  We report results on the control of barrier transparency in InAs/InP nanowire
quantum dots via the electrostatic control of the device electron states.
Recent works demonstrated that barrier transparency in this class of devices
displays a general trend just depending on the total orbital energy of the
trapped electrons. We show that a qualitatively different regime is observed at
relatively low filling numbers, where tunneling rates are rather controlled by
the axial configuration of the electron orbital. Transmission rates versus
filling are further modified by acting on the radial configuration of the
orbitals by means of electrostatic gating, and the barrier transparency for the
various orbitals is found to evolve as expected from numerical simulations. The
possibility to exploit this mechanism to achieve a controlled continuous tuning
of the tunneling rate of an individual Coulomb blockade resonance is discussed.
