From nanoLEDs to the realization of RGB-emitting microLEDs

MicroLED technology is expected to be the technology of choice for next-generation displays. Its advantages in various applications are reviewed. The challenges of microLED manufacturing, including red microLED realization, adequate efficiency, mass transfer, and structure and process design from a system perspective, are discussed with a special emphasis on how nano-scale material science may open new avenues toward solutions to key issues. Technical solutions to the main challenges are discussed in detail, including epitaxial growth of GaN nanowires, relaxed InGaN templates and InGaN planar red LEDs, as well as mass transfer technologies. Two primary approaches are described, one with extreme down-scaling of well-developed planar LED technology, the other where an emphasis is on the realization of nanoLEDs, on submicrometer scale, used as building blocks for all pixel sizes.