Polarization-reversed III-nitride light emitting device
View Patent ↗A device structure includes a III-nitride wurtzite semiconductor light emitting region disposed between a p-type region and an n-type region. A bonded interface is disposed between two surfaces, one of the surfaces being a surface of the device structure. The bonded interface facilitates an orientation of the wurtzite c-axis in the light emitting region that confines carriers in the light emitting region, potentially increasing efficiency at high current density.
1. A structure comprising:
a device structure comprising a III-nitride light emitting region disposed between a p-type region and an n-type region, the light emitting region comprising a wurtzite crystal structure; and
a non-III-nitride material disposed between two surfaces, wherein:
one of the surfaces is a surface of a wurtzite crystal portion of the device structure, the wurtzite crystal portion of the device structure comprising alternating layers of group III atoms and group V atoms, wherein the surface of the wurtzite crystal portion of the device structure comprises a surface of a layer of group III atoms; and
the other of the surfaces is a surface of a wurtzite crystal portion of a second structure, the wurtzite crystal portion of the second structure comprising alternating layers of group III atoms and group V atoms, wherein the surface of the wurtzite crystal portion of the second structure comprises a surface of a layer of group III atoms; and
the non-III-nitride material is in direct contact with the two surfaces;
wherein across an interface disposed between the light emitting region and the p-type region, a wurtzite c-axis, defined as pointing from a nitrogen face of a III-nitride unit cell to a group III atom face of the III-nitride unit cell, points toward the light emitting region.
2. The structure of claim 1 wherein the two surfaces are both GaN surfaces.
3. The structure of claim 1 wherein one of the two surfaces is selected from the group of GaN, AlN, and InGaN.
4. The structure of claim 1 wherein the surface of the wurtzite crystal portion of the device structure is a III-nitride surface that is one of p-type, n-type, and undoped.
5. The structure of claim 1 wherein one of the two surfaces is textured.
6. The structure of claim 5 wherein the textured surface comprises a periodic array of holes formed in the textured surface.
7. The structure of claim 6 wherein the periodic array of holes has a lattice constant between 0.1λ and 4λ, wherein λ is a wavelength of light in the light emitting region.
8. The structure of claim 1 wherein the non-III-nitride material is a metal layer.
9. The structure of claim 1 wherein the non-III-nitride material is a metal-semiconductor alloy.
10. The structure of claim 1 further comprising contacts electrically connected to the n-type region and the p-type region.
11. The structure of claim 1 further comprising:
a mesa including a portion of the light emitting region; and
laser facets disposed on opposite ends of the mesa.
12. The structure of claim 1 wherein the device structure and the second structure are separately-grown III-nitride structures.
13. The structure of claim 8 wherein the metal layer comprises one of Zn and Sn.
14. The structure of claim 9 wherein the metal-semiconductor alloy comprises Al.
15. The structure of claim 1 wherein the non-III-nitride material is a dielectric.
16. The structure of claim 1 wherein the non-III-nitride material is an oxide of silicon.