Université Grenoble Alpes, Grenoble, France, CEA, INAC-SPINTEC, Grenoble, France, CNRS, INAC-SPINTEC, Grenoble, France, CNRS, Institut NEEL, Grenoble, France, CEA, INAC-PHELIQS, Grenoble, France, CEA, LETI, Minatec Campus, Grenoble, France, CEA, INAC-MEM, Grenoble, France

Molecular beam epitaxy technique has been used to deposit a single layer and a bilayer of MoSe2 on sapphire. Extensive characterizations including in-situ and ex-situ measurements show that the layered MoSe2 grows in a scalable manner on the substrate and reveals characteristics of a stoichiometric 2H-phase. The layered MoSe2 exhibits polycrystalline features with domains separated by defects and boundaries. Temperature and magnetic field dependent resistivity measurements unveil a carrier hopping character described within two-dimensional variable range hopping mechanism. Moreover, a negative magnetoresistance was observed, stressing a fascinating feature of the charge transport under the application of a magnetic field in the layered MoSe2 system. This negative magnetoresistance observed at millimeter-scale is similar to that observed recently at room temperature in WS2 flakes at a micrometer scale [Zhang et al., Appl. Phys. Lett. 108, 153114 (2016)]. This scalability highlights the fact that the underlying physical mechanism is intrinsic to these two-dimensional materials and occurs at very short scale. © 2017 Author(s).

Magnetic fields, Molecular beam epitaxy, Sapphire, Micrometer scale, Millimeter-scale, Negative magneto-resistance, Physical mechanism, Polycrystalline, Resistivity measurement, Two-dimensional materials, Variable range hopping, Magnetoresistance