Light emitting devices
Light-emitting devices, and related components, systems and methods are disclosed. The light-emitting device can include a multi-layer stack of materials including a light-generating region and a first layer supported by the light-generating region. A surface of the first layer can be 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 of the first layer can have a dielectric function that varies spatially according to a complex periodic pattern.
1. A light-emitting device, comprising:
a multi-layer stack of materials including a light-generating region and a layer of n-doped semiconductor material supported by the light-generating region, and
a support, and
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,
a current-spreading layer supported by the light-generating region and formed between the layer of n-doped semiconductor material and the light-generating region,
wherein:
the light-generating region is between the layer of n-doped semiconductor material and the support;
a surface of the layer of n-doped semiconductor material is configured so that light generated by the light-generating region can emerge from the light-emitting device via the surface of the layer of n-doped semiconductor material;
the surface has a dielectric function that varies spatially according to a complex periodic pattern; and
a distance between a 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.
2. The light-emitting device of claim 1 , wherein the pattern is selected from the group consisting of honeycomb patterns and Archimidean 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 1 , wherein the light-generating region is between the layer of n-doped semiconductor material and the layer of p-doped semiconductor material.
5. The light-emitting device of claim 1 , further comprising a p-ohmic contact layer between the layer of p-doped material and the layer of reflective material.
6. The light-emitting device of claim 1 , wherein the multi-layer stack of materials comprise semiconductor materials.
7. The light-emitting device of claim 6 , wherein the semiconductor materials are selected from the group consisting of III-V semiconductor materials, organic semiconductor materials and silicon.
8. The light-emitting device of claim 1 , wherein the pattern does not extend into the light-generating region.
9. The light-emitting device of claim 1 , wherein the pattern does not extend beyond the layer of n-doped semiconductor material.
10. The light-emitting device of claim 1 , wherein the pattern extends beyond the layer of n-doped semiconductor material.
11. The light-emitting device of claim 1 , further comprising electrical contacts configured to inject current into the light-emitting device.
12. The light-emitting device of claim 11 , wherein the electrical contacts are configured to vertically inject electrical current into the light-emitting device.
13. The light-emitting device of claim 1 , wherein the pattern is partially formed of a component selected from the group consisting of holes in the surface of the layer of n-doped semiconductor material, pillars in the layer of n-doped semiconductor material, continuous veins in the layer of n-doped semiconductor material, discontinuous veins in the layer of n-doped semiconductor material and combinations thereof.
14. The light-emitting device of claim 1 , wherein the pattern comprises a honeycomb pattern formed of holes, at least some of the holes having different diameters.
15. The light-emitting device of claim 1 , wherein the pattern is partially formed of holes in the layer of n-doped semiconductor material.
16. 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.
17. 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.
18. The light-emitting device of claim 1 , wherein the light-emitting device comprises a light emitting diode.
19. 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.
20. The light-emitting device of claim 1 , wherein the surface of the layer of n-doped semiconductor material has features with 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.