Angular dependence of four-probe resistance measured in the van der Pauw (vdP) configuration revealed an in-plane anisotropic resistance ratio of ∼100 between the a and b crystal axes, the largest in-plane transport anisotropy effect experimentally reported for two-dimensional (2D) materials to date. This very large resistance anisotropic ratio is explained by the nonuniform current flow in the vdP measurement and an intrinsic mobility anisotropy ratio of 10 between the a and b crystal axes. Room-temperature electron Hall mobility up to 7 cm/(V s) along the high-mobility direction was obtained. This work demonstrates VO as a layered 2D vdW oxide material with strongly anisotropic optical and electronic properties for novel applications.

Binary vanadium pentoxide carbon-graphene foam composites derived from dark red hibiscus sabdariffa for advanced asymmetric supercapacitor

“…Figure 2a exhibited the Raman spectra of V 2 O 5 @C-R 2 HS, V 2 O 5 @C-R 2 HS/20 mg GF and V 2 O 5 @C-R 2 HS/40 mg GF composites. The vibrational modes of V 2 O 5 @C-R 2 HS were in the range of 99-1000 cm −1 [67,68]. Similar Raman bands have been observed in the V 2 O 5 @C-R 2 HS/20 mg GF and V 2 O 5 @C-R 2 HS/40 mg GF composites.…”

“…The D peak is linked to the disorder or defect in the graphitic structure while the G peak is ascribed to the tangential vibration of the sp 2 carbon atoms [75]. In the same range, figure 2a Raman frequency (cm −1 ) vibration assignment references 99 A g [68,72] . same D and G bands in the binary V 2 O 5 @C-R 2 HS/GF composites which were observed at 1335-1350 cm −1 and 1577.2-1581 cm −1 , respectively [76].…”

Research on the Response Characteristics of Vanadium Pentoxide Film to the Irradiation of Ultrafast Pulsed Laser

“…Some transition metal oxides possess excellent nonlinear optical properties, which can be controlled by changing the samples’ shape and thickness, such as VO x , WS 2 , and MoS 2 [ 13 , 14 , 15 ]. Although there are several works related to the optical and electrical properties of V 2 O 5 thin films [ 16 , 17 , 18 ], few studies have been conducted on the performance response of V 2 O 5 induced by ultrafast laser.…”

Calculated phonon modes, infrared, and Raman spectra in ZnGeGa2N4

“…Mechanical exfoliation was recently successfully applied to V 2 O 5 and showed extremely anisotropic behavior or the in-plane electron transport related to 1D chain like elements of the structure. [8] It was also predicted that some of the vibrational modes would show large blue shifts when going from 3D to the monolayer form. [9] Hence the vibrational properties of MoO 3 are also of significant interest.…”