Tungsten Diselenide Crystal


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Order Code: M2111A10

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Size Product code Size description* Quantity (EA) Price
Small M2111A10 >10 mm2 1 £396.5
Medium M2111A25 >25 mm2 1 £636.8
Large** M2111A00 >100 mm2 1 £1727.8

*typical representative size, areas/dimensions may vary

**item with a lead time of 2-3 weeks, please contact for more information


General Information

CAS number 12067-46-8
Chemical formula WSe2
Molecular weight 341.76 g/mol
Bandgap 1.2 eV -1.4 eV [1]
Synonyms Tungsten Selenide, Tungsten (IV) Selenide 
Classification / Family Transition metal dichalcogenides (TMDCs), 2D Semiconductor Materials, Nano-electronics, Nano-photonics, Materials Science

Product Details

Form Single Crystal
Preparation Synthetic - Chemical Vapour Transport (CVT)
Purity ≥ 99.999%
Structure Hexagonal
Electronic properties 2D semiconductor
Melting point ‎> 1200 °C
Colour Black/Dark brown

 

General description

Bulk tungsten diselenide (WSe2) has a high absorption coefficient, high photostability, and a band-gap of 1.2 eV. It is an indirect band-gap semiconducting material that can be both n- and p-doped. The ambipolar nature of WSe2 makes it possible to create electronic devices that include p−n junctions or complementary logic circuits.

Tungsten diselenide single layers are composed of a layer of tungsten atoms positioned between two layers of selenium atoms, with each tungsten atom coordinating through strong covalent-ionic bonds to six selenium atoms in a trigonal prismatic geometry.  As occurs in graphene, black phosphorus and other TMDC materials, multuilayer structures are stabilised by weak Van de Waal forces. These forces are strong enough to hold layers together, but weak enough to allow mechanical exfoliation.

With a lattice structure similar to MoSe2, WSe2 single layers are semiconductors with a trigonal (2H) structure. By reacting with n-butyllithium, the 2H-WS2 can undergo a phase change to 1T-WSe2 (this process being totally reversible).

WSe2-Tungsten Diselenide Crystal product image
The hexagonal structure of Tungsten Diselenide (WSe2).

Applications

Monolayer or few-layer WSfilms that are mechanically exfoliated from bulk WScrystals have been explored for applications in FETs, electrochemical cells, thermoelectrics, sensors, and light-emitting diodes.

The energy gap of WSe2 (1.2 - 1.4 eV) makes it perfect for applications in photovoltaics and solar cells.

Synthesis

Tungsten disulfide WS2 is manufactured via chemical vapour transport (CVT) crystallisation, with a purity in excess of 99.999%.

Usage

Tungsten disulfide WS2 can be used to create monolayer and few-layer WS2 by mechanical or liquid exfoliation.

 

Literature and Reviews

  1. Layer-dependent electronic structure of an atomically heavy two-dimensional dichalcogenide, P-C. Yeh et al., Phys. Rev. B 91, 041407 (2015); DOI: 10.1103/PhysRevB.91.041407.
  2. Strain-Induced Indirect to Direct Bandgap Transition in Multilayer WSe2,
    S. B. Desai et al., Nano Lett., 14 (8), 4592–4597 (2014); DOI: 10.1021/nl501638a.
  3. Large-Area Synthesis of Highly Crystalline WSe2 Monolayers and Device Applications, J. Huang et al., ACS Nano, 8 (1), 923–930 (2014); DOI: 10.1021/nn405719x.
  4. Preparation and Applications of Mechanically Exfoliated Single-Layer and Multilayer MoS2 and WSe2 Nanosheets, H. Li et al., Acc. Chem. Res., 47, 1067−1075 (2014); DIO: 10.1021/ar4002312.
  5. Large-area synthesis of monolayer WSe2 on a SiO2/Si substrate and its device applications, J. Huang et al., Nanoscale, 7, 4193 (2015); DOI: 10.1039/c4nr07045c.