High-Speed Parallel Micro-LED Arrays on Si Substrates Based on Via-Holes Structure for Visible Light Communication
Huaqing Chai, Shunan Yao, Lei Lei, Zihe Zhu, Guoqiang Li, Wenliang Wang
Abstract
In this work, the parallel micro-light-emitting diode ( <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> LED) arrays based on via-holes structure with various array numbers from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1\times 1$ </tex-math></inline-formula> to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$6\times 6$ </tex-math></inline-formula> are proposed. The photoelectric characteristics and frequency response characteristics of the <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> LED arrays under different array numbers are analyzed. The experiment and analysis results show that the −3 dB bandwidth of parallel <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> LED arrays based on via-holes structure improves as the number of arrays increases, and this result is attributed to the decrease in device RC time constant. However, the maximum withstand current density 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> LED arrays decreases as the number of arrays increases, and the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1\times 1\,\,\mu $ </tex-math></inline-formula> LED array achieves an extremely high withstand current density of 15.82 kA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . Among all the arrays, the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3\times 3\,\,\mu $ </tex-math></inline-formula> LED array can reach the highest −3 dB bandwidth of 606 MHz at 7.91 kA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> under the combined effect of withstand current density and array numbers. Meanwhile, the light output power for <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3\times 3\,\,\mu $ </tex-math></inline-formula> LED array is above 15.0 mW. This work sheds light on preparation of high-performance LEDs for visible light communication.