WS2 monolayer-based light-emitting devices in a vertical p-n architecture.

2D semiconductors represent an exciting new material class with great potential for optoelectronic devices. In particular, WS2 monolayers are promising candidates for light-emitting devices (LEDs) due to their direct band gap with efficient recombination in the red spectral range. Here, we present a novel LED architecture by embedding exfoliated WS2 monolayer flakes into a vertical p-n layout using organic p- and inorganic n-supporting layers. Laser lithography was applied to define the current path perpendicular to the WS2 flake. The devices exhibit rectifying behavior and emit room temperature electroluminescence with luminance up to 50 cd m-2 in the red spectral range.