Size dependent swift heavy ion induced Au nanoparticle elongation in SiO2 matrix

Abstract

The elongation of spherical Au nanoparticles embedded in SiO2 under swift heavy ion (SHI) irradiation is an extensively studied phenomenon. The use of a TEM grid as a substrate facilitates the identification of the same nanoparticle before and after the irradiation. Since the underdensification of SiO2 inside the ion track plays a key role, the elongation is sensitive to the matrix material properties. Therefore, we studied the elongation process of SHI irradiated Au spherical nanoparticles of various diameters (5–80 nm) embedded either in atomic layer deposition (ALD) or plasma-enhanced chemical vapor deposition (PECVD) SiO2. The results show that a different elongation ratio is achieved depending on the particle initial size, ion fluence, and a different SiO2 deposition method. The embedded nanoparticles in ALD SiO2 elongate roughly 100% more than the nanoparticles embedded in PECVD SiO2 at the biggest applied fluence (5×1014ions/cm2). On the other hand, at fluences lower than 1014ions/cm2, nanoparticles elongate slightly more when they are embedded in PECVD SiO2