Three-dimensional patterning methods and related devices
Three-dimensional patterning methods of a three-dimensional microstructure, such as a semiconductor wire array, are described, in conjunction with etching and/or deposition steps to pattern the three-dimensional microstructure.
1. A silicon microscale wire solar cell, comprising:
a plurality of aligned microscale wires,
each of the plurality of aligned microscale wires having a length with a first portion and a second portion,
the first portion of the length having a cladding portion on a core portion,
the core portion doped with a first type of dopant and the cladding portion doped with a second type of dopant,
the core portion and the cladding portion defining a radial junction in the first portion of the length, and
the second portion of the length being doped with the first type of dopant but excluding the second type of dopant;
dopant barriers that are each on a different one of the wires such that each barrier is on the second portion of the length without being positioned on the first portion of the length; and
the second portion of the length being embedded in a polymer;
a plurality of light scattering particles embedded into the polymer and between the wires;
a first electrical contact in electrical communication with the first portion of the length for each of the wires; and
a second electrical contact in electrical communication with the second portion of the length for each of the wires, the second contact acting as a back reflector.
2. The solar cell of claim 1 , wherein the first electrical contact is on a top side of the wires and the second electrical contact is on a bottom side of the wires or vice versa.
3. The solar cell of claim 1 , wherein the first electrical contact and the second electrical contact are on a same side of the wires.
4. The solar cell of claim 3 , wherein the same side is a bottom side of the wires.
5. The solar cell of claim 1 , wherein the light scattering particles are Al 2 O 3 particles.
6. The solar cell of claim 1 , wherein the polymer is PDMS.
7. The solar cell of claim 1 , wherein the first electrical contact is a transparent contact made of indium tin oxide.
8. The solar cell of claim 1 , wherein the second portion of the length exludes radial junctions.
9. The solar cell of claim 1 , wherein the first type of dopant and the second second type of dopant are selected such that the radial junction is a p-n junction.
10. The solar cell of claim 1 , wherein each cladding portion surrounds one of the core portions.
11. The solar cell of claim 1 , wherein each dopant barrier surrounds the second portion of the length of one of the wires.
12. The solar cell of claim 1 , wherein the dopant barriers are an oxide.
13. The solar cell of claim 1 , wherein the dopant barriers are SiO 2 .
14. The solar cell of claim 12 , wherein the polymer surrounds the dopant barriers.
15. The solar cell of claim 1 , wherein the barriers are each on a third portion of the length of one of the wires,
the third portion of the length including the first type of dopant and the second type of dopant, and
the third portion of the length contacting the first portion of the length and the second portion of the length.
16. The solar cell of claim 1 , wherein the wires extend upward from a substrate such that the each wire has the second portion of the length between the substrate and the first portion of the length, and
the second portion of the length of each wire is in direct physical contact with the substrate.
17. The solar cell of claim 16 , wherein the second portion of the length of each wire is continuous with the substrate.
18. The solar cell of claim 1 , wherein the first type of dopant is the only type of dopant included in the second portion of the length of each wire.
19. The solar cell of claim 1 , wherein the first portion of the length of each wire intersects one of the second portions of the length such that a perimeter of the first portion of the length is flush with a perimeter of the second portion of the length at the intersection.
20. The solar cell of claim 1 , wherein each second portion of the length and one of the cladding portions defines an axial junction.
21. The solar cell of claim 1 , wherein the wires have diameters of at least 1 micron with an aspect ratio greater than 5.