Toward BaSi2/Si Heterojunction Thin‐Film Solar Cells: Insights into Heterointerface Investigation, Barium Depletion, and Silicide‐Mediated Silicon Crystallization

The knowledge of the structural and compositional details of Si/BaSi2/Si heterostructure annealed at high temperature is a prerequisite for BaSi2 application in heterojunction thin‐film solar cells. For this purpose, Si/BaSi2/Si heterostructures deposited by magnetron sputtering with different Si layer thickness are submitted to systematic structural and compositional characterizations. Results reveal a BaSi2/Si heterointerfacial variation caused by surface oxidation and Ba diffusion at the high temperature. Its effects on the optical and electrical properties of Si/BaSi2/Si heterostructure are presented. The outcomes of this work can be extended to BaSi2 deposited by other techniques, and generate substantial advantages in BaSi2 development ranging from improvement on material qualities and eventual deployment in thin‐film solar cells. Comprehensive structure and composition investigations upon the sputtered Si/BaSi2/Si heterojunction reveal the complex interfacial variations, such as surface oxidation, Ba depletion, and Si crystallization, which alter its optical and electrical properties for photovoltaic applications. The outcome provides knowledge for BaSi2 material improvement and its eventual deployment in thin‐film solar cells.