Berlin 2018 – scientific programme

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DS: Fachverband Dünne Schichten

DS 3: Oxide Semiconductors for Novel Devices (Focussed Session): Session I

DS 3.7: Talk

Monday, March 12, 2018, 11:00–11:15, E 020

Modulation of the In₂O₃ surface electron transport properties by acceptor doping — •Alexandra Papadogianni¹, Julius Rombach¹, Theresa Berthold², Stefan Krischok², Marcel Himmerlich², and Oliver Bierwagen¹ — ¹Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5–7, 10117 Berlin, Germany — ²Institut für Physik und Institut für Mikro- und Nanotechnologien, Technische Universität Ilmenau, PF 100565, 98684 Ilmenau, Germany

In₂O₃ is a natively n-type transparent semiconducting oxide possessing a surface electron accumulation layer (SEAL) like several other relevant oxides, such as SnO₂ and ZnO. While the SEAL is within the core of In₂O₃-based conductometric gas sensors, it hinders numerous applications of In₂O₃ in electronic devices that require the formation of Schottky contacts. Tunability of the SEAL is hence necessary to unlock the entire spectrum of possible device applications of In₂O₃.
Oxygen plasma treatment of the In₂O₃ surface has been previously shown to effectively deplete surface electrons. Annealing the material, however, has been proven to reverse this effect, which renders this solution unsuitable for devices operating at elevated temperatures. As an alternative, we demonstrate strong reduction of the SEAL by doping with the deep compensating acceptors Mg and Ni performing X-Ray Photoelectron Spectroscopy (XPS) and transport measurements on high quality single-crystalline In₂O₃(111) films grown by plasma-assisted molecular beam epitaxy (PA-MBE). This method also allows for fine-tuning of the electrical transport properties of the SEAL through controllably selecting its degree of depletion.