Regensburg 2016 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 23: Oxide Semiconductors I
HL 23.6: Vortrag
Dienstag, 8. März 2016, 10:45–11:00, H13
Influence of thermal and oxidative treatments on the electronic surface properties of In2O3 films — •Theresa Berthold1, Thomas Stauden1, Stefan Krischok1, Marcel Himmerlich1, Markus Mischo2, Volker Cimalla2, Julius Rombach3, and Oliver Bierwagen3 — 1Institut für Mikro- und Nanotechnologien, Technische Universität Ilmenau — 2Fraunhofer-Institut für Angewandte Festkörperphysik, Freiburg — 3Paul-Drude-Institut für Festkörperelektronik, Berlin
In2O3 is widely used as sensitive gas sensor material. As grown films typically exhibit a high surface electron concentration, which can be modified by an oxygen plasma treatment [1]. In this study, the surface composition and electronic properties of undoped and Mg-doped In2O3 films grown by MBE or MOCVD are characterized by photoelectron spectroscopy to investigate the underlying mechanisms. We analyze the influence of different surface preparation methods, like thermal annealing in vacuum or O2, oxygen plasma treatment as well as exposure to O3, on formation of adsorbates, oxygen vacancies and defects as well as on variation in band bending, electron concentration and electric dipoles at the In2O3 surface. Oxygen plasma and other oxidative surface treatments induce attachment of negative O adsorbates forming an effective negative dipole at the surface that increases the barrier for electron emission and induces depletion of the surface electron layer via charge transfer, which can be reversed by adsorbate desorption. [1] O. Bierwagen, et al., Appl. Phys. Lett. 98, 172101 (2011)