Full-color monolithic InGaN micro-LEDs through tunnel junctions with true red emission

Full-color monolithic InGaN micro-LEDs can achieve the transfer of full-color subpixels through a single flip-chip bonding process, offering advantages such as simplified fabrication processes and reduced production costs for micro-LED display. In this paper, we demonstrate a structure that utilizes a pseudo-quantum well to achieve long-wavelength red emission, which is applied to full-color monolithic InGaN micro-LEDs. Subsequently, we present the full-color monolithic InGaN micro-LEDs, which stack red (R), green (G), and blue (B) epitaxial layers through tunnel junctions. The entire structure is grown epitaxially by metal organic chemical vapor deposition. Micro-LEDs with a mesa size of 20×20 μm² for RGB are fabricated. The red micro-LED exhibits emission with a peak wavelength of 650 nm at an injection current density of 1 A/cm², with a dominant wavelength of approximately 620 nm, achieving a true red emission. Even under an injection of 100 A/cm², it can still maintain a dominant wavelength of over 600 nm. The true red emission and broad color gamut coverage of the full-color monolithic InGaN micro-LEDs demonstrate their significant potential for applications in micro-LED display.