Jaroslav Pavlík

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Group subject:

SnO2 thin films and nanometer surface analysis


Name and Curriculum vitae of contact person:

Jaroslav Pavlík (Doc., RNDr. , CSc.)

Affiliation:

Department of Physics, Faculty of Education, J. E. Purkyně University

Position - Vice-dean of research and foreign relations at Fac. of Education

Fields of scientific activity:

Research of structure properties a surface morphology of thin films prepared mainly by plasma oxidation, aimed at new materials for gas sensors:

• Preparation of thin oxide films (Al2O3, SnO2) by plasma oxidation.

• Experimental characterization of structural properties (Secondary Ion Mass Spectrometry - SIMS) and surface morphology properties (Atomic Force Microscopy - AFM) of different materials.

• Study of relation between the thin oxide films surface morphology (studied by AFM), structural properties (studied by RBS, XPS and SIMS) and plasma parameters.

• Plasma characterization (Langmuir Probe – LP, Optical Emission Spectroscopy – OES, sampling by Quadrupole Mass Spectrometry – QMS and Gas Chromatography – CG) during processes of plasma surface modification.

• Morphological analysis thin films by computer experiments.

• The supervisor of 8 successful diploma theses and 1 bachelor work.

Publications:

Author or co-author of more than 60 scientific publications (more than 23 were published in international journals) to which 8 references appeared in the literature. Amongst these there are common papers with the other academic institutions (Université de Sciences et Technologies de Lille, Institut des Matériaux Jean Rouxel in Nantes, Universite Paul Sabatier in Toulouse, Charles University Prague, Nuclear Institute of AS ČR, University of South Bohemia, Czech Technical University Prague) and development companies (Welding Research Institute in Bratislava and VAKUUM Praha spol. s. r.o. in Prague).

Study stays abroad:

• In 1981 1 month’s stay at Institute of Fluid Flow Machinery Polish Academy of Sciences, Department of Plasma Dynamics, Gdansk, Poland (Prof. Jerzy Mizeraczyk Lab. – plasma parameter measurements of He – Kr+ laser)

• In 1999 short stay (1 week) at University Gent, Faculty of Engineering, Department of Applied Physics, Gent, Belgium (Prof. Christophe Leyes Lab. – OES measurement of CO2 – N2 – He slab laser plasma)

• In 2002 short stay (1 week) at Fraunhofer – Institut für Angewandte Festkörperpsysik, Freiburg, Germany (dr. Manfred Maier Lab. – SIMS measurement of SnO2 thin films)

Selected solved projects:

• COPERNICUS CIPA-CT-94-0183, “Industrial Applications of Low Temperature Plasmas”, 1995 – 1997

• INCO–COPERNICUS ERB IC 15 CT98 0805,“Development of Plasma-Based Products and Processes”,1998–2001

• In frame COST action “Plasma Polymers and Related Materials”, project COST 527.50, “Polymer Thin Film Study by AFM and Improvement of Plasma Diagnostics Methods”, 2000 – 2005

Selected related publications from last 5 years:

• J. Pavlík, R. Hrach, P. Hedbávný and P. Šťovíček: Study of Argon/Oxygen Plasma Used for Creation of Aluminium Oxide Thin Films, Superficies Y Vacio 9, 131 – 134, (1999) (http://www.fis.cinvestav.mx/~smcsyv/supyvac)

• J. Pavlík, P. Špatenka, Z. Strýhal, V. Hrachová, A. Kaňka, J. Čáp, J. Zicha: Application of Chromatic Monitoring as a Plasma Diagnostic Technique, Materials and Manufacturing Processes 16, 863 – 874 (2001)

• Z. Strýhal, J. Pavlík, S. Novák, A. Macková, V. Peřina, K. Veltruská: Investigations of SnO2 Thin Films Prepared by Plasma Oxidation, Vacuum 67, 665 – 671 (2002)

• R. Hrach, D. Novotný, S. Novak, J. Pavlik: Multilevel Morphological Analysis of Semicontinuous and Continuous Metal Films, Thin Solid Films 433, 135 - 139 (2003)

