A 64 × 64 GaN Micro LED Monolithic Display Array: Fabrication and Light Crosstalk Analysis

Area of Science:

• Optoelectronics
• Materials Science
• Nanotechnology

Background:

• Monolithic micro LED display arrays are promising for augmented reality (AR) devices.
• Optical crosstalk between adjacent micro LEDs reduces display definition due to short pixel distances.
• Existing micro LED fabrication methods require optimization to mitigate crosstalk.

Purpose of the Study:

• To fabricate a monolithic 64x64 Gallium Nitride (GaN) micro LED display array.
• To suppress optical crosstalk between adjacent micro LEDs.
• To enhance the display definition of micro LED arrays.

Main Methods:

• Fabrication of a 64x64 GaN micro LED array on a silicon-based drive circuit (20 μm x 20 μm pixels, 28 μm pitch).
• Etching of a photonic crystal structure on the micro LED sapphire substrate using focused ion beam (FIB).
• Analysis using near-field electroluminescence (EL) measurements and finite element method (FEM) calculations.

Main Results:

• Successfully fabricated a monolithic GaN micro LED display array.
• Demonstrated effective suppression of optical crosstalk using etched photonic crystals.
• Confirmed light expansion confinement within the photonic crystal micro LEDs with thinner substrates via EL and FEM.

Conclusions:

• Photonic crystal structures effectively control optical crosstalk in monolithic micro LED arrays.
• The developed fabrication technique offers a viable solution for high-definition micro LED displays.
• This work provides valuable insights for future micro LED display advancements, particularly for AR applications.