Light emitting devices with inhomogeneous quantum well active regions
View Patent ↗A method of fabricating a light emitting device includes modulating a crystal growth parameter to grow a quantum well layer that is inhomogeneous and that has a non-random composition fluctuation across the quantum well layer.
1. A light-emitting device comprising:
a first quantum well; and
first sub-layers included in the first quantum well, an alloy composition of one layer of the first sub-layers different than an alloy composition of another layer of the first sub-layers, a wavelength of the light emitted by the first quantum well defined by a bandgap of an average composition of the first sub-layers.
2. The light-emitting device of claim 1 , wherein the first sub-layers constitute a superlattice that exhibits a periodic composition fluctuation.
3. The light-emitting device of claim 1 , further comprising:
a second quantum well;
second sub-layers included in the second quantum well, an alloy composition of one layer of the second sub-layers different than an alloy composition of another layer of the second sub-layers, a wavelength of the light emitted by the second quantum well defined by a bandgap of an average composition of the second sub-layers; and
a barrier layer disposed between the first and second quantum wells.
4. The light-emitting device of claim 3 , the barrier layer comprising third sub-layers, an alloy composition of one layer of the third sub-layers different than an alloy composition of another layer of the third sub-layers, an energy offset between the barrier layer and one of the first and second quantum wells defined by a bandgap of an average composition of the third sub-layers.
5. The light-emitting device of claim 2 , the first sub-layers comprising alternating layers of different materials.
6. The light-emitting device of claim 5 , at least one element in the alternating layers of different materials exhibiting a periodic composition fluctuation across the alternating layers of different materials.
7. The light-emitting device of claim 6 , each one of the alternating layers of different materials consisting of a binary alloy.
8. The light-emitting device of claim 7 , a first one of the alternating layers selected from a first group consisting of AlN, InN, and GaN, a second one of the alternating layers selected from a second group consisting of the members of the first group that were not selected for the first one of the alternating layers.
9. The light-emitting device of claim 6 , each one of the alternating layers of different material consisting of a ternary alloy.
10. The light-emitting device of claim 1 , wherein at least one layer of the first sub-layers is doped with an impurity.
11. The light-emitting device of claim 10 , the impurity selected from the group consisting of Si and Mg.
12. The light-emitting device of claim 1 , wherein the wavelength of the light emitted by the first quantum well is red-shifted relative to the bandgap of the average composition of the first sub-layers.
13. A light emitting device comprising:
barrier layers; and
quantum well layers separated by and disposed between the barrier layers, the quantum well layers exhibiting a controlled composition fluctuation across each of the quantum well layers, the quantum well layers forming a single quantum well.
14. The light emitting device of claim 13 , the quantum well layers structured to achieve peak emission for a wavelength in a deep UV range.
15. The light emitting device of claim 13 , the quantum well layers structured to achieve peak emission for a green wavelength.
16. The light emitting device of claim 13 , the quantum well layers exhibiting a periodic composition fluctuation across each of the quantum well layers.
17. The light emitting device of claim 16 , the quantum well layers comprising:
a first layer having a first composition;
a second layer having a second composition different from the first composition; and
a third layer having the first composition.
18. A light-emitting device comprising:
a first quantum well;
a second quantum well disposed below the first quantum well; and
a barrier layer disposed between the first and second quantum wells, the barrier layer comprising first sub-layers, an alloy composition of one layer of the first sub-layers different than an alloy composition of another layer of the first sub-layers with regard to one element of the alloy composition, an energy offset between the barrier layer and one of the first and second quantum wells defined by a bandgap of an average composition of the first sub-layers.
19. A light emitting device comprising:
barrier layers; and
quantum well layers separated by and disposed between the barrier layers, the quantum well layers exhibiting a controlled composition fluctuation across each of the quantum well layers, the quantum well layers exhibiting a periodic composition fluctuation across each of the quantum well layers, and the quantum well layers comprising:
a first layer having a first composition;
a second layer having a second composition different from the first composition; and
a third layer having the first composition.