Ion beam shaping of Au nanoparticles in silica: Particle size and concentration dependence

Abstract

Irradiation with swift heavy ions of spherical Au nanoparticles confined within a silica matrix shapes them into prolate nanorods and nanowires whose principal axes are aligned along the beam direction. In the present paper, we investigate the role that is played by the initial nanoparticle size and concentration in this so-called ion-shaping mechanism. We have produced silica films wherein Au nanoparticles with average diameters of 15, 30, and 45 nm were embedded within a single plane and have irradiated these films at 300 K at normal incidence with 18, 25, and 54 MeV Ag ions. We demonstrate the existence of both threshold and saturation fluences for the elongation effects mentioned. The values of these critical fluences depend both on the ion energy and the initial nanoparticle size. Moreover, we show that 45 nm Au particles are not deformed when irradiated with 18 MeV Ag ions, such that this value corresponds to an energy threshold for the deformation process. As far as the influence of the nanoparticle concentration on the shaping characteristics is concerned, we have found that above the critical irradiation fluence, the deformation effect becomes very sensitive to the initial concentration of the nanoparticles.

Localized Plasmonic Resonances of Prolate Nanoparticles in a Symmetric Environment: Experimental Verification of the Accuracy of Numerical and Analytical Models

“…The effects of swift heavy-ion irradiation on metallic NPs embedded in SiO 2 have been studied by different groups [60,61,64,65,67] who observed that, during irradiation, the silica matrix dilates perpendicular to the beam direction, while the metallic NP deforms and elongates along the beam direction. Moreover, the deformation and elongation of the metallic NP depends on its initial size and shape, its chemical composition, the irradiation fluence, and the position where the NP is placed in the matrix with respect to the substrate [67].…”

Zn nanoparticles irradiated with swift heavy ions at low fluences: Optically-detected shape elongation induced by nonoverlapping ion tracks

“…[8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] Here we summarize early discussion of the elongation mechanism, while any decisive mechanisms have yet to be proposed. D'Orleans et al 7 pointed out that the lattice temperature of smaller NPs increases to a greater extent based on the thermal spike model.…”

Ion engineering of embedded nanostructures: From spherical to facetted nanoparticles

“…Deformation can be induced indirectly by embedding the NPs into an ion-deformable amorphous host matrix. [2][3][4][5][6] With this technique, spherical NPs deform into prolate nanorods and nanowires, with an aspect ratio that can be tuned by varying the irradiation conditions ͑ion type, energy and fluence͒. In this work, we show that the ion-shaping mechanism is not only limited to the transformation of spherical NPs into prolate nanorods/nanowires, but that, depending on the NP size and irradiation conditions, a different class of ionshaped NPs can be obtained, namely, embedded NPs with a facettedlike morphology.…”

“…For more details about the sample preparation we refer the reader to the literature. 6,9 The experiments were carried out with the aid of the GANIL facilities in Caen ͑France͒. High energy ͑HE͒ was used to obtain 5 GeV Pb ions.…”