Sponge-like and columnar porous silicon implanted with nitrogen by plasma immersion ion implantation (PIII)

Sponge-like and columnar porous silicon (PS) were prepared from p- and n-type (100) monocrystalline silicon wafers using different anodization conditions (hydrofluoric acid concentration, current density and anodization time) and then implanted with nitrogen by plasma immersion ion implantation (PIII). The effect of the implantation and of the compounds formed was analyzed by measuring the reflectance of the implanted samples for wavelengths between 220 and 800 nm. A reduction in reflectance in the ultraviolet (UV) region of the spectrum was observed for polished Si samples and for all kinds of PS samples. Increased UV-induced photoluminescence in these samples caused by the increase in absorption in the UV region is expected.