Porous silicon (PS) was manufactured by the stain etching method as an antireflection coating. Despite its known efficiency, the rapid degradation of the PS surface is a problem. Therefore, two solutions are realized to ensure its stability. The porous silicon surface is thermally treated under oxygen flux to obtain silicon dioxide  Nickel oxide  is deposed on the porous silicon by sol-gel method. The evolution of their stability is monitored for 18 months. Porous silicon  and silicon dioxide on top of the porous silicon  are unstable while the nickel oxide on top of the porous silicon  remains stable during this period. The Fourier transform infrared spectroscopy (FTIR) analysis showed the oxidation kinetics. The UV-visible-infrared spectroscopy analysis showed that the PS reflectivity was considerably lowered up to 7%, but its highly reactive surface resulted in the reflectivity increase up to 10%. The  and  reflectivity dropped to 6%. Only  achieved stability during 18 months.

porous silicon, silicon dioxide, nickel oxide, antireflection coating.