1 research outputs found
Mapping the Coulomb Environment in Interference-Quenched Ballistic Nanowires
The
conductance of semiconductor nanowires is strongly dependent
on their electrostatic history because of the overwhelming influence
of charged surface and interface states on electron confinement and
scattering. We show that InAs nanowire field-effect transistor devices
can be conditioned to suppress resonances that obscure quantized conduction
thereby revealing as many as six sub-bands in the conductance spectra
as the Fermi-level is swept across the sub-band energies. The energy
level spectra extracted from conductance, coupled with detailed modeling
shows the significance of the interface state charge distribution
revealing the Coulomb landscape of the nanowire device. Inclusion
of self-consistent Coulomb potentials, the measured geometrical shape
of the nanowire, the gate geometry and nonparabolicity of the conduction
band provide a quantitative and accurate description of the confinement
potential and resulting energy level structure. Surfaces of the nanowire
terminated by HfO<sub>2</sub> are shown to have their interface donor
density reduced by a factor of 30 signifying the passivating role
played by HfO<sub>2</sub>