Controlling the resistivity of multi-walled carbon nanotube networks by copper encapsulation

The resistivity of multi-walled carbon nanotube networks can be changed by filling Cu into the nanotubes as well as by preparing the nanotube networks with various densities. The resistivity can be controlled to be lower than the c-axis resistivity of graphite, and has a low temperature coefficient of −1.12 × 10−5/K over the temperature range of 20–500 K. Filling Cu into the nanotubes decreases the intra-tube resistivity, but the temperature coefficient of the resistivity is governed by the inter-tube resistivity of the nanotube network.

► We studied the effects of Cu filling on the resistivity of carbon nanotube networks.
► Cu was filled into the multi-walled nanotubes by laser ablation.
► The resistivity can be controlled to be lower than c-axis resistivity of graphite.
► Filling Cu into the nanotubes decreases the intra-tube resistivity.
► The inter-tube resistivity of the networks governs its temperature coefficient.