Assisted electrochemical etching of photonic luminescent multilayers of porous silicon

Porous silicon is produced by electrochemical etching of crystalline silicon substrates in an electrolyte usually composed of aqueous HF and ethanol. Under this condition, photonic multilayers can be built with highly p-type-doped (p(+)) substrates, or luminescent layers can be produced with lightly p-type-doped (p(-)) substrates. The task of building structures with both features has not been successfully achieved. In this paper, it is shown that assisted electrochemical etching of p(+) substrates with polyoxometalate and H2O2 can produce multilayers with both features: luminescence in the visible region and optical quality for photonic applications.