High-Efficiency Thin-Film Solar Cells

1 . A three-dimensional solar cell, comprising:

a plurality of ridges on the surface of a semiconductor substrate defining an opening of an inverted pyramidal cavity;

a plurality of walls defining said inverted pyramidal cavity;

emitter metallization regions on said ridges forming the opening of said inverted pyramidal cavity; and

base metallization regions on a region forming an apex of said inverted pyramidal cavity.

2 . The solar cell of claim 1 , wherein said semiconductor substrate is a mono-crystalline silicon substrate.

3 . The solar cell of claim 1 , wherein said base metallization regions are mounted on a metal surface of a carrier plate to form base interconnects.

4 . The solar cell of claim 1 , wherein a diagonal dimension defining said base opening of said inverted pyramidal cavity is in the range of 1 um to 1 mm.

5 . The solar cell of claim 1 , wherein said semiconductor substrate comprises a plurality of said inverted pyramidal cavities.

6 . The solar cell of claim 5 , wherein said plurality of said inverted pyramidal cavities have a plurality of pyramidal shapes.

7 . The solar cell of claim 5 , wherein said plurality of said inverted pyramidal cavities have a plurality of pyramidal sizes.

8 . The solar cell of claim 5 , wherein said ridges forming the opening of each of said inverted pyramidal cavities have a width ranging from 10 um to 100 um.

9 . The solar cell of claim 5 , wherein said apex of said inverted pyramidal cavities further is substantially planar.

10 . The solar cell of claim 5 , wherein said plurality of said inverted pyramidal cavities are arranged in arrays on the silicon substrate.

11 . The solar cell of claim 5 , wherein said plurality of said inverted pyramidal cavities are arranged in a staggered pattern on the silicon substrate.

12 . The solar cell of claim 5 , wherein said plurality of said inverted pyramidal cavities comprise:

a first plurality of inverted pyramidal cavities; and

a second plurality of inverted pyramidal cavities,

wherein a diagonal dimension defining said base opening of said second plurality of inverted pyramidal cavities is smaller than a diagonal dimension defining said base opening of said first plurality of inverted pyramidal cavities.

13 . The solar cell of claim 12 , wherein said plurality of said inverted pyramidal cavities are arranged in a staggered pattern on the silicon substrate.

14 . The solar cell of claim 12 , wherein said apex of said inverted pyramidal cavities of said first plurality of inverted pyramidal cavities is substantially planar.

15 . A method for fabrication of a three-dimensional thin-film solar cell from an inverted pyramidal three-dimensional thin-film silicon substrate, the method comprising:

doping ridges forming an opening of an inverted pyramidal cavity on a first side of said silicon substrate with a n-type dopant to form an emitter region;

doping a region forming an apex of said inverted pyramidal cavity on a second side of said silicon substrate with a p-type dopant to form a base region;

adding a surface passivation layer to said first side and said second side of said silicon substrate;

selectively etching said passivation layer on said emitter region and said base region to form contact openings; and

concurrently metallizing said emitter region and said base region.

16 . The method of claim 15 , wherein said step of doping ridges forming an opening of an inverted pyramidal cavity further comprises:

selectively coating ridges forming an opening of an inverted pyramidal cavity on a first side of said silicon substrate with a n-type dopant; and

forming an emitter region on said ridges forming an opening according to a thermal annealing process.

17 . The method of claim 15 , wherein said step of doping a region forming an apex of said inverted pyramidal cavity further comprises:

selectively coating a region forming an apex of said inverted pyramidal cavity on a second side of said silicon substrate with a p-type dopant; and

forming a base region on said region forming an apex according to a thermal annealing process.

18 . The method of claim 15 , wherein said step of adding a surface passivation layer to said first side and said second side of said silicon substrate comprises adding a thermally grown silicon dioxide.

19 . The method of claim 15 , further comprising the step of mounting said base region onto a metal surface of a carrier plate to form metal base interconnects.

20 . A method for fabrication of a three-dimensional thin-film solar cell from an inverted pyramidal three-dimensional thin-film silicon substrate, the method comprising:

doping ridges forming an opening of an inverted pyramidal cavity on a first side of said silicon substrate with a p-type dopant to form a base region;

doping a region forming an apex of said inverted pyramidal cavity on a second side of said silicon substrate with a n-type dopant to form an emitter region;

adding a surface passivation layer to said first side and said second side of said silicon substrate;

selectively etching said passivation layer on said emitter region and said base region to form contact openings; and

concurrently metallizing said emitter region and said base region.