Fig.1

a) Photograph of the device assembled with a WS2 monolayer and a 30 μm electrode, the white dotted frame indicates the WS2 monolayer; b) Schematic cross-sectional view of the measurement area of the device, the electric field distributions are simulated using Comsol Multiphysics software; Pictured here are cross-sectional electric field distributions and partial magnified views of a pair of c) 30 μm and d) 10 μm electrodes before and after attaching a monolayer "

Fig.2

a) PL of monolayer at A with bias; b) Scatter plot of peak position at A with bias; c) PL of monolayer at B with bias; and d) Scatter plot of peak position at B with bias. The arrow indicates the direction of the bias change from –30 V to 30 V "

Fig.3

a) Photograph of the device assembled with a WS2 monolayer and a 10 μm electrode; the white dotted frame indicates the WS2 monolayer; b) The exciton peak intensity varies with the bias; ① has a decreasing trend (blue bar), ② has an increasing trend (red bar), and ③ has a no single change trend (purple bar) "

Fig.4

At a temperature of 10 K: a) PL of monolayer at C with bias; b) Scatter plot of peak position at C with bias; c) PL of monolayer at D with bias; and d) Scatter plot of peak position at D with bias. The arrow indicates the direction of the bias change from –30 V to 30 V "