Light-emitting devices including a nonperiodic pattern
Light-emitting devices, and related components, systems and methods are disclosed. In some embodiments, the light-emitting devices include a multi-layer stack of materials. The stack of materials includes a light-generating region and a first layer supported by the light-generating region. The surface of the first layer is configured so that light generated by the light-generating region can emerge from the light-emitting device via the surface of the first layer. The surface has a dielectric function that varies spatially according to a nonperiodic pattern.
1. A light-emitting device, comprising:
a multi-layer stack of materials including a light-generating region and a first layer supported by the light-generating region, wherein:
a surface of the first layer is configured so that light generated by the light-generating region can emerge from the light-emitting device via the surface of the first layer; and
the surface has a dielectric function that varies spatially according to a nonperiodic pattern that is configured to increase light extraction from the device via the surface, the nonperiodic pattern is created by the configuration of a plurality of holes, wherein the holes are not encircled by other holes, wherein when viewed in a direction in which the holes extend from the surface into the first layer, the non-periodic pattern has no translational symmetry along the surface over a unit cell that has a length that is at least 50 times the peak wavelength of light generated by the light-generating region.
2. The light-emitting device of claim 1 , wherein the nonperiodic pattern is selected from the group consisting of quasicrystalline patterns, Robinson patterns, and Amman patterns.
3. The light-emitting device of claim 1 , wherein the multi-layer stack of materials comprises a multi-layer stack of semiconductor materials.
4. The light-emitting device of claim 3 , wherein the first layer comprises a layer of n-doped semiconductor material, and the multi-layer stack further comprises a layer of p-doped semiconductor material.
5. The light-emitting device of claim 4 , wherein the light-generating region is between the layer of n-doped semiconductor material and the layer of p-doped semiconductor material.
6. The light-emitting device of claim 5 , further comprising a support that supports the multi-layer stack of materials.
7. The light-emitting device of claim 6 , further comprising a layer of reflective material that is capable of reflecting at least about 50% of light generated by the light-generating region that impinges on the layer of reflective material, the layer of reflective material being between the support and the multi-layer stack of materials.
8. The light-emitting device of claim 7 , wherein a distance between the layer of p-doped semiconductor material and the layer of reflective material is less than a distance between the layer of n-doped semiconductor material and the layer of reflective material.
9. The light-emitting device of claim 8 , further comprising a p-ohmic contact layer between the layer of p-doped material and the layer of reflective material.
10. The light-emitting device of claim 1 , further including a current-spreading layer between the first layer and the light-generating region.
11. The light-emitting device of claim 1 , wherein the multi-layer stack of materials comprise semiconductor materials.
12. The light-emitting device of claim 11 , wherein the semiconductor materials are selected from the group consisting of III-V semiconductor materials, organic semiconductor materials and silicon.
13. The light-emitting device of claim 1 , wherein the pattern does not extend into the light-generating region.
14. The light-emitting device of claim 1 , wherein the pattern does not extend beyond the first layer.
15. The light-emitting device of claim 1 , wherein the pattern extends beyond the first layer.
16. The light-emitting device of claim 1 , further comprising electrical contacts configured to inject current into the light-emitting device.
17. The light-emitting device of claim 16 , wherein the electrical contacts are configured to vertically inject electrical current into the light-emitting device.
18. The light-emitting device of claim 1 , wherein the pattern comprises a Penrose pattern.
19. The light-emitting device of claim 1 , wherein the pattern is configured so that light emitted by the surface of the first layer has a spectrum of radiation modes, and the spectrum of radiation modes is substantially the same as a characteristic emission spectrum of the light-generating region.
20. The light-emitting device of claim 1 , wherein the light-emitting device is selected from the group consisting of light-emitting diodes, lasers, optical amplifiers, and combinations thereof.
21. The light-emitting device of claim 1 , wherein the light-emitting device comprises a light emitting diode.
22. The light-emitting device of claim 1 , wherein the light-emitting device is selected from the group consisting of OLEDs, flat surface-emitting LEDs, HBLEDs, and combinations thereof.
23. The light-emitting device of claim 1 , wherein the holes in the surface of the first layer have a size of less than about λ/5, where λ is a wavelength of light that can be generated by the light-generating region and that can emerge from the light-emitting device via the surface of the first layer.
24. The light-emitting device of claim 1 , wherein a majority of the holes have substantially the same size.
25. The light-emitting device of claim 1 , wherein a majority of nearest neighbor distances between the holes are substantially the same.
26. The light-emitting device of claim 1 , wherein the pattern has in-plane symmetry.
27. The light-emitting device of claim 1 , wherein the pattern has in-plane rotational symmetry.