The Drift Response to a High-Electric-Field in Carbon Nanotubes

The carrier statistics in carbon nanotubes (CNTs) with nonparabolic energy spectrum is studied in order to predict the ultimate (intrinsic) drift velocity as a function of temperature, concentration, and chirality. The extremely high mobilities in CNTs do not necessarily lead to higher saturation velocity that is limited to the intrinsic velocity calculated using Arora's formalism [V. K. Arora, Current Nanoscience 5, 227(2009)]. The ballistic nature of the mobility when CNT length is smaller than the scattering-limited mean free path is delineated. The results are of enormous importance in extracting carrier transport properties from a variety of experiments performed on CNTs.