Low-Field Transport Model for Semiconducting Carbon Nanotubes

Transport models for carrier transport in a semiconducting carbon nanotube are presented. Results encompass tubes of varying diameter and chirality. The focus is on transport in response to a small, axially applied electric field. Models for phonon-limited transport are developed whereby carriers scatter with stretching, twisting, and radial breathing acoustic phonons. The resulting mobility model agrees well with experiments, showing very large mobility (>10⁵cm2/Vs) at room temperature. Furthermore, the transport model predicts a mean free path in large diameter tubes very close to experimental results (700nm). Our model predicts that the mobility and the mean free path will increase with tube diameter and decrease with temperature when phonon scattering dominates. Nonparabolic corrections to the band structure are found to greatly impact transport modeling. The transport regime dominated by scattering from localized charges is also considered. A low-field mobility model for carrier scattering with interface charge is presented. Results show mobility increasing rapidly with tube diameter and increasing slowly with temperature.