High-speed AlGaInP micro-resonant-cavity LED arrays enabled by materials and structural engineering

This study investigates the process optimization and array miniaturization of AlGaInP micro-resonant-cavity light-emitting diodes (μ-RCLEDs) for high-speed visible light communication (VLC). N-GaAs thinning, Al 2 O 3 sidewall passivation, and Nb 2 O 5 /SiO 2 distributed Bragg reflector (DBR) design were systematically optimized, followed by fabrication of 1×1, 2×2, 5×5, and 10×10 parallel arrays with a constant total emitting area of approximately 7850 μm 2 . A 150 nm N-GaAs layer was selected by balancing electrical transport and optical performance, providing 86% increases in both light output power (LOP) and external quantum efficiency (EQE) and a 129% increase in electroluminescence peak intensity at 2 mA relative to the 870 nm reference. A 25 nm Al 2 O 3 layer reduced the reverse leakage current at −5 V to 2.51 × 10 −11 A, while a 4-pair Nb 2 O 5 /SiO 2 DBR increased both LOP and EQE by 20% relative to the 3-pair structure. Using these optimized conditions, increasing the array from 1×1 to 10×10 reduced the turn-on voltage by 26% and increased both LOP and EQE by 39%, reaching 0.534 mW and 13.44% at 2 mA. The full divergence angle decreased from 123° without the DBR to 71° with the 4-pair DBR and remained at 75° for the 10×10 array. The 10×10 array achieved −3 dB bandwidths of 128, 133, and 143 MHz at 1, 3, and 5 mA, corresponding to improvements of 19.63%, 3.10%, and 3.62% over the 1×1 array. These results demonstrate the potential of optimized miniaturized AlGaInP μ-RCLED arrays for high-speed VLC and high-density optoelectronic integration.