Defect-induced negative differential resistance in single-walled carbon nanotubes

The authors report on the observation of a negative differential resistance (NDR) behavior in tunneling spectra recorded on hydrogen and nitrogen plasma-induced atomic defects on semiconducting single-walled carbon nanotubes (SWNTs). The NDR is observed only in the positive bias range of the spectra. This bias asymmetry and the spectral shape in the NDR region can be explained on the basis of a bias-dependent tunneling barrier height model. Within this model the NDR behavior can be directly related to defect-induced sharp electronic states in the SWNT band gap created at the defect sites.