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Roman Holovchak

Associate Professor

Physics, Engineering and Astronomy

 

* Dr.Sc. (Habilitation) in Solid State Physics (dissertation “Structural-topological self-organization in network systems of chalcogenide glasses”, June 9, 2016 at Vlokh Institute of Physical Optics, Ministry of Education and Science of Ukraine)

* Ph.D. in Optics and Laser Physics (dissertation “Optical-spectroscopic peculiarities of radiation-induced effects in mixed arsenic-germanium sulphide glasses”, February 3, 2004 at Institute of Physical Optics, Lviv, Ukraine)

* B.Sc. and M.Sc. Degree in Physics & Electronics (specialization – Radioelectronic Materials Engineering, 1997, Ivan Franko National University of Lviv, Ukraine

High resolution X-ray photoelectron spectroscopy (Scienta ESCA 300 at Lehigh University); EXAFS, XANES, quick EXAFS (beamlines X18B, X19A, X15B at Brookhaven National Lab); time-resolved XAFS (beamline BESSRC/XOR 11 at APS, Argonne National Lab); neutron scattering (NOMAD beamline, SNS, Oak Ridge National Lab); optical spectroscopy (Varian 7000e FT-IR, Varian 6000 UMA, Specord M40, Specord 75IR, Ocean Optics, Avantes, etc.); fluorescent spectroscopy (Horiba Fluorolog 3), Raman spectroscopy (Horiba XploRa); glass synthesis; wet etching technology; photo-lithography; thin film technology; ceramic technology; scanning electron microscopy (Hitachi 4300) with EBSD, EDX; microhardness; positron annihilation lifetime spectroscopy (ORTEC); thermal analysis (NETZSCH 404/3/F, NETZSCH 204, TA 2920 Temperature-modulated DSC); BET/BJH nitrogen adsorption porosimetry; AFM (Solver Next); low energy ion scattering (IONTOF Qtac 100); transmission electron microscopy (JEOL 1200); programming.

Topological self-organization phenomena in disordered networks; relaxation phenomena in disordered solids; spectroscopy of electronic and atomic states in glasses; interaction of light and ionizing radiation with amorphous solids; surface science in application to solid state disordered media; nanostructuring of non-oxide glasses; amorphous optical IR materials for micro- and nano-photonics; chalcogenide glasses for sensor applications; thin film technology; materials characterization at the level of atomic- and void-species structure; properties and application of bioactive glasses.

 

Recent Research Projects:

* 2017-2019 – Major Research Instrumentation Grant “MRI: Acquisition of Positron Annihilation Lifetime Spectrometer for enhanced materials characterization” – Austin Peay State University, U.S. National Science Foundation (Principal Investigator);

* 2016 – Research Project "Nanocrystallites formation in novel Bi/Ga/Sb-modified chalcogenide glasses" - Austin Peay State University, NOMAD (Oak Ridge National Laboratory);

* 2014-2017 Research Project "Radiation selectivity of photo-induced structural transformations in covalently bonded glassy thin films" - Austin Peay State University, U.S. National Science Foundation (Senior Personnel);

* 2013 – Research Project "Relaxation of structure in network glasses throughout glass-to-supercooled liquid transition: neutron scattering" - Austin Peay State University, NOMAD (Oak Ridge National Laboratory);

* 2013 – Research Project "Structural relaxation in network glasses: role of medium range order" - Lehigh University, Austin Peay State University, NOMAD (Oak Ridge National Laboratory);

* 2013-2014 – Research Project "Thermally- and light-activated molecular switching in network glasses" - Lehigh University, NSLS (Brookhaven National Laboratory);

* 2013-2014 – Research Project "Role of Ga in enhancing the properties of Ge-Se(Te) glasses and glass-ceramics for photonics" - Lehigh University, NSLS (Brookhaven National Laboratory);

* 2013-2014 – Research Project "Structural origin of ‘phase-change’ and ‘threshold electrical switching’ phenomena in amorphous binary chalcogenide thin films" - Lehigh University, NSLS (Brookhaven National Laboratory);

* 2012-2014 – Research Project “Assessment and optimization of fabrication process parameters for the control of nanoscale porosity in novel bioactive glass scaffolds for biomedical applications” – PoC Fund, Lehigh University.

* 2010-2012 – Research Project “Infrared detector arrays based on printable, flexible, suspended carbon nanotube microbolometers” – Lehigh University, Nano-C, Inc., US Army ARDEC, US Army Lab.

* 2011-2012 – Research Project “Self-adaptive functional glasses for high-reliable IR applications” (Participants: SRC “Carat”, Lviv, Ukraine and Rennes University, Rennes, France) – Ukrainian-French Program “Dnipro” (Principal Investigator).

* 2008-2011 – Research Project "Relaxation of structure in network glasses through the glass-to-supercooled liquid transition: QEXAFS" - Lehigh University, NSLS (Brookhaven National Laboratory)

 

Other Relevant Research Projects

* 2008-2010 Project "Nanovoid-structured photorefractive amorphous media for information technologies" – Science and Technology Center in Ukraine (STCU).

* 2006-2008 – Research Project “Radiation-sensitive recording media based on chalcogenide glasses” – Civilian Research and Development Foundation (CRDF)

* 2007-2010 Project “Post-technological structural modification of chalcogenide vitreous semiconductors for multifunctional device application” – Science and Technology Center in Ukraine (STCU).

* 2007-2008 Project “Natural and physical ageing in inorganic glasses: new principal resolutions for advanced device developments” (Participants: SRC “Carat”, Lviv, Ukraine and Rouen University, Rouen, France) – Ukrainian-French Program “Dnipro”.

* 2002-2007 Project “Thermally- and radiation-induced modification processes in multicomponent semiconducting glasses and ceramics” (Participants: SRC “Carat”, Lviv, Ukraine and Fachhohschulle Muenster, Muenster, Germany) – BMBF-WTZ Germany.

* 2005-2007 Project “Development of Semiconducting Ceramic Composites based on Ternary Nickel, Cobalt, Manganese and Copper Spinels” – Science and Technology Center in Ukraine (STCU).

* 2004-2006 Project “Development of high-sensitive active elements for humidity sensors based on alumomagnesium ceramics with spinel structure” – Science and Technology Center in Ukraine (STCU).

* 2002-2004 Project “Magnetooptische Granatschichten fur Sensoren und Modulatoren”(Participants: SRC “Carat”, Lviv, Ukraine, Fachhohschulle Muenster, ImpEx HighTech, Germany) – BMWi Germany.

* 2001-2004 Project “Dynamic radiation-induced effects and relaxation transformations in chalcogenide vitreous semiconductors” – Fund of Fundamental Investigations of Ministry of Education and Science of Ukraine

* 2000-2002 Joint Ukrainian-Polish Project “Radiation-induced phenomena in the materials of electronic technique” (Participants: SRC “Carat”, Lviv, Ukraine and Physics Institute, Pedagogical University of Czestochowa, Poland) – Ministry of Education and Science of Ukraine and Polish State Committee on Scientific Research

* 1999-2002 Joint Ukrainian-Polish Project “Investigation of influence of radiation, temperature and biological corrosion on physical properties of amorphous vitreous semiconductors and choice of degradation models describing these phenomena” (Participants: SRC “Carat”, Lviv, Ukraine and Warsaw University of Technology, Poland) – Ministry of Education and Science of Ukraine and Polish State Committee on Scientific Research

* 1998-2001 Joint Ukrainian-Bulgarian Project “Influence of gamma-irradiation on the structure and optical properties of chalcogenides based on Sb (As) and Ge” (Participants: SRC “Carat”, Lviv, Ukraine and Institute of Solid State Physics of National Academy of Sciences of Bulgaria; funding institutions – National Academies of Sciences of Ukraine and Bulgaria)

* 1997-2000 Research Project “Radiation-induced anisotropy in amorphous solids” – Fund of Fundamental Investigations of Ministry of Education and Science of Ukraine

Technical referee for:

US National Science Foundation, US Department of Energy, Physical Review B, Physica B, Physica Status Solidi, Solid State Communications, Journal of Physics, Journal of Non-Crystalline Solids, Journal of Physical Chemistry, Journal of Materials Research, Vacuum, Nuclear Instruments and Methods in Physics Research, Journal of Materials Science, Journal of Materials Chemistry, Thin Solid Films, Journal of Molecular Structure, Acta Materialia, Philosophical Magazine, Materials Research Bulletin, Journal of Alloys and Compounds, Optical Materials, Optical Materials Express, Journal of Chemical Physics, Fibers, Macromolecular Symposia, Journal of Applied Physics, Journal of Applied Glass Science, Nanoscale Research Letters, Journal of the American Ceramic Society, Applied Surface Science, Materials Chemistry and Physics, Applied Physics Letters, Materials Characterization, Polymers in Medicine, Acta Biomaterialia, Thermochimica Acta, Applied Nanoscience, Ceramics International

 

LIST OF PUBLICATIONS (130+ journal papers, 80+ conference contributions, 1500+ citations, h-index – 22)

 

Books/Chapters:

[1] O. Shpotyuk, R. Golovchak, A. Kozdras. Chpt. 8 “Physical aging of chalcogenide glasses”, in: Chalcogenide Glasses: Preparation, properties and application. J-L. Adam and X. Zhang (Ed.). Woodhead Publishing series in Electronic and Optical Materials No.44, 2014. P.209-264 (682 pp.).

 

Patents:

[1] H. Jain, R. Golovchak, M. Falk. “Bioactive glass preparation and use”. U.S. Patent No.: 9,757,417. Filed: October 19, 2016. Issued: September 12, 2017.

 

 

 

Papers in peer-reviewed journals:

[1] R. Golovchak, V. Nazabal, B. Bureau, J. Oelgoetz, A. Kovalskiy, H. Jain. ”Chemical order in Ga or Sb modified germanium sulfide glasses around stoichiometry: High-resolution XPS and Raman studies”, J. Non-Cryst. Solids, Vol. 499, 2018. P. 237–244.

[2] J. Szlęzak, J. Kelly, A. Ingram, Ya. Shpotyuk, S. Adamiak, A. Dziedzic, J. Cebulski, R. Golovchak. ”Role of Bi and Ga additives in the physical properties and structure of GeSe4-GeTe4 glasses”, Materials Characterization, Vol. 142, 2018. P. 50-58.

