Anisotropic deformation of colloidal particles under MeV ion irradiation

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

卷:175

Article; Proceedings Paper

van Dillen, T ; Snoeks, E ; Fukarek, W ; van Kats, CM ; Velikov, KP ; van Blaaderen, A ; Polman, A

关键词: anisotropic deformation;    ion irradiation;    colloid;    SiO2;    thermal spike;   

DOI  :  10.1016/S0168-583X(00)00611-X

来源: Elsevier

【 摘 要 】

Spherical silica colloids with a diameter of 1.0 mum, made by wet chemical synthesis, were irradiated with 2-16 MeV Au ions at fluences ranging from 2 x 10(14) to 11 x 10(14) cm(-2). The irradiation induces an anisotropic plastic deformation turning the spherical colloids into ellipsoidal oblates. After 16 MeV Au irradiation to a fluence of 11 x 10(14) cm(-2) a size-aspect ratio of 4.7 is achieved. The size polydispersity (similar to3%) remains unaffected by the irradiation. The transverse diameter increases with the electronic energy loss above a threshold value of similar to0.6 keV/nm. Non-ellipsoidal colloids are observed in the case that the projected ion range is smaller than the colloid diameter. The deformation effect is also observed for micro-crystalline ZnS and amorphous TiO2 colloids, as well as ZnS/SiO2 core/shell particles. No deformation is observed for crystalline Al2O3 and Ag particles. The data provide strong support for the thermal spike model of anisotropic deformation. (C) 2001 Elsevier Science B.V. All rights reserved.

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