The effect of topological defects and oxygen adsorption on the electronic transport properties of single-walled carbon-nanotubes

Interaction of methane with carbon nanotube thin films: role of defects and oxygen adsorption

“…4 -7 are fully consistent with the corresponding band structure and the DOS results presented in Ref. [21], and can be summarized as follows. (a) Adsorbed O 2 molecules on defects increase the electrical resistance of the CNTs, but this effect is essentially annulled by degassing the adsorbed O 2 molecules.…”

“…[21] by the theoretical simulations performed on a single-walled nanotube may be realistic to give an explanation of the results reported in Figs. 4 -7. The findings reported in Fig.…”

“…Before one can hope to fully rationalize the aforementioned effects of the exposure of nanotubes to the molecular oxygen on the electronic transport properties of CNTs, the phenomenon of molecular oxygen adsorption to the CNTs' walls needs to be explained better. On this regard, Grujicic et al [21] have shown by computational method that in semiconducting SWNTs, oxygen molecules are physisorbed to the defect free nanotube walls but when such walls contain topological defects, oxygen molecules become strongly chemisorbed. They found that physisorbed O 2 molecules significantly increase electrical conductance while the effect of topological defects is practically annulled by chemisorbed O 2 molecules [21].…”

“…(a) the variation of the resistance of the nanotube films under exposure to oxygen, (b) the possibility to compare the experimental results observed on multiwall CNT film with the calculation performed for a single-walled nanotube as reported on Ref [21],. (c) an explanation on the behaviour of the electrical resistance in presence of gases in the light of the theoretical calculations.…”

Electronic and vibrational properties of chemically modified single-wall carbon nanotubes

“…As a first possibility, oxygen may covalently bind to defects on the sidewall, as suggested by the chemisorption energy of À0.3 eV predicted for an oxygen molecule at a Stone-Wales defect [392,393]. However, it is still unclear whether such attachment is also kinetically favourable, and further experimental work will be required to elucidate the chemical reactivity of various types of defects in SWCNTs.…”