The thickness of the surface layer of porous silicon

For the first time, the thickness of the surface layer of porous silicon was determined. Monocrystalline silicon has a layer thickness of about 2 nm. This thickness can be experimentally determined using sliding x-rays in the mode of total internal reflection. The d(I)Si layer of atomically smooth single-crystal silicon is a nanostructure. The number of silicon particles in the monolayer is n=d(I)Si/a ≈ 4. It is shown that, starting from 80% porosity, silicon, by its properties of the d(II)Si layer, goes beyond the Gleiter nanostructure.