[3] R. Golovchak, Ya. Shpotyuk, J. Szlęzak, A. Dziedzic, A. Ingram, J. Cebulski. ”Giant visible and infrared light attenuation effect in nanostructured narrow-bandgap glasses”, Optics Letters, Vol. 43, № 3, 2018. P. 387-390.

[4] R. Golovchak, A. Kozdras, T. Hodge, J. Szlęzak, C. Boussard-Pledel, Ya. Shpotyuk, B. Bureau. ”Optical and thermal properties of Sb/Bi-modified mixed Ge-Ga-Se-Te glasses”, J. Alloys and Compounds, Vol. 750, 2018. P. 721-728.

[5] M. Shpotyuk, A. Kovalskiy, R. Golovchak, O. Shpotyuk. “Phenomenology of γ-irradiation-induced changes in optical properties of chalcogenide semiconductor glasses: a case study of binary arsenic sulfides”, J. Non-Cryst. Solids, Vol. 498, 2018. P. 315–322.

[6] O. Shpotyuk, A. Kozdras, J.-M. Saiter, R. Golovchak. “Comment on “Molecular origin of aging of pure Se glass: Growth of inter-chain structural correlations, network compaction, and partial ordering” [J. Chem. Phys. 146 224506 (2017)]”, J. Chemical Physics, Vol. 148, 2018. P.157101(2).

[7] T.J. Kowal, R. Golovchak, T. Chokshi, J. Harms, U. Thamma, H. Jain, M.M. Falk. “Role of phase separation on the biological performance of 45S5 Bioglass®”, J. Materials Science: Materials in Medicine, Vol. 28, № 10, 2017. P.161(16).

[8] J. Bunton, L. Calvez, V. Kadan, I. Blonskyi, O. Shpotyuk, R. Golovchak. “Near-IR emission of Er3+ ions in CsCl-Ga-Ge-S glasses excited by visible light”, Optical Materials, Vol.72, 2017. P.195-200.

[9] R. Golovchak, M.J. Davis, P. Vullo, A. Astashkin, L. Nichols, A. Ingram, H. Jain. “The charge state of titanium ions in Pd-doped Ti:CMAS glass and glass-ceramics”, J. American Ceramic Society, Vol.100, №6, 2017. P.2568-2581.

[10] A. Kovalskiy, M. Vlcek, K. Palka, J. Buzek, J. York-Winegar, J. Oelgoetz, R. Golovchak, O. Shpotyuk, H. Jain. “Structural Origin of Surface Transformations in Arsenic Sulfide Thin Films upon UV-Irradiation”, Applied Surface Science, Vol.394, 2017. P.604-612.

[11] S. Novak, V. Singh, C. Monmeyran, A. Ingram, Zh. Han, H. Lin, N. Borodinov, N. Patel, Q. Du, J. Hu, I. Luzinov, R. Golovchak, A. Agarwal, K. Richardson. “Positron annihilation lifetime spectroscopy (PALS) studies of gamma irradiated As2Se3 films used in MIR integrated photonics”, J. Non-Cryst. Solids, Vol.455, 2017. P.29-34.

[12] R. Golovchak, A. Kozdras, O. Shpotyuk, V. Balitska. “Crossover between cooperative and fractal relaxation in complex glass-formers”, J. Physics: Condensed Matter, Vol.28, 2016. P. 355101(10).

[13] Y.G. Choi, S.Y. Shin, R. Golovchak, B. Cheong, H. Jain. “Comparative study of atomic arrangements in equiatomic GeSe and GeTe films before and after crystallization”, J. Alloys and Compounds, Vol. 686, 2016. P. 273-280.

[14] L. Saturday, C. Johnson, A. Thai, J. Szlęzak, Ya. Shpotyuk, R. Golovchak. “Devitrification of Bi- and Ga-containing germanium-based chalcogenide glasses”, J. Alloys and Compounds, Vol. 674, 2016. P. 207-217.

[15] O. Shpotyuk, A. Kozdras, V. Balitska, R. Golovchak. “On the compositional diversity of physical aging kinetics in chalcogenide glasses”, J. Non-Cryst. Solids, Vol. 437, 2016. P.1-5.

[16] J. Trimble, R. Golovchak, J. Oelgoetz, C. Brennan, A. Kovalskiy. “Structural characterization of tin fluorophosphate glasses doped with Er2O3”, Phys. Chem. of Glasses: European J. of Glass Science and Technology part B, Vol.57, № 1, 2016. P.27-31.

[17] R. Golovchak, Ya. Shpotyuk, C.M. Thomas, V. Nazabal, C. Boussard-Pledel, B. Bureau, H. Jain. “Peculiarities of Ga and Te incorporation in glassy arsenic selenides”, J. Non-Cryst. Solids, Vol. 429, 2015. P.104-111.

[18] R. Golovchak, Ya. Shpotyuk, V. Nazabal, C. Boussard-Pledel, B. Bureau, J. Cebulski, H. Jain. “Study of Ga incorporation in glassy arsenic selenides by high-resolution XPS and EXAFS”, J. Chemical Physics, Vol.142, 2015. P.184501(10).

[19] R. Golovchak, Y.G. Choi, S. Kozyukhin, Yu. Chigirinsky, A. Kovalskiy, P. Xiong-Skiba, J. Trimble, R. Pafchek, H. Jain. “Oxygen incorporation into GST phase-change memory matrix”, Applied Surface Science, Vol. 332, 2015. P.533–541.

[20] R. Golovchak, P. Lucas, J. Oelgoetz, A. Kovalskiy, J. York-Winegar, Ch. Saiyasombat, O. Shpotyuk, M. Feygenson, J. Neuefeind, H. Jain. “Medium range order and structural relaxation in As-Se network glasses through FSDP analysis”, Materials Chem. and Physics, Vol. 153, 2015. P. 432-442.

[21] Y.G. Choi, S.Y. Shin, R. Golovchak, S. Lee, B. Cheong, H. Jain. “EXAFS spectroscopic refinement of amorphous structures of evaporation-deposited Ge-Se films”, J. Alloys and Compounds, Vol. 622, 2015. P. 189–193.

[22] O. Shpotyuk, A. Ingram, R. Szatanik, M. Shpotyuk, R. Golovchak. “Structural-relaxation phenomena in As-S glasses as probed with combined PALS/DBAR technique”, Materials Chemistry and Physics, Vol. 155, 2015. P. 76-82.

[23] J. Cook, S. Slang, R. Golovchak, H. Jain, M. Vlcek, A. Kovalskiy. “Structural features of spin-coated thin films in binary AsxS1-x chalcogenide glass system”, Thin Solid Films, Vol. 589, 2015. P. 642–648.

[24] O.I.Shpotyuk, J. Filipecki, A. Ingram, R. Golovchak, M. Vakiv, H. Klym, V. Balitska, M. Shpotyuk, A. Kozdras. “Positronics of subnanometer atomistic imperfections in solids as a high-informative structure characterization tool”, Nanoscale Res. Letters, Vol. 10, 2015. P. 77.

[25] R. Golovchak, P. Thapar, A. Ingram, D. Savytskii, H. Jain. “Influence of phase separation on the devitrification of 45S5 bioglass”, Acta Biomaterialia, Vol.10, 2014. P. 4878-4886.

[26] R. Golovchak, J. Oelgoetz, M. Vlcek, A. Esposito, A. Saiter, J.-M. Saiter, H. Jain. “Complex structural rearrangements in As-Se glasses”, J. Chemical Physics, Vol. 140, 2014. P.054505.

[27] R. Golovchak, M.J. Davis, P. Vullo, Ch. Saiyasombat, H. Jain. “Nature of Pd and Ti metals in the structure of CMAS glass and ceramics”, J. American Ceramic Society, Vol. 97, №6, 2014. P.1971-1978.

[28] R. Golovchak, A. Kozdras, O. Shpotyuk. “Kinetics of light-assisted physical ageing in chalcogenide glasses”, J. Materials Science, Vol.49, №7, 2014. P.2844-2852.

[29] S.Y. Shin, R. Golovchak, S. Lee, B. Cheong, H. Jain, Y.G. Choi. “Structural basis of temperature-dependent electrical resistance of evaporation-deposited amorphous GeSe film”, Scripta Materialia, Vol. 86, 2014. P. 56–59.

[30] Ya. Shpotyuk, B. Bureau, C. Boussard-Pledel, V. Nazabal, R. Golovchak, P. Demchenko, I. Polovynko. “Effect of Ga incorporation in the As30Se50Te20 glass”, J. Non-Cryst. Solids, Vol. 398–399, 2014. P.19-25.

[31] O. Shpotyuk, B. Bureau, V. Boyko, A. Ingram, R. Golovchak, C. Roiland. “Long-term natural physical aging in glassy Ge5Se95 as probed by combined NMR and PAL spectroscopy”, J. Non-Cryst. Solids, Vol. 392–393, 2014. P.1-5.

[32] V. Balitska, R. Golovchak, A. Kozdras, O. Shpotyuk. “Fine kinetics of natural physical ageing in glassy As10Se90”, Physica B, Vol. 434, 2014. P.21-25.

[33] A.S. Hacinliyan, Y. Skarlatos, I. K. Aybar, O.O. Aybar, O. Shpotyuk, R. Golovchak, V. Balitska, A. Kozdras. “Natural Physical Ageing in Glassy As-Se: a comparative study of chaotic behavior with enhanced results analysis”, J. Non-Cryst. Solids, Vol. 386, 2014. P.8-13.

[34] M. Shpotyuk, O. Shpotyuk, R. Golovchak, J. McCloy, B. Riley. “Compositional trends of γ-induced optical changes observed in chalcogenide glasses of binary As-S system”, J. Non-Cryst. Solids, Vol. 386, 2014. P. 95-99.

[35] D. Savytskii, M. Sanders, R. Golovchak, B. Knorr, V. Dierolf, H. Jain. “Crystallization of stoichiometric SbSI glass”, J. American Ceramic Society, Vol. 97, №1, 2014. P. 198–205.

[36] K. Strabala, S. Meagher, C. Landais, L. Delbreilh, M. Negahban, J.-M. Saiter, J. Turner, A. Ingram, R. Golovchak. “Anisotropic loss of toughness with physical aging of work toughened polycarbonate”, Polymer Eng. & Science, Vol. 54, №4, 2014. P.794-804.

