1T-phase vanadium diselenide (VSe2) has a metallic behavior with charge density wave (CDW) and superconducting response, and most recently shown to be a room temperature (300K) ferromagnetic material [Nature Nanotechnology, 13, 289–293 (2018)]. It exhibits incommensurate CDW state at T<113K. Our crystals are grown using flux zone growth method without using any foreign chemicals to achieve world's only 6N (99.9999%) confirm purity and single-crystalline quality. We specialize in reducing the off stoichiometry to produce defect free crystals. 1T-VSe2 exhibits only around high 1E9cm-2 and low 1E-10 cm-2 defect density which is considered gold standards in the field. We are the only commercial source that guarantees CDW behavior. VSe2 is also handled using non-magnetic tweezers and in non-magnetic environment with tools that are free of magnetic impurities to ensure intrinsic magnetic properties can be confidently measured and probed.
Important characteristics of our VSe2 crystals
1. Environmental stability: We understand that defects actually cause these material to be unstable, and we specialize in lowering the defect density (using unique growth techniques) to create environmentally stable crystals
2. Stoichiometry: We sell 100% 1:2 stoichiometric ratios. They have exact stoichiometric value.
3. Defects: We are in business for more than 10 years and during these years, we have perfected our materials syshesis lines to achieve 1 out of 10000 site defect density or lower.
4. Grain size: Our grain size reaches really large and therefore you can get monolayers with 90% transfer rate (using our techniques) and get rather large areas (because single crystal grain size is large!).
5. Electronic and optical response: We characterize our samples usingstate of techniques to confirm excitonic dynamics (ultra fast spectroscopy), TEM, HRTEM, nano XPS and AES, SIMS (1ppm impurity resolution). We also make sure that residual resistance is minimized.
Growth method matters> Flux zone or CVT growth method? Contamination of halides and the presence point defects in layered crystals are well known cause for their weak CDW response, high electronic resistivity, and environmental instability. Flux zone technique is a halide free and slow growth technique used for synthesizing high-quality vdW crystals. This method distinguishes itself from chemical vapor transport (CVT) technique used by others in the following regard: CVT is a quick (~2 weeks) growth method but exhibits poor crystalline quality and the defect concentration reaches to 1E11 to 1E12 cm-2 range. In contrast, flux method takes long (~3 months) growth time, but ensures slow crystallization for perfect atomic structuring, and impurity free crystal growth with defect concentration as low as 1E9 - 1E10 cm-2. During check out just state which type of growth process is preferred (CVT vs Flux zone). We recommend flux zone, and unless otherwise stated, 2Dsemiconductors ships Flux zone crystals as a default choice.
XRD data collected from our 1T-VSe2 crystals
EDS data collected from our 1T-VSe2 crystals