Pixel‐Engineered Deep Ultraviolet Micro‐LED Arrays for High‐Speed Optical Interconnects

ABSTRACT

Micro‐LEDs are promising transmitters for free‐space and guided optical interconnects. However, increasing pixel density within a constant emitting footprint introduces competing optical, electrical, and thermal effects that constrain link performance. Here, we investigate parallel‐connected AlGaN micro‐LED arrays with controlled pixel densities by partitioning a 400 × 400 µm ² emission region into 1, 4, 16, 64, and 256 pixels. All devices exhibit comparable turn‐on voltages with extremely low‐leakage currents, confirming that pixel subdivision does not substantially degrade junction quality. Increasing pixel density enhances light output from 2.71 mW in the single‐pixel device to 3.75 mW in the 256‐pixel array, which optical simulations attribute to shortened in‐plane photon propagation and enhanced sidewall‐assisted extraction. Thermal behavior shows a non‐monotonic dependence on pixelation, with intermediate arrays operating at lower temperatures than both structural extremes. However, increasing pixel density also raises effective capacitance and reduces the peak −3 dB bandwidth. As a result, the optimum communication performance emerges at an intermediate pixelation level, where the 16‐pixel array delivers a maximum data rate of 3.07 Gbps. Proof‐of‐concept fiber‐guided transmission up to 2 m further validates the optimized device architecture for compact guided DUV signal delivery. These results provide an effective design strategy for micro‐LED‐based high‐speed optical interconnects.