[37] R. Golovchak, L. Calvez, B. Bureau, H. Jain. “Structural evolution of Ga-Ge-Te glasses by combined EXAFS and XPS analysis”, J. Chemical Physics, Vol. 139, 2013. P. 054508(9).

[38] R. Golovchak, A. Kovalskiy, O. Shpotyuk, H. Jain. “Structural organization of As-rich selenide glasses”, Solid State Commun., Vol. 165, 2013. P.22-26.

[39] Y. Liu, R. Golovchak, W. Heffner, O. Shpotyuk, G. Chen, H. Jain. “Influence of Bi on topological self-organization in arsenic and germanium selenide networks”, J. Materials Chemistry C, Vol. 1, 2013. P. 6677-6683.

[40] R. Golovchak, B. Bureau, O. Shpotyuk, V. Boyko, M. Hyla. “Bond-changing structural rearrangement in glassy As3Se7 associated with long-term physical ageing”, J. Non-Cryst. Solids, Vol. 377, 2013. P. 43-45.

[41] R. Golovchak, L. Calvez, E. Petracovschi, B. Bureau, D. Savitskii, H. Jain. “Incorporation of Ga into the structure of Ge-Se glasses”, Materials Chem. & Physics, Vol.138, 2013. P. 909-916.

[42] M. Shpotyuk, O. Shpotyuk, R. Golovchak, P. Demchenko. “FSDP-related correlations in γ-irradiated chalcogenide semiconductor glasses: the case of glassy arsenic trisulphide g-As2S3 revised”, J. Phys. Chem. Solids, Vol. 74, 2013. P.1721–1725.

[43] A. Kovalskiy, R. Golovchak, M. Vlcek, H. Jain. “Electronic and atomic structure of amorphous thin films with high-resolution XPS: examples of applications & limitations”, J. Non-Cryst. Solids, Vol. 377, 2013. P.155-158.

[44] R. Golovchak, A. Ingram, S. Kozyukhin, O. Shpotyuk. “Free volume fragmentation in glassy chalcogenides during natural physical ageing as probed by PAL spectroscopy” J. Non-Cryst. Solids, Vol. 377, 2013. P.49-53.

[45] V. Balitska, R. Golovchak, O. Shpotyuk. “On the kinetics description of below-Tg structural relaxation in network glass formers”, Solid State Phenomena, Vol. 200, 2013. P. 162-167.

[46] O. Shpotyuk, R. Golovchak, A. Ingram, V. Boyko, L. Shpotyuk. “Comparative study of extended free-volume defects in As- and Ge-based glassy semiconductors: theoretical prediction and experimental probing with PAL technique”, Physica Status Solidi C, Vol.10, №1, 2013. P. 117-120.

[47] R. Golovchak, A. Kozdras, V. Balitska, O. Shpotyuk. “Step-wise kinetics of natural physical ageing in arsenic selenide glasses”, J. Physics: Condensed Matter, Vol.24, 2012. P.505106(10).

[48] R. Golovchak, S. Wang, H. Jain, A. Ingram. “Positron annihilation lifetime spectroscopy of nano-macroporous bioactive glasses” J. Materials Research, Vol.27, №19, 2012. P.2561-2567.

[49] R. Golovchak, A. Ingram, A. Kozdras, M. Vlcek, C. Roiland, B. Bureau, O. Shpotyuk. “Initial stage of physical ageing in network glasses”, Phil. Magazine, Vol.92, №33, 2012. P.4182-4193.

[50] A. Ingram, A. Kozdras, O. Shpotyuk, R. Golovchak. “PAL signature of physical ageing in chalcogenide glasses”, Physica Status Solidi B, Vol. 249, № 5, 2012. P.1017–1019.

[51] A. Ingram, R. Golovchak, M. Kostrzewa, S. Wacke, M. Shpotyuk, O. Shpotyuk. “Compositional dependences of average positron lifetime in binary As-S/Se glasses”, Physica B, Vol.407, 2012. P.652-655.

[52] D. Sati, A. Kovalskiy, R. Golovchak, H. Jain. “Structure of SbxGe40-xSe60 glasses around 2.67 average coordination number”, J. Non-Cryst. Solids, Vol.358, 2012. P.163-167.

[53] M.M. Vakiv, R. Golovchak, D. Chalyy, M. Shpotyuk, S. Ubizskii, O. Shpotyuk. “Peculiarities of valence bands formation in As-Ge-Se semiconductor glasses”, Semicond. Physics, Quantum Electr. & Optoelectr., Vol. 15, № 1, 2012. P. 32-34.

[54] O. Shpotyuk, R. Golovchak. “Frontiers of self-organization in covalent-bonded glass-forming networks: a complexity originates from molecular-clustering and chain-crossing in glassy germanoselenides” J. Optoelectronics Adv. Materials, Vol. 14, № 7- 8, 2012. P. 596 – 602.

[55] S. K. Sundaram, J. S. McCloy, B. J. Riley, M. K. Murphy, Hong (Amy) Qiao, C. F. Windisch, Jr., Eric Walter, Jarrod Crum, R. Golovchak, O. Shpotyuk. “Gamma Radiation Effects on Physical, Optical, and Structural Properties of Binary As-S glasses”, J. American Ceramic Society, Vol.95, №3, 2011. P.1048-1055.

[56] R. Golovchak, A. Kovalskiy, O. Shpotyuk, H. Jain. “In search of energy landscape for network glasses”, Appl. Phys. Letters, Vol. 98, 2011. P. 171905–3.

[57] R. Golovchak, A. Kozdras, O. Shpotyuk, Cz. Gorecki, A. Kovalskiy, H. Jain. “Temperature-dependent structural relaxation in As40Se60 glass”, Phys. Letters A, Vol.375, 2011. P.3032-3036.

[58] A. Kozdras, R. Golovchak, O. Shpotyuk, S. Szymura, A. Saiter, J.-M. Saiter. “Light-assisted physical ageing in chalcogenide glasses: dependence on the wavelength of incident photons” J. Materials Research, Vol. 26, №18, 2011. P.2420-2427.

[59] R. Golovchak, O. Shpotyuk, M. Iovu, A. Kovalskiy, H. Jain. “Topology and chemical order in AsxGexSe1-2x glasses: a high-resolution X-ray photoelectron spectroscopy study”, J. Non-Cryst. Solids, Vol.357, 2011. P.3454-3460.

[60] R. Golovchak, O. Shpotyuk, S. Kozyukhin, M. Shpotyuk, A. Kovalskiy, H. Jain. “Short-range order evolution in S-rich Ge-S glasses by X-ray photoelectron spectroscopy”, J. Non-Cryst. Solids, Vol.357, 2011. P.1797-1803.

[61] R. Golovchak, O. Shpotyuk, A. Kozdras, B.J. Riley, S.K. Sundaram, J.S. McCloy. “Radiation effects in physical aging of binary As-S and As-Se glasses” J. Thermal Analysis and Calorimetry, Vol.103, №1, 2011. P.213-218.

[62] S. Kozyukhin, R. Golovchak, A. Kovalskiy, O. Shpotyuk, H. Jain. “Valence band structure of binary chalcogenide vitreous semiconductors by high-resolution XPS”, Semiconductors, Vol.45, №4, 2011. P. 423-426.

[63] O. Shpotyuk, R. Golovchak, V. Boyko, M. Hyla. “Topological controversies in the adaptability concept for glassy germanium selenides”, J. Non-Cryst. Solids, Vol.357, 2011. P.479-482.

[64] O. Shpotyuk, A. Kozdras, R. Golovchak, M. Iovu. “Is the marginality of non-reversible heat flow in MDSC experiments a sufficient criterion for self-organization in network glass-formers?”, Phys. Stat. Solidi C, v.8, №11-12, 2011. P.3043-3046.

[65] O. Shpotyuk, R. Golovchak. “Pseudo-self-organized topological phases in glassy selenides for IR photonics”, Phys. Stat. Solidi C, v.8, № 9, 2011. P. 2572-2576.

[66] R. Golovchak, O. Shpotyuk, J.S. McCloy, B.J. Riley, C.F. Windisch, S.K. Sundaram, A. Kovalskiy, H. Jain. “Structural model of homogeneous As-S glasses derived from Raman spectroscopy and high-resolution XPS”, Phil. Magazine, Vol. 90, №34, 2010. P. 4489–4501.

[67] R. Golovchak, A. Kozdras, O. Shpotyuk. “Optical signature of structural relaxation in glassy As10Se90”, J. Non-Cryst. Solids, Vol.356, №23-24, 2010. P.1149-1152.

[68] O. Shpotyuk, R. Golovchak, V. Boyko, S. Kozyukhin. “Cluster modeling of quasi-adaptive phases in vitreous germanium selenides”, Physica Status Solidi C, Vol.7, №3-4, 2010. P.921-924.

[69] R. Golovchak, S. Kozyukhin, A. Kozdras, O. Shpotyuk, V. Novotortsev. “Physical aging of chalcogenide glasses”, Inorganic Materials, Vol. 46, №8, 2010. P. 919–921.

[70] R. Golovchak, O. Shpotyuk, S. Kozyukhin, A. Kovalskiy, A.C. Miller, H. Jain. “Structural paradigm of Se-rich Ge-Se glasses by high-resolution X-ray photoelectron spectroscopy”, J. Appl. Physics, Vol. 105, 2009. P. 103704 (7).

[71] A. Saiter, J.-M. Saiter, R. Golovchak, M. Shpotyuk, O. Shpotyuk. “Cooperative rearranging region size and free volume in As-Se glasses”, J. Physics: Condensed Matter, Vol. 21, 2009. P.075105(7).

[72] R. Golovchak, A. Kozdras, S. Kozyukhin, O. Shpotyuk. “High-energy g-irradiation effect on physical ageing in Ge-Se glasses”, Nuclear Instr. and Methods in Physics Res. B, Vol. 267, 2009. P.2958-2961.

[73] R. Golovchak, A. Kozdras, O. Shpotyuk, S. Kozyukhin, J.-M. Saiter. “Long-term ageing behaviour in Ge-Se glasses”, J. Materials Science, Vol.44, No15, 2009. P.3962-3967.