• A. Macková, V. Peřina, Z. Strýhal, J. Pavlík, M. Švec, A. Quédé, P. Supiot, G. Borvon, A. Granier, P. Raynaud: Combined study by RBS, ERDA and AFM analytical methods of organosilicon films obtained from PECVD and PACVD, Surface Science, accepted

Group members:

Jaroslav Pavlík, Stanislav Novák, Zdeněk Strýhal

Main Research Subjects:

The first subject is preparation and study of thin oxide films (SnO2) by a thermal evaporation of metal (Sn) films followed by in situ plasma oxidation. The phenomenon that the adsorption of some gases on the surface of oxide semiconductors can result in a significant change in electrical resistance of the material was discovered several decades ago. The change of surface conductance is caused by the reactions between the reducing gases and the preadsorped oxygen species on the surface. Owing to the high sensitivity to low concentration of reducing gases, SnO2 has been widely used as a primary material for reducing gas sensors. The electrical and gas sensing properties of the films are strongly dependent on the structural properties like porosity, grain size, grain geometry, and chemical composition. Since the properties of the material can depend on the procedure of preparation, the different plasma sources have been employed to obtain SnO2 thin films by plasma oxidation. The aim is to study the effect of technological parameters (e.g. plasma parameters, oxidation time, substrate holder temperature, and bias voltage applied to the substrate during oxidation) on the properties of the prepared oxide films. The post-deposition analysis of tin and tin dioxide films includes Atomic Force Microscopy (AFM), Rutherford backscattering spectrometry (RBS), X-ray Photoelectron Spectroscopy (XPS) and Secondary Ion Mass Spectrometry (SIMS).

The second subject is research of structure properties of composite films. Composite film structure influences their mechanical, electrical and optical properties. As a new tool for the morphological analysis a computer experiment seems to be very suitable.

Selected Specific Equipment:

Since 1999 we are equipped with the next Scanning Probe Microscopes:

• Atomic Force Microscope – Burleigh - METRIS 2001NC. This system enables provide all standard AFM imaging modes (contact, non-contact phase and lateral phase at the ambient atmosphere). The scanning area is 25x25 m2, resolution better as 17 Å.

• Scanning Tunneling Microscope – Nanosurf AG – EasyScan STM System. The scanning area is 0.5 x 0.5 m2, resolution better as 0.15 Å.

In the year 2003 we installed and started into operation the analytical Secondary Ion Mass Spectrometry system Atomika ADIDA 3000 (argon and oxygen primary ion gun with ion beam energy range 0.5 – 15 keV, Cs 431Ion Gun with ion beam energy range 2 keV – 15 keV, QMS to 350 amu).

We are preparing the future XPS system. Since 2003 we are equipped with the energy analyzer SPECS - PHOIBOS 100.

Additional recent selected publications by group members:

• J. Pavlík, Z. Strýhal and S. Novák::AFM Study of Al2O3 Thin Films Prepared by Plasma Oxidation, Le Vide: science, technique et application 55, No. 295 - suppl., 390 – 392 (2000)

• R. Hrach, D. Novotný, S.Novák, J.Pavlík: Morphological Analysis of Continuous Metal Films, Vacuum 57, 259-265 (2000)

• S. Novák, M. Sobotka, R.Hrach : Study of Morphology of Composite Films Thin Solid Films 373, 203-206, (2000)

• Z. Strýhal, J. Pavlík, A. Macková, V. Peřina: Properties of the Thin SnO2 Layers Produces by Plasma Oxidation, Le Vide: science, technique et application 56, No. 300 – suppl., 278 – 280 (2001)

• S. Novák, R. Hrach: Computer Study of Object Disribution in Composite Films, Materials and Manufacturing Processes 17, 97 – 102 (2002)

• Z. Strýhal, J. Pavlík, S. Novák: Studium povrchu plazmaticky oxidovaných tenkých vrstev cínu pomocí AFM, Čs. čas. fyz. 53, 101 - 104 (2003)
© 2005