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Piezoelectric effect in chemical vapour deposition-grown atomic-monolayer triangular molybdenum disulfide piezotronics.

Qi J, Lan YW, Stieg AZ, Chen JH, Zhong YL, Li LJ, Chen CD, Zhang Y, Wang KL - Nat Commun (2015)

Bottom Line: Here we report the experimental study of the theoretically predicted piezoelectric effect in triangle monolayer MoS2 devices under isotropic mechanical deformation.The underlying mechanism of strain-induced in-plane charge polarization is proposed and discussed using energy band diagrams.Our results provide evidence for strain-gating monolayer MoS2 piezotronics, a promising avenue for achieving augmented functionalities in next-generation electronic and mechanical-electronic nanodevices.

View Article: PubMed Central - PubMed

Affiliation: School of Materials Science and Engineering, University of Science and Technology Beijing, Xueyuan Road 30, Beijing 100083, China.

ABSTRACT
High-performance piezoelectricity in monolayer semiconducting transition metal dichalcogenides is highly desirable for the development of nanosensors, piezotronics and photo-piezotransistors. Here we report the experimental study of the theoretically predicted piezoelectric effect in triangle monolayer MoS2 devices under isotropic mechanical deformation. The experimental observation indicates that the conductivity of MoS2 devices can be actively modulated by the piezoelectric charge polarization-induced built-in electric field under strain variation. These polarization charges alter the Schottky barrier height on both contacts, resulting in a barrier height increase with increasing compressive strain and decrease with increasing tensile strain. The underlying mechanism of strain-induced in-plane charge polarization is proposed and discussed using energy band diagrams. In addition, a new type of MoS2 strain/force sensor built using a monolayer MoS2 triangle is also demonstrated. Our results provide evidence for strain-gating monolayer MoS2 piezotronics, a promising avenue for achieving augmented functionalities in next-generation electronic and mechanical-electronic nanodevices.

No MeSH data available.


Related in: MedlinePlus

Characterization of the MoS2 monolayer and device structure.(a) AFM image of a triangular MoS2 monolayer. Inset shows the histogram analyses of multiple topographic AFM images confirmed the MoS2 film thickness to be ∼0.75 nm. (b) High-resolution TEM image of the synthesized MoS2 monolayer. Inset is the corresponding diffraction pattern. (c) A typical AFM image of a MoS2 monolayer device. (d) Schematic illustration of a MoS2 device under mechanical load applied by an AFM tip.
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f1: Characterization of the MoS2 monolayer and device structure.(a) AFM image of a triangular MoS2 monolayer. Inset shows the histogram analyses of multiple topographic AFM images confirmed the MoS2 film thickness to be ∼0.75 nm. (b) High-resolution TEM image of the synthesized MoS2 monolayer. Inset is the corresponding diffraction pattern. (c) A typical AFM image of a MoS2 monolayer device. (d) Schematic illustration of a MoS2 device under mechanical load applied by an AFM tip.

Mentions: High-quality monolayer MoS2 films were synthesized by CVD method (See Methods). Two distinct morphologies are known to be dominant in CVD MoS2 triangles363738, where one involves a zigzag edge that comprises molybdenum and the other a zigzag edge that comprises sulphur. The former has a straighter edge than the latter and is entirely used in this work. An atomic force microscopy (AFM) image of the as-synthesized MoS2 sheet on a Si substrate shown in Fig. 1a indicates a smooth surface topography, combined cross-sectional and image histogram analyses of multiple topographic AFM images confirmed the MoS2 film thickness to be ∼0.75 nm as seen in Fig. 1a inset. Figure 1b shows a typical transmission electron microscopy (TEM) image of the synthesized MoS2 sheet, which reveals the periodic atom arrangement of the monolayer MoS2 film. The inset displays the corresponding diffraction pattern that indicates one set of hexagonal lattice structure, confirming that the synthesized MoS2 sheet has a monolayer structure with the highly crystalline quality. It is also noted from TEM-based energy-dispersive spectroscopy analysis (Supplementary Fig. 1) that the atomic percentage ratio between Mo and S is 1:2.