[74] R. Golovchak, O. Shpotyuk, A. Kovalskiy, A.C. Miller, J. Cech, H. Jain. “Coordination defects in bismuth-modified arsenic selenide glasses: High-resolution x-ray photoelectron spectroscopy measurements”, Phys. Rev. B, Vol.77, 2008. P. 172201(4).

[75] R. Golovchak, H. Jain, O. Shpotyuk, A. Kozdras, A. Saiter, J.-M. Saiter. “Experimental verification of the reversibility window concept in binary As-Se glasses subjected to a long-term physical ageing”, Phys. Rev. B, Vol.78, 2008. P. 014202(6).

[76] R. Golovchak, O. Shpotyuk, A. Kozdras, M. Vlcek, B. Bureau, A. Kovalskiy, H. Jain. “Long-term physical ageing in As-Se glasses with short chalcogen chains”, J. Physics: Condensed Matter, Vol. 20, 2008. P.245101(7).

[77] R. Golovchak, A. Kozdras, O. Shpotyuk. “Physical ageing in glassy As-Se induced by above-bandgap photoexposure”, Solid State Commun., Vol. 145, 2008. P.423-426.

[78] O. Shpotyuk, M. Hyla, V. Boyko, R. Golovchak. “Reversibility windows in selenide-based chalcogenide glasses”, Physica B: Condensed Matter, Vol. 403, 2008. P.3830-3837.

[79] A. Ganjoo, R. Golovchak. “Computer program PARAV for calculating optical constants of thin films and bulk materials: Case study of amorphous semiconductors”, J. Optoelectronics Adv. Materials, Vol. 10, №6, 2008. P. 1328-1332.

[80] O.I. Shpotyuk, R.Ya. Golovchak, H. Jain, A. Kovalskiy. “Radiation-induced functionality of chalcogenide glasses probed by high-resolution XPS”, Phys. and Chem. of Glasses: European Journal of Glass Science and Technology Part B, Vol. 49, No6, 2008. P.314-316.

[81] R. Golovchak, A. Kovalskiy, A.C. Miller, H. Jain, O. Shpotyuk. “The structure of Se-rich As-Se glasses by high-resolution X-ray photoelectron spectroscopy”, Phys. Rev. B, Vol. 76, 2007. P. 125208 (7).

[82] R. Golovchak, O. Shpotyuk, A. Kozdras, B. Bureau, M. Vlcek, A. Ganjoo, H. Jain. “Atomistic model of physical ageing in Se-rich As-Se glasses”, Phil. Magazine, Vol. 87, № 28, 2007. P.4323-4334.

[83] R. Golovchak, O. Shpotyuk, A. Kozdras. “On the reversibility window in binary As-Se glasses”, Physics Letters A, Vol. 370, 2007. P.504-508.

[84] A. Kozdras, R. Golovchak, O. Shpotyuk. “Physical ageing in the above-bandgap photoexposured glassy arsenic selenides”, J. Phys.: Conference series, Vol.79, 2007. P. 012016(4).

[85] O. Shpotyuk, R. Golovchak, H. Jain, A. Kozdras. “Radiation-induced physical ageing of the structure of an arsenic-selenide glass”, J. Phys. Chem. Solids, Vol. 68, №5-6, 2007. P.901-905.

[86] O.I. Shpotyuk, A.P. Kovalskiy, R.Ya. Golovchak, A. Zurawska, H. Jain. “Radiation-induced defects in chalcogenide glasses characterized by combined optical spectroscopy, XPS and PALS methods”, Physica Status Solidi C, Vol. 4, №3, 2007. P.1147-1150.

[87] A.P. Kovalskiy, H. Jain, A.C. Miller, R.Ya. Golovchak, O.I. Shpotyuk. “A study of reversible g-induced structural transformations in vitreous Ge23.5Sb11.8S64.7 by high-resolution X-ray photoelectron spectroscopy”, J. Phys. Chem. B, Vol. 110, № 45, 2006. P. 22930-22934.

[88] R. Golovchak, Cz. Gorecki, A. Kozdras, O. Shpotyuk. “Physical ageing effects in vitreous arsenic selenides”, Solid State Commun., Vol. 137, №1-2, 2006. P.67-69.

[89] R. Golovchak, A. Kozdras, Cz. Gorecki, O. Shpotyuk. “Gamma-irradiation-induced physical ageing in As-Se glasses”, J. Non-Cryst. Solids, Vol. 352, № 42-49, 2006. P.4960-4963.

[90] O. Shpotyuk, R. Golovchak. “Physical aging effects in selenide glasses accelerated by highly energetic g-irradiation”, J. Non-Cryst. Solids, Vol. 352, 2006. P.704-708.

[91] R. Golovchak, A. Kozdras, O. Shpotyuk. “Physical ageing in vitreous As13.5Ge4.5Se82 modified by high-energy gamma-irradiation”, Physica B: Condensed Matter, Vol. 371, №2, 2006. P.323-326.

[92] R. Golovchak, A. Kozdras, M. Shpotyuk, O. Shpotyuk. “Long-term physical ageing in vitreous arsenic selenides”, J. Phys. Studies, Vol. 10, №1, 2006. P.35-38.

[93] R. Golovchak, O. Shpotyuk, V. Boyko, A. Zurawska. “On the temperature behaviour of optical transmission spectra of g-modified vitreous As2S3”, Ukr. J. of Physical Optics, Vol. 7, №1, 2006. P.18-23.

[94] R. Golovchak, O. Shpotyuk. “Radiation-induced bond switching in mixed Ge-As sulphide glasses”, Phil. Magazine, Vol. 85, № 25/1, 2005, P. 2847-2860.

[95] R. Golovchak, O. Shpotyuk, A. Kozdras, S. Szymura, M. Shpotyuk. “Structural relaxation in vitreous arsenic selenide induced by g-irradiation”, Phys. and Chem. of Glasses, Vol. 46, № 6, 2005. P. 579-582.

[96] O.I. Shpotyuk, A.P. Kovalskiy, T.S. Kavetskyy, R.Ya. Golovchak. “Threshold restoration effects in g-irradiated chalcogenide glasses”, J. Non-Cryst. Solids, v.351, 2005, p.993-997.

[97] R. Golovchak, O. Shpotyuk, M. Shpotyuk, Cz. Gorecki, A. Kozdras. “Ageing effects in As10Se90 chalcogenide glasses induced by g-irradiation”, Ukr. J. of Physics, v. 50, №7, 2005, P. 690-693.

[98] R. Golovchak, O. Shpotyuk. “Radiation-induced defect formation in ternary Ge-As-S vitreous semiconductors”, Defects and Diffusion Forum, v. 230-232, 2004, P. 67-80.

[99] T. Kavetskyy, R. Golovchak, O. Shpotyuk, J. Filipecki, J. Swiatek. “On the compositional trends in IR impurity absorption of Ge–As(Sb)–S glasses”, J. Optoelectron. Adv. Mater., 2004, v.6, №4, p. 1141 - 1146.

[100] V.O.Balitska, R.Ya.Golovchak, A.P.Kovalskiy, E.Skordeva, O.I.Shpotyuk. “Effect of Co60 g-irradiation on the optical properties of As-Ge-S glasses”, J. Non-Cryst. Solids, v.326-327, 2003, p.130-134.

[101] O.I.Shpotyuk, R.Ya.Golovchak, A.P.Kovalskiy, T.S.Kavetskyy. “Time and temperature stability of radiation-induced changes in optical properties of ternary chalcogenide glassy semiconductor systems”, Functional Materials, v.10, №2, 2003, p.317-321.

[102] O. Shpotyuk, A. Kovalskiy, T. Kavetskyy, R. Golovchak. “Post-irradiation thermally stimulated restoration effects in some ternary chalcogenide glasses”, J. Optoelectron. Adv. Mater., 2003, v.5, №5, p.1169-1179.

[103] O. Shpotyuk, A. Kovalskiy, T. Kavetskyy, R. Golovchak, M. Popescu “Chemical interaction of chalcogenide vitreous semiconductors with absorbed impurities induced by g-irradiation”, J. Optoelectron. Adv. Mater., 2003, v.5, №5, p.1181-1185.

[104] O.I.Shpotyuk, R.Ya.Golovchak, A.P.Kovalskiy, V.Pamukchieva, E.Skordeva, D.Arsova. “On the mechanism of radiation-induced optical effects in vitreous As2S3-GeS2”, Ukr. J. of Physical Optics, v.3, №2, 2002, p.134-143.

[105] O.I. Shpotyuk, R.Ya. Golovchak, A.P. Kovalskiy, M.M.Vakiv, V.D. Pamukchieva, D.D. Arsova, E.R. Skordeva. “Radiation optical effects in As2S3-GeS2 semiconducting glasses”, Physics and Chemistry of Glasses, v.42, №2, 2001, p.95-100.

[106] B.Butkievicz, R.Golovchak, A.Kovalskiy, O.Shpotyuk, M.Vakiv. “On the problem of relaxation for radiation-induced optical effects in some ternary chalcogenide glasses”, Radiation Effects & Defects in Solids, v.153, 2001, p.211-219.

[107] O.I.Shpotyuk, J.Filipecki, R.Ya.Golovchak, A.P.Kovalskiy, M.Hyla. “Radiation defects in amorphous As-Ge-S studied by positron annihilation techniques”, J. Optoelectron. Adv. Mater., v.3, №2, 2001, p.329-332.

[108] O.I.Shpotyuk, J.Filipecki, M.Hyla, A.P.Kovalskiy, R.Ya.Golovchak. “Coordination defects in chalcogenide amorphous semiconductors studied by positron annihilation lifetime”, Physica B, v.308-310, 2001, p.1011-1014.

[109] O. I. Shpotyuk, R. Ya. Golovchak, T. S. Kavetsky, A.P. Kovalskiy, M.M.Vakiv. "Radiation-optical effects in glassy Ge-As(Sb)-S systems", Nuclear Instr. and Methods in Phys. Res. B, 2000, v.166-167, p. 517-520.

[110] E. Skordeva, D. Arsova, V. Pamukchieva, E. Vateva, R. Golovchak, A. Kovalskiy, O. Shpotyuk. "g-induced changes in Ge-As-S glasses", J. Optoelectron. Adv. Mater., v.2, №3, 2000, p. 259-266.

