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Tracing temperature in a nanometer size region in a picosecond time period.

Nakajima K, Kitayama T, Hayashi H, Matsuda M, Sataka M, Tsujimoto M, Toulemonde M, Bouffard S, Kimura K - Sci Rep (2015)

Bottom Line: This ultrafast local heating result in formation of nanostructures, which provide a number of potential applications in nanotechnologies.Here, we propose a novel method for tracing temperature in a nanometer region in a picosecond time period by utilizing desorption of gold nanoparticles around the ion impact position.The feasibility is examined by comparing with the temperature evolution predicted by a theoretical model.

View Article: PubMed Central - PubMed

Affiliation: Department of Micro Engineering, Kyoto University, Kyoto 615-8540, Japan.

ABSTRACT
Irradiation of materials with either swift heavy ions or slow highly charged ions leads to ultrafast heating on a timescale of several picosecond in a region of several nanometer. This ultrafast local heating result in formation of nanostructures, which provide a number of potential applications in nanotechnologies. These nanostructures are believed to be formed when the local temperature rises beyond the melting or boiling point of the material. Conventional techniques, however, are not applicable to measure temperature in such a localized region in a short time period. Here, we propose a novel method for tracing temperature in a nanometer region in a picosecond time period by utilizing desorption of gold nanoparticles around the ion impact position. The feasibility is examined by comparing with the temperature evolution predicted by a theoretical model.

No MeSH data available.


Evolution of the deposited energy along the ion path calculated using Monte Carlo simulation when 420 MeV Au ion travels through a-SiO2.Small dots show the results of each simulations and the closed circles show the mean value. The solid line shows the result of exponential curve fitting.
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f6: Evolution of the deposited energy along the ion path calculated using Monte Carlo simulation when 420 MeV Au ion travels through a-SiO2.Small dots show the results of each simulations and the closed circles show the mean value. The solid line shows the result of exponential curve fitting.

Mentions: Finally the difference in the nanoparticle cleared radius between the front and rear surface irradiations is discussed. A possible origin of the observed difference is the effect of high-energy secondary electrons (so-called δ-rays) produced by the projectile ions. The δ-rays carry away the deposited energy and do not contribute to heating the place of production but do contribute in the deeper region. As a result, the deposited energy is smaller than the energy loss in the entrance region and increases with depth. The evolution of the deposited energy along the ion path was calculated using Monte Carlo simulations23. Figure 6 shows the result of the MC simulations for 420 MeV Au ions travelling through a-SiO2. The result of each simulation is shown by small dots and the averaged result is shown by solid circles. The result was fitted by an exponential function and is shown by a solid line. The deposited energy at the entrance surface is 20.4 keV/nm and increases with depth. Eventually, it reaches equilibrium at ~15 nm. The deposited energy at the exit surface of the 20-nm a-SiO2 film is 23.7 keV/nm, which is about 16% larger than that of the entrance surface. Using these deposited energies, the radii of the region where the energy per atom exceeds Ed were calculated to be 6.4 nm and 7.0 nm at the entrance and exit surfaces, respectively, for a-SiO2. These radii are slightly larger than the observed results, 5.1 ± 0.6 and 6.0 ± 0.7 nm (see Table 1), but the difference between the front and rear irradiation is well reproduced. For a-SiN, the calculated radii are 6.9 and 7.6 nm at the entrance and exit surfaces, respectively, showing good agreement with the observed ones, 7.5 ± 0.9 and 8.1 ± 1.0 nm (see Table 1). These results demonstrate that the desorption of gold nanoparticles can be used to measure the temperature of the localized area of nm size in a short time period. In passing we note that similar measurements of nanoparticle desorption from a-SiN films of different thicknesses upon impact of 0.72 and 1.1 MeV C60 ions were performed using different kinds of nanoparticles, platinum and gold nanoparticles with different sizes. In spite of very different experimental conditions, the observed nanoparticle cleared radii agree with the i-TS calculations. This supports that the present approach is a robust method.


