Light-emitting devices with high light collimation
Light-emitting devices, and related components, systems and methods are disclosed. In some embodiments, the devices (e.g., light-emitting diodes) comprise a multi-layer stack of materials including a light generating region and a first layer supported by the light generating region. The surface of the first layer may have a dielectric function that varies spatially according to a pattern. The pattern may be configured so that light that emerges from the device via the surface of the first layer is more collimated than a Lambertian distribution of light.
1. A light-emitting diode comprising:
a multi-layer stack of materials including a light-generating region and a first layer supported by the light-generating region,
wherein:
the first layer comprises a semiconductor material and a surface of the first layer is configured so that light generated by the light generating region can emerge from the light-emitting diode via the surface of the first layer;
the surface of the first layer has a dielectric function that varies spatially according to a pattern, wherein the pattern is defined, at least in part, by a plurality of non-concentric holes; and
the pattern is configured so that light generated by the light-generating region that emerges from the light-emitting diode via the surface of the first layer is substantially incoherent and more collimated than a Lambertian distribution of light.
2. The light-emitting diode of claim 1 , wherein, when light generated by the light-generating region emerges from the light-emitting diode via the surface of the first layer, at least about 40% of the light emerging via the surface of the first layer emerges within at most about 30° of an angle normal to the surface of the first layer.
3. The light-emitting diode of claim 1 , wherein the filling factor of the light-emitting diode is at least about 10%.
4. The light-emitting diode of claim 3 , wherein the filling factor of the light-emitting diode is at most about 75%.
5. The light-emitting diode of claim 1 , wherein the filling factor of the light-emitting diode is at most about 75%.
6. The light-emitting diode of claim 1 , further comprising a support that supports the multi-layer stack of materials.
7. The light-emitting diode 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 diode of claim 7 , wherein the reflective material is a heat sink material.
9. The light-emitting diode of claim 8 , wherein the heat sink material is configured so that the heat sink material has a vertical heat gradient during use of the light-emitting diode.
10. The light-emitting diode of claim 7 , further comprising a heat sink material.
11. The light-emitting diode of claim 10 , wherein the heat sink material is configured so that the heat sink material has a vertical heat gradient during use of the light-emitting diode.
12. The light-emitting diode of claim 1 , further including a current-spreading layer between the first layer and the light-generating region.
13. The light-emitting diode of claim 1 , further comprising electrical contacts configured to inject current into the light-emitting diode.
14. The light-emitting diode of claim 13 , wherein the electrical contacts are configured to vertically inject electrical current into the light-emitting diode.
15. The light-emitting diode of claim 1 , wherein the light-emitting diode is selected from the group consisting of OLEDs, flat surface-emitting LEDs, HBLEDs, and combinations thereof.
16. The light-emitting diode of claim 1 , wherein the pattern does not extend into the light-generating region.
17. The light-emitting diode of claim 1 , wherein the pattern does not extend beyond the first layer.
18. A light-emitting diode comprising:
a multi-layer stack of materials including a light-generating region and a first layer supported by the light-generating region,
wherein:
the first layer comprises a semiconductor material and a surface of the first layer is configured so that light generated by the light generating region can emerge from the light-emitting diode via the surface of the first layer;
the surface of the first layer has a dielectric function that varies spatially according to a pattern, wherein the pattern is defined, at least in part, by a plurality of separate features; and
the pattern is configured so that light generated by the light-generating region that emerges from the light-emitting diode via the surface of the first layer is substantially incoherent and more collimated than a Lambertian distribution of light,
wherein the pattern extends beyond the first layer.
19. The light-emitting diode of claim 1 , 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,
wherein the light-generating region is between the layer of reflective material and the first layer.
20. The light-emitting diode of claim 1 , wherein the pattern is a nonperiodic pattern or a complex periodic pattern.
21. A wafer, comprising:
a plurality of light-emitting diodes, at least some of the light-emitting diodes comprising:
a multi-layer stack of materials including a light-generating region and a first layer supported by the light-generating region, the first layer comprises a semiconductor material and a surface of the first layer is configured so that light generated by the light-generating region can emerge from the light-emitting diode via the surface of the first layer, the surface of the first layer having a dielectric function that varies spatially according to a pattern defined, at least in part, by a plurality of non-concentric holes, and the pattern being configured so that light generated by the light-generating region that emerges from the light-emitting diode via the surface of the first layer is substantially incoherent and more collimated than a Lambertian distribution of light,
wherein the wafer includes at least about five light-emitting diodes per square centimeter.
22. The wafer of claim 21 , wherein the wafer includes at least about 25 light-emitting diodes per square centimeter.
23. The wafer of claim 21 , wherein the wafer includes at least about 50 light-emitting diodes per square centimeter.
24. The light-emitting diode of claim 1 , wherein the surface of the first layer 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 diode via the surface of the first layer.
25. The wafer of claim 21 , wherein the surface of the first layer 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 diode via the surface of the first layer.
26. The light-emitting diode of claim 1 , wherein the dielectric function varies spatially according to a nonperiodic pattern.
27. The light-emitting diode of claim 1 , wherein the dielectric function varies spatially according to a complex periodic pattern.
28. The wafer of claim 21 , wherein, for the at least some of the light-emitting diodes, the dielectric function varies spatially according to a nonperiodic pattern.
29. The wafer of claim 21 , wherein, for the at least some of the light-emitting diodes, the dielectric function varies spatially according to a complex periodic pattern.
30. The light-emitting diode of claim 1 , wherein the dielectric function varies spatially according to a periodic pattern.
31. The wafer of claim 25 , wherein, for the at least some of the light-emitting diodes the dielectric function varies spatially according to a periodic pattern.
32. The light-emitting diode of claim 1 , wherein the surface of the first layer has holes with a size of less than about 90 nm.
33. The wafer of claim 21 , wherein the surface of the first layer has holes with a size of less than about 90 nm.
34. A light-emitting diode comprising:
a multi-layer stack of materials including a light-generating region and a first layer supported by the light-generating region,
wherein:
the first layer comprises a semiconductor material and a surface of the first layer is configured so that light generated by the light generating region can emerge from the light-emitting diode via the surface of the first layer;
the surface of the first layer has a dielectric function that varies spatially according to a pattern defined, at least in part, by a plurality of holes being devoid of material within a perimeter defined by the first layer; and
the pattern is configured so that light generated by the light-generating region that emerges from the light-emitting diode via the surface of the first layer is more collimated than a Lambertian distribution of light.
35. The light-emitting diode of claim 34 , wherein the dielectric function varies spatially according to a nonperiodic pattern.
36. The light-emitting diode of claim 34 , wherein, when light generated by the light-generating region emerges from the light-emitting diode via the surface of the first layer, at least about 40% of the light emerging via the surface of the first layer emerges within at most about 30° of an angle normal to the surface of the first layer.
37. The light-emitting diode of claim 34 , wherein the filling factor of the light-emitting diode is at least about 10%.
38. The light-emitting diode of claim 26 , wherein a majority of the nonperiodic pattern has order.
39. The wafer of claim 28 , wherein a majority of the nonperiodic pattern has order.
40. The light-emitting diode of claim 35 , wherein a majority of the nonperiodic pattern has order.