Embedded Electrode Micro-LEDs With High Modulation Bandwidth for Visible Light Communication

Abstract

GaN-based light-emitting diodes (LEDs) are the ideal light sources for visible light communication (VLC). However, both the low modulation bandwidth (MB) and unstable lighting output power (LOP) of LEDs at high current density restrict the further development of VLC. In this work, micro-LEDs ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula> LEDs) with embedded <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${N}$ </tex-math></inline-formula> electrodes have been proposed, possessing high MB and remarkable stability. The as-prepared <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula> LEDs show a high MB of 240 MHz at 8.5 kA/cm2 and a small LOP aging rate of 6% under high temperature and humidity conditions due to the embedded electrode structure, which can effectively improve the uniformity of current spreading and increase the injection saturation current density, thereby effectively broadening the −3-dB MB and improving the LOP stability of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula> LEDs in harsh environments with high temperature and high humidity. Such high MB and reliable <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula> LEDs shed light on a promising solution for industrial fabrication and chip arrays in underwater VLC systems.