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Thin oxide films by PLD: "Tracing" the oxygen and understanding its role

English title Thin oxide films by PLD: "Tracing" the oxygen and understanding its role
Applicant Wokaun Alexander
Number 117642
Funding scheme Project funding (Div. I-III)
Research institution Laboratorium für Physikalische Chemie D-CHAB ETH Zürich
Institution of higher education Paul Scherrer Institute - PSI
Main discipline Physical Chemistry
Start/End 01.01.2008 - 31.12.2010
Approved amount 199'544.00
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Keywords (8)

Thin films; Oxides; Plasma mass spectrometry; SIMS; RBS; thin oxide films; pulsed laser deposition; perovskites

Lay Summary (English)

Lead
Lay summary
This research project is related to the general framework of the deposition of thin oxide films with well-defined oxygen contents, which for many compounds determines the properties of these materials. The thin films with controlled composition, structure, interface, stress etc., can be used to improve the fundamental understanding in material science, but also to optimize material properties for certain application. The research topics in this project are aimed at two fundamental problems in thin oxide film deposition, i.e. how to determine the oxygen content quantitatively and how to control the oxygen content. Two approaches, both based on mass spectrometry, are selected:
1.Test/application/development of secondary ion mass spectrometry (SIMS) as a tool to determine the content of oxygen and of other elements in thin oxide films;
2.Analysis of the ablation plume with plasma mass spectrometry (P-MS) as a function of irradiation fluence and laser wavelength; testing whether correlations of the film composition with the composition of the ablation plume exist, with a special emphasis on the abundance of diatomic oxidic species.
The materials that will be used in this study are mainly the materials which have been studied in detail previously in our group (La0.6Ca0.4CoO3-? and La0.6Ca0.4MnO3-?). Both belong to the class of perovskites and are used in (La0.6Ca0.4CoO3-? as electrocatalyst in re-chargeable Zn-Air batteries) or have the potential (La0.6Ca0.4MnO3-? for storage or information transfer, a field called also “spintronics” for these type of materials) to be used industrial applications.
The analysis of the thin oxide films will be performed for standard/reference materials which can be prepared from the same materials using pulsed laser deposition (PLD) as deposition method and Rutherford backscattering spectrometry as analytical tool to determine the oxygen content in the thin films. Dynamic SIMS will then be used to obtain elemental depth profiles through the film layer. It will be tested whether the signal intensities in SIMS can be applied to yield quantitative compositional information. This would be an important progress, as the feedback from the compositional analysis would be available much faster for optimizing the growth conditions.
The direct analysis of the plasma plume as function of the laser fluence and wavelength allows to determine whether the composition of the plume, especially the abundance of diatomic oxidic species, which could have a pronounced influence on the oxygen content of the film, can be controlled by the laser parameters. The successive deposition and analysis of films under conditions where pronounced differences have been detected by P-MS will show whether such a correlation between plasma composition and film composition exists. If this correlation could be established, then an additional parameter for the control of the oxygen content in thin films would be available, allowing to tune the oxygen content for the desired properties.
Direct link to Lay Summary Last update: 21.02.2013

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Associated projects

Number Title Start Funding scheme
126783 Single crystalline films of ion conductors 01.11.2009 Project funding (Div. I-III)
134577 Negative ions: the overlooked species in thin film growth by pulsed laser deposition 01.04.2011 Project funding (Div. I-III)
128735 Erneuerung des ETH Tandem Beschleunigers 01.03.2010 R'EQUIP
133793 Pulsed laser deposition chamber for an advanced in situ growth control of oxide thin films and multilayers for materials research 01.12.2010 R'EQUIP
107536 Laser ablation of inorganic materials and thin film deposition studied by mass spectrometry and in-situ surface analysis 01.04.2005 Project funding (Div. I-III)

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