Nanowire sized opto-electronic structure and method for manufacturing the same
View Patent ↗An opto-electric structure includes a plurality of nano elements arranged side by side on a support layer, where each nano element includes at least a first conductivity type semiconductor nano sized core, and where the core and a second conductivity type semiconductor form a pn or pin junction. A first electrode layer that extends over the plurality of nano elements and is in electrical contact with at least a portion of the second conductivity type semiconductor, and a mirror provided on a second conductivity type semiconductor side of the structure.
1. A method of manufacturing an opto-electronic structure, comprising:
providing a support layer;
providing a plurality of nano elements arranged side by side on the support layer, wherein each nano element comprises at least a first conductivity type semiconductor nano sized core, wherein the core and a second conductivity type semiconductor form a pn or pin junction;
providing a sacrificial layer with a first thickness over a first portion of the plurality of nano elements and a second thickness over a second portion of the plurality of nano elements, wherein the first thickness is different from the second thickness;
providing a first electrode layer that extends over the plurality of nano elements and is in electrical contact with at least a portion of the second conductivity type semiconductor; and
providing a mirror on a second conductivity type semiconductor side of the structure.
2. The method of claim 1 , wherein the first conductivity type comprises n-type, the second conductivity type comprises p-type and the first electrode layer comprises a p-electrode layer.
3. The method of claim 2 , further comprising depositing a second n-electrode layer which electrically connects to the n-type cores.
4. The method of claim 3 , wherein the second conductivity type semiconductor comprises a semiconductor shell which is part of the nano element, and each nano element comprises a nanostructure containing the core, the shell and an active region between the core and the shell.
5. The method of claim 3 , wherein: the second conductivity type semiconductor comprises a bulk semiconductor element that is not part of the nano element; the core comprises a semiconductor nanowire of the first conductivity type or the semiconductor nanowire of the first conductivity type and at least one semiconductor shell of the first conductivity type; and each nano element comprises a nanostructure containing the core, and an active region between the core and the bulk semiconductor element.
6. The method of claim 3 , wherein the first electrode layer is reflective and comprises the mirror, such that the steps of providing the first electrode and providing the mirror occur in the same step.
7. The method of claim 3 , wherein the first electrode layer is transparent and the mirror comprises a reflective conductive layer deposited in electrical contact the first electrode layer.
8. The method as claimed in claim 7 , further comprising depositing a transparent insulating layer over the first electrode layer, planarizing the transparent insulating layer and forming an opening in the transparent insulating layer, wherein the reflective conductive layer is deposited on the transparent insulating layer and in the opening to be in electrical contact the first electrode layer.
9. The method of claim 8 , wherein the transparent insulating layer comprises a spin-on glass.
10. The method of claim 8 , further comprising depositing a diffusion barrier layer over the mirror and depositing a eutectic bonding layer over the diffusion barrier layer.
11. The method of claim 10 , further comprising flip-chip bonding the structure onto contact electrodes on a carrier using the eutectic bonding layer.
12. The method of claim 11 , wherein a first portion of the carrier is electrically connected to the first electrode layer by the eutectic bonding layer, the diffusion barrier layer and the mirror, and a second portion of the carrier is connected to the second electrode layer by a wire.
13. The method of claim 7 , wherein the substrate is removed by etching, grinding or polishing.
14. The method of claim 13 , wherein the buffer layer is roughened or etched to increase extraction of light.
15. The method of claim 1 , wherein the step of providing the first electrode layer comprises providing the first electrode layer over the first and the second portions of the sacrificial layer.
16. The method of claim 15 , further comprising removing the first electrode layer from over the first portion of the sacrificial layer while the first electrode layer remains over the second portion of the sacrificial layer.
17. The method of claim 16 , further comprising removing the first portion of the sacrificial layer and removing the second portion of the sacrificial layer from under the first electrode layer such that the first electrode layer forms an air-bridge over an empty space between the plurality of nano elements.
18. The method of claim 17 , wherein the sacrificial layer comprises photoresist.