Visible light communication (VLC) has emerged as a promising communication method in 6G. However, the development of receiving devices is much slower than that of transmitting devices, limited by materials, structures, and fabrication. In this paper, we propose and fabricate an InGaN/GaN multiple-quantum-well-based vertical-structure micro-LED-based photodetector (μPD) on a Si substrate. A comprehensive comparison of the photoelectrical performance and communication performance of three sizes of μPDs, 10, 50, and 100 μm, is presented. The peak responsivity of all three μPDs is achieved at 400 nm, while the passband full-widths at half maxima are 87, 72, and 78 nm for 10, 50, and 100 μm μPDs, respectively. The − 20 dB cutoff bandwidth is up to 822 MHz for 50 μm μPD. A data rate of 10.14 Gbps is experimentally demonstrated by bit and power loading discrete multitone modulation and the proposed digital pre-equalizer algorithm over 1 m free space utilizing the self-designed 4 × 4 50 μm μPD array as a receiver and a 450 nm laser diode as a transmitter. This is the first time a more than 10 Gbps VLC system has been achieved utilizing a GaN-based micro-PD, to the best of our knowledge. The investigation fully demonstrates the superiority of Si substrates and vertical structures in InGaN/GaN μPDs and shows its great potential for high-speed VLC links beyond 10 Gbps.

In this letter, we report a monolithically photonic integrated device based on the configuration of an InGaN/GaN micro-light-emitting diode ( $\mu $ LED) in series with an AlGaN/GaN high-electron-mobility transistor (HEMT). As an ultraviolet phototransistor, the HEMT unit can act as both the optical and the electrical input ports of this integrated device. When the device is used as a transmitter, a 3-dB modulation bandwidth of approximate 300 MHz can be obtained. When the device is used as a receiver, a response time of < 10 ms and a responsivity of ~10 ⁷ A/W was demonstrated under 365 nm ultraviolet light. In addition, the received ultraviolet light signal can be converted into a higher-intensity visible light signal and emitted through the $\mu $ LED. The proposed monolithically integrated device shows great potential for on-chip optical interconnection and communication.