Sensitivity of Anatase and Rutile Phases of TiO2 to ion irradiation: Examination of the applicability of Coulomb Explosion and Thermal Spike Models

Abstract

Sensitivity of the anatase and rutile phases of titanium dioxide to Swift Heavy Ion (SHI) irradiation was experimentally probed and compared with the predictions of the Coulomb explosion, analytical and inelastic thermal spike models of ion-matter interaction. Conforming to the predictions of all these models, our study indicated higher sensitivity of anatase to these ions than the rutile phase. A detailed examination however revealed that Coulomb explosion model cannot explain either the nature of variation of the interaction cross section of SHI with the energy deposited by these ions, Se to the target electrons, or the relative values of the threshold electronic energy loss, Seth of anatase and rutile. The analytical thermal spike (a-TS) model, using the available physicochemical data for this oxide, predicted that tracks cannot form either in anatase or in rutile by 297 MeV and 511 MeV Ni ions, while inelastic thermal spike (i-TS) model predicted formation of ion tracks by 297 MeV Ni ions and their absence with 511 MeV Ni ions in both anatase and rutile. Our observation agreed with the predictions of i-TS model albeit with a difference in the radius of the tracks. In addition, we observed halo of defect ridden crystalline region of much larger radius around the ion track. Interestingly, the radius of the halo scales with the velocity of the ions, which is opposite to the conventionally observed velocity effect.

The impact of fluence dependent 120 MeV Ag swift heavy ion irradiation on the changes in structural, electronic, and optical properties of AgInSe2 nano-crystalline thin films for optoelectronic applications

“…Suppression of the GIXRD peak with increasing ion uence indicates 120 MeV Ag ion irradiationinduced damage in the structure of the AgInSe 2 thin lm, while the peak disappearing at high ion uences indicates amorphous track formation along the ion path. [32][33][34] Though the value of S eth for the creation of amorphized latent tracks in AgInSe 2 is not known as yet, our observation revealed its value to be less than the S e (16.5 keV nm À1 ) of 120 MeV Ag ions, which completely amorphized this compound at high ion uences. To extract the radius of ion tracks, we have tted the uence versus normalized area under the (112) GIXRD peak to Poisson equation…”

Simulation of Two-Dimensional Images for Ion-Irradiation Induced Change in Lattice Structures and Magnetic States in Oxides by Using Monte Carlo Method

“…The previous TEM (transmission electron microscope) observations, however, clearly show that just inside the ion-track in TiO 2 , the structure becomes amorphous, and outside the iontrack, the crystal structure is maintained [26,27]. The XRD peaks for TiO 2 samples which are almost completely amorphized by high energy heavy ion irradiation are much smaller than for the unirradiated crystalline TiO 2 and are scarcely observed [22]. These experimental results, therefore, justify the above model for the analysis of ion track overlapping in TiO 2 , and the fraction of amorphized area can be estimated by the decrease in XRD peak intensity.…”

“…A lot of studies have been performed in order to investigate the individual ion-track structures and their dependence on the electronic stopping power, Se, of the irradiating ions [10][11][12][13][14][15]. The effects of the ion-track overlapping on lattice structures of target materials, which appear for the high fluence irradiation, have also been investigated so far [10,[16][17][18][19][20][21][22].…”

Probing the beam‐induced heating effect inside a transmission electron microscope by nanoparticle labels

“…A method developed by Liu and Risbud is employed to semiquantitatively calculate the heat accumulation during electron-beam irradiation by treating the system as spherical particles embedded in thin films [26]. The input power is generated from electron collisions considered as cylindrical thermal spikes [27,28], and the heat dissipation is thermal conduction from the surrounding film. When the high energy electrons interact with the sample atoms, beam-induced temperature increase can be modelled as…”