Tight-binding and effective mass modeling of armchair carbon nanoribbon FETs

We show that a ballistic quantum transport model based on the effective-mass approximation can fairly well describe the I-V characteristics of armchair carbon nanoribbon FETs in all bias conditions, including the regimes dominated by direct or band-to-band tunneling, provided first-order nonparabolic corrections are included in the simulation. This is achieved by means of an energy (position) dependent effective mass. The analysis is supported by comparisons with a full atomistic tight-binding model.