Toward high-bandwidth yellow-green micro-LEDs utilizing nanoporous distributed Bragg reflectors for visible light communication

Abstract

In this study, high <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m1"> <mml:mrow> <mml:mo form="prefix">−</mml:mo> <mml:mn>3</mml:mn> <mml:mtext> </mml:mtext> <mml:mi>dB</mml:mi> </mml:mrow> </mml:math> bandwidth yellow-green InGaN/GaN micro-LEDs grown on polar c-plane GaN substrates are realized by using nanoporous distributed Bragg reflectors, which can increase light extraction efficiency and serve as strain-relaxed buffers to mitigate the quantum-confined Stark effect, resulting in improved external quantum efficiency. Moreover, atomic layer deposition technology is introduced for surface defect passivation, thereby reducing the leakage current. As a result, the device exhibits the highest <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m2"> <mml:mrow> <mml:mo form="prefix">−</mml:mo> <mml:mn>3</mml:mn> <mml:mtext> </mml:mtext> <mml:mi>dB</mml:mi> </mml:mrow> </mml:math> bandwidth up to 442 MHz and a data transmission rate of 800 Mbit/s at a current density of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m3"> <mml:mrow> <mml:mn>2.5</mml:mn> <mml:mtext> </mml:mtext> <mml:mi>kA</mml:mi> <mml:mo>/</mml:mo> <mml:msup> <mml:mrow> <mml:mi>cm</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> with on–off keying modulation, and holds great promise for future high-speed visible light communication applications.