Resonant cavity micro-LED array using embedded reflector
A light emitting diode (LED) array includes bottom reflectors patterned as an array of closed shapes on a top plane of a base layer for III-N growth. A three-dimensional III-N structure is epitaxially grown around the array of closed shapes and extending above the bottom reflectors. The three-dimensional III-N structures is a contiguous crystalline structure extending across the array. A laterally grown III-N layer is formed in contact with both the reflectors and the three-dimensional III-N structures, and III-N LED layers are grown on the laterally grown layer. One or more top reflectors are grown or deposited on the III-N LED layers and located over the bottom reflectors.
1 . A light emitting diode (LED) array comprising:
a semiconductor base layer for III-N growth;
bottom reflectors patterned as an array of closed shapes on a top plane of the base layer;
a three-dimensional III-N structure epitaxially grown around the array of closed shapes and extending above the bottom reflectors, the three-dimensional III-N structure being a contiguous crystalline structure extending across the array;
a laterally grown III-N layer formed in contact with both the reflectors and the three-dimensional III-N structure;
III-N LED layers grown on the laterally grown III-N layer;
one or more top reflectors grown or deposited on the III-N LED layers and located over the bottom reflectors; and
an array of electrical contacts coupled to respective p-type materials and n-type materials of the III-N LED layers, current delivered by the electrical contacts causing non-coherent, spontaneous light emissions through one of the top reflectors or the bottom reflectors.
2 . The LED array of claim 1 , wherein the bottom or top reflectors comprise distributed Bragg reflectors (DBRs).
3 . The LED array of claim 2 , wherein the top or bottom DBRs comprise dielectric multilayer structures.
4 . The LED array of claim 1 , wherein the top reflectors comprise one or more metallic films.
5 . The LED array of claim 4 , wherein the one or more metallic films comprise one of Ag or Al.
6 . The LED array of claim 1 , wherein the bottom reflectors comprise Bragg gratings.
7 . The LED array of claim 1 , wherein the top reflectors, the bottom reflectors, and the electrical contacts form individually addressable light emitting elements that are between 0.2-20 μm in diameter.
8 . The LED array of claim 1 , wherein the base layer, the three-dimensional III-N structure, and the laterally grown III-N layer comprise an n-type material compatible with epitaxial growth of the III-N LED layers.
9 . The LED array of claim 1 , wherein the closed shapes comprise one or more of hexagons and triangles.
10 . The LED array of claim 1 , wherein the semiconductor base layer comprises III-N films on a sapphire or silicon substrate.
11 . The LED array of claim 10 , wherein the base layer comprises the silicon substrate with <111> crystal orientation.
12 . The LED array of claim 1 , wherein the three-dimensional III-N structure comprises a GaN structure.
13 . The LED array of claim 1 , wherein the non-coherent, spontaneous light emissions have a preferred directionality.
14 . The LED array of claim 1 , wherein the one of the top reflectors or the bottom reflectors through which light is emitted has a mirror reflectivity of less than 95%.
15 . An augmented or virtual reality display comprising the LED array of claim 1 .
16 . A light emitting diode (LED) comprising:
a semiconductor base layer for III-N growth;
a bottom reflector patterned as a closed shape on a top plane of the base layer;
a three-dimensional III-N structure epitaxially grown around the closed shapes and extending above the bottom reflector;
a laterally grown III-N layer formed in contact with both the reflector and the three-dimensional III-N structure;
III-N LED layers grown on the laterally grown III-N layer;
a top reflector grown or deposited on the III-N LED layers and located over the bottom reflector, the top reflector comprising a metal film; and
electrical contacts coupled to respective p-type materials and n-type materials of the III-N LED layers, current delivered by the electrical contacts causing non-coherent, spontaneous light emissions through one of the top reflector or the bottom reflector.
17 . The LED of claim 16 , wherein one or both of the bottom reflector and the top reflectors comprise distributed Bragg reflectors (DBRs).
18 . The LED of claim 16 , wherein the non-coherent, spontaneous light emissions have a preferred directionality.
19 . The LED of claim 16 , wherein the one of the top reflector or the bottom reflector through which light is emitted has a mirror reflectivity of less than 95%.
20 . The LED of claim 16 , wherein the three-dimensional III-N structure is part of a contiguous structure that extends across an array of closed shapes that defines an array of other LEDs formed on the base layer.
21 . A method comprising:
patterning bottom reflectors as an array of closed shapes on a top plane of a base layer for epitaxial growth of III-N materials;
selectively growing epitaxial three-dimensional III-N structures around and extending above the array of closed shapes, the three-dimensional III-N structures being a contiguous crystalline structure that extends across the array of closed shapes;
laterally growing a III-N layer in contact with both the bottom reflectors and the three-dimensional III-N structures;
growing III-N LED layers on the laterally grown III-N layer;
depositing or growing one or more top reflectors on the III-N LED layers; and
depositing electrical contacts on respective p-type material and n-type material of the III-N LED layers.