High-bandwidth InGaN self-powered detector arrays toward MIMO visible light communication based on micro-LED arrays

摘要： This work reports the use of the chip-based GaN-based micro-LED (μLED) arrays for multifunctional applications as micro-display, data transmitters, photodetectors and solar cells. The functions of display and transmitter have been reported, and particularly we experimentally demonstrated that μLED arrays could be used as self-powered, high-performance and wavelength-selective photodetectors (PDs) enabling high-speed multiple-input multiple-output (MIMO) visible light communications (VLC) under on-off keying (OOK) modulation scheme using 405 nm violet laser diodes (LDs) as transmitters. The optoelectronic and communication characteristics of the μLED-based PDs with diameters of 40 μm, 60 μm and 100 μm were systematically studied. The optoelectronic analysis shows superior performances of μLED-based PDs at 405 nm wavelength compared with other previously reported GaN-based PDs. Under a bias voltage of -5 V, the comparable peak responsivities of 0.27, 0.31 and 0.24 A/W, specific detectivities of 1.1 × 1011, 2.3 × 1012 and 2.1 × 1012 cm ? H1/2 ? W-1, and linear dynamic ranges (LDRs) of 152, 162 and 164 dB were achieved for 40-μm, 60-μm and 100-μm μLEDs, respectively. Even at zero-bias, i.e. self-powered mode, we have achieved high peak responsivities of 0.24, 0.29 and 0.21 A/W, high specific detectivities of 7.5 × 1012, 1.5 × 1013 and 1.3 × 1013 cm?H1/2?W-1 and high LDR up to 186, 196 and 197 dB for 40-μm, 60-μm and 100-μm μLEDs, respectively. The μLEDs could also be used to harvest the optical energy of the system, working as solar cells. The μLED-based PD arrays were tested as receivers in VLC system to implement high-speed parallel communication, which yields maximum data rates of 180 Mbps, 175 Mbps and 185 Mbps for a single 40-μm, 60-μm and 100-μm μLED-based PDs at a distance of 1 m with BERs of 3.5 × 10-3, 3.7 × 10-3 and 3.5 × 10-3, respectively. Furthermore, 2 × 2 MIMO parallel VLC system was achieved to increase the VLC data rate, which suggests the potential of using large μLED-based PD arrays for multiple Gbps and even Tbps VLC applications.