Dynamics of low frequency noise in the power-law region of metallic carbon nanotubes

We have investigated the low frequency noise in the power-law regime of metallic single walled and multiwalled carbon nanotubes at low temperature. The relative noise appear to be independent of applied bias for individual metallic nanotubes in the power-law regime in
agreement with theoretical predictions. As the bias voltage increases beyond the power law regime, the conductance of single walled nanotubes gets suppressed due to scattering with optical phonons. This supression is accompanied by a reduction of the relative noise also by an order of magnitude. This unexpected reduction in the magnitude has been ascribed to optical phonon scattering and modeled by using a modified mobility fluctuation picture. In multiwalled carbon nanotubes no such reduction in relative noise magnitude with bias is observed. The findings have important implications for using metallic nanotubes as interconnects in nanoelectronic devices.