(a) Schematic representation of a single ion-SWCNT bundle interaction illustrating the various Frenkel-pair defects that may result from ion irradiation of the thin-film sample. (b) Pre- and (c) post-irradiation AFM images and photographs of a representative M-SWCNT thin-film are shown, respectively. Although there are only minimal changes observed in the AFM images, an increase in the micro-scale porosity is evident. At the macro-scale, the film hue changes from transparent green to transparent grey after irradiation with 150 keV 11B + to a fulence of 5 × 1014 ions/cm2.
(a) and (b) represent the Raman spectra for the metallic and semiconducting SWCNT thin-films irradiated with 150 keV 11B+, respectively, while (c)and (d) represent the metallic and semiconducting SWCNT thin-films irradiated with 150 keV 31P+, respectively. In each figure, the pre-irradiated spectrum (black) for each film is given as a reference, and the intensity of each irradiated sample is normalized to the G band intensity of the starting material.
(a) The Raman D/G and (b) D/G′ ratios are shown as a function of increasing fluence after ion irradiation with 150 keV 11B+ and 31P+. These ratios are then normalized and plotted against DDD as a means to compare the (c) D/G and (d) D/G′ ratios independent of the ionic species used to irradiate the SWCNT thin-film samples. The green and blue stars in (a) and (b) represent M-SWCNT control samples irradiated to high fluence in a single irradiation event, rather than through iterative irradiations, using 150 keV 11B+ and 150 keV 31P+, respectively.
(a) Analysis of the normalized sheet resistance for the electronic-type-separated SWCNT thin-film samples as a function of increasing fluence and (b) DDD.
(a) Changes in the normalized Raman D/G′ ratio and normalized Rs with DDD for B+ and P+ irradiated M-SWCNTs and S-SWCNTs, and C+ irradiated graphene (Ref. 42). The dashed line is a least squares curve fit of Eq. (4) to all D/G′ and Rs values. (b) The dependence of the mean inter-vacancy length (or vacancy-free segment length) on DDD and Carbon Atoms per Vacancy for a (10,10) SWCNT based on the inverse of Eq. (1). SWCNT renderings are provided to visualize the length and number of carbon atoms separating vacancies in (10,10) SWCNTs with increasing radiation exposure. At the highest DDD the number of vacancies per unit length approach and exceed unity making it more appropriate to consider the number of carbon atoms in a defect-free region along the SWCNT (illustrated as graphene nanoflakes).
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