White light emitting device
A high quality white light emitting device suitable for miniaturization. The white light emitting device according to the present invention includes a substrate and a light emitting structure composed of an n-semiconductor layer, an active layer and a p-semiconductor layer. The light emission structure emits first emission light. The white light emitting device also includes a wavelength-converting film for absorbing and converting the first emission light to second emission light of another wavelength. The wavelength-converting film is made of europium-silicate.
1. A white light emitting device comprising:
a substrate;
a light emission structure comprising an n-semiconductor layer, an active layer and a p-semiconductor layer sequentially formed on the substrate, the light emission structure emitting first emission light; and
a wavelength-converting film for absorbing and converting the first emission light to second emission light of another wavelength,
wherein the wavelength-converting film comprises europium-silicate.
2. The white light emitting device according to claim 1 , wherein a portion of the first emission light is combined with the second emission light to produce white light.
3. The white light emitting device according to claim 1 , wherein each of the p-semiconductor layer, the active layer and the n-semiconductor layer comprises a nitride semiconductor.
4. The white light emitting device according to claim 1 , wherein the europium-silicate comprises a material having a composition formula of Eu x Si y O z , where 0<X<30, 0<Y<30 and 0<Z<30.
5. The white light emitting device according to claim 1 , wherein the europium-silicate comprises a material having a composition formula of Eu x Si y O z , where, 0<x<10, 0<y<10 and 0<z<10.
6. The white light emitting device according to claim 1 , wherein the europium-silicate comprises a material having a composition formula of Eu x Si y O z , where 0<x<6, 0<y<6 and 0<z<6.
7. The white light emitting device according to claim 1 , wherein the wavelength-converting film is formed on at least one location selected from the group consisting of a bottom surface of the substrate, an upper surface of the p-semiconductor layer and between the substrate and the n-semiconductor layer.
8. The white light emitting device according to claim 7 , wherein the first emission light comprises blue light, and the second emission light comprises light in a wavelength range from green to red, or yellow light.
9. The white light emitting device according to claim 7 , wherein the first emission light comprises light in a wavelength range from blue to green, and the second emission light comprises yellow light.
10. The white light emitting device according to claim 7 , wherein the first emission light comprises ultraviolet rays, and the second emission light comprises light in a wavelength range from blue to red.
11. The white light emitting device according to claim 7 , wherein white light is emitted in a direction from the light emission structure upward, opposite to the substrate.
12. The white light emitting device according to claim 7 , wherein white light is emitted in a direction from the substrate downward, opposite to the light emission structure.