Dependence of DC characteristics of CNT MOSFETs on bandstructure models

Since their discovery in the early 1990s, the interest in carbon nanotube (CNT) electronics has exploded. One main factor that controls the device performance of CNT field-effect transistors (CNT MOSFETs) is the electronic structure of the nanotube. In this paper we use three different bandstructure models: 1) extended Huumlckel theory (EHT); 2) orthogonal p_z tight-binding (OTB); and 3) parabolic effective mass model (EFM) to investigate the bandstructure effects on the device characteristics of a CNT MOSFET using semiclassical and quantum treatments of transport. We find that, after proper calibration, the OTB model is essentially identical to the EHT over the energy range of interest. We also find that an even simpler parabolic EFM facilitates CNT MOSFET simulations within practically applied bias ranges