Activation of P-Type Layers of Tunnel Junctions in Micro-LEDs

Researchers at the University of California, Santa Barbara have created a novel method for fabricating micro-LEDs with low forward voltage tunnel junctions enabling improved performance and integration of multicolor displays. This approach fabricates III-nitride μLEDs incorporating an epitaxial tunnel junction made of p+GaN, InxAlyGazN insertion layers, and n+GaN layers grown by MOCVD. The InxAlyGazN insertion layers possess a smaller bandgap than GaN, reducing depletion width and increasing tunneling probability, which leads to low and stable forward voltages across device sizes ranging from 25 to 10,000 μm². The approach also includes chemical treatment between growth steps to activate the p-type layer despite previously limiting hydrogen compensation challenges. These advancements enable better current spreading, simplified fabrication, higher output power, and facilitate cascaded integration of μLEDs emitting blue, green, and red light in a single device.

• Next-generation micro-LED displays, including near-eye and head-up displays
• High-brightness, low-power display panels for wearable and augmented reality devices
• Multicolor display integration in compact micro-scale lighting systems
• Advanced lighting applications requiring efficient, small-area light sources
• Commercial and industrial LED lighting solutions benefiting from improved device efficiency