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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

Current response of monolayer MoS2 strain sensor.Current response of CVD monolayer MoS2 device at repeated compressive (a) and tensile (b) strains at a fixed bias voltage of 1 V. (c) Measured current response when the device is free of strain (0 nN) and under mechanical loads equivalent to 5 and 10 nN, respectively. (d) Rise time and decay time of the MoS2 piezotronic device.
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f5: Current response of monolayer MoS2 strain sensor.Current response of CVD monolayer MoS2 device at repeated compressive (a) and tensile (b) strains at a fixed bias voltage of 1 V. (c) Measured current response when the device is free of strain (0 nN) and under mechanical loads equivalent to 5 and 10 nN, respectively. (d) Rise time and decay time of the MoS2 piezotronic device.

Mentions: To investigate the observed device response towards sensor applications, the induced device current was measured as a function of time at a fixed bias voltage of 1 V under a periodically switched applied load. Figure 5a,b shows the time-resolved measurement of the device current response under compressive and tensile strain, controlled by the spatial location of the loading force, respectively. While applying a loading force of 10 nN, the measured current is immediately decreased under compressive strain and increased under tensile strain. The response was highly repeatable in many on/off cycles, indicating the stability of the device. The accessibility of multiple steady states in the device, characterized by the measured current under different loading forces (0, 5 and 10 nN) as shown in Fig. 5c, will enable the development of logic circuit applications based on these triangular MoS2 monolayer devices. The response time of the MoS2 strain sensor was evaluated as shown in Fig. 5d, in which the rise time and decay time were about 1.79 and 1.23 s, respectively. The performance of a strain sensor was also characterized using gauge factor, which is defined as [ΔΙ(ɛ)/Ι(0)]/Δɛ. The highest gauge factor in our CVD monolayer MoS2 strain sensors (Supplementary Fig. 4) was ∼1,160, a value much larger than that of the conventional metal sensors (1∼5), graphene (∼2)46 and doped-Si (∼200)47, and even greater than that of the highest reported gauge factor for CNTs (∼1,000)48. This increase can be attributed to the piezoelectric polarization and the detailed mechanism discussed in the next section. These results clearly demonstrate the utility of triangular MoS2 monolayer devices as force/strain sensors, to monitor the mechanical changes at the nanoscale range or smaller.


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)

Current response of monolayer MoS2 strain sensor.Current response of CVD monolayer MoS2 device at repeated compressive (a) and tensile (b) strains at a fixed bias voltage of 1 V. (c) Measured current response when the device is free of strain (0 nN) and under mechanical loads equivalent to 5 and 10 nN, respectively. (d) Rise time and decay time of the MoS2 piezotronic device.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f5: Current response of monolayer MoS2 strain sensor.Current response of CVD monolayer MoS2 device at repeated compressive (a) and tensile (b) strains at a fixed bias voltage of 1 V. (c) Measured current response when the device is free of strain (0 nN) and under mechanical loads equivalent to 5 and 10 nN, respectively. (d) Rise time and decay time of the MoS2 piezotronic device.
Mentions: To investigate the observed device response towards sensor applications, the induced device current was measured as a function of time at a fixed bias voltage of 1 V under a periodically switched applied load. Figure 5a,b shows the time-resolved measurement of the device current response under compressive and tensile strain, controlled by the spatial location of the loading force, respectively. While applying a loading force of 10 nN, the measured current is immediately decreased under compressive strain and increased under tensile strain. The response was highly repeatable in many on/off cycles, indicating the stability of the device. The accessibility of multiple steady states in the device, characterized by the measured current under different loading forces (0, 5 and 10 nN) as shown in Fig. 5c, will enable the development of logic circuit applications based on these triangular MoS2 monolayer devices. The response time of the MoS2 strain sensor was evaluated as shown in Fig. 5d, in which the rise time and decay time were about 1.79 and 1.23 s, respectively. The performance of a strain sensor was also characterized using gauge factor, which is defined as [ΔΙ(ɛ)/Ι(0)]/Δɛ. The highest gauge factor in our CVD monolayer MoS2 strain sensors (Supplementary Fig. 4) was ∼1,160, a value much larger than that of the conventional metal sensors (1∼5), graphene (∼2)46 and doped-Si (∼200)47, and even greater than that of the highest reported gauge factor for CNTs (∼1,000)48. This increase can be attributed to the piezoelectric polarization and the detailed mechanism discussed in the next section. These results clearly demonstrate the utility of triangular MoS2 monolayer devices as force/strain sensors, to monitor the mechanical changes at the nanoscale range or smaller.

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