Nanopinhole-Enabled, Hole-Selective Poly-Si/SioxNy Passivating Contacts on Textured c-Si for Si Solar Cells

The next-generation silicon photovoltaics will be based on passivating electron- and hole-selective contacts with both very low interface recombination and contact resistivities. While the emerging mainstream TOPCon technology has developed excellent electron-selective poly-Si/tunneling SiOx contacts, hole-selective contacts, especially on textured surfaces, have remained a significant challenge. This contribution introduces novel high-performance hole selective poly-Si contacts on pyramid-textured Si, enabled by electrochemically produced hole transport nanopinholes in a 10 nm oxynitride passivating dielectric stack capped by p+ poly-Si. The highly passivating oxynitride layer is produced via atomic intermixing of O and N atoms in the initial SiOx/SiNy layer stack upon thermal annealing. Carrier transport is governed by nanopinhole density and size are tuned by Ag nanoparticle electrodeposition and surface attachment chemistries. This results in passivating hole contact resistivities in the m..omega..-cm2 range, while preserving interface recombination current prefactor around 5 fA/cm2.. Authors: Steyn, Dirk [National Laboratory of the Rockies, Golden, CO (United States)]; Nemeth, William [National Laboratory of the Rockies, Golden, CO (United States)]; Guthrey, Harvey [National Laboratory of the Rockies, Golden, CO (United States)] (ORCID:0000000315743379); Harvey, Steven [National Laboratory of the Rockies, Golden, CO (United States)] (ORCID:0000000161207062); Young, David [National Laboratory of the Rockies, Golden, CO (United States)]. DOE Contract: AC36-08GO28308. Subjects: 14 SOLAR ENERGY; passivating contacts; photovoltaic; pinholes; silicon