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Thickness-modulated metal-to-semiconductor transformation in a transition metal dichalcogenide.

ABSTRACT: The possibility of tailoring physical properties by changing the number of layers in van der Waals crystals is one of the driving forces behind the emergence of two-dimensional materials. One example is bulk MoS2, which changes from an indirect gap semiconductor to a direct bandgap semiconductor in the monolayer form. Here, we show a much bigger tuning range with a complete switching from a metal to a semiconductor in atomically thin PtSe2 as its thickness is reduced. Crystals with a thickness of ~13?nm show metallic behavior with a contact resistance as low as 70??·µm. As they are thinned down to 2.5?nm and below, we observe semiconducting behavior. In such thin crystals, we demonstrate ambipolar transport with a bandgap smaller than 2.2?eV and an on/off ratio of ~105. Our results demonstrate that PtSe2 possesses an unusual behavior among 2D materials, enabling novel applications in nano and optoelectronics.

SUBMITTER: Ciarrocchi A

PROVIDER: S-EPMC5834615 | biostudies-literature | 2018 Mar

REPOSITORIES: biostudies-literature

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Thickness-modulated metal-to-semiconductor transformation in a transition metal dichalcogenide.

Ciarrocchi Alberto A Avsar Ahmet A Ovchinnikov Dmitry D Kis Andras A

Nature communications 20180302 1

The possibility of tailoring physical properties by changing the number of layers in van der Waals crystals is one of the driving forces behind the emergence of two-dimensional materials. One example is bulk MoS2, which changes from an indirect gap semiconductor to a direct bandgap semiconductor in the monolayer form. Here, we show a much bigger tuning range with a complete switching from a metal to a semiconductor in atomically thin PtSe2 as its thickness is reduced. Cryst ...[more]

PMID: 29500434

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