Atomically thin p–n junctions based on two-dimensional materials

The two-dimensional (2D) transition metal dichalcogenide (TMD) family has the potential to be used as an active material for the next-generation p-n junction (opto-) electronics devices because of its fascinating electronic, optical, and physical properties. The main obstacle is the lack of homogenously p- and n-type doped 2D-TMD due to the doping challenge during growth. Beyond the conventional doping techniques during growth, several approaches have been employed to achieve p- and n-type 2D-TMDs. In this study, n- and p-type WS2 and WSe2 based p-n junction diodes were fabricated, and the effect of traditional doping and post-growth doping (dichloroethane and ultraviolet ozone for n- and p- type, respectively) on the diode parameters and emission profile of the devices were investigated. It has been observed superior emission properties in the conventionally doped 2D-TMDs-based junctions, while the post-growth doped materials-based p-n junctions exhibit better diode characteristics in terms of electrical properties