Size-Dependent Bifunctional Micro-LED Arrays for Visible Light Communication

Abstract

In recent years, micro-LED (µ-LED) array has attracted significant attention in the field of high-speed visible light communication (VLC), but further size optimization research is still needed to enhance communication performance. In this paper, we systematically investigate the size effects of µ-LED arrays in the duplex integration between the transmitter and photodetector (PD). By fabricating suspended thin-film blue µ-LED arrays with diameters of 20 µm, 30 µm, and 40 µm, the optoelectronic characteristics and modulation bandwidth of the three devices were characterized. The experimental results indicate that the 40 µm device exhibited the highest emission efficiency and photocurrent, while the 20 µm device achieved the highest modulation bandwidth of 13.86 MHz under an injection current of 50 mA. To investigate the size-dependent VLC performance of µ-LED array-based transmitter and PD, we employed both on-off keying and discrete multitone modulation schemes. A maximum data transmission rate of 158.8 Mbps was achieved using a 20 µm µ-LED array as the transmitter, while a 30 µm array used as the PD yielded a maximum data reception rate of 222.7 Kbps, indicating 20 µm and 30 µm as the optimal sizes for transmission and detection units, respectively. This finding not only provides device-level design guidelines for duplex VLC systems but also lays the key technological foundation for the practical implementation of full-duplex VLC through innovative device integration.