SEMICONDUCTOR LIGHT EMITTING DEVICES INCLUDING IN-PLANE LIGHT EMITTING LAYERS
A semiconductor light emitting device includes an in-plane active region that emits linearly-polarized light. An in-plane active region may include, for example, a {11 2 0} or {10 1 0} InGaN light emitting layer. In some embodiments, a polarizer oriented to pass light of a polarization of a majority of light emitted by the active region serves as a contact. In some embodiments, two active regions emitting the same or different colored light are separated by a polarizer oriented to pass light of a polarization of a majority of light emitted by the bottom active region, and to reflect light of a polarization of a majority of light emitted by the top active region. In some embodiments, a polarizer reflects light scattered by a wavelength converting layer.
1 - 14 . (canceled)
15 . A semiconductor light emitting device comprising:
an epitaxial structure comprising an active region sandwiched between an n-type region and a p-type region, the active region configured to emit light at least 50% polarized when forward biased;
a first mirror; and
a second mirror;
wherein the first mirror and second mirror form a resonant cavity.
16 . The device of claim 15 wherein the active region is configured to emit light at least 50% polarized when forward biased below a lasing threshold of the device.
17 . The device of claim 15 wherein the active region comprises at least one layer of {11 2 0} InGaN.
18 . The device of claim 15 wherein the active region comprises at least one layer of {10 1 0} InGaN.
19 . The device of claim 15 wherein:
the first mirror is a dielectric distributed Bragg reflector having a reflectivity greater than 99%, the first mirror being parallel to and proximate the n-type region; and
the second mirror is a dielectric distributed Bragg reflector having a reflectivity greater than 99%, the second mirror being parallel to and proximate the p-type region.
20 . The device of claim 19 wherein the n-type region is a first n-type region, the device further comprising:
a tunnel junction; and
a second n-type region;
wherein the tunnel junction and second n-type region are disposed between the p-type region and the second mirror.
21 . The device of claim 15 wherein:
the first mirror is a dielectric distributed Bragg reflector having a reflectivity greater than 99%, the first mirror being proximate the n-type region; and
the second mirror is a metal layer having a reflectivity less than 99%, the first mirror being proximate the p-type region.
22 . The device of claim 15 wherein the first mirror and second mirrors are cleaved facets at opposite ends of the device, the cleaved facets being perpendicular to a plane of the epitaxial structure.
23 . A semiconductor light emitting device comprising:
an epitaxial structure comprising an active region sandwiched between an n-type region and a p-type region, the active region configured to emit light at least 50% polarized when forward biased; and
a photonic crystal formed in at least one of the p-type region, n-type region, and active region.
24 . The device of claim 23 wherein the photonic crystal comprises a periodic array of holes formed in the n-type region.
25 . The device of claim 24 wherein the holes are arranged in a square lattice.
26 . The device of claim 23 wherein the photonic crystal comprises a plurality of parallel grooves formed in the n-type region.
27 . The device of claim 23 wherein the active region comprises at least one layer of {11 2 0} InGaN.
28 . The device of claim 23 wherein the active region comprises at least one layer of {10 1 0} InGaN.
29 . A semiconductor light emitting device comprising:
an epitaxial structure comprising an active region sandwiched between an n-type region and a p-type region, the active region configured to emit light at least 50% polarized when forward biased;
a polarization shifting surface proximate to one of the n-type region and the p-type region.
30 . The device of claim 29 wherein the active region comprises at least one layer of {11 2 0} InGaN.
31 . The device of claim 29 wherein the active region comprises at least one layer of {10 1 0} InGaN.
32 . The device of claim 29 wherein the polarization shifting surface randomizes a polarization of light emitted by the active region.
33 . The device of claim 29 wherein the polarization shifting surface rotates a polarization of light emitted by the active region.
34 . The device of claim 29 wherein the polarization shifting surface comprises a roughened semiconductor surface.
35 . A structure comprising:
an epitaxial structure comprising an active region sandwiched between an n-type region and a p-type region, the active region configured to emit light having a polarization ratio, defined as (|I p −I s |/ I p +I s )×100% where I p is an intensity of vertically polarized light and I s is an intensity of horizontally polarized light, of at least 50% when forward biased;
a reflective polarizer disposed in a path of light emitted by the active region, wherein the polarizer is oriented to transmit light of a polarization of a majority of light emitted by the active region;
a host substrate bonded to the epitaxial structure; and
a reflective contact disposed between the p-type region and the host substrate, wherein the polarizer is disposed on the n-type region and forms an electrical contact to the n-type region.
36 . The structure of claim 35 wherein the active region is configured to emit light having a polarization ratio of at least 80% when forward biased.
37 . The structure of claim 35 wherein the active region comprises at least one layer of {11 2 0} InGaN.
38 . The structure of claim 35 wherein the active region comprises at least one layer of {10 1 0} InGaN.
39 . The structure of claim 35 wherein the polarizer comprises a plurality of evenly spaced, parallel metal lines.
40 . The structure of claim 39 wherein:
each of the metal lines is between about 10 nm and about 1000 nm thick; and
the metal lines are spaced between about 10 nm and about 1000 nm apart.
41 . The structure of claim 39 wherein:
each of the metal lines is between about 50 nm and about 80 nm thick; and
the metal lines are spaced between about 100 nm and about 200 nm apart.
42 . The structure of claim 39 wherein the evenly spaced, parallel metal lines comprise at least one of gold, silver, aluminum, and rhodium.
43 . The structure of claim 35 wherein a total thickness of the n-type region, p-type region, and active region is between about 0.1 and about 1 micron.
44 . The device of claim 35 wherein the host substrate is bonded to the epitaxial structure after growth of the epitaxial structure is completed.
45 . The device of claim 35 wherein the reflective contact comprises a reflective metal.