Method for making solar cell having crystalline silicon p-n homojunction and amorphous silicon heterojunctions for surface passivation

Abstract

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.