Solar cells with tunnel dielectrics
A solar cell can have a first dielectric formed over a first doped region of a silicon substrate. The solar cell can have a second dielectric formed over a second doped region of the silicon substrate, where the first dielectric is a different type of dielectric than the second dielectric. A doped semiconductor can be formed over the first and second dielectric. A positive-type metal and a negative-type metal can be formed over the doped semiconductor.
1. A solar cell, comprising:
a first dielectric formed over a first portion of a silicon substrate;
a first doped semiconductor formed over the first dielectric, wherein the first dielectric comprises an electron barrier greater than a hole barrier at the first portion between the first doped semiconductor and the silicon substrate;
a second dielectric formed over second portion of the silicon substrate;
a second doped semiconductor formed over the second dielectric, wherein the second dielectric comprises an electron barrier less than a hole barrier at the second portion between the second doped semiconductor and the silicon substrate;
a first metal contact formed over the first doped semiconductor and the first dielectric; and
a second contact formed over the second doped semiconductor and over the second dielectric.
2. The solar cell of claim 1 , wherein the first dielectric comprises at least an oxide monolayer in contact with the silicon substrate.
3. The solar cell of claim 1 , wherein the second dielectric comprises a plurality of oxide monolayers.
4. The solar cell of claim 1 , wherein the first dielectric comprises silicon nitride.
5. The solar cell of claim 1 , wherein the second dielectric comprises silicon dioxide.
6. The solar cell of claim 1 , wherein the first emitter region comprises a first doped polysilicon and the second emitter region comprises a second doped polysilicon.
7. A solar cell, comprising:
a first dielectric formed over a first portion of a silicon substrate;
a P-type doped polysilicon formed over the first dielectric, wherein the first dielectric comprises an electron barrier greater than a hole barrier at the first portion between the P-type doped polysilicon and the silicon substrate;
a second dielectric formed over second portion of the silicon substrate;
a N-type doped polysilicon formed over the second dielectric, wherein the second dielectric comprises an electron barrier less than a hole barrier at the second portion between the P-type doped polysilicon and the silicon substrate;
a positive-type metal contact formed over the P-type doped polysilicon and the first dielectric; and
a negative-type metal contact formed over the N-type doped polysilicon and over the second dielectric.
8. The solar cell of claim 7 , wherein the first dielectric comprises at least an oxide monolayer in contact with the silicon substrate.
9. The solar cell of claim 7 , wherein the second dielectric comprises a plurality of oxide monolayers.
10. The solar cell of claim 7 , wherein the first dielectric comprises silicon nitride.
11. The solar cell of claim 7 , wherein the second dielectric comprises silicon dioxide.
12. The solar cell of claim 7 , wherein the silicon substrate comprises a first doped region under the first dielectric and a second doped region under the second dielectric.
13. The solar cell of claim 12 , wherein a dopant concentration ratio between the P-type doped polysilicon and the first doped region is at least 10.
14. The solar cell of claim 12 , wherein a dopant concentration ratio between the N-type doped polysilicon and the second doped region is at least 10.
15. A solar cell, comprising:
a first dielectric formed over a first portion of a silicon substrate;
a P-type doped amorphous silicon formed over the first dielectric, wherein the first dielectric comprises an electron barrier greater than a hole barrier at the first portion between the P-type doped amorphous silicon and the silicon substrate;
a second dielectric formed over second portion of the silicon substrate;
a N-type doped amorphous silicon formed over the second dielectric, wherein the second dielectric comprises an electron barrier less than a hole barrier at the second portion between the P-type doped amorphous silicon and the silicon substrate;
a positive-type metal contact formed over the P-type doped amorphous silicon and the first dielectric; and
a negative-type metal contact formed over the N-type doped amorphous silicon and over the second dielectric.
16. The solar cell of claim 15 , wherein the first dielectric comprises at least an oxide monolayer in contact with the silicon substrate.
17. The solar cell of claim 15 , wherein the second dielectric comprises a plurality of oxide monolayers.
18. The solar cell of claim 15 , wherein the first dielectric comprises silicon nitride.
19. The solar cell of claim 15 , wherein the second dielectric comprises silicon dioxide.
20. The solar cell of claim 15 , wherein the silicon substrate comprises a first doped region under the first dielectric and a second doped region under the second dielectric.