High efficiency green LEDs using II-VI color converters

摘要

II-VI semiconductors can exhibit strong photoluminescence throughout the visible spectrum and are excellent candidates for filling the so-called "green gap". We report on the performance of green color-converted LEDs fabricated by bonding CdMgZnSe multiple quantum well structures to high-efficiency blue-emitting GalnN LEDs. A device efficacy of 181 lm/W at 537 nm (dominant) is measured under room temperature, 350 mA/mm~2 quasi-cw conditions, more than twice as efficient as typical commercial green LEDs today. The thermal roll-off is shown to be comparable to that of typical green GalnN LEDs. Finally, the implications of the availability of high-efficiency, narrow-band, green and yellow emitters in display applications will be discussed.