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An efficient method is developed for multiband simulation of quantum transport in nanowire electronic devices within nonequilibrium Green's function formalism. The efficiency relies on a model order reduction technique, which projects the k · p Hamiltonian into a much smaller subspace constructed by sampling the Bloch modes of each cross-section layer. Several sampling approaches are discussed to obtain a minimum and accurate basis with reduced computational overhead. The technique is verified by calculating the valence bands of silicon nanowires (SiNWs) and by solving I-V curves of p-type SiNW transistors. This enables us to study for the first time the performances of large cross-section p-type junctionless (JL) transistors in the quantum ballistic transport limit. The influences of doping density, transport direction, channel length, and cross-section size are examined. We find that larger doping densities may lead to worse sub-threshold slopes due to the enhanced source-to-drain tunneling. Compared with their counterparts, i.e., classical inversion-mode (IM) transistors, they have better sub-threshold behaviors, but they do not necessarily provide a better ON/OFF ratio except when the channel is short or thin. In addition, unlike IM transistors,  and  channel directions in JL transistors are very robust against channel thicknes scaling.
Date of Publication: July 2013