Effect of capping layers on the near-surface region of SrVO3 films

Abstract

Surfaces of correlated electron oxides are of significant interest from both fundamental and applied perspectives. Many such oxides feature a near-surface region (NSR) that differs from the bulk's properties. The NSR can significantly affect the interpretation of the material's electronic structure, especially for those in thin film form, and have detrimental effects for applications such as field effect devices and catalysts. In this work, we study the changes in the composition and the electronic structure of the NSR of SrVO 3 (SVO) thin films. We employ x-ray photoelectron spectroscopy (XPS) and compare TiO x -capped SVO films to identical uncapped films that were exposed to ambient conditions. The significant overoxidation of the SVO surface in the bare film, illustrated by a primary V 5+ component, is prevented by the TiO x layer in the capped film. The capped film further exhibits a decrease in Sr surface phases. These results demonstrate the importance and potential of such capping layers in preserving the bulk properties of correlated oxides in their NSR, enabling more accurate probes for their underlying physics and offering a route for their integration into devices.

Artificial Aging of Thin Films of the Indium-Free Transparent Conducting Oxide SrVO3

“…First, a protection layer to be deposited on top of the SVO film can be developed. For SVO, TiO 2 was tested, but a comparable approach as what has been done for SrTiO 3 would be possible, too. Here, Al-based oxides or even an ultrathin metallic Al film, oxidized by the SrTiO 3 itself, have shown a protecting effect concerning oxygen exchange with the atmosphere, even at high temperatures .…”

Thickness and temperature dependence of the atomic-scale structure of SrRuO$_3$ thin films

“…While this analysis assumes no structural or chemical changes occur upon the surface exposure to ambient conditions, in some oxides such changes can be quite significant. [50] SRO films exposed to ambient atmosphere and heated in vacuum may decompose. [51] However, the strong signal originating both from the half order reflections and the RSMs (Figure 5) indicate that even at 3 uc, a significant portion of the film retains its high quality crystalline structure.…”

Bandwidth Control and Symmetry Breaking in a Mott‐Hubbard Correlated Metal

“…were epitaxially grown on (001)‐oriented (cubic/pseudocubic) LAO, LSAT, STO, and LGO substrates (CrysTec GmbH). This thickness was chosen to reduce the contribution of possible surface effects [ 48 ] while ensuring the coherent epitaxy of the films. The growth was done using oxide molecular beam epitaxy (MBE) at a background pressure of molecular oxygen of $$\sim 5 \times {10}^{ - 7}$$ Torr and substrate (thermocouple) temperature of 1000 °C.…”