Phosphor Free High-Luminous-Efficiency White Light-Emitting Diodes Composed of InGaN Multi-Quantum Well

Abstract

We fabricated two types of high-efficiency white light-emitting diodes (LEDs) composed of an InGaN multi-quantum well (MQW), which emit light of two or three different colors without phosphors. The Type-1 white LED emits light of two colors (blue and yellow) from the MQW active layer, while the Type-2 LED emits light of three colors (blue, green and red). When the Type-1 white LED was operated at a forward current of 20 mA at room temperature, the color temperature (Tcp), average color rendering (Ra) and luminous efficiency were 7600 K, 42.7 and 11.04 lm/W, respectively. When the Type-2 white LED was operated at a forward current of 20 mA at room temperature, Tcp, Ra and luminous efficiency were 5060 K, 80.2 and 7.94 lm/W, respectively.