High‐strength nanostructured black‐silicon wafer for photovoltaic applications

Silicon nanostructures can improve the bending strength of wafers, but often trap particle contaminates. A double‐sided surface nanostructure with a morphology controlled via wet chemical etching is used to both improve the mechanical strength and reduce surface reflection. Compared with a conventional polished silicon wafer, the bending strength was increased by 3.4 times and the surface reflection was reduced to 1%, and so can provide a promising solution for photovoltaic applications. The optically unused side of the wafer was protected by a thin silicon layer that prevented the entrapment of particles that might cause glitches in subsequent fabrication processes, all the while maintaining the enhancement in strength. The particle test confirmed that incorporating protection layer intacts the particle count with polished silicon sample.