Suniva, Inc.

Alliance for Sustainable Energy, LLC

Daniel L Meier

Ajeet Rohatgi

David Samuel Ginley

Howard M Branz

Vinodh Chandrasekaran

James Scott Ward

Vernon Yost

Anna Duda

Adam M Payne

A thin silicon solar cell is described. An example solar cell may be fabricated from a crystalline silicon wafer having a thickness of approximately 50 micrometers to 500 micrometers. The solar cell comprises a first region having a p-n homojunction, a second region that creates heterojunction surface passivation, and a third region that creates heterojunction surface passivation. Amorphous silicon layers are deposited on both sides of the silicon wafer. A final layer of transparent conductive oxide is formed on both sides. Metal contacts are applied to the transparent conductive oxide.

Method for making solar cell having crystalline silicon P&#x2014;N homojunction and amorphous silicon heterojunctions for surface passivation

Solar cells and methods for fabrication thereof are provided. A method may include forming a via through at least one dielectric layer formed on a semiconductor wafer by using a laser to ablate a region of the at least one dielectric layer such that at least a portion of the surface of the semiconductor wafer is exposed by the via. The method may further include applying a self-doping metal paste to the via. The method may additionally include heating the semiconductor wafer and self-doping metal paste to a temperature sufficient to drive at least some dopant from the self-doping metal paste into the portion of the surface of the semiconductor wafer exposed by the via to form a selective emitter region and a contact overlying and self-aligned to the selective emitter region.

Solar cells and methods of fabrication thereof

A thin silicon solar cell is described. Specifically, the solar cell may be fabricated from a crystalline silicon wafer having a thickness of approximately 50 micrometers to 500 micrometers. The solar cell comprises a first region having a p-n homojunction, a second region that creates heterojunction surface passivation, and a third region that creates heterojunction surface passivation. Amorphous silicon layers are deposited on both sides of the silicon wafer at temperatures below approximately 400 degrees Celsius to reduce the loss of passivation properties of the amorphous silicon. A final layer of transparent conductive oxide is formed on both sides at approximately 165 degrees Celsius. Metal contacts are applied to the transparent conductive oxide. The low temperatures and very thin material layers used to fabricate the outer layers of used to fabricate the outer layers of the solar cell protect the thin wafer from excessive stress that may lead to deforming the wafer.

Method for making solar cell having crystalline silicon P-N homojunction and amorphous silicon heterojunctions for surface passivation

A method () of texturing silicon surfaces () such to reduce reflectivity of a silicon wafer () for use in solar cells. The method () includes filling () a vessel () with a volume of an etching solution () so as to cover the silicon surface) of a wafer or substrate (). The etching solution () is made up of a catalytic nanomaterial () and an oxidant-etchant solution (). The catalytic nanomaterial () may include gold or silver nanoparticles or noble metal nanoparticles, each of which may be a colloidal solution. The oxidant-etchant solution () includes an etching agent (), such as hydrofluoric acid, and an oxidizing agent (), such as hydrogen peroxide. Etching () is performed for a period of time including agitating or stirring the etching solution (). The etch time may be selected such that the etched silicon surface () has a reflectivity of less than about 15 percent such as 1 to 10 percent in a 350 to 1000 nanometer wavelength range.

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Atlanta, GA, United States of America

Daniel L Meier