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E u r o s c i c o n C o n f e r e n c e o n
Physical Chemistry and
Analytical Separation Techniques
October 08-09 , 2018
Amsterdam, Nether l ands
Journal of Organic & Inorganic Chemistry
ISSN: 2472-1123
Physical Chemistry and Analytical Separation Techniques 2018
H
igh-performance piezoelectricity in monolayer semiconducting transition metal dichalcogenides is highly desirable for
the development of nanosensors, piezotronics and photopiezotransistors. Here, we report the experimental study of the
theoretically predicted piezoelectric effect in triangle monolayer MoS
2
devices under isotropic mechanical deformation. The
experimental observation indicates that the conductivity of MoS
2
devices can be actively modulated by the piezoelectric charge
polarization-induced built-in electric eld 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 MoS
2
strain/force sensor built using a monolayer MoS
2
triangle is also demonstrated. Our results
provide evidence for strain-gating monolayer MoS
2
piezotronics, a promising avenue for achieving augmented functionalities
in next-generation electronic and mechanical-electronic nanodevices. Developing nanoelectronics that utilize the vertical sub-
nanometer thickness of two-dimensional materials is desirable for achieving miniaturization of circuit elements. However, only a
few researches have been studied in the vertical transport of atomic layered materials so far. Here, the vertical electrical transport
behaviour of bilayer MoS
2
under coupling of photons and force is explored by the use of conductive atomic force microscopy.
We found that the current-voltage behaviour across the tip-MoS
2
-Pt junction is a tunnelling current which can be well fitted by a
Simmons approximation. Among which, direct tunneling is dominated at low bias voltages whereas Fowler-Nordheim tunneling is
happened at high bias voltages. The bias voltages in transition point between direct and Fowler-Nordheim tunneling are matched
with the tunnelling barrier height of energy band shape difference. Furthermore, the source-drain current dropping surprisingly
appears when we continually increase force in which the dropping point is altered by light provided. The potential mechanism is
responsible for the tuning in tunnelling barrier height and width by force and photons. These results provide a new way to design
devices that takes advantage of ultrathin two-dimensional materials. Such ultra-short channel length electronic components that
possess tunnelling current are important for establishing high-efficiency electronic and optoelectronic systems.
junjieqi@ustb.edu.cnInterface engineering and force tuning
electrical transport behaviour of nano-devices
based on atomic layered MoS
2
Junjie Qi and Feng Li
University of Science and Technology Beijing, People’s Republic of China
J Org Inorg Chem 2018 Volume: 4
DOI: 10.21767/2472-1123-C6-018