Nanowire LED structure and method for manufacturing the same
View Patent ↗A method for ablating a first area of a light emitting diode (LED) device which includes an array of nanowires on a support with a laser is provided. The laser ablation exposes a conductive layer of the support that is electrically connected to a first conductivity type semiconductor nanowire core in the nanowires, to form a first electrode for the LED device. In embodiments, the nanowires are aligned at least 20 degrees from the plane of the support. A light emitting diode (LED) structure includes a first electrode for contacting a first conductivity type nanowire core, and a second electrode for contacting a second conductivity type shell enclosing the nanowire core, where the first electrode and/or at least a portion of the second electrode are flat.
1. A LED structure comprising a plurality of nanowires arrayed on a support that comprises a substrate layer, a buffer layer, and a dielectric masking layer, wherein the structure comprises:
(i) a first electrode region comprising the substrate and the buffer layer that is uncovered by the nanowires, wherein the buffer layer serves as a first electrode layer, and
(ii) a second electrode region comprising
(a) a central area that is uncovered by the nanowires comprising the substrate, an insulating layer on the substrate, and a second electrode layer on the insulating layer, and
(b) a peripheral area comprising the substrate, the buffer layer, the masking layer, a plurality of nanowires comprising a first conductivity type semiconductor nanowire core that is in electrical contact with the buffer layer and an enclosing second conductivity type semiconductor shell, wherein the core and the shell are configured to form a pn or pin junction that in operation provides an active region for light generation and the shell is insulated from the buffer layer by the masking layer, an insulating layer on at least some of the nanowires, the insulating layer is contiguous with the insulating layer of the central area, and the second electrode layer is contiguous with the electrode layer of the central area, and contacting the nanowire shells.
2. The LED structure of claim 1 further comprising a conductive contact pad in electrical contact with the second electrode layer of the central area.
3. The LED structure of claim 2 wherein the conductive contact pad is a metallic pad.
4. The LED structure of claim 3 wherein the conductive contact pad comprises Al.
5. The LED structure of claim 1 further comprising a conductive contact pad in electrical contact with the buffer layer in the first electrode region.
6. The LED structure of claim 5 wherein the conductive contact pad is a metallic pad and the first electrode region surrounds the second electrode region.
7. The LED structure of claim 6 wherein the conductive contact pad comprises Al.
8. The LED structure of claim 1 , wherein the first conductivity type comprises n-type, the second conductivity type comprises p-type and the second electrode layer comprises a p-electrode layer.
9. The LED structure of claim 1 , wherein the support layer is reflective.
10. The LED structure of claim 9 wherein the support layer comprises a Ag bottom layer to provide the reflectivity.
11. The LED structure of claim 1 , wherein the support layer is transparent.