Growth and characterization of phosphor-free white light-emitting diodes based on InGaN blue quantum wells and green–yellow quantum dots

• We reported phosphor-free white light-emitting diodes based on InGaN blue quantum wells and green–yellow quantum dots.
• The InGaN quantum wells and quantum dots were observed by TEM.
• The electroluminescence was studied under different injection currents and different temperature.
• The current dependency of electroluminescence spectrum was explained.

Phosphor-free white light-emitting diodes consisting of 4 layers of InGaN/GaN quantum dots and 4 layers of quantum wells have been grown by metal organic chemical vapor deposition. A white emission was demonstrated under electrical injection by mixing the green–yellow light from quantum dots and the blue light from quantum wells. At the injection current of 5 mA, the electroluminescence peak wavelengths of quantum dots and quantum wells were 548 nm and 450 nm, respectively, resulting in the color-rendering index Ra of 62. As the injection current increased, a faster emission enhancement of quantum well and an emission blue shift of the quantum dots were observed, which led to the decrease of Ra.