Asymmetric surface texturing for use in a photovoltaic cell and method of making
AssigneeGTAT Corporation
InventorChristopher J Petti
Life of this patent
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Abstract
A novel surface texturing provides improved light-trapping characteristics for photovoltaic cells. The surface is asymmetric and includes shallow slopes at between about 5 and about 30 degrees from horizontal as well as steeper slopes at about 70 degrees or more from horizontal. It is advantageously used as either the front or back surface of a thin semiconductor lamina, for example between about 1 and about 20 microns thick, which comprises at least the base or emitter of a photovoltaic cell. In embodiments of the present invention, the shallow slopes are formed using imprint photolithography.
Claims10
A photovoltaic assembly comprising:
- a monocrystalline semiconductor lamina having a thickness between about 0.5 and about 20 microns, the semiconductor lamina having a first textured surface and a second surface substantially parallel to the first textured surface, wherein
- at least 50 percent of the first textured surface area is first faces and second faces, wherein the first faces are at an angle between ten and twenty-five degrees from horizontal, and the second faces are at least seventy degrees from horizontal, wherein the semiconductor lamina has a lamina widest dimension;
- and
- a receiver element having a receiver widest dimension, wherein the semiconductor lamina is affixed to the receiver element at the second surface, wherein the receiver widest dimension does not exceed the lamina widest dimension by more than about 50 percent,
- wherein the photovoltaic assembly comprises a photovoltaic cell.
A photovoltaic cell comprising:
- a front surface of the photovoltaic cell;
- a back surface of the photovoltaic cell;
- and
- a monocrystalline silicon lamina between about 0.5 and about 20 microns thick;
- wherein incident light enters the photovoltaic cell at the front surface, and at least a fraction of the incident light is reflected from the back surface,
- wherein the incident light is reflected or refracted at a textured surface, wherein the textured surface is the front surface, the back surface, or a third surface between the front surface and the back surface, and
- wherein at least 50 percent of the textured surface comprises first faces and second faces, wherein the first faces are at an angle between ten and twenty-five degrees from horizontal, and the second faces are at least seventy degrees from horizontal.
Dependencies are inferred from the claim text.