Electrical anisotropies of carbon-nanotube-embedded graphene composite films

Graphite oxide (GO) was prepared by using the chemical oxidation of pristine graphite, and the GO dispersions in water were sprayed onto substrates. The prepared GO film was soaked in a hydrogen iodide (HI) water solution to make reduced graphite oxide (rGO) film. The resulting rGO film was analyzed using a 4-pin probe analyzer and current-voltage measurements, and the film's conductivities were compared in both the in-plane and the out-of-plane directions. In addition, the film's conductivities were analyzed according to the loadings (10-30 wt.%) of multiwalled carbon nanotubes (MWNTs) added to the rGO films. The experimentally-measured conductivities were compared and are discussed based on the film structures of rGO and MWNT-embedded rGO.