| Abstract: | This work reports the fabrication of via-thin-film light-emitting diode (via-TF-LED) to improve the light output power (LOP) of blue/white GaN-based LEDs grown on Si (111) substrates.The as-fabricated via-TF-LEDs were featured with a roughened n-GaN surface and the p-GaN surface bonded to a wafer carrier with a silver-based reflective electrode,together with an array of embedded n-type via pillar metal contact from the p-GaN surface etched through the multiple-quantum-wells (MQWs) into the n-GaN layer.When operated at 350 mA,the via-TF-LED gave an enhanced blue LOP by 7.8％ and over 3.5 times as compared to the vertical thin-film LED (TF-LED) and the conventional lateral structure LED (LS-LED).After covering with yellow phosphor that converts some blue photons into yellow light,the via-TF-LED emitted an enhanced white luminous flux by 13.5％ and over 5 times,as compared with the white TF-LED and the white LS-LED,respectively.The significant LOP improvement of the via-TF-LED was attributed to the elimination of light absorption by the Si (111) epitaxial substrate and the finger-like n-electrodes on the roughened emitting surface. |
