Thermal spikes induced sublimation of carbon nanotubes

Abstract

We report and provide justification for the consistently observed four experimental facts of the mass spectrometric data of carbon cluster emission from the low-energy Cs irradiated single-walled carbon nanotubes . Firstly, the diatomic carbon C(2) is the most abundant sputtered species for Cs+ in the energy range 0.2 keV to 2.0 keV. Secondly, monatomic carbon C(1) is emitted with the least sputtering yield. Thirdly, at low cesium energies i the emitted species are C(2), C(3) and C(4). Lastly, as the irradiating Cs+ energy increases, the normalized yield of atomic carbon monotonically increases while clusters show gradual decrease and saturation. Sputtering of clusters is proved here to be due to thermal spikes. Binary collision cascade theory does not explain cluster sputtering. A statistical thermal model is developed to explain the experimentally observed data. The probability of a cluster C(x) to be emitted is shown to be proportional to that for the creation of an x-member vacancy with formation energy E at temperature T as {exp(E/kT)+1}^(-1). The energies of formation of single and double vacancies from DFT calculations and the ratio of normalized experimental yields have been used to estimate spike temperature. We show that by invoking thermal spikes, cluster emission from, and the multiple vacancy generation in, the Cs+-irradiated SWCNTs can be explained. We also suggest modifications to Monte Carlo type calculations of sputtering.

arXiv comment15 pages, 3 figures

References in corpus (4)

• Dynamics of fragmentation and multiple vacancy generation in irradiated single-walled carbon nanotubes
• Evolution of clusters in energetic heavy ion bombarded amorphous graphite-III: Photo-emission and velocity analysis of sputtered carbon clusters
• Mass spectrometric identification of C60 fragmentation regimes under energetic Cs+ bombardment
• Cs+ sputtered clusters from multi-walled carbon nanotubes and graphite

Cited by in corpus (4)

• Space-filling, multi-fractal, localized thermal spikes in silicon, germanium and zinc oxide
• An information theoretic model for the linear and nonlinear dissipative structures in irradiated single-walled carbon nanotubes
• Experimental and Theoretical Aspects of the Fragmentation of Carbon's Single and Multi-Walled Nanotubes
• Dynamic emergence of fragmenting, exploding cages of irradiated single-walled carbon nanotubes and C60