Wafer-Scale Monolithic Integration of Blue Micro-Light-Emitting Diodes and Green/Red Quantum Dots for Full-Color Displays

We demonstrated a simple method for achieving green and red colors by patterning quantum dots (QDs) on GaN-based blue micro-light-emitting diodes (mu LEDs) using standard photolithography and dry etching process. The QDs could be patterned as small as 2 mu m in size on a 4-inch wafer, revealing the ultra-high resolution and throughput capability of this method. The individual color converted green and red mu LEDs in a size of 10 mu m x 10 mu m exhibited a peak external quantum efficiency (EQE) of 9.6% and 14.7%, respectively. We also achieved the monolithic integration of red, green, and blue (RGB) mu LEDs as a single pixel by sequentially patterning red and green QDs. The color gamut of the RGB mu LEDs covered 83.4% of the Rec. 2020 color space in the CIE 1931 diagram. This method is very effective for patterning color-converted QDs with down to 2 mu m-size-resolution and achieving high performance for red/green mu LEDs, while enabling scalable fabrication of full color mu LED displays.

Automated summary

We have developed a simple method for producing green and red colors on GaN-based blue micro-light-emitting diodes (mu LEDs) by patterning quantum dots (QDs) using standard photolithography and dry etching. The fabricated QDs exhibited ultra-high resolution and throughput, with a minimum size of 2 μm on a 4-inch wafer. The individual color converted green and red mu LEDs achieved a peak external quantum efficiency (EQE) of 9.6% and 14.7%, respectively. We further demonstrated the monolithic integration of red, green, and blue (RGB) mu LEDs as a single pixel by sequentially patterning red and green QDs. The resulting RGB mu LEDs covered 83.4% of the Rec. 2020 color space in the CIE 1931 diagram. This method enables high-performance red/green mu LEDs with small feature sizes and scalable fabrication of full-color mu LED displays.