High-efficiency InGaN red micro-LEDs for visible light communication

Abstract

In this study, we present a high-efficiency InGaN red micro-LED fabricated by the incorporation of superlattice structure, atomic layer deposition passivation, and a distributed Bragg reflector, exhibiting maximum external quantum efficiency of 5.02% with a low efficiency droop corresponding to an injection current density of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m1"> <mml:mrow> <mml:mn>112</mml:mn> <mml:mtext> </mml:mtext> <mml:msup> <mml:mrow> <mml:mi mathvariant="normal">A</mml:mi> <mml:mo>/</mml:mo> <mml:mi>cm</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> . The fast carrier dynamics in the InGaN is characterized by using time-resolved photoluminescence, which is correlated to a high modulation bandwidth of 271 MHz achieved by a <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m2"> <mml:mrow> <mml:mn>6</mml:mn> <mml:mo form="postfix">×</mml:mo> </mml:mrow> </mml:math> 25-μm-sized micro-LED array with a data transmission rate of 350 Mbit/s at a high injection current density of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m3"> <mml:mrow> <mml:mn>2000</mml:mn> <mml:mtext> </mml:mtext> <mml:msup> <mml:mrow> <mml:mi mathvariant="normal">A</mml:mi> <mml:mo>/</mml:mo> <mml:mi>cm</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> . It holds great promise for full-color micro-displays as well as high-speed visible light communication applications based on monolithic InGaN micro-LED technologies.