| Summary: | We report a facile approach based on piezoelectric-driven nanotips inside a scanning electron microscope to contact and electrically characterize ultrathin MoS2 (molybdenum disulfide) flakes on a SiO2/Si (silicon dioxide/silicon) substrate. We apply such a method to analyze the electric transport and field emission properties of chemical vapor deposition-synthesized monolayer MoS<sub>2</sub>, used as the channel of back-gate field effect transistors. We study the effects of the gate-voltage range and sweeping time on the channel current and on its hysteretic behavior. We observe that the conduction of the MoS<sub>2</sub> channel is affected by trap states. Moreover, we report a gate-controlled field emission current from the edge part of the MoS<sub>2</sub> flake, evidencing a field enhancement factor of approximately <inline-formula> <math display="inline"> <semantics> <mrow> <mn>200</mn> </mrow> </semantics> </math> </inline-formula> and a turn-on field of approximately<inline-formula> <math display="inline"> <semantics> <mrow> <mo> </mo> <mn>40</mn> <mo> </mo> <mi mathvariant="normal">V</mi> <mo>/</mo> <mrow> <mi mathvariant="sans-serif">μ</mi> <mi mathvariant="normal">m</mi> </mrow> </mrow> </semantics> </math> </inline-formula> at a cathode−anode separation distance of <inline-formula> <math display="inline"> <semantics> <mrow> <mn>900</mn> <mo> </mo> <mi>nm</mi> </mrow> </semantics> </math> </inline-formula>.
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