RNDr. Jiří Zavadil, PhD

 

Graduated from Faculty of Mathematics and Physics, Charles University, Prague (1967)

 

RNDr in Theoretical Physics, Charles University, Prague (1972)

 

PhD in Physics, Institute of Physics, Czechoslovac Academy of Sciences, Prague (1973)

 

He has long experience in the calculation of electronic structure of solid surfaces and strongly localised defects in III-V semiconductors. Since 1993 he has been involved in the optical characterisation of semiconductor and glass materials and structures for optoelectronics, by means of electro and photoluminescence spectroscopy. In recent years he has been working both theoretically and experimentally in the research of electroluminescent spectra of InGaAsP/InP structures and diodes and in the modeling of their waveguiding properties. His major interest now is the study of luminescent properties of InP based semiconductor and chalcogenide glass materials doped with rare-earth elements and characterization of related structures and nanostructures.

 

Currently coordinated projects.

Special glass materials for photonics applications (GA104/08/0734)

2008 – 2010

The project is concerned with the preparation and characterization of special glass systems, those doped with selected rare-earth (RE) elements and with drawing of optical fibres that effectively transmit or emit radiation in the infrared spectral range. The following subjects will be pursued: (1) Development of novel methods for synthesis and purification of chalcogenide and heavy metal oxide (HMO) systems to obtain high quality rods and performs; (2) Preparation and investigation of new vitreous HMO systems based on Sb2O3 or Bi2O3 and chalcogenide glasses with higher contents of Te as compared to systems (e.g. Ge20Se(80-x)Tex) previously studied in our laboratory; (3) Finding of suitable RE dopant - glass matrix combinations in view of photonics applications; (4) Fibre drawing technology and fibre characterization; (5) An attempt will also be done to develop approaches for the preparation of capillary and microstructure fibres from the prepared materials.

 

Investigation of Lead Iodide for X-ray Detection (GC104/08/J025)

2008 – 2010

The aim of the proposed project is the preparation of PbI2 single crystals and optimization of their structural, electrical and optical properties in view of efficient detection of rtg radiation at room and elevated temperature up to 130°C. A modification of electro-optical properties in dependence on addition of suitable admixtures (rare earths, Au etc.) will be studied. PbI2 material will be prepared by direct synthesis from the elements of Pb and I2 and purified by zone melting. The Bridgman-Stockbarger growing apparatus will be used for growing single crystals. The oriented sapphire nucleus will be used to achieve the growth in the required direction. The structural properties of PbI2 will be studied by scanning electron microscopy and high resolution X-ray diffractometry. The electrical and optical properties will be evaluated by measuring I-V characteristics, the temperature dependent Hall effect and low-temperature photoluminescence. SIMS will be used to check elemental depth profiles and GDMS for elemental analysis of bulk material. Defects will be characterized by synchrotron X-ray topography 90SRXT. The detection efficiency of prepared structures will be characterized by charge collection efficiency and by spectral resolution.

 

Nanostructures of Controlled Size and Dimensions (KAN401220801)

2008 – 2012

The project proposes to concentrate on detailed study (modelling and experimental realization) of nanostructures, with target controlled dimensions from several nm and especially controlled organization on dimensions of tens to hundreds nm. The method of nanosphere lithography will be utilized, in combination with other methods as ion implantation, sputtering and deposition, electrolytic methods, iontophoresis, and sedimentation. The goal will be the preparation of both metallic (eg.Pd, Ni,Ag,Au), semiconducting (eg. Si,CdS,oxids-Fe,Zn), and possibly also dielectric nanostructures. Regulation of nanoparticle dimensions will be resolved using organic layers, micelar systems, growth stabilizers and chemical ablation. To characterize the nanostructures of interest, a wide range of methods will be used, including HRTEM, SEM, AFM, STM, etc. Given structures will be studied in various optical and optoelectronic applications, in connection with both passive and active structures.

 

 

List of selected recent publications.

D. Ležal, J. Zavadil and M. Procházka: Sulfide, selenide and telluride glassy systems for optoelectronic applications, Journal of Optoelectronics and Advanced Materials 7 (5) (2005) 2281-2292.

K. Zdansky, J. Zavadil, L. Pekarek, V. Gorodynsklyy and H. Kozak: Investigation of copper doped InP single crystals grown by Czochralski technique for use in X-ray detection, phys. stat. sol (a) 202 (2005) 555-560.

J. Zavadil, O. Procházková and P. Gladkov: Optical properties of InP layers prepared with the addition of Ce, Tm and Lu in the growth melt, Cryst. Res. Technol. 40 (2005) 498-502.

L. Horák, J. Zavadil, V. Ducháč, S. Javorský, F. Kostka, A. Švec and D. Ležal: Autofluorescence spectroscopy of colorectal carcinoma-ex vivo study, Journal of Optoelectronics and Advanced Materials, 8(1) (2006) 396-400.

