Surface & Plasma
Technology

National Institute of Standards and Technology (NIST)

SESSA: Simulation of electron Spectra for Surface Analysis : A Database for quantitative electron spectroscopy developed in cooperation with Dr. C.J. Powell of the National Institute of Standards and Technology (NIST)

Auger and X-ray photoelectron spectroscopy (AES and XPS) are important surface analysis techniques in industrial and fundamental research. Although individual processes governing the experimental spectrum are thoroughly understood nowadays, quantitative analysis frequently suffers from the lack of a comprehensive data base providing the required information to quantitatively interpret a spectrum. Such a data base is presently under devopment and is being prepared for release through the Standard Reference Data Program (SRDP) of NIST. The data base automatically retrieves data relevant for AES/XPS for a material specified by the user. In this way it is possible to gain information on a sample of unknown composition by comparison of experimental and theoretical spectral features. User interaction is possible via a graphical user interface, or, alternatively via a command line interface enabling large retrieval operations in batch mode.The data base is a Windows 32 application to ensure widest possible dissemination of the product. An OS-X (linux) version is also available.
For further details see the SESSA-homepage.

Institute of Nuclear Research of the Hungarian Academy of Sciences Debrecen, Hungary (ATOMKI)

ATOMKI

We have an ongoing cooperation with the research group of Dr. Laszlo Kover on various aspects of fundamentals and applications of electron spectroscopy. Presently the emphasis is on establishing "A World Wide Web based Database for Quantitative Surface Electron Spectroscopy"
We are defining a procedure that allows to establish a database of lineshapes to be used for quantitative spectrum modelling via the world wide web. The following aspects distinguish the planned database from existing (commercial) databases:

• It will made available on a by-the-community-for-the-community basis, i.e. use of the database by the members of the community (of electron spectroscopists worldwide) is free, all members of the community can submit data.
• It will be dynamic by the use of the WWW as an exchange platform. This implies i.a. that when a new group of materials becomes of interest to the community, it takes considerably less time for reference data to become available for all members of the community.
• The data themselves will not be raw measured data (as is the case for all presently available databases), but will be preprocessed with special regard for instrumental effects and effects caused by the electron transport as relevant for future use in spectrum modelling. This implies that finding, developing and testing a well defined procedure for spectrum deconvolution is an essential part of proposed project.
• The quallity of the database will be certified by means of a peer reviewing process (by the community of users via the world wide web) of the submitted raw data as well as the data processing it was subjected to.

Czech Academy of Sciences

Institute of Physics (cukrovarnicka), Czech Academy of Sciences

We have an ongoing cooperation with the research group of Dr. J. Zemek on various aspects of fundamentals and applications of electron spectroscopy. Presently we are performing a comparative study on "Attenuation of Electron Beams in Ordered and Unordered Surfaces"

• Measurement of the inelastic mean free path in several non-crystalline materials (Si, Fe, Cu, Ag, Au) for different angles to test the model for non-coherent electron transport developed in the framework of the cooperation.
• Experimental investigation of the electron attenuation lenghts in a near-surface region of ordered surfaces and structures based on GaAs, GaAlAs, and GaAs:Mn prepared by molecular beam epitaxy.
• Development of a model for electron beam attenuation in substances with and without long range order for medium and low energies.

