Improving Optical Properties of White LED Fabricated by a Blue LED Chip with Yellow/Red Phosphors

White light-emitting diodes (LEDs) were fabricated by associating an InGaN-based blue LED chip with highly luminescent phosphors, (YAG:Ce) and . The thermal stability of these phosphors, depending weakly on the composition and the activator concentration, remains high over a wide range of temperatures . When a mixture of YAG:Ce and was coated on a blue LED, the resultant white LED had a high luminous efficiency of , a high color rendering index of , and a color temperature of (at 50 mA). Additionally, the color coordinates, Ra and , of the white LED tend to remain constant against an appreciable variation in applied current.