[111] O.I.Shpotyuk, A.P.Kovalskiy, E.Skordeva, E.Vateva, D.Arsova, R.Ya.Golovchak, M.M.Vakiv. “Effect of gamma-irradiation on the optical properties of GexAs40-xS60 glasses”, Physica B, v.271, 1999, p.242-247.

[112] O.I.Shpotyuk, Е.Skordeva, R.Ya.Golovchak, V.Pamukchieva, А.P.Коvalskiy. “Radiation-stimulated changes in optical transmission of chalcogenide As2S3-Ge2S3 glasses”, J. Applied Spectroscopy, Vol.66, No5, 1999. P.657-660 (in Russian).

Other papers:

[113] J. Szlęzak, Ya. Shpotyuk, C. Boussard-Pledel, J. Cebulski, B. Bureau, R. Golovchak. “Effect of bismuth modification on crystallization of chalcogenide glasses”, Materialy Ceramiczne /Ceramic Materials, Vol. 69, №2, 2017. P.120-124.

[114] O. Shpotyuk, V. Balitska, R. Golovchak, A. Kozdras. “Step-wise Fractal Kinetics in Physical Ageing: Compositional Complexity in Network Glass-Formers”, Chaotic Modeling and Simulation (CMSIM), Vol. 2, 2015. P.149-156.

[115] S. Binu, P. Khan, A. R. Barik, R. Sharma, R. Golovchak, H. Jain, K.V. Adarsh. “Photoinduced formation of Ag nanoparticles on the surface of As2S3/Ag thin bilayer”, Materials Research Express, Vol. 1, 2014. P. 045025.

[116] A. Kovalskiy, M. Vlcek, K. Palka, R. Golovchak, H. Jain. “Wavelength dependence of photostructural transformations in As2S3 thin films”, Physics Procedia, Vol. 44, 2013. P. 75-81.

[117] D. Chalyy, M. Shpotyuk, R. Golovchak, S. Ubizskii, O. Shpotyuk. “The structure and chemical order of GexAsxSe1-2x glasses”, J. Physical Studies, Vol. 16, №1/2, 2012. P.1601-1607 (in Ukrainian).

[118] R. Golovchak. “Dynamics of thermoinduced nanostructural perturbations in chalcogenide glasses”, Visnyk of Lviv Polytechnic National University, Electronics, №708, 2011. P. 3-11.

[119] M. Shpotyuk, R. Golovchak. “Peculiarities of radiation-induced physical ageing in sulphide and selenide network glasses”, Bulletin of Lviv Polytechnik National University. Electronics, № 681, 2010. P. 30-34.

[120] R.Ya.Golovchak. “Structural model of long- and short-term physical ageing in selenium-rich glasses”, Visnyk of Lviv University. Series Physical, № 43, 2009. P.209-225.

[121] O. Shpotyuk, R. Golovchak, A. Kozdras, S. Szymura. “A unified model of physical ageing in chalcogenide glasses”, Archives of Materials Science, Vol. 27, №4, 2006. P.159-165.

[122] Cz. Gorecki, T. Gorecki, A. Zurawska, R.Ya. Golovchak, S. Wacke. “Kinetics of phase transitions in semiconducting chalcogenides AsxSe1-x as studied by differential thermal analysis and exoelectron emission techniques”, Visnyk of Lviv University. Series Physical, №38, 2005. P.399-403.

[123] M.M. Vakiv, R.Ya. Golovchak, A.P. Kovalskiy, O.I. Shpotyuk. “Conditions of exploitation of chalcogenide melts in dosimetry of high-energy g-quanta”, Technology & Developments in Electronic devices, No 1 (55), 2005, P.60-61. (in Russian)

[124] A.P. Kovalskiy, O.I. Shpotyuk, R.Ya. Golovchak, M.M. Vakiv. “Post-radiation relaxation of radiation-induced changes in optical absorption for chalcogenide As-Ge-S glasses”, Sensor Electronics and Microsystem Technologies, Vol. 1, 2005, P. 52-56. (in Russian)

[125] R. Golovchak, O. Shpotyuk, M. Shpotyuk, Cz. Gorecki, A. Kozdras, S. Szymura. “Radiation-induced ageing in As10Se90 chalcogenide glasses”, Visnyk of Lviv University. Series Physical, №38, 2005. P.429-440.

[126] M.M. Vakiv, M.V. Shpotyuk, R.Ya.Golovchak “Structural transformations of vitreous arsenic selenides during physical ageing”, Bulletin of Lviv Polytechnik National University. Electronics, №558, 2006. P. 3-6.

[127] T. Kavetskyy, R. Golovchak, O. Shpotyuk, J. Filipecki, J. Swiatek. “On the compositional trends in IR impurity absorption of Ge-As(Sb)-S glasses”, Chalcogenide Letters, Vol. 1(10), 2004, P.125-130.

[128] O.I.Shpotyuk, V.O. Balitska, M.M. Vakiv, R.Ya.Golovchak, T.S. Kavetskyy, A.P.Kovalskiy, A.O. Matkovskiy. “Radiation-induced phenomena in chalcogenide vitreous semiconductors (a review)”, Bulletin of Lviv Polytechnik National University. Electronics, №459, 2002, P. 179-193.

[129] O.I.Shpotyuk, J.Filipecki, R.Ya.Golovchak, A.P.Kovalskiy, M.Hyla. “Application of positron annihilation lifetime technique for g-irradiation stresses study in chalcogenide vitreous semiconductors”, Adv. Engineering Materials, Vol.4, № 8, 2002, p. 571-574.

[130] R.Ya. Golovchak. “Radiation-induced degradation processes in vitreous chalcogenide semiconductors: optical changes”, Works of Pedagogical University in Czestochowa: chemistry, 2001, №5, p.199-207.

[131] R.Ya. Golovchak. “Impurity absorption in chalcogenide glasses of As-Ge-S family”. Bulletin of Lviv University, Physics and Chemistry of Materials, No33, 2000, p.88-93 (in Ukrainian).

[132] O.I.Shpotyuk, M.M. Vakiv, A.P.Kovalskiy, E.Skordeva, E.Vateva, D.Arsova, R.Ya.Golovchak, R.V. Lutsiv. “Radiation-induced effects in Ge-As-S chalcogenide glasses”, Rus. Phys. and Chem. of Glasses, 2000, Vol.26, №3, P. 374-380.

[133] O.I.Shpotyuk, A.P.Kovalskiy, R.Ya.Golovchak. “Role of the surface in the statical radiation-stimulated changes of optical properties of chalcogenide vitreous semiconductors”, Problems of Atomic Science and Technique, No6 (71-78), 1998, p. 260-262 (in Russian).

[134] M.M.Vakiv, O.I.Shpotyuk, R.Ya.Golovchak, A.P.Kovalskiy, V.O.Balitska. “Radiation-stimulated changes of the optical transmission spectral characteristics in chalcogenide glasses of As2S3-Ge2S3 system”, Bulletin of Lviv University, Physics and Chemistry of Materials, No31, 1998, p.20-22 (in Ukrainian).

 

Conference proceedings

[1] A. Kovalskiy, M. White, J. Allen, R. Golovchak, J. Oelgoetz, O. Shpotyuk, K. Palka, S. Slang, M. Vlcek. “Photoresponse of inorganic-organic thin film composites based on chalcogenide glasses”, 9th International Conference on “Times of Polymers and Composites”, AIP Conference Proceedings, Vol. 1981, 2018. P. 020030(1-4).

[2] S. Novak, V. Singh, C. Monmeyran, A. Ingram, Zh. Han, N. Borodinov, N. Patel, Q. Du, J. Hu, I. Luzinov, R. Golovchak, A. Agarwal, K. Richardson. “Effect of gamma exposure on chalcogenide glass films for microphotonic devices”, Radiation Effects Data Workshop (REDW), 2016 IEEE. P. 1-4. DOI: 10.1109/NSREC.2016.7891712

[3] O. Shpotyuk, V. Balitska, R. Golovchak, A. Kozdras. “Step-wise Fractal Kinetics in Physical Ageing: Compositional Complexity in Network Glass-Formers”, Proceedings, 7th Chaotic Modeling and Simulation International Conference, Lisbon, Portugal. 7 – 10 June, 2014. P.443-450.

[4] O. Shpotyuk, A. S. Hacinliyan, R. Golovchak, Y. Skarlatos, V. Balitska, I. K. Aybar, A. Kozdras, O. O. Aybar. “Observation of Chaotic Behaviour in Physical Ageing of Chalcogenide Glasses”, Proceedings, 6th Chaotic Modeling and Simulation International Conference, Istanbul, Turkey. 11 - 14 June, 2013. P. 595-604.

[5] V. Balitska, R. Golovchak, O. Shpotyuk. “Kinetics Complexity in Physical Ageing of Chalcogenide Glassy Semiconductors”, Proceedings, 6th Chaotic Modeling and Simulation International Conference, Istanbul, Turkey. 11 - 14 June, 2013. P. 69-75.

[6] V. Balitska, O. Shpotyuk, R. Golovchak, A. Kozdras. “On the kinetics description of below-Tg structural relaxation in network glass formers”, International Conference on Oxide Materials for Electronic Engineering – fabrication, properties and application (OMEE-2012), Lviv, Ukraine. September 3-7, 2012. P. 85-86.

[7] M. Shpotyuk, R.Golovchak, A. Kozdras, O.I.Shpotyuk. “Radiation-induced physical ageing in network arsenic- sulfide/selenide glasses”, IOP Conf. Series: Materials Science and Engineering, Vol. 15, 2010. P.012056(6).

[8] R. Golovchak. “Comprehensive investigations of physical ageing effect in selenium-rich glasses”, 14th International seminar on Physics and Chemistry of Solids. Selected proceedings. / ed. M. Vakiv, Lviv: Liga Press, 2008, 240 p. P. 22-37.

[9] V. Balitska, R.Golovchak, A. Kovalskiy, E. Skordeva, O. Shpotyuk. “The effect of thermoradiation influences on optical properties of As-Ge-S glasses”, 13th Intern. Symp. on Non-Cryst. Glasses and New Optical Glasses. Extended Abstracts. Pardubice, Czech Republic. Sept. 9-13, 2002. P. 405-408.

