Limits...
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

Electromechanical behaviour of a MoS2 device measured between different S–D electrodes.(a,b) Typical I–Vb characteristics of the device at different applied forces in the centre of the device measured between two S–D electrodes shown in the inset. (c) The I–Vb curves with both positive and negative bias voltage from −1 to 1 V. The inset is the fitting of lnI as a function of V1/4 by the I–Vb curve without strain using the thermionic emission–diffusion theory for a reversely biased Schottky barrier. The black dotted lines are experimental data points and the red line is a linear fitting. (d) The derived change of the barrier height as a function of applied force at a D–S bias of −1 and 1 V, respectively. The blue line is a linear fitting.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4491182&req=5

f3: Electromechanical behaviour of a MoS2 device measured between different S–D electrodes.(a,b) Typical I–Vb characteristics of the device at different applied forces in the centre of the device measured between two S–D electrodes shown in the inset. (c) The I–Vb curves with both positive and negative bias voltage from −1 to 1 V. The inset is the fitting of lnI as a function of V1/4 by the I–Vb curve without strain using the thermionic emission–diffusion theory for a reversely biased Schottky barrier. The black dotted lines are experimental data points and the red line is a linear fitting. (d) The derived change of the barrier height as a function of applied force at a D–S bias of −1 and 1 V, respectively. The blue line is a linear fitting.

Mentions: To further investigate the coupling effect of mechanical deformation and electric field, I–Vb curves similar to those shown in Fig. 3a,b were acquired in the central region of the sample under variable load, using different S–D electrode pairs as marked in the inset, respectively. It is noted that before the application of a mechanical loading force, different S–D combinations demonstrated small variations in their I–Vb characteristics with device conductance of the same order of magnitude. We attribute this to differing levels of electron scattering as mobile electrons traverse through different distances. Application of a loading force at the centre of the device results in a significant drop in the measured current that scales directly with the magnitude of the applied force. Figure 3c displays I–Vb curves in other two measured electrodes when a bipolar sweep voltage was applied to the device from −1 to 1 V. The same trend of the current change at the positive and negative bias was obtained. The observation of this phenomenon between all S–D combinations indicates that the position and directionality of the measured electrodes are not relevant to the deformation-induced modulation of conductance.


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)

Electromechanical behaviour of a MoS2 device measured between different S–D electrodes.(a,b) Typical I–Vb characteristics of the device at different applied forces in the centre of the device measured between two S–D electrodes shown in the inset. (c) The I–Vb curves with both positive and negative bias voltage from −1 to 1 V. The inset is the fitting of lnI as a function of V1/4 by the I–Vb curve without strain using the thermionic emission–diffusion theory for a reversely biased Schottky barrier. The black dotted lines are experimental data points and the red line is a linear fitting. (d) The derived change of the barrier height as a function of applied force at a D–S bias of −1 and 1 V, respectively. The blue line is a linear fitting.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f3: Electromechanical behaviour of a MoS2 device measured between different S–D electrodes.(a,b) Typical I–Vb characteristics of the device at different applied forces in the centre of the device measured between two S–D electrodes shown in the inset. (c) The I–Vb curves with both positive and negative bias voltage from −1 to 1 V. The inset is the fitting of lnI as a function of V1/4 by the I–Vb curve without strain using the thermionic emission–diffusion theory for a reversely biased Schottky barrier. The black dotted lines are experimental data points and the red line is a linear fitting. (d) The derived change of the barrier height as a function of applied force at a D–S bias of −1 and 1 V, respectively. The blue line is a linear fitting.
Mentions: To further investigate the coupling effect of mechanical deformation and electric field, I–Vb curves similar to those shown in Fig. 3a,b were acquired in the central region of the sample under variable load, using different S–D electrode pairs as marked in the inset, respectively. It is noted that before the application of a mechanical loading force, different S–D combinations demonstrated small variations in their I–Vb characteristics with device conductance of the same order of magnitude. We attribute this to differing levels of electron scattering as mobile electrons traverse through different distances. Application of a loading force at the centre of the device results in a significant drop in the measured current that scales directly with the magnitude of the applied force. Figure 3c displays I–Vb curves in other two measured electrodes when a bipolar sweep voltage was applied to the device from −1 to 1 V. The same trend of the current change at the positive and negative bias was obtained. The observation of this phenomenon between all S–D combinations indicates that the position and directionality of the measured electrodes are not relevant to the deformation-induced modulation of conductance.

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