We present an investigation in the device parameter space of band-to-band tunneling in nanowires with a diamond cubic or zincblende crystalline structure. Results are obtained from quantum transport simulations based on Non-Equilibrium Greens functio
ns with a tight-binding atomistic Hamiltonian. Interband tunneling is extremely sensitive to the longitudinal electric field, to the nanowire cross section, through the gap, and to the material. We have derived an approximate analytical expression for the transmission probability based on WKB theory and on a proper choice of the effective interband tunneling mass, which shows good agreement with results from atomistic quantum simulation.
