Abstract
The absorption and color conversion characteristics of nanophosphor-coupled nanoporous layers in III-nitride micro-light emitting diodes (micro-LED) arrays have been numerically analyzed along with their impacts on the application of micro-LED matrices in colorful display panels. Nanoporous gallium nitride (GaN) layers in the micro-LED pixels have been reported to function as the color-converting element by incorporating quantum dot-based nanophosphors inside the porous cavity, which absorbs the blue output from the underlying emissive quantum wells and then re-emits in red and green spectra. While this color conversion scheme was proposed as a promising venue of implementing full-color micro-LED displays, our computational study reveals that there remain some key challenges to be addressed down the road: the extraction efficiencies of both excitation (blue) and down-conversion (red) light from the nanophosphor-coupled LED structure have been shown to decrease dramatically with increasing porosity and thickness of the porous down-conversion layer beyond certain thresholds. Additionally, it is found from the simulation that the cross-talk of down-conversion light between adjacent micro-LED pixels is substantially higher compared to the excitation light cross-talk due to the location of the phosphors in the pore cavities and the resultant strong scattering by the surrounding nanopores. Studying and attempting to overcome those color-conversion challenges of the nanoporous GaN-based micro-LEDs could pave the way for developing full-color micro-LED display panels that simultaneously preserve the high-resolution and efficiency performances of micro-LED display devices.