Abstract: A light emitting diode (LED) is added aluminum atom in every layer of InGaN light emitting diode to emit a UV light with wavelength between 300 nm and 380 nm which is not able to see by humans. This LED can co-operate with different colors of luminescent material layer or quantum well/quantum dot structures to emit different color (wavelength) of light, which are different colors (wavelengths) of LED.

Abstract: A quantum dot/quantum well light emitting diode (LED) is provided with a LED at one side of a substrate, and a second light emitting layer and a third light emitting layer at the other side of the substrate. When a proper forward bias is applied to the LED to emit a first light by the first light emitting layer, the first light is used to excite the second light emitting layer and the third light emitting layer to generate the second light output and the third light output of different colors respectively. Then, the light output of a desired color can be generated by mixing the first light, the second light and the third light.