Micro-light-emitting-diode array with dual functions of visible light communication and illumination**Project supported by the Science and Technology Program Project for the Innovation of Forefront and Key Technology of Guangdong Province, China (Grant Nos. 2014B010119004, 2014B010121001, and 2013B010204065), the Institute of Science and Technology Collaborative Innovation Major Project of Guangzhou City, Guangdong Province, China (Grant No. 201604010047), the Special Project for

Abstract

We demonstrate high-speed blue 4 × 4 micro-light-emitting-diode (LED) arrays with 14 light-emitting units (two light-emitting units are used as the positive and negative electrodes for power supply, respectively) comprising multiple quantum wells formed of GaN epitaxial layers grown on a sapphire substrate, and experimentally test their applicability for being used as VLC transmitters and illuminations. The micro-LED arrays provide a maximum −3-dB frequency response of 60.5 MHz with a smooth frequency curve from 1 MHz to 500 MHz for an optical output power of 165 mW at an injection current of 30 mA, which, to our knowledge, is the highest response frequency ever reported for blue GaN-based LEDs operating at that level of optical output power. The relationship between the frequency and size of the device single pixel diameter reveals the relationship between the response frequency and diffusion capacitance of the device.