Impact of a van der Waals interface on intrinsic and extrinsic defects in an MoSe 2 monolayer

Carlos Alvarez (1) , Minh Tuan Dau (2) , Alain Marty (2) , Céline Vergnaud (2) , Hélène Le Poche (3) , Pascal Pochet (1) , Matthieu Jamet (2) , Hanako Okuno (4)

1 LSIM - Laboratory of Atomistic Simulation
2 SPINTEC - SPINtronique et TEchnologie des Composants
3 LITEN - Laboratoire d'Innovation pour les Technologies des Energies Nouvelles et les nanomatériaux
4 LEMMA - Laboratoire d'Etude des Matériaux par Microscopie Avancée

In this work, we study growth and migration of atomic defects in MoSe 2 on graphene using multiple advanced transmission electron microscopy techniques to explore defect behavior in vdW heterostructures. A MoSe 2 /graphene vdW heterostructure is prepared by a direct growth of both monolayers, thereby attaining an ideal vdW interface between the monolayers. We investigate the intrinsic defects (inversion domains and grain boundaries) in synthesized MoSe 2 , their evolution amid growth processing steps, and their influence on the formation and movement of extrinsic defects. Electron diffraction identifies a preferential interlayer orientation of 2° between MoSe 2 and graphene, which is caused by the presence of intrinsic IBD defects. Extrinsic defects (point and line defects) are generated by in situ electron irradiation in the MoSe 2 layer. Our results shed light on how to independently modify the MoSe 2 atomic structure in vdW heterostructures for potential utilization in device processing.

Keywords: MoSe2; van der waals heterostructure; molecular beam epitaxy; transition metal dichalcogenides; transmission electron microscopy

Domains: Physics [physics]; Condensed Matter [cond-mat]; Materials Science [cond-mat.mtrl-sci]

Carlos Alvarez, Minh Tuan Dau, Alain Marty, Céline Vergnaud, Hélène Le Poche, et al.. Impact of a van der Waals interface on intrinsic and extrinsic defects in an MoSe 2 monolayer. Nanotechnology, 2018, 29 (42), pp.425706. ⟨10.1088/1361-6528/aad66f⟩. ⟨cea-01962213⟩