High density of (pseudo) periodic twin-grain boundaries in molecular beam epitaxy-grown van der Waals heterostructure: MoTe{sub 2}/MoS{sub 2}

Journal Article · Mon May 09 00:00:00 EDT 2016 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4949559· OSTI ID:22591703

Diaz, Horacio Coy; Ma, Yujing; Chaghi, Redhouane; Batzill, Matthias ^[1]

---

1. Department of Physics, University of South Florida, Tampa, Florida 33620 (United States)

Growth of transition metal dichalcogenide heterostructures by molecular beam epitaxy (MBE) promises synthesis of artificial van der Waals materials with controllable layer compositions and separations. Here, we show that MBE growth of 2H-MoTe{sub 2} monolayers on MoS{sub 2} substrates results in a high density of mirror-twins within the films. The grain boundaries are tellurium deficient, suggesting that Te-deficiency during growth causes their formation. Scanning tunneling microscopy and spectroscopy reveal that the grain boundaries arrange in a pseudo periodic “wagon wheel” pattern with only ∼2.6 nm repetition length. Defect states from these domain boundaries fill the band gap and thus give the monolayer an almost metallic property. The band gap states pin the Fermi-level in MoTe{sub 2} and thus determine the band-alignment in the MoTe{sub 2}/MoS{sub 2} interface.

• OSTI ID: 22591703
• Journal Information: Applied Physics Letters, Vol. 108, Issue 19; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
DENSITY
FERMI LEVEL
GRAIN BOUNDARIES
MOLECULAR BEAM EPITAXY
MOLECULAR BEAMS
MOLYBDENUM SULFIDES
MOLYBDENUM TELLURIDES
PERIODICITY
SCANNING TUNNELING MICROSCOPY
SILICON OXIDES
SPECTROSCOPY
SUBSTRATES
TELLURIUM
TRANSITION ELEMENTS
TUNNEL EFFECT
VAN DER WAALS FORCES