Template synthesis of monodisperse submicrometer spherical nanoporous silicon particles

Monodisperse spherical nanoporous silicon ($np$-Si) particles of submicrometer size are fabricated with mesoporous silica particles as a template. Silicon is synthesized within the mesopores of monodisperse silica particles by the thermal decomposition of monosilane. Then, the template material ($a$-SiO$_2$) is removed by wet etching. The particles obtained have a small root-mean-square size scatter (no more than 10%) and large specific surface area (250 m$^2$ g$^{-1}$) and pore volume (0.5 cm$^3$ g$^{-1}$). It is shown that $np$-Si particles exhibit photoluminescence in the visible and near-IR (infrared) spectral ranges.