High-power high-efficiency green LEDs

Abstract

High-power green LEDs in mass-production is reaching a new WPE (wall-plug-efficiency) level of 35%, and this progress results from both band- and strain-engineering in the active multiple-quantum-well region and optimal p- and n-electrodes layout for uniform current spreading. For high-power green LEDs of chip size 45 mil×45 mil (4545 chips), the forward voltage at 350 mA is as low as 2.8 V, with emitting power of 345 mW and emitting flux of 152 lumen at a dominant wavelength of 525 nm. These data translate into an external quantum efficiency of 41.7% and a luminous efficacy of 153 lm/W, with peak luminous efficacy over 280lm/W. It is envisioned that these high-power high-efficiency green LEDs will open up new market applications such as high-end healthy-lighting and mitigate the so-called “green-gap” for another level of the solid-state general lighting.