Recent Advances in III-Nitrides for High Efficiency 1 to 10 micron scale MicroLED Devices

The developments of high performance InGaN based RGB micro-light-emitting diodes (µLEDs) are discussed. Through novel epitaxial growth and processing, and transparent packaging we have achieved external quantum efficiencies as high as 58% EQE at blue wavelengths (450nm) and 21% for green (520nm) for microLEDs. The critical challenges of µLEDs, namely full-color scheme, decreasing pixel size and mass transfer technique, and their potential solutions are explored. Recently, we have demonstrated efficient microLEDs emitting in the blue to red at dimensions as small of 1 micron. Using metalorganic chemical vapor deposition (MOCVD) and strain relaxation methods we have also extending the wavelength range of the InGaN alloys as into the red with emission as long as 640nm. Red InGaN based red MicroLEDs with efficiencies of 6% has been fabricated, and they display superior temperature performance in comparison to AlGaInP based devices. Recently, we have employed tunnel junction technology to vertically stack blue and green MicroLEDs monolithically on the same wafer. Independent control of the BG colors with high efficiency is demonstrated with tunnel junctions. This work was supported by the Solid State Lighting and Energy Electronics Center(SSLEEC) at UC Santa Barbara.