Mechanical Stress Modulation of Resistance in MoS<sub>2</sub> Junctions.

Chaudhary, Pradeep; Lu, Haidong; Loes, Michael; Lipatov, Alexey; Sinitskii, Alexander; Gruverman, Alexei · Nano Lett · 2022

basic_science · Level V

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Abstract

Strain engineering is a powerful strategy to control the physical properties of material-enabling devices with enhanced functionality and improved performance. Here, we investigate a modulation of the transport behavior of the two-dimensional MoS<sub>2</sub> junctions under the mechanical stress induced by a tip of an atomic force microscope (AFM). We show that the junction resistance can be reversibly tuned by up to 4 orders of magnitude by altering a tip-induced force. Analysis of the stress-induced evolution of the <i>I</i>-<i>V</i> characteristics indicates a combined effect of the tip-induced strain and strain gradient on the energy barrier height and profile. In addition, we show that the tip-generated flexoelectric effect leads to significant enhancement of the photovoltaic effect in the MoS<sub>2</sub> junctions. A combination of the optical and mechanical stimuli facilitates reversible photomechanical tuning of resistance of the narrow-band 2D semiconductors and development of devices with an enhanced photovoltaic response.