Through adsorption of bromine vapor, the electrical conductivity of multi-walled carbon nanotubes (MWNT) can be enhanced by 3 times. Raman spectrum, UV-Vis spectra, IR, NIR and XPS spectra were used to characterize the material. The result indicates that there is a conjugative effect between MWNT and bromine, which induces the change of electron distribution on the MWNT surface. It increased the carrier density and the electrical conductivity of MWNT became higher.

Key words: MWNT, electrical conductivity, adsorption, carrier