Abstract

LEDs emitting white light either employ phosphor to down covert a high energy photon to low energy or use the colour mixing (i.e. RGB or RYGB) approach. A monolithic approach employs colour mixing by emission of photons of different energies (in the visible range), typically blue and yellow/green, from different quantum wells in the same device [1]. The white emission from these state-of-the-art devices can find application in general lightning only with improved quantum efficiency, colour rendering index (CRI) and correlated colour temperature (CCT) [2]. For achieving high CRI broad emission linewidth is suitable [2]. Broadened di-chromatic white LEDs usually demonstrate CRI in the range of 10-60 [3]. In this work we report on CRI as high as 67 achieved at the typical operation current of 350 mA.

© 2015 IEEE