*typical representative size, areas/dimensions may vary
||Tantalum (IV) selenide, Bis(selanylidene)tantalum
|Classification / Family
Transition metal dichalcogenides (TMDCs), 2D charge density wave (CDW) materials, Nano-electronics, Nano-photonics, Superconductivity, Photovoltaic, Materials science
||Synthetic - Chemical Vapour Transport (CVT)
||2D CDW materials
||> 1,300 °C
Tantalum diselenide (TaSe2) is a family member of Group VB transition metal dichalcogenides (TMDCs). Group VB is one of the most heavily-studied group of TMDCs due to their diverse permutations of stable compounds and electronic behaviour.
2H-TaSe2 is a metal (or semi-metal) with no band gap. The crystal structures of TaSe2 contain Ta in trigonal prismatic coordination within Se-Ta-Se layers. The weak interlayer van der Waals (vdW) bonding leads to various TaSe2 polytypes, which differ simply in the relative orientations of the layers and their stacking arrangements.
1T-TaSe2, however, is metallic in the bulk structure but insulating in a single-layer. It has thickness- and temperature-dependent properties in the commensurate charge density wave (CCDW) accompanied by a periodic lattice distortion (PLD).
Devices with nanometer-scale thicknesses strongly exhibit non-linear current-voltage characteristics, unusual optical response, and electrical gating at room temperature. In principle, such current-voltage characteristics can be used for implementing radiation-hard, all-metallic logic circuits.
Tantalum diselenide is manufactured using chemical vapour transport (CVT) crystallisation, with crystals having a purity in excess of 99.999%.
Tantalum diselenide single crystals can be used to prepare monolayer and few-layer TaSe2 by mechanical or liquid exfoliation.
Literature and Reviews
All-metallic electrically gated 2H-TaSe2 thin-film switches and logic circuits, J. Renteria et al., J. Appl. Phys., 115, 034305 (2014); doi: 10.1063/1.4862336.
Phonon and thermal properties of exfoliated TaSe2 thin films, Z. Yan et al.,
J. Appl. Phys., 114, 204301 (2013); 10.1063/1.4833250.
Observation of charge density waves in free-standing 1T-TaSe2 monolayers by transmission electron microscopy, P. C. Börner et al., Appl. Phys. Lett. 113, 173103 (2018); doi: 10.1063/1.5052722.
Persistent Charge-Density-Wave Order in Single-Layer TaSe2, H. Ryu et al., Nano Lett., 18, 689−694 (2018); DOI: 10.1021/acs.nanolett.7b03264.
Selective Fabrication of Mott-Insulating and Metallic Monolayer TaSe2, Y. Nakata et al., ACS Appl. Nano Mater., 1, 1456−1460 (2018); DOI: 10.1021/acsanm.8b00184.
Fast and reliable identification of atomically thin layers of TaSe2 crystals, A. Castellanos-Gomez et al., Nano Res., 6(3): 191–199 (2013); DOI 10.1007/s12274-013-0295-9.
Broken hexagonal symmetry in the locked-in state of 2Ha-TaSe2 and the discommensurate microstructure of its incommensurate CDW states, J. Phys. C: Solid State Phys., 14, 5417-5432 (1981), doi: 10.1088/0022-3719/14/35/004.
Mechanical Exfoliation and Characterization of Single and Few-Layer Nanosheets of WSe2 , TaS2 , and TaSe2, H. Li et al., small, 9, 11, 1974–1981 (2013); DOI: 10.1002/smll.201202919.