Determining surface Fermi level pinning position of InN nanowires using electrolyte gating

We demonstrate quantitative determination of surface Fermi level pinning position in InN nanowires using polymer electrolyte gating and three-dimensional (3D) electrostatic modeling of charge distribution. We find pinning of the Fermi level 0.6–0.7 eV above the conduction band minimum at the surface of the nanowires. After taking into account the Fermi level pinning, doping concentration and carrier mobilities are also evaluated and compared with InN thin films. This general approach of combining electrolyte gating experiments with 3D numerical modeling can be applied to nanowires of other materials to determine their surface Fermi level pinning position.