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

One hundred and twenty keV Gion 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 similar to435 +/- 10 nm was formed in all ion irradiated samples and a weak ultraviolet PL band centred at similar to380 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 S-e when S-e < 4.85 keV/nm but increases for S-e > 4.85 keV/nm. Furthermore, the peak central position of the blue-violet PL is shifted slightly to violet with increasing S, 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 S-c. Possible origins and formation mechanism of light-emitters corresponding to the observed PL bands are discussed. (C) 2002 Elsevier B.V. All rights reserved.