J. Zavadil, O. Prochazkova, K. Zdansky and P. Gladkov: Ce and Yb doped InP layers grown for radiation detection, phys stat sol (c) 4 (2007) 1444-1447

J. Pedlíková, J. Zavadil, O. Procházková and D. Ležal:  Special glasses for IR applications, Journal of Optoelectronics and Advanced Materials 9 (2007) 1679-1682.

K. Žďánský, P. Kacerovský, J. Zavadil, J. Lorinčík and A. Fojtík: Layers of Metal Nanoparticles on Semiconductors Deposited by Electrophoresis from Solutions with Reverse Micelles, Nanoscale Res. Letters 2 (2007) 450-454.

J. Zavadil, O. Procházková, K. Žďánský, P. Gladkov: Ce and Yb doped InP layers grown for radiation detection, phys. stat. sol. (c) 4 (2007) 1444-1447.

J. Zavadil, O. Procházková, K. Žďánský, P. Gladkov: InP p-type epitaxial layers grown with the addition of rare-earth elements for use in radiation detection, J. Optoelectronics & Advanced Mat. 9 (2007) 1221-1226.

Kaluzny J, Pedlikova J, Zavadil J, et al.: Changes of sulphide glasses caused by the presence of As, Journal of Optoelectronics and Advanced Materials 9 (2007) 3076-3078.

 Kubliha M, Kaluzny J, Pedlikova J, et al: Electrical and dielectrical properties of As-Se-Teglasses, , Journal of Optoelectronics and Advanced Materials 9 (2007) 3082-3087.

O. Procházková, J. Grym, L. Pekárek, J. Zavadil, K. Žďánský: InP based semiconductor structures for radiation detection, J. Mater Sci: Mater Electron 19 (2008) 770-775.

O. Procházková, J. Grym, J. Zavadil, J. Lorinčík, K. Žďánský: Influence of Yb and Yb2O3 addition on the properties of InP layers, J. of Optoelectronics and Advanced Materials 10 (2008) 3261-3264.

J. Zavadil, J. Pedlikova, K. Zdansky, R. Yatskiv, P. Kostka, D. Lezal: Preparation and characterization of telluride glasses, Journal of Non-Cryst. Solids 354 (2008) 486-491.

M. Matuchova, K. Zdansky, J. Zavadil, A. Danilewsky, J. Maixner, D. Alexiew: Electrical, optical and structural properties of lead iodide, JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS 20 (2008) 289-294.

M. Matuchova, K. Zdansky, J. Zavadil: Lead iodide crystals prepared under stochiometric and nonstochiometric conditions, Materials Science and Engineering B, 165, (2009) 60-63

M. Matuchova, K. Zdansky, J. Zavadil., A. Danilewsky, F. Riesz., M.A.S. Hassan, D. Alexiev, R. Kral: Study of the influence of the rare-earth elements on the properties of lead jodide, J. of Crystal Growth 311 (2009) 3557-3562.

J. Grym, O. Procházková, J. Zavadil, K. Žďánský: LPE growth of InP layers from rare-earth melts for radiation detector structures, Materials Science and Engineering B 165 (2009) 94-97.

J. Zavadil, P. Kostka, J. Pedlíková, K. Žďánský, M. Kubliha, V. Labaš, J. Kalužný: Electro-optical characterization of Ge-Se-Te glasses, J Non-Cryst Solids 355 (2009) 2083-2087.

J. Kalužný, J. Pedlíková, J. Zavadil, V. Labaš, M. Kubliha, P. Kostka: Electrical methods for optimization of structural changes and defects in sulphide glasses, J Optoelectronics & Adv. Materials 11 (2009) 2053-2057.

J. Kalužný, J. Pedlíková, P. Kostka, V. Labaš, , M. Kubliha, J. Zavadil, S. Minarik: Investigation of electrical and dielectric properties of Ge20Se80-xTex glasses doped by Er, Ho, Pr, J Optoelectronics & Adv. Materials 11 (2009) 2063-2068.

K. Žďánský, J. Zavadil, P. Kacerovský, F. Kostka, and A. Fojtík: Electrophoretic deposition of reverse micelle metal nanoparticles, phys. stat. sol. (c) 6, No. 12 (2009) 2722-2724.

K. Zdansky, J. Zavadil, P. Kacerovsky, J. Lorincik, J. Vanis, F. Kostka, O. Cernohorsky, A. Fojtik, J. Reboun, J. Cermak: Electrophoresis deposition of metal nanoparticles with reverse micelles onto InP, Int. J. Mat. Res. (formerly Z. Metallkd.) 100, No. 9 (2009) 1234-1238.

M. Matuchova, K. Zdansky, J. Zavadil et al.: Study of the influence of the rare-earth elements on the properties of lead iodide, Journal of Crystal Growth 311 (2009) 3557-3562.