Abstract: Laser processing schemes are disclosed for producing various types of hetero-junction and homo-junction solar cells. The methods include base and emitter contact opening, selective doping, and metal ablation. Also, laser processing schemes are disclosed that are suitable for selective amorphous silicon ablation and selective doping for hetero-junction solar cells. These laser processing techniques may be applied to semiconductor substrates, including crystalline silicon substrates, and further including crystalline silicon substrates which are manufactured either through wire saw wafering methods or via epitaxial deposition processes, that are either planar or textured/three-dimensional. These techniques are highly suited to crystalline semiconductor, including crystalline silicon.

Abstract: A method for making a back contact solar cell. Base isolation regions are formed in a crystalline silicon back contact solar cell substrate having a substrate thickness in the range of approximately 1 micron to 100 microns. Pulsed laser ablation of a substance on the crystalline silicon back contact solar cell substrate is performed to form base openings, wherein the substance is at least one of silicon oxide, silicon nitride, aluminum oxide, silicon oxynitride, or silicon carbide. Emitter regions are selectively doped and base regions are selectively doped. Contact openings are formed for the selectively doped base regions and the selectively doped emitter regions. Metallization is formed on the selectively doped base regions and the selectively doped emitter regions.

Abstract: One embodiment of the present invention provides a heterojunction solar cell. The solar cell includes a metallurgical-grade Si (MG-Si) substrate, a layer of heavily doped crystalline-Si situated above the MG-Si substrate, a layer of lightly doped crystalline-Si situated above the heavily doped crystalline-Si layer, a backside ohmic-contact layer situated on the backside of the MG-Si substrate, a passivation layer situated above the heavily doped crystalline-Si layer, a layer of heavily doped amorphous Si (a-Si) situated above the passivation layer, a layer of transparent-conducting-oxide (TCO) situated above the heavily doped a-Si layer, and a front ohmic-contact electrode situated above the TCO layer.

Abstract: One embodiment of the present invention provides a heterojunction solar cell. The solar cell includes a metallurgical-grade Si (MG-Si) substrate, a layer of heavily doped crystalline-Si situated above the MG-Si substrate, a layer of lightly doped crystalline-Si situated above the heavily doped crystalline-Si layer, a backside ohmic-contact layer situated on the backside of the MG-Si substrate, a passivation layer situated above the heavily doped crystalline-Si layer, a layer of heavily doped amorphous Si (a-Si) situated above the passivation layer, a layer of transparent-conducting-oxide (TCO) situated above the heavily doped a-Si layer, and a front ohmic-contact electrode situated above the TCO layer.

Abstract: One embodiment of the present invention provides a method for fabricating a solar cell. The method includes: melting a metallurgical-grade (MG) Si feedstock, lowering a single-crystalline Si seed to touch the surface of the molten MG-Si, slowly pulling out a single-crystal Si ingot of the molten MG-Si, processing the Si ingot into single crystal Si wafers to form MG-Si substrates for subsequent epitaxial growth, leaching out residual metal impurities in the MG-Si substrate, epitaxially growing a layer of single-crystal Si thin film doped with boron on the MG-Si substrate, doping phosphor to the single-crystal Si thin film to form an emitter layer, depositing an anti-reflection layer on top of the single-crystal Si thin film, and forming the front and the back electrical contacts.

Abstract: Laser processing schemes are disclosed for producing various types of hetero-junction and homo-junction solar cells. The methods include base and emitter contact opening, selective doping, and metal ablation. Also, laser processing schemes are disclosed that are suitable for selective amorphous silicon ablation and selective doping for hetero-junction solar cells. These laser processing techniques may be applied to semiconductor substrates, including crystalline silicon substrates, and further including crystalline silicon substrates which are manufactured either through wire saw wafering methods or via epitaxial deposition processes, that are either planar or textured/three-dimensional. These techniques are highly suited to thin crystalline semiconductor, including thin crystalline silicon films.

Abstract: One embodiment of the present invention provides a heterojunction solar cell. The solar cell includes a metallurgical-grade Si (MG-Si) substrate, a layer of heavily doped crystalline-Si situated above the MG-Si substrate, a layer of lightly doped crystalline-Si situated above the heavily doped crystalline-Si layer, a backside ohmic-contact layer situated on the backside of the MG-Si substrate, a passivation layer situated above the heavily doped crystalline-Si layer, a layer of heavily doped amorphous Si (a-Si) situated above the passivation layer, a layer of transparent-conducting-oxide (TCO) situated above the heavily doped a-Si layer, and a front ohmic-contact electrode situated above the TCO layer.

Abstract: Laser processing schemes are disclosed for producing various types of hetero-junction and homo-junction solar cells. The methods include base and emitter contact opening, selective doping, and metal ablation. Also, laser processing schemes are disclosed that are suitable for selective amorphous silicon ablation and selective doping for hetero-junction solar cells. These laser processing techniques may be applied to semiconductor substrates, including crystalline silicon substrates, and further including crystalline silicon substrates which are manufactured either through wire saw wafering methods or via epitaxial deposition processes, that are either planar or textured/three-dimensional. These techniques are highly suited to thin crystalline semiconductor, including thin crystalline silicon films.

Abstract: One embodiment of the present invention provides a heterojunction solar cell. The solar cell includes a metallurgical-grade Si (MG-Si) substrate, a layer of heavily doped crystalline-Si situated above the MG-Si substrate, a layer of lightly doped crystalline-Si situated above the heavily doped crystalline-Si layer, a backside ohmic-contact layer situated on the backside of the MG-Si substrate, a passivation layer situated above the heavily doped crystalline-Si layer, a layer of heavily doped amorphous Si (a-Si) situated above the passivation layer, a layer of transparent-conducting-oxide (TCO) situated above the heavily doped a-Si layer, and a front ohmic-contact electrode situated above the TCO layer.

Abstract: One embodiment of the present invention provides a method for fabricating a solar cell. The method includes: melting a metallurgical-grade (MG) Si feedstock, lowering a single-crystalline Si seed to touch the surface of the molten MG-Si, slowly pulling out a single-crystal Si ingot of the molten MG-Si, processing the Si ingot into single crystal Si wafers to form MG-Si substrates for subsequent epitaxial growth, leaching out residual metal impurities in the MG-Si substrate, epitaxially growing a layer of single-crystal Si thin film doped with boron on the MG-Si substrate, doping phosphor to the single-crystal Si thin film to form an emitter layer, depositing an anti-reflection layer on top of the single-crystal Si thin film, and forming the front and the back electrical contacts.