STRUCTURAL INVESTIGATION OF THE MoTe2 PHASES

Nir Ophek 1 Gili Yaniv 1 Sergiy Krylyuk 2 Albert V. Davydov 2 Viktor Zenou 3 David Fuks 1 Louisa Meshi 1
1Department of Material Engineer, Ben-Gurion University of the Negev, Beer-Sheva, Israel
2Materials Science and Engineering Division, Materials Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland, USA
3., Nuclear Research Center, Negev, Israel

MoTe2 belongs to the class of the 2D transition metal dichalcogenides (TMDs). Electrical properties of the MoTe2 change as a function of the crystallographic structure. This phase has three structural polymorphs: 2H hexagonal (α) phase with semiconducting properties, 1T’ monoclinic (b) which exhibits metallic properties [1]. Third polymorph was reported to exist at low temperatures and it has orthorhombic Td structure. Thus this material has high potential to be implemented in various electronic devices including phase-change memory and logic.

α and b phases are stable at room temperature. Transition between them occurs at about 900°C and depends on the cooling rate. Matter of reversibility of phase transition is under debate [2, 3, for example].

In current research structure and defects of the MoTe2 were studied in Transmission Electron Microscope as a function of thermal cycling and growth parameters. Structural relationships between the α and b phases will be discussed.

Bibliography

  1. Semiconductor to Metal Transition in MoTe2. M. B. VELLINGA*, R. DE JONGEt, AND C. HAAS. Groningen, Netherlands : JOURNAL OF SOLID STATE CHEMISTRY, 1970, Vol. 2.
  2. Bandgap opening in few-layered monoclinic MoTe2. Dong, Hoom Keum, et al., et al. 482–486, s.l. : Nature Physics, 2015, Vol. 11. 10.1038/nphys3314.
  3. Changes in structure and chemical composition of α-MoTe2 and β-MoTe2 during heating. Fukushima, Keiji Ueno* and Koji. 095201, s.l. : Applied Physics Express, 2015, Vol. 8.








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