Regensburg 2019 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 24: Nitrides: Preparation and characterization I

HL 24.13: Talk

Wednesday, April 3, 2019, 12:45–13:00, H31

Electron affinity and surface states of GaN m-plane facets: Implication for electronic self-passivation — Verena Portz¹, Michael Schnedler¹, Holger Eisele², Rafal E. Dunin-Borkowski¹, and •Philipp Ebert¹ — ¹Peter Grünberg Institut, Forschungszentrum Jülich GmbH, Jülich, 52425, Germany — ²Institut für Festkörperphysik, Technische Universität Berlin, Germany

The electron affinity and surface states are of utmost importance for designing the potential landscape within (heterojunction) nanowires and hence for tuning conductivity and carrier lifetimes. Therefore, we determined for stoichiometric nonpolar GaN(1010) m-plane facets, i.e., the dominating sidewalls of GaN nanowires, the electron affinity to 4.06±0.07 eV and the energy of the empty Ga-derived surface state in the band gap to 0.99±0.08 eV below the conduction band minimum using scanning tunneling spectroscopy. These values imply that the potential landscape within GaN nanowires is defined by a surface state-induced Fermi-level pinning, creating an upward band bending at the sidewall facets, which provides an electronic passivation.