  In recent past extensive device simulation work has already been done on
TFETs. Various ways have been suggested to model TFETs. In our paper we look at
one such particular way to model these devices. The Non equilibrium green's
formalism has proved effective in modeling nano scale devices. We model
complete SiGe and GaAs tunnel FET for the first time using the NEGF formalism,
also taking acoustic phonon scattering into account. We analyze them on the
grounds of I-V curve, Ion-Ioff ration and subthreshold slope. The poisson
equation and the equilibrium statistical mechanical equation has been solved by
providing the potential profile.
