Effect of the Chemical Functionalization on Charge Transport in Carbon Nanotubes at the Mesoscopic Scale

We present first-principles calculations of quantum transport in chemically functionalized metallic carbon nanotubes with lengths reaching the micrometer scale and random distributions of functional groups. Two typical cases are investigated, namely, a sp(2)-type bonding between carbene groups (CH2) and the nanotube sidewalls and a sp(3)-type bonding of nanotubes with paired phenyl groups. For similar molecular coverage density, charge transport is found to range from a quasi-ballistic-like to a strongly diffusive regime, with corresponding mean free paths changing by orders of magnitude depending on the nature of the chemical bonding.