氮化镓基蓝光LED具有量子效率高和水下光功率衰减低等优点，有望应用于高速水下无线光通信。但目前用于照明的蓝光LED的光电调制带宽仅为几MHz，LED的调制带宽低并且相关机理尚未被阐明是制约LED水下通信速率的瓶颈问题。本项目提出使用新型氮化镓基蓝光micro-LED阵列器件进行水下通信并分析其调制带宽机理，micro-LED的典型尺寸为40微米，不仅调制带宽可达几百MHz，阵列器件还具备并行通信的前景。我们将重点研究综合解释调制带宽和量子效率变化机理的载流子复合模型，研究micro-LED和封装电路的高频电容对调制带宽的影响，研究信号调制电压和量子阱自发/压电极化电场影响调制带宽的机理；通过分析micro-LED在水下通信中的数据传输特性，为优化micro-LED调制带宽等特性提供反馈和指导。相关研究调制带宽机理的成果有望为发展高带宽LED技术、高速水下通信技术和深海探测技术打下基础。

GaN-based blue LEDs have advantages of high quantum efficiency and low underwater attenuation of light output power, enabling their potential application in high-speed underwater optical wireless communication (UOWC). However, currently the electrical-to-optical modulation bandwidth of blue LEDs for general lighting is only several MHz, and the low bandwidth and unclear related mechanisms limit the data communication speed of UOWC. In this project, we propose that new-type GaN-based blue micro-LED arrays can be applied in UOWC and the related mechanisms of modulation bandwidth will be analyzed. The typical size of a micro-LED is 40μm, with bandwidth of several hundreds of MHz and potential of parallel UOWC. We will mainly investigate the carrier recombination models to explain the modulation bandwidth and quantum efficiency, the effect of high-frequency capacitance of micro-LEDs and their packages on the modulation bandwidth, and the effect of electric field caused by signal modulation and spontaneous and piezoelectric polarizations on the modulation bandwidth; through testing the data communication characteristics of UOWC, we can provide feedbacks for optimizing the characteristics of modulation bandwidth etc. We expect that the research output of this project will help the development of techniques of high-bandwidth LEDs, high-speed UOWC and deep-sea exploration.