High resolution monolithic RGB arrays
A light emitting diode structure comprising a p-type region an n-type region; and a light emitting region for recombination of carriers injectable by the p-type region and the n-type region, wherein at least one of the n-type region and the p-type region is at least partially formed in a via passing through the light emitting region, wherein the via defines the perimeter of a light emitting surface of at least one pixel.
1 . A light emitting diode structure comprising:
a p-type region;
an n-type region; and
a light emitting region for recombination of carriers injectable by the p-type region and the n-type region, wherein at least one of the n-type region and the p-type region is at least partially formed in a via passing through the light emitting region, wherein the via defines the perimeter of a light emitting surface of at least one pixel.
2 . The light emitting diode structure of claim 1 , wherein the light emitting region comprises at least one epitaxial quantum well layer and/or wherein the via enables lateral carrier injection in the light emitting region.
3 . The light emitting diode structure of claim 1 , wherein both the n-type region and the p-type region are at least partially formed in vias passing through the light emitting region.
4 . The light emitting diode structure of claim 1 , wherein the light emitting region and a further light emitting region are separated by an undoped region thereby to provide a stack of light emitting regions, wherein the via passes through both the light emitting region and the further light emitting region, wherein the light emitting region and the further light emitting region are configured to emit light of different wavelengths, wherein the light emitting region and the further light emitting region are arranged such that the surface areas of the light emitting region and further light emitting region partially overlap.
5 . The light emitting diode structure of claim 1 , wherein the via is a grid via defining an array comprising a plurality of pixels, wherein the grid is arranged to provide a common electrode.
6 . The light emitting diode structure of claim 1 , wherein the light emitting surface has an area based on the diffusion length of carriers within the light emitting region.
7 . The light emitting diode structure of claim 1 , wherein the at least one pixel is defined peripherally entirely by a single electrode.
8 . A high resolution micro LED array comprising the light emitting diode structure of any of claim 1 .
9 . The high resolution micro LED array of claim 8 , wherein the array is a multi-colour array and wherein the array has a pixel pitch less than 10 microns.
10 . A method of forming a light emitting diode structure comprising:
a p-type region;
an n-type region; and
an light emitting region for recombination of carriers injectable by the p-type region and the n-type region, wherein at least one of the n-type region and the p-type region is at least partially formed in a via passing through the light emitting region, wherein the via defines the perimeter of a light emitting surface of at least one pixel,
the method comprising:
growing a plurality of epitaxial layers to form an epitaxial structure, the epitaxial layers comprising the n-type region and the light emitting region;
forming the via in the light emitting region; and
forming, at least partially, one of the n-type region and the p-type region in the via.
11 . The method of claim 10 wherein the light emitting region comprises at least one epitaxial quantum well layer and wherein the via enables lateral carrier injection in the light emitting region.
12 . The method of claim 10 , comprising:
forming both the n-type region and the p-type region in vias passing through the light emitting region, comprising providing a further via, wherein the via and the further via are arranged respectively to provide an anode and a cathode.
13 . The method of claim 12 , further comprising growing a further light emitting region, wherein the light emitting region and the further light emitting region are separated by an undoped region thereby to provide a stack of light emitting regions, wherein the light emitting region and the further light emitting region are arranged such that the surface areas of the light emitting region and further light emitting region partially overlap.
14 . The method of claim 12 , comprising growing at least three light emitting regions, wherein one of the light emitting regions emits blue light, one of the light emitting regions emits green light and one of the light emitting regions emits red light.
15 . The method of claim 10 , wherein the via is a grid via defining a plurality of pixels.
16 . The method of claim 10 , comprising forming the n-type region and/or the p-type region in the via by selected area growth of n-type material and/or p-type material respectively.
17 . The method of claim 10 , comprising etching through the light emitting region to form the via.
18 . A method of forming a high resolution LED array comprising claim 10 .
19 . The method of claim 18 , wherein the array is a multicolour array, and wherein the array has a pixel pitch of less than 10 microns.