The Itinerant 2D Electron Gas of the Indium Oxide (111) Surface: Implications for Carbon‐ and Energy‐Conversion Applications
[6];
- National Isotope Center GNS Science MacDiarmid Institute for Advanced Materials and Nanotechnology Lower Hutt Wellington 5010 New Zealand, School of Chemical Sciences The University of Auckland Auckland 1010 New Zealand
- Physikalisches Institut Universität Würzburg Würzburg D‐97074 Germany, Advanced Light Source Lawrence Berkeley National Laboratory Berkeley CA 94720 USA
- Paul‐Drude‐Institut für Festkörperelektronik Leibniz‐Institut im Forschungsverbund Berlin e.V. Hausvogteiplatz 5‐7 Berlin 10117 Germany
- Advanced Light Source Lawrence Berkeley National Laboratory Berkeley CA 94720 USA
- Advanced Light Source Lawrence Berkeley National Laboratory Berkeley CA 94720 USA, Department of Physics University of California Davis CA 95616 USA
- National Isotope Center GNS Science MacDiarmid Institute for Advanced Materials and Nanotechnology Lower Hutt Wellington 5010 New Zealand
- Department of Physics Boston University Boston MA 02215 USA
Abstract Transparent conducting oxides (TCO) have integral and emerging roles in photovoltaic, thermoelectric energy conversion, and more recently, photocatalytic systems. The functional properties of TCOs, and thus their role in these applications, are often mediated by the bulk electronic band structure but are also strongly influenced by the electronic structure of the native surface 2D electron gas (2DEG), particularly under operating conditions. This study investigates the 2DEG, and its response to changes in chemistry, at the (111) surface of the model TCO In 2 O 3 , through angle resolved and core level X‐ray photoemission spectroscopy. It is found that the itinerant charge carriers of the 2DEG reside in two quantum well subbands penetrating up to 65 Å below the surface. The charge carrier concentration of this 2DEG, and thus the high surface n‐type conductivity, emerges from donor‐type oxygen vacancies of surface character and proves to be remarkably robust against surface absorbents and contamination. The optical transparency, however, may rely on the presence of ubiquitous surface adsorbed oxygen groups and hydrogen defect states that passivate localized oxygen vacancy states in the bandgap of In 2 O 3 .
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- AC02-05CH11231; FG02-98ER45680
- OSTI ID:
- 1560691
- Journal Information:
- Small, Journal Name: Small Journal Issue: 12 Vol. 16; ISSN 1613-6810
- Publisher:
- Wiley Blackwell (John Wiley & Sons)Copyright Statement
- Country of Publication:
- Germany
- Language:
- English
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