Ni–Cu Nanoparticles-Embedded Ag-Based Reflector for High-Efficiency Light-Emitting Diodes

Abstract

<jats:p>We investigated the use of a silver reflector embedded with Ni–Cu nanoparticles to achieve low resistance and high reflectivity in GaN-based flip-chip light-emitting diodes. Compared to a single layer of Ag, the NC-NPs/Ag reflector exhibits a higher light reflectance of ~90% at a wavelength of 450 nm, a lower contact resistance of 4.75 × 10<jats:sup>−5</jats:sup> II cm<jats:sup>2</jats:sup>, and improved thermal stability after annealing at 400°C. The NC-NPs formed after the annealing process prevents agglomeration of the Ag layer, while also reducing the Schottky barrier height between the <jats:italic>p</jats:italic>-GaN layer and metal reflector. The LED fabricated with a NC-NPs/Ag reflector exhibited a forward-bias voltage of 3.13 V and an improvement in light output power of 36.6% (at 20 mA), when compared with the LED composed of a Ag SL. This result indicates that the NC-NPs/Ag reflector is a promising <jats:italic>p</jats:italic>-type reflector for high-intensity light-emitting diodes.</jats:p>

Enhanced Light Output Power on Near-Infrared Light-Emitting Diodes with TITO/Ag Multilayer Reflector

“…However, the easy thermal oxidation and thermal agglomeration of Ag single reflectors caused serious operational instability problems of LEDs. Therefore, some researchers have proposed a single reflector consisting of silver-based metal alloys with superior reflectivity and better thermal durability, such as AgCu, ITO/Ag (indium-doped SnO 2 ) and AgIn, as new reflector candidates [ 9 , 10 , 11 ]. Meanwhile, some groups suggested a multilayer reflective structure for transparent insulator/Ag forms, such as Si 3 N 4 and SiO 2 , which can improve reflectance performance by engineering optical transport paths [ 12 ].…”