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Purification/annealing of graphene with 100-MeV Ag ion irradiation.

Kumar S, Tripathi A, Singh F, Khan SA, Baranwal V, Avasthi DK - Nanoscale Res Lett (2014)

Bottom Line: We report swift heavy ion (SHI) irradiation-induced annealing and purification effects in graphene films, similar to that observed in our studies on fullerenes and carbon nanotubes (CNTs).This indicates that SHI induces annealing effects at lower fluences.The results suggest that SHI irradiation fluence may be used as one of the tools for defect annealing and manipulation of the number of graphene layers. 60.80.x; 81.05.ue.

View Article: PubMed Central - HTML - PubMed

Affiliation: Materials Science Group, Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067, India.

ABSTRACT

Unlabelled: Studies on interaction of graphene with radiation are important because of nanolithographic processes in graphene-based electronic devices and for space applications. Since the electronic properties of graphene are highly sensitive to the defects and number of layers in graphene sample, it is desirable to develop tools to engineer these two parameters. We report swift heavy ion (SHI) irradiation-induced annealing and purification effects in graphene films, similar to that observed in our studies on fullerenes and carbon nanotubes (CNTs). Raman studies after irradiation with 100-MeV Ag ions (fluences from 3 × 10(10) to 1 × 10(14) ions/cm(2)) show that the disorder parameter α, defined by I D/I G ratio, decreases at lower fluences but increases at higher fluences beyond 1 × 10(12) ions/cm(2). This indicates that SHI induces annealing effects at lower fluences. We also observe that the number of graphene layers is reduced at fluences higher than 1 × 10(13) ions/cm(2). Using inelastic thermal spike model calculations, we estimate a radius of 2.6 nm for ion track core surrounded by a halo extending up to 11.6 nm. The transient temperature above the melting point in the track core results in damage, whereas lower temperature in the track halo is responsible for annealing. The results suggest that SHI irradiation fluence may be used as one of the tools for defect annealing and manipulation of the number of graphene layers.

Pacs: 60.80.x; 81.05.ue.

No MeSH data available.


Related in: MedlinePlus

The simulated curve for disorder parameter α (ID/IG) with fluence.
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Figure 8: The simulated curve for disorder parameter α (ID/IG) with fluence.

Mentions: In Equation 1, the first term represents exponential decay due to the annealing effect of irradiation in an annular region and the second term represents exponential increase due to damage effects within the ion track core. Constants a and b are the values of ID/IG when the fluence ϕ is zero and infinity, respectively. The values of σ1 and σ2 give cross sections for annealing and damage, respectively. For the best fit, the values of parameters a, σ1, b and σ2 were obtained as 0.71 ± 0.1, (1.0 ± 0.1) × 10−12 cm2, 4.3 ± 0.2 and (6.7 ± 0.8) × 10−14 cm2 respectively, with chi-square value of 0.04. The simulated curve with the above parameters is shown in Figure 8.


Purification/annealing of graphene with 100-MeV Ag ion irradiation.

Kumar S, Tripathi A, Singh F, Khan SA, Baranwal V, Avasthi DK - Nanoscale Res Lett (2014)

The simulated curve for disorder parameter α (ID/IG) with fluence.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4012553&req=5

Figure 8: The simulated curve for disorder parameter α (ID/IG) with fluence.
Mentions: In Equation 1, the first term represents exponential decay due to the annealing effect of irradiation in an annular region and the second term represents exponential increase due to damage effects within the ion track core. Constants a and b are the values of ID/IG when the fluence ϕ is zero and infinity, respectively. The values of σ1 and σ2 give cross sections for annealing and damage, respectively. For the best fit, the values of parameters a, σ1, b and σ2 were obtained as 0.71 ± 0.1, (1.0 ± 0.1) × 10−12 cm2, 4.3 ± 0.2 and (6.7 ± 0.8) × 10−14 cm2 respectively, with chi-square value of 0.04. The simulated curve with the above parameters is shown in Figure 8.

Bottom Line: We report swift heavy ion (SHI) irradiation-induced annealing and purification effects in graphene films, similar to that observed in our studies on fullerenes and carbon nanotubes (CNTs).This indicates that SHI induces annealing effects at lower fluences.The results suggest that SHI irradiation fluence may be used as one of the tools for defect annealing and manipulation of the number of graphene layers. 60.80.x; 81.05.ue.

View Article: PubMed Central - HTML - PubMed

Affiliation: Materials Science Group, Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067, India.

ABSTRACT

Unlabelled: Studies on interaction of graphene with radiation are important because of nanolithographic processes in graphene-based electronic devices and for space applications. Since the electronic properties of graphene are highly sensitive to the defects and number of layers in graphene sample, it is desirable to develop tools to engineer these two parameters. We report swift heavy ion (SHI) irradiation-induced annealing and purification effects in graphene films, similar to that observed in our studies on fullerenes and carbon nanotubes (CNTs). Raman studies after irradiation with 100-MeV Ag ions (fluences from 3 × 10(10) to 1 × 10(14) ions/cm(2)) show that the disorder parameter α, defined by I D/I G ratio, decreases at lower fluences but increases at higher fluences beyond 1 × 10(12) ions/cm(2). This indicates that SHI induces annealing effects at lower fluences. We also observe that the number of graphene layers is reduced at fluences higher than 1 × 10(13) ions/cm(2). Using inelastic thermal spike model calculations, we estimate a radius of 2.6 nm for ion track core surrounded by a halo extending up to 11.6 nm. The transient temperature above the melting point in the track core results in damage, whereas lower temperature in the track halo is responsible for annealing. The results suggest that SHI irradiation fluence may be used as one of the tools for defect annealing and manipulation of the number of graphene layers.

Pacs: 60.80.x; 81.05.ue.

No MeSH data available.


Related in: MedlinePlus