We present the different approaches we recently followed to achieve intense room temperature photoluminescence (PL) from Si-based materials. On one side we obtained sub-bandgap PL from H-related defects induced by the H 2 plasma treatment of Si photonic crystal (PhC) nanocavities. We demonstrated that a strong and narrow PL emission can be obtained in the PhC nanocavities due to the formation of a damaged layer mainly consisting of nanometric platelets and bubbles. An overall 40000-fold enhancement of the PL signal, with respect to pure crystalline Si, has been achieved and moreover the signal can be tuned in a wide range by only changing the PhC parameters. On the other side, we focused our attention on the properties of SiO 2 and SiOC host matrices doped with Eu ions. C addition produces a strong enhancement of the Eu PL with respect to pure SiO 2 films. The chemical and structural …