Blue–violet PL band formation in C:SiO2 films after swift heavy ion irradiation

One hundred and twenty keV C-ion doped SiO2 films were irradiated at RT with swift Ar, Kr, Xe or U ions and their photoluminescence (PL) properties were examined. From the obtained results, we found that an intense blue–violet PL band centred at ∼435±10 nm was formed in all ion irradiated samples and a weak ultraviolet PL band centred at ∼380 nm was formed only in the samples after Kr, Xe or U ion irradiations. The PL peak intensity of the blue–violet band (i) increases with the increase of the swift heavy ion irradiation fluence, (ii) decreases with the increase of electronic energy loss Se when Se 4.85 keV/nm. Furthermore, the peak central position of the blue–violet PL is shifted slightly to violet with increasing Se and some substructures appeared in the PL spectra of the samples irradiated with Xe or U ions. The appearance of these substructures is due to the high electronic energy loss. For the violet PL band, the intensity increases with Se. Possible origins and formation mechanism of light-emitters corresponding to the observed PL bands are discussed.