Tantalum Diselenide (TaSe2) Powder and Crystal

Tantalum diselenide (2H-TaSe₂), CAS number 12039-55-3, is a layered transition metal dichalcogenide (TMDC) that possesses metallic property with charge density wave characteristics, coupled with strong light absorption and emission due to energy separated bands. 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.

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Different Forms of Tantalum Diselenide

2H-TaSe₂ is a metal (or semi-metal) with no band gap. In its bulk form, 2H-TaSe₂ showed two-step charge-density-wave (CDW) transitions. The first transition from the metallic phase to the incommensurate charge-density-wave (ICDW) phase was at 123K, The next was a commensurate charge-density-wave (CCDW) phase transition at 90K, followed by a superconducting transition at low temperature (Tc ∼ 0.2 K).

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).

The 2H phase is stable at room temperature while the 1T phase is stable at 800 °C.

We supply low price tantalum diselenide in several different forms for a range of applications.

Tantalum Diselenide Powder

Can be used for preparation of tantalum diselenide nanoplates and ultrathin films

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≥99.995% purity

From £350

Tantalum Diselenide Crystals by Size

Can be used to produce single or few-layer tantalum diselenide sheets via mechanical or liquid exfoliation

Small (≥10 mm²) or medium (≥25 mm²) crystals available*

≥99.999% purity

From £520

*Typical representative size, areas/dimensions may vary

Bulk single tantalum diselenide crystal is most commonly used as sources from which single or few-layer sheets can be obtained via either mechanical or liquid exfoliation. 

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Tantalum diselenide powder can also be used to prepare TaSe₂ nanosheets and nanoparticles by liquid-exfoliation (normally assisted by sonication). Lithium, Sodium, Cesium, Iron and Rubidium ions can be intercalated between the layers tantalum diselenide especially for changes in both superconducting and CDW properties.

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• High purity, low price tantalum diselenide
• Available as a powder or as individual crystal
• Can be used to produce single or few-layer sheets
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Structure of Tantalum Diselenide

Tantalum diselenide (TaSe₂), with a crystal structure of hexagonal symmetry. 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.

Hexagonally coordinated 2H-TaSe₂ polytype is the most stable phase at room temperature in bulk while 1T-TaSe₂ phase consists of a layer of Ta atoms sandwiched between two layers of Se atoms in an octahedral coordination.

Properties of 2D Tantalum Diselenide

After exfoliation of crystals or powder, tantalum diselenide typically has the following properties:

• ‎2H-TaSe₂ is a layered TMD that possesses metallic property with charge density wave characteristics
• Hexagonal (2H) structure (space group: P63/mmc)
• 2H-TaSe₂ is a metal (or semi-metal) with no band gap
• 2H-TaSe₂ shows two-step charge-density-wave (CDW) transitions
• 1T-TaSe₂ is metallic in the bulk structure but insulating in a single-layer
• 1T-TaSe₂ has thickness- and temperature-dependent properties in CCDW

Applications of Tantalum Diselenide

Tantalum diselenide single crystals can be used to prepare monolayer and few-layer TaSe₂ by mechanical or liquid exfoliation. Tantalum diselenide powder is suitable for liquid chemical exfoliation to prepare TaSe₂ nanosheets and nanoparticles down to few-layer films. 

TaSe₂ has several other interesting applications. It can function as an interconnect in devices, as well as an energy storage device material with intercalation of lithium ions and high volumetric capacitors. TaSe₂ powder can also be exfoliated into ultra-thin films by liquid chemical exfoliation to explore its superconductivity.

Tantalum Diselenide (TaSe₂) 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.

Few-layer tantalum diselenides (TaSe₂) are typical metallic TMDs exhibiting rich CDW phase transitions. Besides being an important CDW material, TaSe₂ has several other interesting applications. It can function as an interconnect in devices, as well as an energy storage device material with intercalation of lithium ions and high volumetric capacitors.

Also unlike the conventional metals, hot electrons generated by light absorption in TaSe₂ have a rather long lifetime, making TaSe₂ an excellent hot electron injector.

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.
• Mechanical Exfoliation and Characterization of Single and Few-Layer Nanosheets of WSe2 , TaS2 , and TaSe2, H. Li et al, small, 9, No. 11, 1974–1981 (2013); DOI: 10.1002/smll.201202919.
• Zone-Folded Phonons and the Commensurate−Incommensurate Charge-Density-Wave Transition in 1T‑TaSe2 Thin Films, R. Samnakay et al.,  Nano Lett., 15, 2965−2973 (2015); DOI: 10.1021/nl504811s.
• Direct observation of an optically induced charge density wave transition in 1T-TaSe2, S. Sun et al., Phys. Rev. B., 92, 224303 (2015); doi: 10.1103/PhysRevB.92.224303.
• Contrast and Raman spectroscopy study of single- and few-layered charge density wave material: 2H-TaSe2, P. Hajiyev et al., Sci. Rep., 3 : 2593 (2013); DOI: 10.1038/srep02593.
• Structural, electronic and vibrational properties of few-layer 2H- and 1T-TaSe2, J. Yan et al., Sci. Rep., 5 : 16446 (2013); DOI: 10.1038/srep16646.
• Dimensional reduction and ionic gating induced enhancement of superconductivity in atomically thin crystals of 2H-TaSe2, Nanotech., 30, 035702 ((2019); doi:10.1088/1361-6528/aaea3b.