Phonon-assisted Zener tunneling in a p–n diode silicon nanowire

The Zener tunneling current flowing through a biased, abrupt p–n junction embedded in a cylindrical silicon nanowire is calculated. As the band gap becomes indirect for sufficiently thick wires, Zener tunneling and its related transitions between the valence and conduction bands are mediated by short-wavelength phonons interacting with mobile electrons. Therefore, not only the high electric field governing the electrons in the space-charge region but also the transverse acoustic (TA) and transverse optical (TO) phonons have to be incorporated in the expression for the tunneling current. The latter is also affected by carrier confinement in the radial direction and therefore we have solved the Schrödinger and Poisson equations self-consistently within the effective mass approximation for both conduction and valence band electrons. We predict that the tunneling current exhibits a pronounced dependence on the wire radius, particularly in the high-bias regime.

► The Zener current flowing through an abrupt p–n junction in a nanowire is calculated.
► TA and TO phonons have been incorporated in the expression for the Zener current.
► The Zener current exhibits a pronounced dependence on the nanowire radius.