Swift Heavy Ion-Induced Reactivity and Surface Modifications in Indium Thin Films

Abstract

As an energetic ion traverses a target material, it loses its energy through the processes of electronic energy loss ( S e ) and nuclear energy loss ( S n ). Controlled swift heavy ion (SHI) irradiation on solid targets produces its effects through both of these mechanisms, as a consequence of which modifications occur in the structure, surface morphology, and magnetic and optical properties, apart from ion implantation and ion-induced reactivity. A systematic investigation of these effects can be useful in developing standard protocols for creating desired effects in materials using specific ion beams. In this study, indium films of thickness 25 nm were deposited on silicon substrates and were subjected to 100 MeV O 7+ and 100 MeV Si 7+ ion irradiation, with the fluences varying from 1 × 10 11 to 1 × 10 13 ions/cm 2 . The pristine and SHI-irradiated films were then characterized using glancing incidence X-ray diffraction (GIXRD), Rutherford backscattering spectrometry (RBS), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The motive was to identify the effects of irradiation with different ion species having large variations in electronic and nuclear energy losses. While the RBS results suggest that sputtering is extremely low and that there are no major changes in the film composition due to ion beam-induced mixing, the GIXRD analysis indicates that increasing the ion fluence reduces the crystallinity of the film for both the ions. Ion beam irradiation with O 7+ ions, however, results in beam-induced reactivity, as the GIXRD scan shows characteristic peaks from indium oxide (In 2 O 3 ), which become the predominant peaks at the highest fluence used here. Si 7+ ion irradiation results in a narrowing of the particle size distribution on the surface, with no evidence of reactivity. SEM results indicate fusion and fragmentation of grains with the increase in the ion fluences, and AFM images reveal an increase in the surface roughness of a few percent when irradiated with both 100 MeV O 7+ and 100 MeV Si 7+ ions.

Dielectric study of CoFe2O4/MWCNT/epoxy nanocomposites: Effect of temperature, concentration and irradiation

“…[55] According to theory, energetic ions transfer energy to matter through inelastic collisions with electrons and elastic collision with nuclei known as electronic and nuclei stopping, respectively. [56] Atomic scale defects can emerge in the target material if the energy of incident ions were sufficient to prompt the atoms to migrate from their locations in the lattice during bombardment. To tune the dielectric properties, irradiation introduces defects, dopants, lattice distortion and electron density variation in material.…”

Ion Fluence-Dependent Structural and Electrical Characteristics of Electrochemically Synthesized PANI/ZnO Nano

“…Swift heavy ion irradiation can enhance the electrical, optical, magnetic and catalytic properties of the nanocomposite film by inducing changes in the chemical composition, crystal structure, defect density and surface morphology of the material [13][14][15], while low energy ion beams can only reduce or degrade these properties. Swift heavy ion irradiation can control the extent and nature of the modification in the nanocomposite film by adjusting the parameters such as ion energy, fluence and species [16].…”