Hybrid tunnel junction enabled independent junction control of cascaded InGaN blue/green micro-light-emitting diodes

We demonstrate vertical integration of nitride-based blue/green micro-light-emitting diodes (mu LEDs) stacks with independent junctions control using hybrid tunnel junction (TJ). The hybrid TJ was gown by metal organic chemical vapor deposition (p + GaN) and molecular-beam epitaxy (n + GaN). Uniform blue, green and blue/green emission can be generated from different junction diodes. The peak external quantum efficiency (EQE) of the TJ blue mu LEDs and green mu LEDs with indium tin oxide contact is 30% and 12%, respectively. The carrier transportation between different junction diodes was discussed. This work suggests a promising approach for vertical mu LEDs integration to enhance the output power of single LEDs chip and monolithic mu LEDs with different emission colors with independent junction control.