Wigner function approach to nano device simulation

Coherent transport in mesoscopic devices is well described by the Schrödinger equation supplemented by open boundary conditions. When electronic devices are operated at room temperature, however, a realistic transport model needs to include carrier scattering. In this work, the kinetic equation for the Wigner function is employed as a model for dissipative quantum transport. Carrier scattering is treated in an approximate manner through a Boltzmann collision operator. The development of Monte-Carlo algorithms for this quantum kinetic equation is complicated by the fact that, as opposed to the semi-classical case, the integral kernel is no longer positive. This so-called negative sign problem requires the introduction of new numerical techniques in order to obtain stable Monte-Carlo methods. A particular method for the solution of the stationary Wigner equation is presented. Applications to single barrier and double barrier structures are discussed.