Nitride-Based LEDs With a Hybrid Al Mirror $+ {\hbox {TiO}} _{2} /{\hbox {SiO}}_{2}$ DBR Backside Reflector

Abstract

Nitride-based light-emitting diodes (LEDs) with a hybrid backside reflector combining a TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> distributed Bragg reflector (DBR) and an Al mirror were proposed and realized. It was found that we can significantly enhance the 35% reflectivity of the 2-pair TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> DBR to 94% by combining with Al mirror (hybrid reflector). Furthermore, reflectivity of the proposed reflector depends only slightly on incident light wavelength and the incident angle. With 350-mA current injection, it was found that the output powers were 145.7, 178.2, and 201.9 mW for the LEDs with 2-pair DBR, with an Al mirror and with a hybrid reflector, respectively, when packaged in TO-cups. It was also found that reliability for the LED with the hybrid reflector is good.