Mechanically modulated tunneling resistance in monolayer MoS₂

We report on the modulation of tunneling resistance in MoS₂ monolayers using a conductive atomic force microscope (AFM). The resistance between the conductive AFM probe and the bottom electrode separated by a monolayer MoS₂ is reversibly reduced by up to 4 orders of magnitude, which is attributed to enhanced quantum tunneling when the monolayer is compressed by the tip force. Under the Wentzel-Kramers-Brillouim approximation, the experimental data are quantitatively explained by using the metal-insulator-metal tunneling diode model. As an ideal tunneling medium, the defect-free, nanometer-thick MoS₂ monolayer can serve as the active layer for non-impacting nano-electro-mechanical switches.