Van der Waals integrated single-junction light-emitting diodes exceeding 10% quantum efficiency at room temperature.

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Miniaturized light-emitting diodes (LEDs) are crucial for on-chip optoelectronics.
• Achieving high external quantum efficiency (EQE) in room-temperature LEDs remains a significant challenge.

Purpose of the Study:

• To demonstrate high-performance microsized LEDs using layered Ruddlesden-Popper perovskites (RPPs).
• To investigate the potential of van der Waals (vdW) integration for fabricating efficient optoelectronic devices.

Main Methods:

• Fabrication of microsized LEDs using a dry-transfer vdW integration method.
• Utilizing single-crystalline layered RPP nanoflakes as the active layer sandwiched between few-layer graphene contacts.
• Characterization of electroluminescence (EL) properties, including turn-on current density and EQE.

Main Results:

• Demonstrated van der Waals LEDs (vdWLEDs) with strong electroluminescence (EL) emission at room temperature.
• Achieved a low turn-on current density of approximately 20 pA μm⁻².
• Obtained a high external quantum efficiency (EQE) exceeding 10%, setting a new benchmark for vdWLEDs.

Conclusions:

• The developed vdWLEDs exhibit high performance due to RPPs' unique properties and efficient charge injection via Fowler-Nordheim tunneling.
• This work presents a scalable pathway for creating high-performance miniaturized light sources for on-chip optical applications.