[10] R.Ya. Golovchak, T.S. Kavetskyy, O.I. Shpotyuk, A.P. Kovalskiy. “IR spectroscopy study of ternary chalcogenide glasses”, 13-th Conf. on Glass and Ceramics. Abstracts. Varna, Bulgaria. 29 Sept.-1 Oct. 1999. P.181-186.

[11] O.I.Shpotyuk, R.Ya.Golovchak, T.S.Kavetskiy. “IR optical fibers and sensors based on vitreous germanium and arsenic sulphoselenides”, Proc. of the 22-nd Conf. of IMAPS Poland Chapter, Zakopane, Poland, Oct. 1-3, 1998, p. 303-306.

 

Conference presentations

[1] M.J. Seage, R. Golovchak. “Role of Phosphorus in the Crystallization of Bi-modified Chalcogenide Glasses”. 85th Annual Meeting of the APS Southeastern Section (SESAPS-2018). Knoxville, Tennessee, Nov. 8–10, 2018. Bulletin of the American Physical Society. Abstract: D05.00003. Poster.

[2] J.K. Averitt, R. Golovchak. “Design and Preparation Of Positron Source For Non-Destructive Positron Annihilation Lifetime Spectroscopy”. 85th Annual Meeting of the APS Southeastern Section (SESAPS-2018). Knoxville, Tennessee, Nov. 8–10, 2018. Bulletin of the American Physical Society. Abstract: D05.00042. Poster.

[3] R. Golovchak. “Physical aging of glasses: phenomenology and structural models”, 2018 Glass & Optical Materials Division and Deutsche Glastechnische Gesellschaft Joint Meeting (GOMD-2018). San-Antonio, Texas, USA. May 20 - 24, 2018. GOMD-S1-092-2018. Invited.

[4] R. Golovchak. “Glasses for bioscaffold applications”, International Conference on Oxide Materials for Electronic Engineering – fabrication, properties and applications (OMEE-2017). Lviv, Ukraine. May 29 – June 2, 2017. MoL6 Keynote Lecture. Invited.

[5] T. L. Hodge, R. Golovchak, Y. Shpotyuk, B. Bureau, H. Jain. “Structure and properties of complex Bi-containing chalcogenide glasses”, 2016 Glass & Optical Materials Division and Deutsche Glastechnische Gesellschaft Joint Meeting (GOMD-2016). Madison, Wisconsin, USA. May 22 - 26, 2016. GOMD-SP-041-2016. Poster.

[6] J. R. Oelgoetz, J. Allen, C. Thomas, L. R. Nichols, J. Buzek, M. Vlcek, R. Golovchak, H. Jain, A. Kovalskiy. “Influence of light flux and photon energy on photostructural evolution in thermally deposited As-S thin films”, 2016 Glass & Optical Materials Division and Deutsche Glastechnische Gesellschaft Joint Meeting (GOMD-2016). Madison, Wisconsin, USA. May 22 - 26, 2016. GOMD-S3-052-2016. Oral.

[7] R. Golovchak, T. Kowal, T. Chokshi, J. Harms, H. Jain, M. Falk. “Effect of phase separation on protein absorption and cell attachment on 45S5 bioactive glass”, 2016 Glass & Optical Materials Division and Deutsche Glastechnische Gesellschaft Joint Meeting (GOMD-2016). Madison, Wisconsin, USA. May 22 - 26, 2016. GOMD-S2-013-2016. Oral.

[8] C.M. Thomas, Ya. Shpotyuk, R. Golovchak. “Low-temperature fluorescence of Pr-doped TAS glasses”, 2016 Glass & Optical Materials Division and Deutsche Glastechnische Gesellschaft Joint Meeting (GOMD-2016). Madison, Wisconsin, USA. May 22 - 26, 2016. GOMD-SP-040-2016. Poster.

[9] L. Nichols, R. Golovchak. “Fluorescence of Pd-doped Ti: CMAS glass and glass-ceramics”. 83rd Annual Meeting of the APS Southeastern Section (SESAPS-2016). Charlottesville, Virginia, Nov. 10–12, 2016. Bulletin of American Physical Society, Vol. 61, No19. Abstract: K1.00039.

[10] J. Oelgoetz, J. Allen, J. Bunton, L. Nichols, C. Thomas, R. Golovchak, A. Kovalskiy, M. Vlcek. “Photostructural changes as a function of photon energy and intensity in thermally deposited As-S thin films”. 83rd Annual Meeting of the APS Southeastern Section (SESAPS-2016). Charlottesville, Virginia, Nov. 10–12, 2016. Bulletin of American Physical Society, Vol. 61, No19. Abstract: G2.5. Oral.

[11] J. Bunton, O. Shpotyuk, L. Calvez, R. Golovchak. “Fluorescence of Erbium Dopant in CsCl-Ga-Ge-S glasses for IR applications” 83rd Annual Meeting of the APS Southeastern Section (SESAPS-2016). Charlottesville, Virginia, Nov. 10–12, 2016. Bulletin of American Physical Society, Vol. 61, No19. Abstract: K1.00033.

[12] C. Thomas, R. Golovchak, H. Jain, Ya. Shpotyuk. “An Analysis of Structural Changes of Glassy Arsenic Selenides due to Ga and Te Incorporation”, 82nd Annual Meeting of the APS Southeastern Section (SESAPS-2015). Mobile, Alabama, USA. Nov. 18–21, 2015. Bulletin of American Physical Society, Vol. 60, No18. Abstract: J1.00033.

[13] C. Johnson, L. Saturday, R. Golovchak, A. Kovalskiy. “Spin-Coating and Characterization of Chalcogenide Glass Thin Films”, 82nd Annual Meeting of the APS Southeastern Section (SESAPS-2015). Mobile, Alabama, USA. Nov. 18–21, 2015. Bulletin of American Physical Society, Vol. 60, No18. Abstract: J1.00037.

[14] L. Saturday, C. Johnson, R. Holovchak, Ya. Shpotyuk. “Thermal Analysis of Bi/Ga Doped Germanium Chalcogenides”, 82nd Annual Meeting of the APS Southeastern Section (SESAPS-2015). Mobile, Alabama, USA. Nov. 18–21, 2015. Bulletin of American Physical Society, Vol. 60, No18. Abstract: J1.00036.

[15] R. Golovchak. “Structural relaxation in network glasses: do we need a new paradigm?”. 2015 Glass & Optical Materials Division and Deutsche Glastechnische Gesellschaft Joint Meeting (GOMD-2015). Miami, FL, USA. May 16 - 21, 2015. GOMD-S3-147-2015. Oral.

[16] L. Saturday, C. Johnson, Y. Shpotyuk, R. Golovchak. “Thermal analysis of novel multifunctional glasses and glass-ceramics for IR photonics”. 2015 Glass & Optical Materials Division and Deutsche Glastechnische Gesellschaft Joint Meeting (GOMD-2015). Miami, FL, USA. May 16 - 21, 2015. GOMD- S3-P012-2015. Poster.

[17] A. Thai, R. Golovchak, Y. Shpotyuk, W.R. Heffner, H. Jain. “Study of Bi and Ga incorporation in glassy selenides and tellurides”. 2015 Glass & Optical Materials Division and Deutsche Glastechnische Gesellschaft Joint Meeting (GOMD-2015). Miami, FL, USA. May 16 - 21, 2015. GOMD-S3-P017-2015. Poster.

[18] J. Oelgoetz, L. Judy, R. Golovchak, A. Kovalskiy. “Benchmarking the Cation-Interlinking Network Cluster Approach (CINCA) with larger calculations”. 2015 Glass & Optical Materials Division and Deutsche Glastechnische Gesellschaft Joint Meeting (GOMD-2015). Miami, FL, USA. May 16 - 21, 2015. GOMD-S3-114-2015. Oral.

[19] T.J. Kowal, T. Chokshi, R. Holovchak, M.M. Falk, H. Jain. “Cell-bioactive glass scaffold interactions: The role of substrate nano-structure”. 2015 Glass & Optical Materials Division and Deutsche Glastechnische Gesellschaft Joint Meeting (GOMD-2015). Miami, FL, USA. May 16 - 21, 2015. GOMD-S2-013-2015. Oral.

[20] A. Kovalskiy, J. Cook, R. Golovchak, S. Slang, K. Palka, L. Loghina, M. Vlcek, H. Jain. “Features of Photostructural Response in Spin-Coated Chalcogenide Glass Thin Films”. 2015 Glass & Optical Materials Division and Deutsche Glastechnische Gesellschaft Joint Meeting (GOMD-2015). Miami, FL, USA. May 16 - 21, 2015. GOMD-S4-031-2015. Oral.

[21] M.J. Davis, P. Vullo, M. Reich, R. Golovchak, C. Saiyasombat, H. Jain. “Characterization of Pd-doped CMAS-TiO2 Glass-Ceramics”. 2015 Glass & Optical Materials Division and Deutsche Glastechnische Gesellschaft Joint Meeting (GOMD-2015). Miami, FL, USA. May 16 - 21, 2015. GOMD-S3-077-2015. Oral.

[22] R. Golovchak, W. Heffner, Y. Liu, H. Jain. “Study of Bi incorporation in glassy arsenic and germanium selenides by high-resolution XPS”. International Symposium on Non-Oxide and New Optical Glasses (ISNOG 2014), Jeju, Republic of Korea, August 24-26, 2014. Poster 1-20.

[23] A. Kovalskiy, R. Golovchak, J. Oelgoetz, M. Vlcek, K. Palka, H. Jain. “Modification of surface structure in chalcogenide glass thin films: mechanisms and practical applications”. International Symposium on Non-Oxide and New Optical Glasses (ISNOG 2014), Jeju, Republic of Korea, August 24-26, 2014. D2-1. Invited.

[24] Z. Pigott, J. Harms, R. Golovchak, H. Jain. “Interaction of BSA proteins with 45S5 bioactive glass surface”, SESAPS-2014 Conference, Columbia, SC, November 12–15, 2014. Bulletin of the American Physical Society, Vol. 59, № 18.

[25] L. Saturday, C. Johnson, Ya. Shpotyuk, R. Golovchak. “Crystallization kinetics of novel multifunctional glasses for IR photonics”, SESAPS-2014 Conference, Columbia, SC, November 12–15, 2014. Bulletin of the American Physical Society, Vol. 59, № 18.

