29 Sep

New prices for our single crystal MoS2. Buy now!

Looking to buy MoS2? As of 29th September 2015, we are excited to offer new pricing for our MoS2 single crystals, which are up to 50% off.  Our new pricing is as follows:

  1. Lifetime supply: From USD$999, now USD$499 (50% off). A bundle of more than 10 crystals with at least 3  Large.
  2. Large bundle: From USD$249, now USD$199 (25% off). Minimum dimensions 20mm by 15mm. Includes a smaller crystal with minimum dimensions 8mm x 8mm.
  3. Medium: From USD$189, now USD$149 (22% off):  Minimum dimensions 15mm by 10mm.

As always, our pricing includes free DHL Express shipping worldwide with 1-3 day delivery.

29 Sep

Single layer WSe2 actually has indirect band gap

Writing in Nano Letters a team  led by Professor Chih-Kang Shih from the University of Texas at Austin studied the electronic structures of single layer transition metal dichalcogenides WSe2 and WS2, by scanning tunneling spectroscopy.

It is generally well understood within academia that monolayer semiconductor transition metals dichalcogenides, such as WS2, WSe2, MoS2 and others, have an indirect-to-direct band gap transition as they make the transition from bulk to single layer. This is typically manifested as a strong photoluminescence in monolayer flakes.  Although this is true for MoSe2, the team found that the band gap minimum for WS2 is in fact located at the Q-point of the Brillouin zone, instead of the K, although the two states are nearly degenerate.

Manchester Nanomaterials specialize in offering single crystals of transition metals dichalcogenides and more at our webshop!

Further reading: “Probing critical point energies of transition metal dichalcogenides:
surprising indirect gap of single layer WSe2

21 Sep

Superconductivity in graphene intercalated with Ca and hBN

In a paper published on arXiv teams from the University of Manchester and University College London, report superconductivity in graphene when intercalated with calcium.

In this work our hexagonal boron nitride crystals were also used, as a physical spacer for monolayer graphene flakes. The high purity of our crystals and large domain sizes were of imperative importance for this work.

Further reading Superconductivity in Ca-doped graphene

01 Sep

WSe2 Raman spectoscopy

Tungsten diselenide is another layered transition metal dichalcogenide. Like more of the other TMDCs, it is a semiconductor with a band gap in the infrared region. In this article we review the Raman of WSe2 monolayer.

Like MoS2 and WS2, the lattice structure of WSe2 is also trigonal prismatic, while the lattice constant is 3.28 Å. The band gap of WSe2 is around 1eV.

Don’t forget you can purchase WSe2 crystals in our webshop with free worldwide delivery.

Further information

  1. Get a quote for a WSe2 single crystal
  2. Recent papers on WSe2