Elongation mechanism of the ion shaping of embedded gold nanoparticles under swift heavy ion irradiation

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS

卷:451

Article

Vu, T. H. Y.¹  Dufour, C.²  Khomenkov, V.^2,5  Leino, A. A.^3,4  Djurabekova, F.^3,4  Nordlund, K.^3,4  Coulon, P. -E.¹  Rizza, G.¹  Hayoun, M.¹ 

[1] Univ Paris Saclay, Ecole Polytech, CNRS, Lab Solides Irradies,CEA, F-91128 Palaiseau, France

[2] Univ Caen, CNRS, CEA, CIMAP,ENSICAEN, Bd H Becquerel,Botte Postale 5133, F-14070 Caen 5, France

[3] Univ Helsinki, Helsinki Inst Phys, POB 43, FI-00014 Helsinki, Finland

[4] Univ Helsinki, Dept Phys, POB 43, FI-00014 Helsinki, Finland

[5] Inst Nucl Res, 47 Nauky Ave, UA-03680 Kiev, Ukraine

关键词: Nanocomposite;    Silica;    Gold nanoparticles;    Ion irradiation;    Ion shaping;    Simulation;    Three-dimensional thermal spike (3DTS);    Molecular dynamics (MD);   

DOI  :  10.1016/j.nimb.2019.04.067

来源: Elsevier

【 摘 要 】

The elongation process under swift heavy ion irradiation (74 MeV Kr ions) of gold NPs, with a diameter in the range 10-30 nm, and embedded in a silica matrix has been investigated by combining experiment and simulation techniques: three-dimensional thermal spike (3DTS), molecular dynamics (MD) and a phenomenological simulation code specially developed for this study. 3DTS simulations evidence the formation of a track in the host matrix and the melting of the NP after the passage of the impinging ion. MD simulations demonstrate that melted NPs have enough time to expand after each ion impact. Our phenomenological simulation relies on the expansion of the melted NP, which flows in the track in silica with modified (lower) density, followed by its recrystallization upon cooling. Finally, the elongation of the spherical NP into a cylindrical one, with a length proportional to its initial size and a width close to the diameter of the track, is the result of the superposition of the independent effects of each expansion/recrystallization process occurring for each ion impact. In agreement with experiment, the simulation shows the gradual elongation of spherical NPs in the ion-beam direction until their widths saturate in the steady state and reach a value close to the track diameter. Moreover, the simulations indicate that the expansion of the gold NP is incomplete at each ion impact.

【 授权许可】

Free