Selective emitter nanowire array and methods of making same
Another aspect of the present disclosure relates to a device including a substrate, having a top surface and a bottom surface; an array of nanowires having a base and a top surface, the base contacting the top surface of the substrate; a contacting structure including the same material as the substrate having a non-nanostructured surface of a dimension suitable for forming an electrical contact, located on the same side of the substrate as the array of silicon nanowires; wherein the contacting structure is doped with a greater impurity concentration than the nanowire array, thereby forming a selective emitter.
1. A device comprising:
(a) a substrate, having a top surface, a bottom surface and a first impurity type;
(b) an array of silicon nanowires having a second impurity type, a base and a top surface, wherein the base contacting a surface below the top surface of the substrate;
(c) a contacting structure comprised of the same material as the substrate having a non-nanostructured surface of a dimension suitable for forming an electrical contact, located on the same side of the substrate as the array of silicon nanowires, wherein the contacting structure having the second impurity type;
wherein the surface of the contacting structure is doped with a greater impurity concentration than the nanowire array, thereby forming a selective emitter;
wherein the top surface of the array of nanowires is at approximately the same level as the non-nanostructured surface of the contacting structure; and
wherein the doping of the nanowire array results in a p-n junction below the base of the nanowire array.
2. The device of claim 1 , wherein the device is a photovoltaic cell.
3. The device of claim 1 , further comprising: (d) a conductive layer in contact with the non-nanostructured surface of the contacting structure.
4. The device of claim 3 , wherein the conductive layer comprises a metal.
5. The device of claim 1 , wherein the dopant level in the contact region is greater than 1e19 cm −3 .
6. The device of claim 1 , wherein the dopant comprises boron, phosphorous, or arsenic.
7. The device of claim 1 , wherein the dopant level in the nanowires is less than 5e18 cm −3 .
8. A device comprising:
(a) a substrate, having a top surface, a bottom surface and a first impurity type;
(b) a section of black silicon having a second impurity type, a base and a top surface, wherein the base contacting a surface below the top surface of the substrate;
(c) a contacting structure comprised of the same material as the substrate having a non-nanostructured surface of a dimension suitable for forming an electrical contact, located on the same side of the substrate as the section of black silicon, wherein the contacting structure having the second impurity type;
wherein the surface of the contacting structure is doped with a greater impurity concentration than the section of black silicon, thereby forming a selective emitter;
wherein the top surface of the black silicon is at approximately the same level as the non-nanostructured surface of the contacting structure; and
wherein the doping of the nanowire array results in a p-n junction below the base of the black silicon.
9. The device of claim 8 , further comprising: (d) a conductive layer in contact with the non-nanostructured surface of the contacting structure.
10. The device of claim 8 , wherein the conductive layer comprises a metal.
11. The device of claim 8 , wherein the dopant level in the contact region is greater than 1e19 cm −3 .
12. The device of claim 8 , wherein the dopant comprises boron, phosphorous, or arsenic.
13. The device of claim 8 , wherein the dopant level in the section of black silicon is less than 5e18 cm −3 .
14. The device of claim 8 , wherein the section of black silicon comprises an array of nanowires.
15. The device of claim 8 , wherein the section of black silicon comprises porous silicon.
16. The device of claim 8 , wherein the section of black silicon comprises silicon having a graded index of refraction.
17. The device of claim 8 , wherein the section of black silicon comprises silicon having a needle-shaped surface structure.