For modeling the transport of carriers in nanoscale devices, a
Green-function formalism is the most accurate approach. Due to the
complexity of the formalism, one should have a deep understanding of the
underlying principles and use smart approximations and numerical methods
for solving the kinetic equations at a reasonable computational time.
In this book the required concepts from quantum and statistical
mechanics and numerical methods for calculating Green functions are
presented. The Green function is studied in detail for systems both
under equilibrium and under nonequilibrium conditions. Because the
formalism enables rigorous modeling of different scattering mechanisms
in terms of self-energies, but an exact evaluation of self-energies for
realistic systems is not possible, their approximation and inclusion in
the quantum kinetic equations of the Green functions are elaborated. All
the elements of the kinetic equations, which are the device Hamiltonian,
contact self-energies and scattering self-energies, are examined and
efficient methods for their evaluation are explained. Finally, the
application of these methods to study novel electronic devices such as
nanotubes, graphene, Si-nanowires and low-dimensional thermoelectric
devices and photodetectors are discussed.