[26] J. Trimble, R. Holovchak, J. Oelgoetz, C. Brennan, A. Kovalskiy. “Fluorescence spectroscopy and structure of erbium doped tin fluorophosphate glass”, SESAPS-2014 Conference, Columbia, SC, November 12–15, 2014. Bulletin of the American Physical Society, Vol. 59, № 18.

[27] P. Thapar, R. Golovchak, H. Jain. “Role of nanoscale phase separation in the devitrification of 45S5 bioactive glass”. 1st Joint Meeting of DGG – ACerS GOMD, Aachen, Germany, May 25-30, 2014.

[28] J. Oelgoetz, R. Golovchak, A. Kovalskiy, M. Feygenson, J. Neuefeind. “On the origin of first sharp diffraction peak in arsenic selenide glasses”. American Conference on Neutron Scattering, Knoxville, TN, June 1-5, 2014.

[29] J. Harms, R. Golovchak, H. Jain. “BSA protein adsorption on bioglass and bioceramic surfaces”, SESAPS-2013 Conference, Bowling Green, KY, November 20-23, 2013. Bulletin of the American Physical Society, Vol. 58, № 17.

[30] E. Juelfs, J. Taylor, R. Golovchak, A. Kovalskiy, J. Oelgoetz. “Investigating Relaxation in Chalcogenide Using Reverse Monte Carlo Modeling”, SESAPS-2013 Conference, Bowling Green, KY, November 20-23, 2013. Bulletin of the American Physical Society, Vol. 58, № 17.

[31] T. Tanner, J. Oelgoetz, R. Golovchak, C. Brennan, A. Kovalskyy. “Structure of Tin-Fluorophosphate Glasses for Solar Energy Applications”, SESAPS-2013 Conference, Bowling Green, KY, November 20-23, 2013. Bulletin of the American Physical Society, Vol. 58, № 17.

[32] R. Golovchak, T. Chokshi, T. Kowal, N. Murthy, M.M. Falk, H. Jain. “Control of nano/micro structure of bioactive glass and its influence on cell response”, Materials Science & Technology 2013, Montreal, Canada (MS&T-2013). October 27-31, 2013. Invited.

[33] R. Golovchak, A. Kozdras, H. Jain. “Physical aging of chalcogenide glass”, 2012 Glass & Optical Materials Division Annual Meeting, St. Louis, USA (GOMD-SI-105-2012). May 20-24, 2012, P.19. Invited.

[34] H. Jain, R. Golovchak, A. Kovalskiy, “Atomic defects and their impact on the properties of covalent glasses”, 2012 MRS Fall Meeting & Exhibit, Boston, MA, USA. November 25 - 30, 2012. Invited.

[35] M. Davis, P. Vullo, R. Golovchak, H. Jain. “Percolative electrically-conductive glass-ceramics”, 10th International Symposium on Crystallization in Glasses and Liquids, Goslar, Germany. September 23-26, 2012. Oral.

[36] R. Golovchak. “On the criterion for identification of intermediate phases in network glasses”, 2012 Glass & Optical Materials Division Annual Meeting, St. Louis, USA (GOMD-SI-105-2012). May 20-24, 2012, P.20. Oral.

[37] O. Shpotyuk, R. Golovchak. “Self-adaptability in glass-forming network systems: from mean-field rigidity theory to real experimental observations”, European Conference on Complex Systems ECCS’11, Vienna, Austria. September 12-16, 2011. P. 124. Poster.

[38] R. Golovchak, A. Kozdras, O. Shpotyuk, H. Jain. “Structural relaxation in network glasses caused by physical ageing”, 19th University Conference on Glass Science at RPI, New-York, USA. August 3-5, 2011.

[39] R. Golovchak. “Structural development within AsxGexSe1-2x glass system”, XVIIth International Seminar on Physics and Chemistry of Solids, Bystre, Poland. June 12-15, 2011. Oral.

[40] A.Kovalskiy, H.Jain, B.Koel, A.C.Miller, J.Whittkamper, J.Erb, R.Golovchak, M.Vlcek, K.Antoine, M.Mitkova. “Exploring glass surface with high-resolution XPS and LEIS: Examples of Fundamental Studies and Applications.” A Unique Surface Analysis Symposium: Cutting Edge Surface Analysis Instrumentation, Lehigh University, Bethlehem, PA, March 23, 2011. Oral.

[41] H. Jain, A. Kovalskiy, R. Golovchak. “Determination of structural defects in chalcogenide glasses by high-resolution XPS”, Glass and Optical Materials Division Meeting, Corning, New York, USA. May 16 - 20, 2010. Oral.

[42] R. Golovchak, A. Saiter, O.I. Shpotyuk, J.-M, Saiter. “Molecular dynamics for As-Se glasses during long-term natural physical ageing: evolution of Cooperative Rearranging Region Size”, 6th International Discussion Meeting on Relaxations in Complex Systems: New results, Directions and Opportunities, Rome, Italy. 30 August – 5 September, 2009. Poster #106.

[43] R. Golovchak. “Quick EXAFS provides new insight of structural reorganization during glass transition in selenide glasses”, Seminar at Brookhaven National Laboratory. May 1, 2009. Oral.

[44] R.Golovchak, A.Kovalskiy, H.Jain. “Effect of Physical Ageing on the Optical Transmission of Chalcogenide Glasses.” COT Open House Poster Session, Lehigh University, Bethlehem, PA, October 13, 2008.

[45] R. Golovchak, O.I. Shpotyuk, A. Kozdras. “Comparative analysis of chemical and physical ageing in covalent-bonded network glasses”, The 11th European Conference on Solid State Chemistry (ECSSC XI). Program schedule and abstract book. Caen, France, September 11-13, 2007. P.203.

[46] R. Golovchak, A. Kozdras, A. Kovalskiy, H. Jain. “On the origin of structural relaxation in the vicinity of glass-to-undercooled liquid transition in network glasses”, ACerS 2007 Glass and Optical Materials Division Meeting and 18th University Conference on Glass. Meeting Guide and Abstract Book. Rochester, USA. May 20-23, 2007. P. 30.

[47] O.I. Shpotyuk, R.Ya. Golovchak, H. Jain, A. Kozdras. “New externally-attained functionality in chalcogenide network glasses exemplified by radiation-induced physical ageing”, 7th International Conference Solid State Chemistry 2006. Book of abstracts. Pardubice, Czech Republic. September 24-29, 2006. P. 92.

[48] A.Kovalskiy, H.Jain, R.Golovchak, O.Shpotyuk. “Probing of charged defects in vitreous chalcogenides by high-resolution XPS.” Program & Abstract Book: 10th International Conference on the Structure of Non-Crystalline Materials, Prague, Czech Republic. September 18-22, 2006. P. 220.

[49] A.Kovalskiy, O.Shpotyuk, R.Golovchak, H.Jain. “Application of chalcogenide glasses in the dosimetry of high-energy gamma-radiation.” Abstract book: Spring 2006 Glass & Optical Materials Division Meeting, Greenville, South Carolina, USA. May 15-20, 2006. P. 30.

[50] O.Shpotyuk, A.Kovalskiy, R.Golovchak, A.Zurawska, H.Jain. “Radiation-induced defects in chalcogenide glasses characterized by combined optical spectroscopy, XPS and PALs methods.” Conference program and book of abstracts of “10th Europhysical Conference on Defects in Insulating Materials”, Milano, Italy. July 10-14, 2006. P. 355.

[51] O.Shpotyuk, H.Jain, A.Kovalskiy, R. Golovchak. “Probing of radiation-induced coordination defects in chalcogenide glasses with high-resolution X-ray photoelectron spectroscopy.” Book of abstracts of 6th European Conference on Luminescent Detectors and Transformers of Ionizing Radiation, Lviv, Ukraine. June 19-23, 2006. P. 202.

[52] A.Kovalskiy, O.Shpotyuk, R.Golovchak, H. Jain. “Dosimetry of High-Dose Gamma-Radiation with Chalcogenide Glass”. COT Open House Poster Session, Lehigh University, Bethlehem, PA May 19, 2006.

[53] R.Golovchak, A.Kovalskiy, O.Shpotyuk, H.Jain “Physical ageing in As-Se glasses”. COT Open House Poster Session, Lehigh University, Bethlehem, PA, May 19, 2006.

[54] O.I. Shpotyuk, R.Ya. Golovchak. “Physical ageing in chalcogenide glasses: methodological basis and developed approach”, Second International Workshop on Amorphous and Nanostructured Chalcogenides, Sinaia, Romania. June 20-24, 2005. P.50.

[55] O.I. Shpotyuk, R.Ya. Golovchak. “Natural ageing in g-irradiated As-Se glasses”, 5th International Discussion Meeting on Relaxation in Complex Systems. New results, Directions and Opportunities, Lille, France. July 7-13, 2005. P.165.

[56] M.M. Vakiv, R.Ya. Golovchak, O.I.Shpotyuk, Cz. Gorecki, A. Kozdras, S. Szymura. “Structural relaxation in radiation-modified chalcogenide vitreous semiconductors studied with DSC method”, X-th International seminar on Physics and Chemistry of Solids (ISPCS’04), Lviv, Ukraine. 6-9 June, 2004. P.80.

[57] A.Kovalskiy, O. Shpotyuk, M. Vakiv, V. Balitska, T. Kavetskyy, R.Ya. Golovchak. “Radiation-induced effects in amorphous chalcogenide semiconductors”, CONCIM 2003 Conference on Non-Crystalline Inorganic Materials: Synthesis, Structure, Modelling. Book of Abstracts. Germany, Bonn. April 8-12, 2003. P. 104.

[58] A.Kovalskiy, O.Shpotyuk, M.Vakiv, V.Balitska, T.Kavetskyy, R.Golovchak. “Radiation-structural transformations in ternary chalcogenide glasses.” Proc. II Intern. Conf. “Physics of Disordered Systems”, October, 14-16, 2003. Lviv, Ukraine. P. 51-52.

[59] O.Shpotyuk, A.Kovalskiy, M.Vakiv, V.Balitska, T.Kavetskyy, R.Golovchak. “The features of temperature annealing of post-radiation g-induced optical effects in chalcogenide vitreous semiconductors.” Abstr. IV Intern. School-Conf. “Actual problems of semiconductor physics”, June 24-27, 2003, Drohobych, Ukraine. P. 208.

