Ivan Ošťádal

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Group subject:

Nucleation and growth of metals on Si for nanoelectronics


Name and Curriculum vitae of contact person:

Ivan Ošťádal (Doc.,RNDr , CSc.)

Affiliation:

Faculty of Mathematics and Physics, Charles University in Prague, Department of Electronics and Vacuum Physics

Position - Associated professor, Head of the Thin Films Group

Fields of scientific activity:

Physics of thin films and surfaces, STM study of metal heteroepitaxy on Si surfaces; STM technique - design of UHV STM systems;

Electrical transport, relaxations and noise in thin film metal-insulator systems - study of noise and conductance of 2D metal films near the percolation threshold.

• The supervisor of 5 successful diploma theses, 2 PhD theses

Publications:

Author or co-author of more than 47 scientific publications (24 in international journals)

Selected study stays abroad:

• In 1989 10 month’s at Kings College London supported by The British Council

• In 1992 2 month‘s, DeMontfort University, Leicester; Kings College London, (in the frame of TEMPUS JEP 1213/91-93)

• 1994 2 month, University of Lancaster; Kings College London, (TEMPUS IMG-93-CZ-2381)

Selected solved projects:

• GAUK-293 STM and STS study of structure and electronic properties at surfaces (1993-95)

• GAUK-34/97 STM study of epitaxial thin metal films (1997-99)

• GAČR 202/97/1109 STM investigation of initial stages of metal epitaxy on Si(001) and Si(111) surfaces (1997-99)

• GAUK-147/1999/B FYZ/MFF In-vivo STM study of growth of Ag (Pb) on Si(111) surface at temperatures 100-400K (1999-2001)

• GAČR 202/01/0928 Study of heteroepitaxial growth of metals on Si surfaces by means of STM (2001-2003)

Selected related publications from last 5 years:

• P.Sobotík , I.Ošťádal, J.Mysliveček , T. Jarolímek: STM study of nucleation of Ag on Si(111)-(7x7) at submonolayer coverage, Surf. Sci. 454-456 (2000) 847-850

• J. Mysliveček, P.Sobotík, I. Ošťádal, and T. Jarolímek: Unconventional features of Ag epitaxy on Si(111)7x7 surface, Phys. Rev. B 63 (2001) 045403

• I.Ošťádal, R.M.Hill: dc conduction of stable ultrathin Pt films below the percolation threshold, Phys. Rev. B 64 (2001) 033401-033404

• T. Jarolímek, J. Mysliveček, P. Sobotík and I. Ošťádal, Adsorption and diffusion of Ag atoms on Si(111)-(7x7) surface, Surf. Sci. 482-485 (2001) 386-390

• P.Sobotík, I.Ošťádal, J.Mysliveček, T.Jarolímek, F.Lavický: Transition from 2D to3D growth during Ag/ Si(111)-(7x7) heteroepitaxy, Surf. Sci. 482-485 (2001) 797-801

• I.Ošťádal, P. Kocán, J. Mysliveček, P. Sobotík: Ag/ Si(111) 7x7 heteroepitaxy – STM experiment and KMC simulations, Czech. J. Phys. 53 (2003) 41-48

• P. Sobotík, P. Kocán, I. Ošťádal: Direct observation of Ag intercell hopping on the Si(111)-(7x7) surface, Surf. Sci. 537 (2003) L442-446

 

Group members:

Ivan Ošťádal, Pavel Sobotík, Pavel Kocán, Josef Mysliveček, Miroslav Kotrla

Main Research Subjects:

The main research activity is study of mechanisms controlling initial stages of thin films growth by means of scanning tunneling microscopy. The group is focused on epitaxial growth of metals on reconstructed silicon surfaces. Spontaneous growing of areas containing uniform and regularly arranged metal islands is important for using new material structures in nanoelectronics and developing single electron devices. Understanding mechanisms controlling the surface diffusion, nucleation and island growth during heteroepitaxy and finding corresponding physical parameters need experimental study of processes on atomic level – using UHV STM.

The second subject is theoretical study of the growth using kinetic Monte Carlo (KMC) simulations. Models based on the experimental data are used for KMC simulations to be verified and model parameters obtained.

The latest experimental effort is focused on direct observation of growth dynamics and details of adatom interactions at surfaces. Such an approach allows e.g. obtaining diffusion parameters directly. We prepare an additional tool for the better surface structures analysis – scanning tunneling spectroscopy technique.

Selected Specific Equipment:

We use two UHV experimental systems equipped by STM heads and control units developed at our group. We can prepare metal structures by various vacuum evaporation techniques using ultra-low evaporation rates at temperature range 100 – 600 K. We designed special evaporators for the direct STM observation. A new chamber being prepared for UHV STM experiments provides changing samples or STM tips without interrupting UHV conditions. A new liquid He cooling equipment will shift the lowest temperature at experiments to about 10 K.

Additional recent selected publications by group members:

• I. Ošťádal, P. Sobotík, J. Mysliveček: Aggregation of gold on HOPG, Vacuum 50 (1998) 179-181

• I. Ošťádal, L. Lečko, P. Sobotík: Current Noise in Thin Film Al/Al2O3/Au Sandwiches, Vacuum 50 (1998) 9-13

• P. Sobotík, I.Ošťádal, Temperature induced change of surface roughness of Au(111) epitaxial films on mica, J. Cryst. Growth 197 (1999) 955-962

• J. Mysliveček , T. Jarolímek, P. Šmilauer, B.Voigtländer, M.Kästner: Magic Islands and Barriers to Attachment: A Si/Si(111) -(7x7) Growth Model, Phys.Rev. B 60 (1999) 13869-13873

• P.Sobotík, I. Ošťádal, J. Mysliveček, T. Jarolímek, F. Lavický, P. Šmilauer: Reconstruction-determined Growth of Silver on Silicon(111)-( 7x7), Atomistic Aspects of Epitaxial Growth, Eds. M. Kotrla N. Papanicolaou, D. D. Vedensky and L. H. Wille, Kluwer 2002, str. 255-265

• P. Sobotík, I. Ošťádal, P. Kocán: Reconstruction determined submonolayer growth of Ag on Si(111)-(7x7) surface, Surf. Sci. 507-510 (2002) 389-393

• J. Mysliveček, C. Shelling, F. Schäffler, G.Springholz, P. Šmilauer, J. Krug, B. Voigtländer: On the microscopic origin of the kinetic step bunching instability on vicinal Si(001), Surf. Sci. 520 (2002) 193-206

• P. Sobotík, I. Ošťádal, P. Kocán, J. Mysliveček, T. Jarolímek: Reconstruction-determined diffusion of Ag adatoms on the Si(111) 7x7 surface, Czech. J. Phys. 53 (2003) 69-74
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