Influence of pixel size and gap on the optoelectronic performance of micro-LED arrays for visible light communication using boron ion implantation

This study investigated the impact of pixel size and inter-pixel gap width on the optoelectronic performance of micro-LED arrays, with a particular focus on their application in visible light communication (VLC). Boron ion implantation was employed to define pixel emission areas and achieve effective channel insulation due to boron's small atomic radius and its ability to suppress electrical conductivity in implanted regions without significantly degrading the optical performance. The micro-LED arrays, with a total emitting area of 14,400 μm², incorporated pixel sizes of 5 μm, 8 μm, and 10 μm, alongside gap widths of 2 μm, 4 μm, 6 μm, and 8 μm. The experimental results demonstrated a consistent increase in light output power and external quantum efficiency (EQE) with decreasing gap widths, which is attributed to reduced leakage currents and minimized non-radiative recombination losses. The small size of boron ions allowed for precise electrical isolation between pixels without affecting emission properties, enabling accurate evaluation of size-dependent performance. In VLC applications, pixel size and gap width not only influenced light output power and EQE but also impacted bandwidth, full-width at half-maximum, and data transmission rates. The 12 × 12 array with a 10 μm pixel size achieved the best VLC performance, with a bandwidth of 171.88 MHz at a current density of 347.2 A/cm².