Exploring silicon carbide- and silicon oxide-based layer stacks for passivating contacts to silicon solar cells

Abstract

We present the development of passivating contacts for high-efficiency silicon solar cells using silicon oxide (SiOx) and silicon carbide (SiCx)-based layers. We discuss a comprehensive optimization of a SiCx-based passivating hole contact reaching implied open circuit voltages >715 mV. In addition, we introduce a passivating hole contact based on nanocrystalline SiOx (nc-SiOx) targeting compatibility with higher process temperatures as well as increased optical transparency for front side application. First planar test devices employing nc-SiOx-based passivating contacts for both charge carrier types are presented, yielding short-circuit current densities >34 mA/cm(2) and fill factors >78%, showing that efficient current extraction is possible despite the added SiOx phase and also indicating potential optical advantages of the concept.