Semiconductor light emitting devices including in-plane light emitting layers
View Patent ↗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. A structure comprising:
a first epitaxial structure comprising a first active region sandwiched between a first n-type region and a first p-type region, the first 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 polarizer disposed in a path of light emitted by the first active region, wherein the polarizer is oriented to transmit light of a polarization of a majority of light emitted by the first active region; and
a second epitaxial structure comprising a second active region sandwiched between a second n-type region and a second p-type region, the second active region configured to emit light having a polarization ratio of at least 50% when forward biased; wherein:
the polarizer comprises a plurality of evenly spaced, parallel metal lines;
the polarizer configured to serve as an electrical contact between the first and second epitaxial structures;
the polarizer is disposed between the first epitaxial structure and the second epitaxial structure; and
the polarizer is oriented to reflect light of a polarization of a majority of light emitted by the second active region.
2. The structure of claim 1 wherein the first active region and the second active region emit light of a same color.
3. The structure of claim 1 wherein the first active region and the second active region emit light of different colors.