Ion irradiation of electronic-type-separated single wall carbon nanotubes: A model for radiation effects in nanostructured carbon

Abstract

The structural and electrical properties of electronic-type-separated (metallic and semiconducting) single wall carbon nanotube (SWCNT) thin-films have been investigated after irradiation with 150 keV 11B+ and 150 keV 31P+ with fluences ranging from 1012 to 1015 ions/cm2. Raman spectroscopy results indicate that the ratio of the Raman D to G′ band peak intensities (D/G′) is a more sensitive indicator of SWCNT structural modification induced by ion irradiation by one order of magnitude compared to the ratio of the Raman D to G band peak intensities (D/G). The increase in sheet resistance (Rs) of the thin-films follows a similar trend as the D/G′ ratio, suggesting that the radiation induced variation in bulk electrical transport for both electronic-types is equal and related to localized defect generation. The characterization results for the various samples are compared based on the displacement damage dose (DDD) imparted to the sample, which is material and damage source independent. Therefore, it is possible to extend the analysis to include data from irradiation of transferred CVD-graphene films on SiO2/Si substrates using 35 keV C+ ions, and compare the observed changes at equivalent levels of ion irradiation-induced damage to that observed in the SWCNT thin-film samples. Ultimately, a model is developed for the prediction of the radiation response of nanostructured carbon materials based on the DDD for any incident ion with low-energy recoil spectra. The model is also related to the defect concentration, and subsequently the effective defect-to-defect length, and yields a maximum defect concentration (minimum defect-to-defect length) above which the bulk electrical transport properties in SWCNT thin-films and large graphene-based electronic devices rapidly degrade when exposed to harsh environments.

Intrinsic diameter dependent degradation of single-wall carbon nanotubes from ion irradiation

“…The variation in vacancy density was described using an empirical model based on an inter-vacancy length, which directly correlates relative Raman ratios to bulk electrical transport for ion-irradiated SWCNTs [22]. These results showed similar stability of SWCNT thin-films based on electronic-type (i.e., metallic vs. semiconducting) for equivalent diameter distribution under identical ion irradiation conditions.…”

“…The resulting CoMoCAT concentrations were calculated based on a measured e = 37.8 mL mg À1 -cm À1 for the E S 22 absorption peak maximum, and the laser SWCNT concentrations were calculated based on the e = 45.5 mL mg À1 cm À1 for the E S 22 absorption peak maximum [27]. Using a previously published procedure [22], the SWCNT dispersions were processed into thin-films via vacuum filtration onto a mixed cellulose ester (MCE) membrane, such that the thin-film had an areal mass density of approximately 17 ± 2 lg/cm 2 . A 5 · 5 mm square was cut from the center of each sample, and the section was subsequently transferred onto a polished quartz wafer (GM Associates, Inc. 150-025FP) via membrane dissolution in acetone [6,22].…”

“…Using a previously published procedure [22], the SWCNT dispersions were processed into thin-films via vacuum filtration onto a mixed cellulose ester (MCE) membrane, such that the thin-film had an areal mass density of approximately 17 ± 2 lg/cm 2 . A 5 · 5 mm square was cut from the center of each sample, and the section was subsequently transferred onto a polished quartz wafer (GM Associates, Inc. 150-025FP) via membrane dissolution in acetone [6,22]. Lastly, the samples were oxidized in air at 300°C to remove residual moisture and MCE [22].…”

“…Recently, the effect of ion irradiation was systematically studied in thin-films of electronic-type separated SWCNTs using Raman spectroscopy and electrical transport [22], both of which are common techniques for characterizing irradiation damage for ensemble structures such as thin-films or bulk papers. The variation in vacancy density was described using an empirical model based on an inter-vacancy length, which directly correlates relative Raman ratios to bulk electrical transport for ion-irradiated SWCNTs [22].…”

“…These results showed similar stability of SWCNT thin-films based on electronic-type (i.e., metallic vs. semiconducting) for equivalent diameter distribution under identical ion irradiation conditions. For comparison, multiple ions were used to show that the radiation response can be described in terms of displacement damage dose (DDD) [22,23]. Thus, a representative ion condition can be used to develop a fundamental understanding of how the SWCNT optoelectronic properties vary with ion irradiation and SWCNT structure (diameter and chirality).…”