Quantum transport of a nanowire field-effect transistor with complex phonon self-energy

In this work, the impact of the real part of the phonon self-energy on the transfer characteristics of a silicon nanowire transistor is investigated. The physical effects of the real part of the self-energy are to create a broadening and a shift on the density of states. This increases the drain current in the sub-threshold region and decreases it in the above-the-threshold region. In the first region, the current is increased as a result of an increase of charge in the middle of the channel. In the second one, the electrostatic self-consistency or the enforcement of charge neutrality in the channel reduces the current because a substantial amount of electrons are under the first subband and have imaginary wave vectors. The change in the phonon-limited mobility due to the real part of self-energy is evaluated for a nanowire transistor and a nanowire in which there is not source to drain barrier. We also assess the validity of Mathiessen's rule using the self-consistent NEGF simulations and the Kubo-Greenwood formalism. (C) 2014 AIP Publishing LLC.