Institute of Materials Science of Seville

CSIC

Augerelectron and photoelectron spectroscopy for investigation of nanoscale electronic screening in solids, cooperation with Dr. Agustin Gonzalez Elipe and Francisco Yubero
The ability of a solid to screen an external perturbation is of great practical as well as fundamental interest. The polarizability governs the optical properties of surfaces and interfaces as well as the energy dissipation of particles traveling inside the solid or near its boundary. Generally, the density of states and the screening characteristics combined describe the main electronic properties of a solid.
Augerelectron and photoelectron spectra contain valuable information on the solid-state screening. This information is unique in that it is representative for the local electronic structure around a given atom since the peaks of signal-electrons liberated from a given chemical species can be distingtuished according to their characteristic energy in the spectrum. The local screening influences an electron spectrum mainly in two ways: the characteristic energies of the (core level) signal-electron peaks exhibits an energy shift due to intra- and extraatomic relaxation effects, polarization etc. Furthermore, the details of the energy dissipation process of signal electrons in the vicinity of their point of liberation in the solid is governed by the local screening. These scattering processes are commonly refered to as intrinsic excitations, to distinguish them from the other modes of the inelastic electron solid interaction: bulk (volume) excitations and surface excitations. The former effect is widely used for the study of the chemistry of surfaces and interfaces, since analysis of peak energy changes is straightforward, at least from an experimental point of view. Although intrinsic excitations are believed to contain much more detailed information on the local dielectric screening, they are seldomly used to study this phenomenon since they are superimposed on the other inelastic excitation modes and it is therefore very complicated to extract information regarding the local screening from experimental data. In the present cooperation we apply a novel general method for spectrum decomposition to extract information on intrinsic excitations from experimental spectra and to demonstrate the existence of a correlation with the characteristic energies (or shifts) of Auger- and photoelectrons. The procedure will be tested and applied to metal oxide systems.

Universita di Roma Tre

Roma 3

We are cooperating with the Group of Prof. Gianni Stefani on the field of Auger Photoelectron Coincidence Spectroscopy (APECS).
We have recently demonstrated that it is possible to select the depth from which photoelectrons escape by measuring them in coincidence with Augerelectrons emitted from the same atom that has lost a certain fraction of its energy (see details)

CASECT

We are developing plasma cells integrated into micro-fluidic devices for Lab-on-Chip applications in cooperation with CASECT Ltd. and R.I.C.. These are to be applied as sensitive detectors for gas chromatographs and similar analytical equipment. See the relevant project for details.

R.I.C.

R.I.C.

We are developing plasma cells integrated into micro-fluidic devices for Lab-on-Chip applications in cooperation with CASECT Ltd. and R.I.C.. These are to be applied as sensitive detectors for gas chromatographs and similar analytical equipment. See the relevant project for details.

AC2T Research GmbH

Homepage

We are a major scientific partner of the Austrian Center of Competence for Tribology, located in Wr. Neustadt, 50 km south of Vienna. Tribology is the science and technology of friction and wear. We are jointly investigating tribologically stressed surfaces at different scales, reaching from the macroscopic via the micro- and nano-range to the molecular level. We are performing investigations of triblogical surfaces with atomic force microscopy (AFM), Scanning Auger Electron microscopy (AES, SAM) and Angular resolved Photoelectron Spectroscopy (AR-XPS, ESCA). The AFM has been equipped with a special fluid cell. At AC2T tribological tests, optical topography measurements and lubricant analyses are performed.
Main focus of this work is the link between surface chemistry and macroscopic wear. Besides fundamental research we are supporting a number application projects of AC2T with nano-analytical services, using the instruments mentioned above.

ECHEM

Homepage

We are cooperating with the "ECHEM Kompetenzzentrum für angewandte Elektrochemie GmbH" (Center for applied electro-chemistry), located in Wr. Neustadt, 50 km south of Vienna. We jointly designed and built an electrochemical cell, permitting the direct transfer of samples to our ESCA spectrometer, where exposure to air is avoided. Using this device, we were able to observe the very early nucleation phase of electrochemically deposited alloy films. Besides fundamental research we are supporting ECHEM with nano-analytical services, using our ESCA and Auger spectrometers.

Nanophysics group at Vienna University of Technology

Nanophysics group at Vienna University of Technology

With Prof. Markus Arndt, head of the Nanophysics group at Vienna University, we collaborate in using the AFM to investigate the quantum mechanical interference of biomolecules.

Alfred Wegener Insitute in Bremerhaven, Germany

Alfred Wegener Insitute in Bremerhaven, Germany

With Prof. Richard Crawford from the Alfred Wegener Insitute in Bremerhaven, Germany, we collaborate concerning our newly founded field of Diatom Tribology. He is the head of one of the largest diatom collections in the world.

Vienna University, Institute for Biology

Vienna University, Institute for Biology

With Manfred Drack, theoretical biologist at Vienna University, we collaborate concerning the interface of biology and engineering.