Electron irradiation effects on Ag nanoparticles

Abstract

In situ electron irradiation effects on shape and size of plate-like Ag nanoparticles (NPs) embedded in silicon nitride self-standing % 70-nm-thick membranes are investigated as a function of the beam energy (120, 160 and 200 keV) and fluence using a conventional transmission electron microscope. The irradiations are performed at room temperature and cause a rapid spheroidization of the initially observed plate-like structures. Preferential sputtering of N and Si atoms exposes the resulting Ag NPs to the vacuum. At this point the sputtering of the Ag atoms causes a size decrease at distinct rates depending on the NP size and on the beam energy. This is modeled considering the influence of a size-dependent surface binding of the Ag atoms on the sputtering process. The results are compared with literature models for size-dependent cohesive energy. Our experiments discloses a new way to modify sizes and shapes and test for the size-dependent properties of thermally unstable nanoscopic objects.

Electron Irradiation Effects in Au thin Flms

“…Figure 7 shows a void-edge cross-section sketch. According to Konrad et al [20], the surface binding energy at curved interfaces scales with the local cohesive energy. In terms of the cohesive energy model from Qu et al [13], the surface binding energy for a surface characterized by a curvature radius r reads…”

“…Ec 0 discussed in the literature for distinct physical properties [20,22]. Based on these assumptions, the irradiation-induced atomic flux across a unit perimeter length reads…”

“…Electron irradiation experiments can also explore the binding condition of surface atoms. In a recent study considering room temperature electron irradiation of Ag NPs (beam energies from 120 to 200 keV), Konrad et al [20] demonstrate that the sputtering rate increases as the NP radius r decreases. The study also shows that the observed surface binding energy E b (r) behavior controlling the sputtering process follows a scaling relation E b (r)…”

“…The scaling concept is also generalized to other physical properties derived from the cohesion energy E c , including, for example, surface diffusivity D s , Young modulus Y , and Debye temperature θ D , which can hardly be experimentally evaluated [13,14,21,22]. The scaling relation derived from electron irradiation experiments seems to link electron irradiation-and thermally-induced processes [20]. If a generalized scaling behavior (e.g.…”