Ion-induced photon emission under nanoparticle fabrication

Metal-ion implantation is well established as a suitable technique for fabrication of nanoparticles embedded in insulators. Photon emission induced by 60 keV Cu − incident ion was in situ measured over a wavelength range from 200 to 900 nm. Special attention was paid to the behavior of the Cu I atomic line emission related to the mass transport of implants. Based on comparison of experimental results for the wide band gap materials (SiO 2 and MgAl 2 O 4 ) with those for metals (W, Mo, Al), it is concluded that, at the beginning of ion bombardment, the radiation is mostly emitted by backscattered atoms. The causes of this are different for the different groups of materials: the high backscattering yield in the case of metals and the high survival probability of the excited backscattered atoms in the case of insulators, when the excitation levels lie below the conduction band edge and the radiative decay is only the available channel for deexcitation. Significant contribution in the Cu I line intensity was observed with increasing dose due to sputtered Cu atoms.