A Waveguide-Integrated Two-Dimensional Light-Emitting Diode Based on p-Type WSe₂/n-Type CdS Nanoribbon Heterojunction

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Two-dimensional (2D) materials like transition metal dichalcogenides (TMDs) are promising for nanoscale light sources.
• Current TMD light-emitting devices (LEDs) require external waveguides for effective light management.
• Integrating TMDs with photonic nanostructures is key for compact and highly integrated 2D optoelectronic chips.

Purpose of the Study:

• To create a room-temperature waveguide-integrated light-emitting device.
• To demonstrate efficient optical routing and confinement using integrated nanostructures.
• To explore the potential for 2D optoelectronic circuits with reduced footprint.

Main Methods:

• Fabrication of a heterojunction diode using p-type monolayer tungsten diselenide (ML WSe2) and n-type cadmium sulfide (CdS) nanoribbon (NR).
• Characterization of the device's electrical rectification and electroluminescence (EL) properties.
• Analysis of EL intensity dependence on driving current to understand carrier injection mechanisms.

Main Results:

• The hybrid LED showed clear rectification and pronounced electroluminescence at 1.65 eV from ML WSe2.
• A superlinear EL intensity profile at high currents indicated facilitated carrier injection via intervalley scattering.
• Efficient coupling and routing of WSe2 EL were achieved using CdS NR waveguides.

Conclusions:

• Waveguide-integrated LEDs based on WSe2/CdS heterojunctions enable efficient light management.
• This approach facilitates carrier injection and light routing for 2D optoelectronic applications.
• These devices serve as dual-role modules for advanced TMD-based optoelectronic circuitries.