Semiconductor light emitting devices including in-plane light emitting layers

Abstract

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.