Piezoelectric effect in chemical vapour deposition-grown atomic-monolayer triangular molybdenum disulfide piezotronics.

Qi J, Lan YW, Stieg AZ, Chen JH, Zhong YL, Li LJ, Chen CD, Zhang Y, Wang KL - Nat Commun (2015)

Characterization of the MoS2 monolayer and device structure.(a) AFM image of a triangular MoS2 monolayer. Inset shows the histogram analyses of multiple topographic AFM images confirmed the MoS2 film thickness to be ∼0.75 nm. (b) High-resolution TEM image of the synthesized MoS2 monolayer. Inset is the corresponding diffraction pattern. (c) A typical AFM image of a MoS2 monolayer device. (d) Schematic illustration of a MoS2 device under mechanical load applied by an AFM tip.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4491182&req=5

f1: Characterization of the MoS2 monolayer and device structure.(a) AFM image of a triangular MoS2 monolayer. Inset shows the histogram analyses of multiple topographic AFM images confirmed the MoS2 film thickness to be ∼0.75 nm. (b) High-resolution TEM image of the synthesized MoS2 monolayer. Inset is the corresponding diffraction pattern. (c) A typical AFM image of a MoS2 monolayer device. (d) Schematic illustration of a MoS2 device under mechanical load applied by an AFM tip.
Mentions: High-quality monolayer MoS2 films were synthesized by CVD method (See Methods). Two distinct morphologies are known to be dominant in CVD MoS2 triangles363738, where one involves a zigzag edge that comprises molybdenum and the other a zigzag edge that comprises sulphur. The former has a straighter edge than the latter and is entirely used in this work. An atomic force microscopy (AFM) image of the as-synthesized MoS2 sheet on a Si substrate shown in Fig. 1a indicates a smooth surface topography, combined cross-sectional and image histogram analyses of multiple topographic AFM images confirmed the MoS2 film thickness to be ∼0.75 nm as seen in Fig. 1a inset. Figure 1b shows a typical transmission electron microscopy (TEM) image of the synthesized MoS2 sheet, which reveals the periodic atom arrangement of the monolayer MoS2 film. The inset displays the corresponding diffraction pattern that indicates one set of hexagonal lattice structure, confirming that the synthesized MoS2 sheet has a monolayer structure with the highly crystalline quality. It is also noted from TEM-based energy-dispersive spectroscopy analysis (Supplementary Fig. 1) that the atomic percentage ratio between Mo and S is 1:2.

Bottom Line: Here we report the experimental study of the theoretically predicted piezoelectric effect in triangle monolayer MoS2 devices under isotropic mechanical deformation.The underlying mechanism of strain-induced in-plane charge polarization is proposed and discussed using energy band diagrams.Our results provide evidence for strain-gating monolayer MoS2 piezotronics, a promising avenue for achieving augmented functionalities in next-generation electronic and mechanical-electronic nanodevices.

View Article: PubMed Central - PubMed

Affiliation: School of Materials Science and Engineering, University of Science and Technology Beijing, Xueyuan Road 30, Beijing 100083, China.

ABSTRACT
High-performance piezoelectricity in monolayer semiconducting transition metal dichalcogenides is highly desirable for the development of nanosensors, piezotronics and photo-piezotransistors. Here we report the experimental study of the theoretically predicted piezoelectric effect in triangle monolayer MoS2 devices under isotropic mechanical deformation. The experimental observation indicates that the conductivity of MoS2 devices can be actively modulated by the piezoelectric charge polarization-induced built-in electric field under strain variation. These polarization charges alter the Schottky barrier height on both contacts, resulting in a barrier height increase with increasing compressive strain and decrease with increasing tensile strain. The underlying mechanism of strain-induced in-plane charge polarization is proposed and discussed using energy band diagrams. In addition, a new type of MoS2 strain/force sensor built using a monolayer MoS2 triangle is also demonstrated. Our results provide evidence for strain-gating monolayer MoS2 piezotronics, a promising avenue for achieving augmented functionalities in next-generation electronic and mechanical-electronic nanodevices.

No MeSH data available.


Related in: MedlinePlus