1. Free-standing electronic character of monolayer MoS2 in van der Waals epitaxy.
- Author
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HoKwon Kim, Dumcenco, Dumitru, Frégnaux, Mathieu, Benayad, Anass, Ming-Wei Chen, Yen-Cheng Kung, Kis, Andras, and Renault, Olivier
- Subjects
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ELECTRONIC amplifiers , *CHEMICAL vapor deposition , *VAPOR-plating , *CRYSTALLOGRAPHIC shear , *CRYSTAL defects - Abstract
We have evaluated as-grown MoS2 crystals, epitaxially grown on a monocrystalline sapphire by chemical vapor deposition (CVD), with direct electronic band-structure measurements by energy-filtered k-space photoelectron emission microscopy performed with a conventional laboratory vacuum ultraviolet He I light source under off-normal illumination. The valence states of the epitaxial MoS2 were mapped in momentum space down to 7 eV below the Fermi level. Despite the high nucleation density within the imaged area, the CVD MoS2 possesses an electronic structure similar to the free-standing monolayer MoS2 single crystal, and it exhibits hole effective masses of 2.41±0.05m0, and 0.81±0.05m0, respectively, at Γ and K high-symmetry points that are consistent with the van der Waals epitaxial growth mechanism. This demonstrates the excellent ability of the MoS2 CVD on sapphire to yield a highly aligned growth of well-stitched grains through epitaxial registry with a strongly preferred crystallographic orientation. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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