Dose-Insensitive Defect Engineering, Carrier Kinetics, and Reproducible Chromaticity Tuning in Ion-Implanted InGaN/GaN Quantum Wells
Post-growth defect engineering via ion implantation provides a powerful pathway for spatial optical profiling and colour patterning in III-V alloying photonic integration. However, the comprehensive recombination kinetics governing deep-level defect saturation and excitonic recovery under high-temperature annealing remain insufficiently understood. Here, we present a systematic study on the optical dynamics, rate-equation kinetics, and chromaticity evolution of indium-implanted InGaN/GaN multiple quantum wells (MQWs) across implantation doses (5E14 to 5E16 ions cm^-2) and subsequent thermal annealing stages (500 to 1100 deg C). Photoluminescence (PL) spectrum analysis reveals that a dose of <= 5E14 ions cm^-2 induces a modification of the optical response that does not further change upon high-dose implantation. A two-channel coupled rate-equation model is fitted to the data, optimised via differential evolution, allowing the extraction of transition rate constants. This demonstrates that thermal processing at 1000 deg C suppresses the carrier capture rate into deep-level states and also reduces its radiative recombination rate. This kinetic bottleneck drives an order-of-magnitude extension in the channel-specific radiative lifetime. Leveraging the excitation power density dependence of the differential recombination kinetics, where deep defects saturate whilst MQW emission scales near-linearly, we achieve a universal and power density-tunable chromaticity trajectory from warm yellow to cool white-blue emission. These insights enable microscopic defect physics to be linked to the macro-scale colour tailoring observed.