Broad-spectrum A1
View Patent ↗A broad-spectrum Al (1-x-y) In y Ga x N light emitting diode (LED), including: a substrate, a buffer layer, an N-type cladding layer, at least one quantum dot emitting layer, and a P-type cladding layer. The buffer layer is disposed over the substrate. The N-type cladding layer is disposed over the buffer layer to supply electrons. The quantum dot emitting layer is disposed over the N-type cladding layer and includes plural quantum dots. The dimensions and indium content of the quantum dots are manipulated to result in uneven distribution of character distribution of the quantum dots so as to increase the FWHM of the emission wavelength of the quantum dot emitting layer. The P-type cladding layer is disposed over the quantum dot emitting layer to supply holes. A broad-spectrum Al (1-x-y) In y Ga x N yellow LED may thus be made from the LED structure of this invention, with an emission wavelength at maximum luminous intensity falling within a range of 530˜600 nm, and FWHM within a range of 20˜150 nm. After packaging an Al (1-x-y) In y Ga x N blue LED to form a solid state white light emitting device, the mixing of blue light and yellow light would generate white light with a high CRI index, high luminous intensity and capable of various color temperature modulation.
1. A broad-spectrum Al (1-x-y) In y Ga x N LED, comprising:
a substrate;
a buffer layer, disposed over the substrate;
an N-type cladding layer, disposed over the buffer layer;
at least one quantum dot emitting layer, disposed over the N-type cladding layer, the quantum dot emitting layer including plural quantum dots with an uneven character distribution so as to increase FWHM of emission wavelength of the quantum dot emitting layer; and
a P-type cladding layer, disposed over the quantum dot emitting layer.
2. The LED of claim 1 , wherein the quantum dots are of different dimensions to result in the uneven character distribution of the quantum dots.
3. The LED of claim 1 , wherein indium content of the quantum dots is different to result in the uneven character distribution of the quantum dots.
4. The LED of claim 2 , wherein indium content of the quantum dots is different to result in the uneven character distribution of the quantum dots.
5. The LED of claim 1 , wherein the quantum dot emitting layer further includes a first barrier layer and a second barrier layer, the first barrier layer being disposed under the quantum dots, the second barrier layer being disposed over the quantum dots, the first barrier layer and the second barrier layer each having an energy band gap that is greater than an energy band gap of the quantum dots.
6. The LED of claim 1 , comprising plural quantum dot emitting layers, the quantum dot emitting layers each having plural quantum dots and an uneven character so as to increase FWHM of emission wavelength of the quantum dot emitting layer.
7. The LED of claim 6 , wherein the quantum dots of the quantum dot emitting layers are of different dimensions to result in the uneven character distribution of the quantum dot emitting layer.
8. The LED of claim 7 , wherein indium content of the quantum dots of the quantum dot emitting layers is different to result in the uneven character distribution of the quantum dot emitting layer.
9. The LED of claim 6 , wherein indium content of the quantum dots of the quantum dot emitting layers is different to result in the uneven character distribution of the quantum dot emitting layer.
10. The LED of claim 6 , wherein the quantum dot emitting layers each further comprise a first barrier layer and a second barrier layer, the first barrier layer being disposed under the quantum dots, the second barrier layer being disposed over the quantum dots, the first barrier layer and the second barrier layer each having an energy band gap being greater than an energy band gap of the quantum dots.
11. The LED of claim 10 , wherein two adjacent barrier layers are of an identical laminar structure so as to omit one of the two adjacent barrier layers to become a single barrier layer.
12. The LED of claim 10 , wherein a content proportion of laminar structure of the first barrier layer or the second barrier layer is manipulated such that the first barrier layer or the second barrier layer includes plural barrier layers of different content proportions.
13. A solid state white light emitting device, comprising:
an Al (1-x-y) In y Ga x N blue LED; and
a broad-spectrum Al (1-x-y) In y Ga x N blue-complimentary LED, packaged with the Al (1-x-y) In y Ga x N blue LED to mix blue light and blue-complimentary light for generating white light, the broad-spectrum Al (1-x-y) In y Ga x N blue-complimentary LED including:
a substrate;
a buffer layer, disposed over the substrate;
an N-type cladding layer, disposed over the buffer layer;
at least one quantum dot emitting layer, disposed over the N-type cladding layer, the quantum dot emitting layer including plural quantum dots with an uneven character distribution so as to increase FWHM of emission wavelength of the quantum dot emitting layer; and
a P-type cladding layer, disposed over the quantum dot emitting layer.
14. The solid state white light emitting device of claim 13 , wherein the broad-spectrum Al (1-x-y) In y Ga x N blue-complimentary LED has an FWHM falling with a range of 20˜150 nm.
15. The solid state white light emitting device of claim 13 , wherein the broad-spectrum Al (1-x-y) In y Ga x N blue-complimentary LED has an emission wavelength at maximum luminous intensity falling within a range of 530˜600 nm.
16. The solid state white light emitting device of claim 13 , wherein the Al (1-x-y) In y Ga x N blue LED includes:
a substrate;
a buffer layer, disposed over the substrate;
an N-type cladding layer, disposed over the buffer layer;
at least one quantum dot emitting layer, disposed over the N-type cladding layer, the quantum dot emitting layer including plural quantum dots with an uneven character distribution so as to increase FWHM of emission wavelength of the quantum dot emitting layer; and
a P-type cladding layer, disposed over the quantum dot emitting layer.
17. The solid state white light emitting device of claim 16 , wherein the Al (1-x-y) In y Ga x N blue LED has an emission wavelength at maximum luminous intensity falling within a range of 400˜500 nm.
18. The solid state white light emitting device of claim 16 , wherein the Al (1-x-y) In y Ga x N blue LED has FWHM falling within a range of 20˜100 nm.
19. The solid state white light emitting device of claim 13 , further comprising red fluorescent powder, packaged with the Al (1-x-y) In y Ga x N blue LED and the broad-spectrum Al (1-x-y) In y Ga x N blue-complimentary LED, to mix the red fluorescent powder with the blue light and blue-complimentary light for generating white light.
20. A solid state white light emitting device, comprising:
a UVA LED;
blue light fluorescent powder;
a broad-spectrum Al (1-x-y) In y Ga x N blue-complimentary LED, packaged with the UVA LED and blue light fluorescent powder, to mix the blue light fluorescent powder and blue-complimentary light for generating white light, the broad-spectrum Al (1-x-y) In y Ga x N blue-complimentary LED including:
a substrate;
a buffer layer, disposed over the substrate;
an N-type cladding layer, disposed over the buffer layer;
at least one quantum dot emitting layer, disposed over the N-type cladding layer, the quantum dot emitting layer including plural quantum dots with an uneven character distribution so as to increase FWHM of emission wavelength of the quantum dot emitting layer; and
a P-type cladding layer, disposed over the quantum dot emitting layer.
21. The solid state white light emitting device of claim 20 , further comprising red fluorescent powder, packaged with the broad-spectrum Al (1-x-y) In y Ga x N blue-complimentary LED, the UVA LED and blue light fluorescent powder, to mix the red fluorescent powder, blue light fluorescent powder and blue-complimentary light for generating white light.