Millimeter-scale layered MoSe 2 grown on sapphire and evidence for negative magnetoresistance

M. T Dau (1) , C. Vergnaud (1) , A. Marty (1) , F. Rortais (1) , C. Beigné (1) , H. Boukari (2) , E. Bellet-Amalric (3) , V. Guigoz (4) , O. Renault (4) , C. Alvarez (5) , H. Okuno (6) , P. Pochet (5) , M. Jamet (1)

1 SPINTEC - SPINtronique et TEchnologie des Composants
2 NEEL - NPSC - Nanophysique et Semiconducteurs
3 NPSC - Nanophysique et Semiconducteurs
4 CEA-LETI - Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information
5 LSIM - Laboratory of Atomistic Simulation
6 LEMMA - Laboratoire d'Etude des Matériaux par Microscopie Avancée

Molecular beam epitaxy technique has been used to deposit a single layer and a bilayer of MoSe 2 on sapphire. Extensive characterizations including in-situ and ex-situ measurements show that the layered MoSe 2 grows in a scalable manner on the substrate and reveals characteristics of a stoichiometric 2H-phase. The layered MoSe 2 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 an application of magnetic field in the layered MoSe 2 system. This negative magnetoresistance observed at millimeter-scale is similar to that observed recently at room temperature in WS 2 flakes at a micrometer scale 1. This scalability highlights the fact that the underlying physical mechanism is intrinsic to these two-dimensional materials and occurs a very short scale.

Mots clés: beam epitaxy; transition metal dichalcogenides MoSe2; molecular beam epitaxy; variable range hopping; negative magnetoresistance; molecular; transition metal dichalcogenide MoSe 2; negative magnetoresistance 2; 2D materials; 2

Domaines: Matière Condensée [cond-mat]

M. T Dau, C. Vergnaud, A. Marty, F. Rortais, C. Beigné, et al.. Millimeter-scale layered MoSe 2 grown on sapphire and evidence for negative magnetoresistance. Applied Physics Letters, 2017, 110 (1), pp.011909. ⟨10.1063/1.4973519⟩. ⟨hal-01664036⟩