Polysilicon Passivating Contacts for Silicon Solar Cells: Interface Passivation and Carrier Transport Mechanism

• DOI: 10.1021/acsaem.8b02149
• Publication Date: 2019-06-25T17:49:25Z
• Authors: Wenzhu Liu; Xinbo Yang; Jingxuan Kang; Shuai Li; Lujia Xu; Song Zhang; Hang Xu; Jun Peng; Feng Xie; Jui-Han Fu; Kai Wang; Jiang Liu; Areej Alzahrani; Stefaan De Wolf
• Keywords: Passivation; Acceptor; Forming gas

Polysilicon passivating contacts, consisting of a stack tunnel-oxide and doped polysilicon layers, can simultaneously provide excellent surface passivation low contact resistivity for silicon solar cells. Nevertheless, the microscopic interfacial characteristics such contacts are not yet fully understood. In this work, by investigating evolution under increasing annealing temperatures, we unveil these characteristics. Before annealing, find that Si O atoms within layer mostly unsaturated, whereas introduce acceptor-like defects. These defects cause Fermi-level pinning high carrier recombination. During identify two distinct chemical regimes driven hydrogenation oxidation. We attribute activated high-temperature (∼850 °C) mainly to tunnel oxide reconstruction, which effectively reduces state density. also subnanometer pits (rather than pinholes) formed in oxide. A combination experimental theoretical investigations demonstrates efficient tunneling majority carriers.