Raman scattering investigation of C-doped a-SiO2 after high energy heavy ion irradiations

Thermally grown amorphous SiO2 films were implanted at room temperature with 100 keV C-ions to 5.0x10(17) or 1.2x10(18) ions/cm(2). These samples were irradiated at room temperature with 853 MeV Pb-ions to 5.0x10(11), 1.0x10(12), 5.0x10(12) ions/cm(2), or with 308 MeV Xe-ions to 1.0x10(12), 1.0x10(13), 1.0x10(14) ions/cm(2), respectively. Then the samples were investigated using micro-Raman spectroscopy. From the obtained Raman spectra, we deduced that Si C bonds and sp(2) carbon sites were created and nano-inclusions may also be produced in the heavy ion irradiated C-doped SiO2. Furthermore, some results show that Pb ion irradiations could produce larger size inclusions than Xe ions and the inclusion size decreased with increasing the irradiation fluence. The possible modification process of C-doped a-SiO2 under swift heavy ion irradiations was briefly discussed.