Photovoltaic devices including curved sub-layers
A photovoltaic device includes an intrinsic layer having two or more sublayers. The sublayers are intentionally deposited to include complementary concave and convex shapes. The sum of these layers resulting in a relatively flat surface for deposition of n- or p-doped layers. The photovoltaic device is optionally bifacial.
1. A photovoltaic device comprising:
a wafer substrate;
a first absorber layer disposed on a first side of the wafer substrate;
a second absorber layer, the first absorber layer being disposed between the wafer substrate and the second absorber layer, the first and second absorber layer sharing a first curved interface;
a first doped layer, a boundary between the second absorber layer and the first doped layer being flatter than the first curved interface;
a first transparent conductive layer, the first doped layer being disposed between the first transparent conductive layer and the wafer substrate;
front conductors in contact with the transparent conductive layer; and
rear conductors disposed on a second side of the wafer substrate.
2. The device of claim 1 , wherein the first absorber layer is concave and the second absorber layer is convex.
3. The device of claim 1 , wherein the first absorber layer is convex and the second absorber layer is concave.
4. The device of claim 1 , further comprising
a third absorber layer disposed on the second side of the wafer substrate;
a fourth absorber layer, the third absorber layer being disposed between the wafer substrate and the fourth absorber layer, the third and fourth absorber layer sharing a second curved interface; and
an second doped layer, a boundary between the fourth absorber layer and the second doped layer being flatter than the second curved interface.
5. The device of claim 4 , further comprising a reflective conductive layer, the second doped layer being disposed between the reflective conductive layer and the wafer substrate.
6. The device of claim 4 , further comprising a second transparent conductive layer, the second doped layer being disposed between the second transparent conductive layer and the wafer substrate.
7. The device of claim 1 , wherein the wafer substrate includes an etched surface.
8. The device of claim 1 , wherein the first and second absorber layer consist of the same materials.
9. The device of claim 1 , wherein the first and second absorber layer consist of the same materials at the same concentrations.
10. The device of claim 1 , wherein the second absorber layer includes a gradient of dopant material, a concentration of the dopant material being greater proximate to the first doped layer.
11. The device of claim 1 , wherein the second absorber layer includes a greater amount of dopant material, relative to the first absorber layer.
12. The device of claim 1 , wherein the second absorber layer includes a seed material configured for growth of the first doped layer.
13. The device of claim 12 , wherein the seed material includes boron.
14. The device of claim 1 , wherein the second absorber layer includes a greater concentration of protons, relative to the first absorber layer.
15. The device of claim 1 , wherein a minimum thickness of the first absorber layer is at least 5% less than a maximum thickness of the first absorber layer.
16. The device of claim 1 , wherein an average total thickness of the first and second absorber layers is less than 50 angstroms.
17. The device of claim 1 , wherein the boundary between the second absorber layer and the p-doped layer is at least 5% more uniform than the first curved surface.
18. The device of claim 1 , wherein the first doped layer is n-doped and the second doped layer is p-doped.
19. The device of claim 1 , wherein the first doped layer is p-doped and the second doped layer is n-doped.