The laser lift-off (LLO) process was employed to fabricate a monochromatic GaN-based green micro-light-emitting-diode (Micro-LED) 14*14 arrays grown on pattern sapphire substrate (PSS) in this research. A new experimental phenomenon and internal mechanism of some epitaxial residues on the top and sidewalls of PSS protrusion after laser stripping were deeply discussed. In addition, the reasons for the formation of micro lattice dislocation of epitaxial layer crystal caused by laser were also analyzed. The leakage current of the chip array devices after LLO was more than 200 times higher than the device before LLO at the same voltage, but the light output current efficiency was discovered to be 109.7% higher under the 500 cd / m2 brightness. The results indicate peak wavelength was blue shift 3 nm once the LLO process had been performed. Furthermore, the optical pattern of green LED array from a "heart-shaped" distribution before LLO was changed into the maximum intensity directly above the array devices. The luminous angle was also reduced from ±75° to ± 65°, which indicates that the collimation of the light after LLO process was increased.The results are of high importance for understanding the optical properties of Micro-LED array devices after LL.

The technical challenge of realizing full-color display by monochromatic integrated 100×100 blue Micro-LED array exciting InP quantum dot color conversion layer was investigated. Using photolithography technology to prepare color film on a separate glass cover glass has the advantages of better accuracy and display resolution. The optimum thickness of the quantum dot photoresist (QDPR) was verified at 12 μm and a 10 μm black matrix was proposed to reduce the light crosstalk between different sub-pixels. The thickness of color filter 1±0.4 μm was made successfully between the QDPR and the cover glass, which can significantly increase the display color gamut from 78.7% to 100.8% NTSC. The red and green conversion efficiency reached 78.1% and 296.5%, respectively. Representative RGB monochromatic pictures with 100% high yield were displayed successfully.

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A detailed theoretical derivation and calculation method of the difference coefficient between a light distribution pattern of a 30 × 20 µ m 2 green micro-LED array and Lambert source is proposed first in this paper, to the best of our knowledge, which establishes an accurate relationship between external quantum efficiency and current efficiency (cd/A). The variation of capacitance with voltage and wavelength blueshift is illustrated by a carrier recombination mechanism. The current efficiency reaches 132.5 cd/A for the 60 × 50 µ m 2 and 121.7 cd/A for the 25 × 15 µ m 2 arrays, and the mechanism caused by size dependence is analyzed in detail combined with the classical ABC model.