LUMIPHORIC MATERIAL STRUCTURES WITHIN LIGHT-EMITTING DIODES AND RELATED METHODS
Solid-state lighting devices including light-emitting diodes (LEDs) and more particularly arrangements of lumiphoric materials within LEDs and related methods are disclosed. Lumiphoric materials are incorporated or otherwise embedded within LED chips and LED wafers. Embedded lumiphoric materials are provided so that at least some portions of light generated by active LED structures are subject to wavelength conversion before exiting LED chip surfaces. Lumiphoric material layers include arrangements of lumiphoric particles and binder layers positioned between reflective layers and active LED structures. Lumiphoric material layers and/or lumiphoric particles may be patterned within regions of LED chips and/or LED wafers. Related methods include depositing lumiphoric particles and binder layers before reflective layers in LED chips and LED wafers.
1 . A light-emitting diode (LED) chip, comprising:
an active LED structure comprising an n-type layer, a p-type layer, and an active layer between the n-type layer and the p-type layer;
a dielectric reflective layer on the active LED structure; and
a lumiphoric material layer between the dielectric reflective layer and the active LED structure, the lumiphoric material layer configured for wavelength conversion of at least a portion of light generated by the active LED structure.
2 . The LED chip of claim 1 , further comprising a metal reflective layer on the dielectric reflective layer such that the dielectric reflective layer is between the metal reflective layer and the lumiphoric material layer.
3 . The LED chip of claim 1 , wherein a lateral edge of the of the lumiphoric material layer is bound by the dielectric reflective layer.
4 . The LED chip of claim 3 , wherein the active LED structure forms a mesa sidewall along portions of the p-type layer, the active layer, and the n-type layer, and the lateral edge of the lumiphoric layer is aligned with the mesa sidewall.
5 . The LED chip of claim 4 , wherein the dielectric reflective layer extends along the mesa sidewall.
6 . The LED chip of claim 1 , wherein the lumiphoric material layer comprises a plurality of lumiphoric particles and a binder layer.
7 . The LED chip of claim 6 , wherein the binder layer comprises aluminum oxide.
8 . The LED chip of claim 1 , wherein the lumiphoric material layer comprises a plurality of lumiphoric particles arranged in a pattern of regions within a binder layer.
9 . A method comprising:
providing an active LED structure comprising an n-type layer, a p-type layer, and an active layer between the n-type layer and the p-type layer;
depositing a plurality of lumiphoric particles on the active LED structure;
deposing a binder layer on the plurality of lumiphoric particles to form a lumiphoric material layer comprising the plurality of lumiphoric particles and the binder layer, the lumiphoric material layer configured for wavelength conversion of at least a portion of light generated by the active LED structure; and
forming a dielectric reflective layer on the lumiphoric material layer such that the lumiphoric material layer is between the dielectric reflective layer and the active LED structure.
10 . The method of claim 9 , wherein depositing the binder layer comprises atomic layer deposition.
11 . The method of claim 10 , wherein the binder layer comprises aluminum oxide.
12 . The method of claim 9 , further comprising selectively removing portions of the plurality of lumiphoric particles over portions of the active LED structure before depositing the binder layer.
13 . The method of claim 12 , wherein the selectively removing portions of the plurality of lumiphoric particles comprises positioning an imprint stamp on the plurality of lumiphoric particles and lifting the imprint stamp away from the active LED structure to selectively remove the portions of the plurality of lumiphoric particles.
14 . The method of claim 13 , wherein the imprint stamp comprises a plurality of pedestals that contact the plurality of lumiphoric particles.
15 . The method of claim 14 , further comprising forming a surface layer on the plurality of pedestals.
16 . The method of claim 9 , further comprising forming a metal reflective layer on the dielectric reflective layer such that the dielectric reflective layer is between the metal reflective layer and the lumiphoric material layer.
17 . A light-emitting diode (LED) wafer, comprising:
an active LED structure comprising an n-type layer, a p-type layer, and an active layer between the n-type layer and the p-type layer; and
a lumiphoric material layer forming a pattern on the active LED structure, the lumiphoric material layer configured for wavelength conversion of at least a portion of light generated by the active LED structure.
18 . The LED wafer of claim 17 , wherein the lumiphoric material layer comprises a plurality of lumiphoric particles and a binder layer.
19 . The LED wafer of claim 18 , wherein the binder layer comprises aluminum oxide.
20 . The LED wafer of claim 19 , wherein the plurality of lumiphoric particles are arranged in a pattern of regions within the binder layer.