[60] A.Kovalskiy, O.Shpotyuk, M.Vakiv, V.Balitska, T.Kavetskyy, R. Golovchak. “Radiation-induced effects in amorphous chalcogenide semiconductors.” Abstr. Conf. Non-Crystalline Inorganic Materials. Synthesis. Structure. Modelling, April 8-12, 2003, Bonn, Germany, p. 104.

[61] A.Kovalskiy, O.Shpotyuk, M.Vakiv, V.Balitska, T. Kavetskyy, R.Golovchak. “Radiation-induced optical phenomena in chalcogenide vitreous semiconductors.” Abstr. IV Intern. School-Conf. “Actual problems of semiconductor physics”, June 24-27, 2003, Drohobych, Ukraine. P. 203.

[62] A.Kozdras, O.Shpotyuk, R.Golovchak, A.Kovalskiy. “Radiation-induced optical effects in As-Ge-S chalcogenide glasses.” Abstr. IXth Intern. Seminar Phys. and Chem. Solids, 28-31 May 2003. Zloty Potok k. Czestochowy, Poland. P. 49.

[63] V.O.Balitska, R.Ya.Golovchak, A.P.Kovalskiy, E.Skordeva, O.I. Shpotyuk. “The effect of thermoradiation influences on optical properties of As-Ge-S glasses.” 13th Intern. Symp. on Non-Cryst. Glasses and New Optical Glasses. Extended Abstracts, September 9-13, 2002. Pardubice, Czech Republic, p. 405-408.

[64] O.Shpotyuk, R.Golovchak, A.Kovalskiy, I.Izhnin. “Time and temperature stability of radiation-induced changes of optical properties of chalcogenide vitreous semiconductors of As-Ge-S system.” Abstr. 1st Ukrainian Conf. on Semiconductor Physics, Vol. 1. 10-14 September, 2002, Odessa, Ukraine, p. 147.

[65] R.Ya. Golovchak, O.I.Shpotyuk. “Radiation-structural transformations in vitreous layered and cross-linked semiconductors”, EPS-12 General Conference: Trends in Physics, Budapest, Hungary. Aug. 26-30, 2002. Р.392.

[66] O.Shpotyuk, A.Kovalskiy, R.Golovchak. “Thermo-radiation effects in vitreous chalcogenide semiconductors.” Progr. & Abstr. Europhysical Conf. on Defects in Insulating Materials, July 1-5, 2002, Wroclaw, Poland, p. Tu-P43.

[67] O.I.Shpotyuk, J.Filipecki, R.Ya.Golovchak, M.Hyla, A.P. Kovalskiy. “Radiation defects in amorphous As-Ge-S studied by positron annihilation techniques.” Program & Abstr. 1st Intern. Workshop on Amorphous and Nanostructured Chalcogenides. Fundamentals and Applications, June 25-28, 2001. Romania, Bucharest. P. 44.

[68] O.I.Shpotyuk, J.Filipecki, M.Hyla, A.P.Kovalskiy, R.Ya. Golovchak. “Coordination defects in chalcogenide amorphous semiconductors studied by positron annihilation lifetime.” Abstr. 21st Intern. Conf. on Defects in Semiconductors, July 16-21, 2001, Germany, Giessen. P. 78.

[69] O.Shpotyuk, V.Balitska, A.Kovalskiy, M.Vakiv, O.Mrooz, R.Golovchak, T.Kavetskyy. “Reversible structural transformations in amorphous arsenic sulphoselenides induced by absorbed laser irradiation.” Quantum Electronics "Laser Physics and Application". Program and Abstr, 18-22 Sept. 2000, Varna, Bulgaria. P. 66.

[70] A.Kovalskiy, O.Shpotyuk, R.Golovchak. “Thermoradiation effects in semiconducting sulphide glasses.” Abstr. Book 8th Intern. Conf. on the Structure of Non-Crystalline Materials, 6-11 August 2000, Aberystwyth, UK. P. 133.

[71] R.Ya. Golovchak. “Radiation-induced optical effects in vitreous Ge-As-S semiconductors”, “Junior-Euromat 2000” Conference, Lausanne, Switzerland. Aug.27 - Sept.1, 2000.P.264-265.

[72] O.Shpotyuk, R.Golovchak, A.Kovalskiy. “Effect of gamma-stimulated optical changes in As-Ge-S chalcogenide glasses.” Abstr. Intern. Conf. "Advanced Optical Materials and Devices", 16-19 Aug., 2000, Vilnius, Lithuania. P. 101.

[73] O.Shpotyuk, R.Golovchak, A.Kovalskiy. “Radiation-induced transformations in As2S3-GeS2 chalcogenide glasses.” Abstr. 14th Intern. Conf. on Defects in Insulating Materials, April 3-7, 2000, Johannesburg, South Africa. P. 205.

[74] J.Filipecki, M.Hyla, O.Shpotyuk, A.Kovalskіy, R.Golovchak. “Application of positron annihilation lifetime technique for gamma-irradiation stresses study in chalcogenide vitreous semiconductors.” Book Abstr. European Materials Research Society Spring Meeting, June 5-8, 2000, Strasburg, France. P. O-6.

[75] A.Kovalskiy, R.Golovchak, T.Kavetskyy, O.Shpotyuk. “IR spectroscopy study of ternary chalcogenide glasses.” Proc. 13th Conf. on Glass and Ceramics, Varna, Bulgaria. 29 September-1 October 1999, p. 181-186.

[76] O.Shpotyuk, R.Golovchak, O.Mrooz, A.Kovalskiy. “On the Problem of Medium-Range Order in Some Ternary Systems of Chalcogenide Glasses.” Abstr. Intern. Conf. “Thermal dynamics and chemical structure of melts and glasses”, 7-9 September, 1999, Sankt-Perterburg, Russia. P. 137.

[77] O.Shpotyuk, T.Kavetskyy, A.Kovalskiy, R.Golovchak. “Radiation-optical effects in Sb(As)2S3-GeS2(Ge2S3) semiconducting glasses.” 3rd Intern. School-Conf. Physical Problem in Material Science of Semiconductors. Abstr. Booklet, 7-11 September, 1999, Chernivtsi, Ukraine. P. 167.

[78] O.Shpotyuk, R.Golovchak, T.Kavetskyy, A.Kovalskiy, M.Vakiv. “Radiation-optical effects in glassy Ge-As(Sb)-S systems.” Abst. 10th Intern. Conf. Radiation Effects in Insulators REI -10, 18-23 July, 1999, Jena, Germany. P. 202.

[79] O.Shpotyuk, A.Kovalskiy, R.Golovchak, T.Kavetskyy. “Infrared spectroscopy of ternary chalcogenide semiconductors for optical application.” The Europ. Maretial Conf. hosted by E-MRS, 1999 Spring Meeting. Sympos. P: Optical Characterization of Semicond. Layers and Surfaces. Book of Abstr, June 1-4, 1999, Strasbourg, France. P. P-34.

[80] O.Shpotyuk, R.Golovchak, A.Kovalskiy, V.Balitska, M.Vakiv. “On the problem of 2D-3D topological phase transition in chalcogenide vitreous semiconductors.” Abstr. Intern. Conf. “Glasses and Solid Electrolites”, 17-19 May, 1999, Sankt-Petersburg, Moscow. P. 82.

[81] E.Vateva, E.Skordeva, V.Pamukchieva, D.Arsova, R.V.Lutciv, O.I.Shpotyuk, M.M.Vakiv, A.Kovalskiy, V.O.Balitska, T.S.Kavetsky, R.Ya. Golovchak. “Radiation-induced effect in Ge-As(Sb)-S glasses: detail discussion on 2D-3D topological phase transition existence.” Abstr. 5th Intern. Seminar on Physics and Chemistry of Solids, 19-22 May, 1999. Zloty Potok k/Czestochowy, Poland. P. 23.

[82] E.Vateva, E.Skordeva, V.Pamukchieva, D.Arsova, R.V.Lutciv, O.I.Shpotyuk, M.M.Vakiv, A.Kovalskiy, V.O.Balitska, T.S.Kavetsky, R.Ya. Golovchak. “Compositional dependence features of IR impurity absorption.” Abstr. 5th Intern. Seminar on Physics and Chemistry of Solids, 19-22 May, 1999. Zloty Potok k/Czestochowy, Poland. P. 47.

[83] O.Shpotyuk, R.Golovchak, A.Kovalskiy. “Radiation-induced changes in ternary chalcogenide glasses.” Abstr. 10th Intern. Conf. on Rapidly Quenched and Metastable Materials, Aug. 23-27, 1999, Bangalore, India. P. A-147.

[84] A.Kovalskiy, R.Golovchak, O. Shpotyuk. “Semiconducting glasses based on germanium and arsenic sulphoselenides for IR optical fibers and sensors.” Abstr. Fall Meeting MRS’98, November 30 - December 3, 1998, Boston, Massachusets, USA. P. 182.

[85] O.Shpotyuk, M.Vakiv, A.Kovalskiy, V.Balitska, R.Golovchak. “Radiation-induced modification of optical memory systems.” 2nd Intern. Symp. on Microelectronics Technologies and Microsystems. Abstr., June 15-17, 1998, Lviv, Ukraine. P. 27.

[86] A.Kovalskiy, L.Shpotyuk, R.Golovchak, O.Shpotyuk, T.Kavetskiy. “Dosimetric characteristics of selenide-based vitreous semiconductors for high-energetic irradiation.” Workshop «Sensors Springtime in Odesa», 29-30 May, 1998, Odesa, Ukraine. P. 57.

[87] O.Shpotyuk, M.Vakiv, A.Kovalskiy, R.Golovchak. “Radiation induced effects in ternary amorphous chalcogenides.” INTAS-Ukraine Workshop on Condensed Matter Physics, May 21-24, 1998, Lviv, Ukraine. P. 131.

[88] A.P. Kovalskiy, R.Ya. Golovchak, O.I. Shpotyuk. “Semiconducting glasses based on germanium and arsenic sulphoselenides for IR optical fibers and sensors”, Fall Meeting’98. MRS - Materials Research Society. Abstracts. Boston, Massachusetts, Nov.30-Dec.4, 1998. P.182.