Probing surfaces and interfaces in complex oxide films via in situ X-ray photoelectron spectroscopy

Abstract

Abstract

Advanced XPS characterization: XPS-based multi-technique analyses for comprehensive understanding of functional materials

“…10 X-ray photoelectron spectroscopy (XPS) has become a wellknown technique in the field of materials science, one which may be used to probe the elemental, electronic and chemical characteristics of a material surface. [11][12][13][14] While the interpretation of XPS data via peak deconstruction is commonplace, fundamental understanding of the technique and an appreciation for correct data handling are often missing. 15 Recently, a series of invaluable guides have been prepared from a community effort among the leading practitioners in the field of XPS, with the aim of enabling researchers new to XPS to plan experiments and understand their data to a high level.…”

In Situ Monitoring of Composition and Sensitivity to Growth Parameters of Pulsed Laser Deposition

“…If a homoepitaxial deposition has an off-stoichiometric plume, the resulting film must account for the excess species somehow. While some of the literature provides explanations for the manner in which the film incorporates an excess species, ,, many do not. ,, Regardless, the specifics will depend on the material and kinetics of the growth event in question. For STO, plausible scenarios to account for small amounts of excess Sr or Ti are the formation of interstitials and/or vacancies or other types of points and line defects .…”

“…For STO, plausible scenarios to account for small amounts of excess Sr or Ti are the formation of interstitials and/or vacancies or other types of points and line defects . However, these fail to account for structure- and surface-dependent growth behaviors such as termination, which are disproportionately influential in thin films. − ,− Furthermore, the Auger electrons detected in AES typically have energies less than 2 keV, which corresponds to inelastic mean free paths (IMFPs) of a few nanometers at most. , This means that the extreme surface sensitivity of AES makes it particularly useful for observing these types of surface-dependent growth behaviors.…”

“…If a homoepitaxial deposition has an off-stoichiometric plume, the resulting film must account for the excess species somehow. While some of the literature provides explanations for the manner in which the film incorporates an excess species, 38,42,43 many do not. 8,9,39 Regardless, the specifics will depend on the material and kinetics of the growth event in question.…”

Operando X-ray characterization of interfacial charge transfer and structural rearrangements

“…39 In this section, we cover the essentials necessary for the discussion of interface-sensitivity and operando characterization with XPS. A more complete description of the physical process of photoemission and the general application of XPS can be found in seminal review articles [42][43][44] and in the recent XPS tutorial series collected by the American Vacuum Society with important instructional works by Baer et al, 45 Powell, 46 Chambers et al, 47 Tougard 48 and others. Similar to XAS, XPS relies on the absorption of photons by electrons.…”