Ion Irradiation of Dielectrics for Photonic Applications by Feng Chen & Hiroshi Amekura & Yuechen Jia

Author:Feng Chen & Hiroshi Amekura & Yuechen Jia
Language: eng
Format: epub
ISBN: 9789811546075
Publisher: Springer Singapore

5.2.4 Mass Non-conservation of Nano-Rods

Dawi et al. [59] deposited chemically synthesized monodisperse colloidal Au NPs in spherical shapes on the surface of oxidized Si substrates, and covered them by SiO2 layer of 150 nm by reactive sputtering. With adjusting the immersion time to the Au NP solution, samples with different NP areal density were prepared. Degree of the elongation was monitored from the width of the Au peak of Rutherford backscattering spectrometry (RBS) using 2 MeV 4He+ with a scattering angle of 120°. (The RBS method is not adequate to detect small elongation such as the elongation threshold as pointed out in Ref. [60], but convenient for detecting large elongation as discussed here.) As shown in Fig. 5.26, the FWHM of the Au peak increases with the fluence up to 2 × 1014 ions/cm2, irrespective of the particle density. Above the fluence, the lowest density sample (2.5 × 109 NPs/cm2) shows saturation in FWHM. The saturation is ascribed to the fact that the minor widths of all the monodispersed NPs reach to ‘the minimum width’ (see Sect. 3.2.2). Since the initial diameters, consequently the volume, of all the NPs were the same irrespective of the NP areal density, and since the elongation speed is consider to be the same between the samples, all the samples should reach to ‘the minimum width’ at the same fluence, irrespective of the NP areal density. However, higher density samples show further increase of the FWHM, indicating the mass transfer between the NPs. Probably some NPs were destroyed by the irradiation. Au atoms from the destroyed NPs transferred to other NPs for further elongation.

Fig. 5.26Fluence dependence of FWHM of Au RBS peak from Au NPs (15 nm diameter) in SiO2 irradiated with 54 MeV Ag8+ ions, for different particle areal densities.

Reproduced with permission from [59], ©2011 American Institute of Physics

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.