Figure 5. Thickness-dependent current rectification of vertical MoS₂ p–n junctions.

(a) Energy band diagrams of the devices prepared with vertical p–n junctions of various MoS₂ thicknesses. The MoS₂ band gap was equal to 1.2 eV for the few-layer structure and 1.8 eV for the monolayer. (b–e) Output characteristics of the p–n MoS₂ FETs with layer numbers of 18, 7, 4 and 1. The red and blue backgrounds indicate the current-on and current-off states, respectively. (f–i) The corresponding Fowler–Nordheim plots of the vertical MoS₂ p–n junctions with layer numbers of 18, 7, 4 and 1. The red line denotes the linear fit to the FNT currents.