Ultra-flexible silicon foils with seamless detachability: the effect of porous multilayered structures prepared through modulated electrolyte composition

A comprehensive evaluation of the effect and limitations of variable current density and electrolyte composition on layer porosity and microstructure changes of porous silicon (pSi) multilayer stacks is reported. Following these results, the development and optimization of a four-layer stack architecture is reported through addition of super-low porosity layers (SLPL) on a low/high porosity layer (LPL/HLP) stack. Thermal treatment of these structures achieved excellent top and bottom surface reconstruction to form sintered porous silicon (SPS) detachable foils, enabling direct foil separation using cello tape from a smooth and specular parent substrate without the need to cut or damage it