High-Power High-Efficiency Green LEDs

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 x45 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.