High throughput parallel backside contacting and periodic texturing for high-efficiency solar cells
Disclosed are configurations of long-range ordered features of solar cell materials, and methods for forming same. Some features include electrical access openings through a backing layer to a photovoltaic material in the solar cell. Some features include textured features disposed adjacent a surface of a solar cell material. Typically the long-range ordered features are formed by ablating the solar cell material with a laser interference pattern from at least two laser beams.
1. A method of fabricating a pattern of long-range ordered electrical access openings through a backing layer of a solar cell to provide access to a photovoltaic material adjacent the backing layer, the method comprising:
directing at least two at least partially overlapping laser beams onto the backing layer to form an interference pattern comprising a plurality of first substantially equally-spaced parallel lines;
directing at least two at least partially overlapping laser beams onto the backing layer to form an interference pattern comprising a plurality of second substantially equally-spaced parallel lines disposed at a non-zero angle with respect to the first parallel lines; and
exposing the backing layer to the interference patterns for a time sufficient to ablate the backing layer to form the pattern of electrical access openings completely through the backing layer to expose the photovoltaic material, the electrical access openings disposed only at locations where the first parallel lines intersect the second parallel lines.
2. The method of claim 1 wherein an average spacing distance between adjacent first parallel lines is within a range from approximately 1 micrometer to approximately 50 micrometers, and wherein an average spacing distance between adjacent second parallel lines is within a range from approximately 1 micrometer to approximately 50 micrometers.
3. The method of claim 1 wherein the electrical access openings have an average width within a range from approximately 0.5 micrometer to less than 10 micrometers.
4. The method of claim 1 wherein a standard deviation in spacing distance between adjacent electrical access openings ranges from about 10 percent to about 50 percent of the average spacing distance.