Tracing temperature in a nanometer size region in a picosecond time period.

Nakajima K, Kitayama T, Hayashi H, Matsuda M, Sataka M, Tsujimoto M, Toulemonde M, Bouffard S, Kimura K - Sci Rep (2015)

Evolution of the deposited energy along the ion path calculated using Monte Carlo simulation when 420 MeV Au ion travels through a-SiO2.Small dots show the results of each simulations and the closed circles show the mean value. The solid line shows the result of exponential curve fitting.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4543984&req=5

f6: Evolution of the deposited energy along the ion path calculated using Monte Carlo simulation when 420 MeV Au ion travels through a-SiO2.Small dots show the results of each simulations and the closed circles show the mean value. The solid line shows the result of exponential curve fitting.
Mentions: Finally the difference in the nanoparticle cleared radius between the front and rear surface irradiations is discussed. A possible origin of the observed difference is the effect of high-energy secondary electrons (so-called δ-rays) produced by the projectile ions. The δ-rays carry away the deposited energy and do not contribute to heating the place of production but do contribute in the deeper region. As a result, the deposited energy is smaller than the energy loss in the entrance region and increases with depth. The evolution of the deposited energy along the ion path was calculated using Monte Carlo simulations23. Figure 6 shows the result of the MC simulations for 420 MeV Au ions travelling through a-SiO2. The result of each simulation is shown by small dots and the averaged result is shown by solid circles. The result was fitted by an exponential function and is shown by a solid line. The deposited energy at the entrance surface is 20.4 keV/nm and increases with depth. Eventually, it reaches equilibrium at ~15 nm. The deposited energy at the exit surface of the 20-nm a-SiO2 film is 23.7 keV/nm, which is about 16% larger than that of the entrance surface. Using these deposited energies, the radii of the region where the energy per atom exceeds Ed were calculated to be 6.4 nm and 7.0 nm at the entrance and exit surfaces, respectively, for a-SiO2. These radii are slightly larger than the observed results, 5.1 ± 0.6 and 6.0 ± 0.7 nm (see Table 1), but the difference between the front and rear irradiation is well reproduced. For a-SiN, the calculated radii are 6.9 and 7.6 nm at the entrance and exit surfaces, respectively, showing good agreement with the observed ones, 7.5 ± 0.9 and 8.1 ± 1.0 nm (see Table 1). These results demonstrate that the desorption of gold nanoparticles can be used to measure the temperature of the localized area of nm size in a short time period. In passing we note that similar measurements of nanoparticle desorption from a-SiN films of different thicknesses upon impact of 0.72 and 1.1 MeV C60 ions were performed using different kinds of nanoparticles, platinum and gold nanoparticles with different sizes. In spite of very different experimental conditions, the observed nanoparticle cleared radii agree with the i-TS calculations. This supports that the present approach is a robust method.

Bottom Line: This ultrafast local heating result in formation of nanostructures, which provide a number of potential applications in nanotechnologies.Here, we propose a novel method for tracing temperature in a nanometer region in a picosecond time period by utilizing desorption of gold nanoparticles around the ion impact position.The feasibility is examined by comparing with the temperature evolution predicted by a theoretical model.

View Article: PubMed Central - PubMed

Affiliation: Department of Micro Engineering, Kyoto University, Kyoto 615-8540, Japan.

ABSTRACT
Irradiation of materials with either swift heavy ions or slow highly charged ions leads to ultrafast heating on a timescale of several picosecond in a region of several nanometer. This ultrafast local heating result in formation of nanostructures, which provide a number of potential applications in nanotechnologies. These nanostructures are believed to be formed when the local temperature rises beyond the melting or boiling point of the material. Conventional techniques, however, are not applicable to measure temperature in such a localized region in a short time period. Here, we propose a novel method for tracing temperature in a nanometer region in a picosecond time period by utilizing desorption of gold nanoparticles around the ion impact position. The feasibility is examined by comparing with the temperature evolution predicted by a theoretical model.

No MeSH data available.