Swift heavy ion irradiation assisted Si nanoparticle formation in HfSiOx nano-composite thin films deposited by RF magnetron sputtering method

Silicon co-deposited HfOx thin films were prepared by RF magnetron sputtering method. The average size of Si co-deposited nanocomposites is around 10–12 nm. 100 MeV Ag ion irradiation induces the Si nano-crystal formation within the nanocomposite. The average grain size of the Si nano-crystals increases with the increase of ion fluence. The observed luminescence at 430 nm is due to oxygen related defect states and the luminescence at 530 nm may be attributed to the emission from Si nanoparticles. Red shift in emission wavelength indicates either the increase in the size of the nanoparticles or ion induced change in the dielectric constant of surrounding medium. The increase in the intensity of the luminescence peak at 440 nm indicates the creation of defect states by ion irradiation. Raman measurements further confirm the formation of Si NPs that are embedded in the composite medium.