Resonant cavity light emitting device
View Patent ↗A light emitting device includes a resonant cavity formed by a reflective metal layer and a distributed Bragg reflector. Light is extracted from the resonant cavity through the distributed Bragg reflector. A light emitting region sandwiched between a layer of first conductivity type and a layer of second conductivity type is disposed in the resonant cavity. In some embodiments, first and second contacts are formed on the same side of the resonant cavity, forming a flip chip or epitaxy up device.
1. A light emitting device comprising:
a structure comprising:
a light emitting region disposed between a region of first conductivity type and a region of second conductivity type; and
a distributed Bragg reflector;
a substrate;
a first contact electrically connected to the region of first conductivity type; and
a second contact electrically connected to the region of second conductivity type, the second contact comprising a first metal layer having a reflectivity to light emitted by the light emitting region greater than 75%, the first metal layer being disposed between the substrate and the structure;
wherein the first contact is electrically connected to the substrate by a second metal layer extending along a side surface of the structure.
2. The device of claim 1 wherein the light emitting region is disposed between the distributed Bragg reflector and the first metal layer.
3. The device of claim 1 wherein the first metal layer comprises a metal selected from the group of Ag, Au, Al, Pt, Pd, Re, Ru, Rh, Tn, Cr, and alloys thereof.
4. The device of claim 1 wherein the distributed Bragg reflector has a reflectivity to light emitted by the light emitting region between about 60% and about 90%.
5. The device of claim 1 wherein the distributed Bragg reflector and the first metal layer form a resonant cavity, and light generated by the light emitting region is extracted from the resonant cavity through the distributed Bragg reflector.
6. The device of claim 1 wherein the distributed Bragg reflector and the first metal layer form a resonant cavity, and a distance between the first metal layer and the distributed Bragg reflector is an integer multiple of λ/2, where λ is the wavelength of light emitted by the light emitting region in the resonant cavity.
7. The device of claim 1 wherein the distributed Bragg reflector is disposed between the first contact and the region of first conductivity type.
8. The device of claim 7 wherein the first contact comprises a ring.
9. The device of claim 7 wherein the first contact comprises a mesh.
10. The device of claim 1 wherein the first metal layer has a reflectivity to light emitted by the light emitting region greater than 80%.
11. The device of claim 1 wherein the distributed Bragg reflector has a reflectivity to light emitted by the light emitting region between about 75% and about 85%.