Data di Pubblicazione:
2022
Citazione:
Evidence of a 2D Electron Gas in a Single-Unit-Cell of Anatase TiO2 (001) / A. Troglia, C. Bigi, I. Vobornik, J. Fujii, D. Knez, R. Ciancio, G. Draži´c, M. Fuchs, D. Di Sante, G. Sangiovanni, G. Rossi, P. Orgiani, A. Giancarlo Panaccione. - In: ADVANCED SCIENCE. - ISSN 2198-3844. - 9:16(2022 May), pp. 2105114.1-2105114.7. [10.1002/advs.202105114]
Abstract:
The formation and the evolution of electronic metallic states localized at the
surface, commonly termed 2D electron gas (2DEG), represents a peculiar
phenomenon occurring at the surface and interface of many transition metal
oxides (TMO). Among TMO, titanium dioxide (TiO2), particularly in its
anatase polymorph, stands as a prototypical system for the development of
novel applications related to renewable energy, devices and sensors, where
understanding the carrier dynamics is of utmost importance. In this study,
angle-resolved photo-electron spectroscopy (ARPES) and X-ray absorption
spectroscopy (XAS) are used, supported by density functional theory (DFT), to
follow the formation and the evolution of the 2DEG in TiO2 thin films. Unlike
other TMO systems, it is revealed that, once the anatase fingerprint is
present, the 2DEG in TiO2 is robust and stable down to a single-unit-cell, and
that the electron filling of the 2DEG increases with thickness and eventually
saturates. These results prove that no critical thickness triggers the
occurrence of the 2DEG in anatase TiO2 and give insight in formation
mechanism of electronic states at the surface of TMO.
Tipologia IRIS:
01 - Articolo su periodico
Elenco autori:
A. Troglia, C. Bigi, I. Vobornik, J. Fujii, D. Knez, R. Ciancio, G. Draži´c, M. Fuchs, D. Di Sante, G. Sangiovanni, G. Rossi, P. Orgiani, A. Giancarlo Panaccione
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