Ion-beam induced 1D to 3D periodic transformation in nanostructured multilayers

TL;DR

This study investigates how ion irradiation induces atomic redistribution and transforms a 1D multilayer structure into a 3D periodic nanocluster arrangement, revealing potential for advanced nanofabrication.

Contribution

It demonstrates that ion irradiation can create off-normal superlattice periodicities in multilayers, enabling 3D nanostructure fabrication from 1D systems.

Findings

Atomic redistribution at high ion fluence

Emergence of off-normal superlattice periodicities

Potential for 3D nanocluster structure fabrication

Abstract

Ion-irradiation-induced modifications of a periodic Pt/C multilayer system containing Fe impurity have been analyzed by transmission electron microscopy (TEM). The multilayer stack with 16 Pt/C layer pairs (period 4.23 nm) was fabricated on a glass substrate. A 2 MeV Au$^{2+}$ ion beam was rastered on the sample to obtain uniformly irradiated strips with fluences from 1$\times10^{14}$ to 1$\times10^{15}$ $ions/cm^2$. Ion-irradiation has been found to cause preferential migration of Fe towards Pt layers [Nucl. Instr. Methods Phys. Res. B212 (2003) 530]. Cross-sectional transmission electron microscopy (XTEM) shows considerable atomic redistribution for irradiation at the highest ion fluence (1$\times10^{15}$ $ions/cm^2$). Individual entities in this structure is like a cluster. Periodic multilayers have periodicity only in the direction normal to the multilayer surface. However, Fourier transform of the XTEM images of the sample irradiated at the highest-fluence shows new off-normal Fourier components of superlattice periodicities arising due to ion irradiation. With a proper understanding of this phenomenon it may be possible to fabricate three dimensional periodic structures of nanoclusters.