Search

Your search keyword '"Šiller, L."' showing total 111 results
Start Over Author "Šiller, L."
111 results on '"Šiller, L."'

15. Reactions and luminescence in passivated Si nanocrystallites induced by vacuum ultraviolet and soft-x-ray photons.

Author

Chao, Y., Krishnamurthy, S., Montalti, M., Lie, L. H., Houlton, A., Horrocks, B. R., Kjeldgaard, L., Dhanak, V. R., Hunt, M. R. C., and Šiller, L.

Subjects
NANOCRYSTALS, SILICON crystals, CRYSTALS, NANOPARTICLES, PHOTONS, LIGHT
Abstract

Alkyl-modified silicon nanocrystallites are efficient fluorophores which are of interest for fundamental spectroscopic studies and as luminescent probes in biology because of their stability in aqueous media. In this work we have investigated these particles using scanning tunneling microscopy, synchrotron-radiation excited photoemission, and x-ray excited optical luminescence (XEOL). During the course of illumination with 145-eV photons we have monitored the evolution of the Si2p core level and, in samples which have suffered prolonged atmospheric exposure, observed in real time the growth of an extra Si2p component attributed to in situ photoinduced oxidation of the Si nanocrystallites. XEOL reveals that two emission bands are active upon soft-x-ray photon excitation and that photoluminescence intensity decreases with photon exposure, which is attributed to charge trapping within the film. [ABSTRACT FROM AUTHOR]

Published
2005
Full Text
View/download PDF

16. Electron-stimulated desorption of D[sub 2]O coadsorbed with CO[sub 2] ice at VUV and EUV energies.

Author

Šiller, L., Sieger, M. T., and Orlando, T. M.

Subjects
*ICE, *PARTICLES (Nuclear physics), *ADSORPTION (Chemistry), *CARBON dioxide, *ELECTRON beams
Abstract

Electron-induced processes in water ice and CO[sub 2] ice are important in planetary science. We have measured desorption yields of positive ion products (C[sup +], O[sup +], D[sup +], D[sub 3]O[sup +], CO[sup +], O[sub 2][sup +]) produced as a result of exposing pure CO[sub 2] and D[sub 2]O adsorbed on CO[sub 2] ices to 10–100 eV (i.e., the vacuum-ultraviolet–extreme-ultraviolet energy region) electron beams. Measurements on pure CO[sub 2] ice irradiated with 40-eV electrons suggest that pores in the CO[sub 2] ice are responsible for trapping molecular precursors for bimolecular reactions that are responsible for O[sub 2][sup +] production. Investigations of pure CO[sub 2] ice irradiated with a 100-eV electron beam reveals production of O[sub 2][sup +] by a second channel attributed to post-ion molecule collisions that are strongly influenced by low-energy electrons trapped in the ice. The most significant finding is that the D[sup +] and D[sub 3]O[sup +] yields as a function of both dose and time indicate that the D[sub 2]O adsorbed on CO[sub 2] at 30 K diffuses into the CO[sub 2] ice or desorbs into vacuum very rapidly. Both processes are a result of electron irradiation. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Published
2003

19. Nitrogen ion irradiation of Au(110): Photoemission spectroscopy and possible crystal structures of gold nitride

Author

Krishnamurthy, S., Montalti, M., Wardle, M., Shaw, M., Briddon, P., Svensson, K., Hunt, M., and Šiller, L.

Subjects
Surface, Energy, Metal nitrides, CU3N films, Implantation, Copper, Electronic-structure
Abstract

Photoemission spectroscopy demonstrates the formation of a surface gold nitride upon irradiation of a Au(110) surface with 500 eV nitrogen ions at room temperature. After irradiation two N1s peaks are observed at binding energies of 396.7±0.2 eV and 397.7±0.2 eV along with a broadening of the Au4d5∕2 line. Changes in valence-band spectra are also observed, including an additional density of states at 1.6 eV binding energy and new states at ∼3.1 eV. Annealing experiments indicate that the two N1s lines are associated with nitrogen compounds of differing thermal stability, possibly due to the formation of more than one nitride phase. To further investigate the properties of gold nitride we have undertaken ab initio pseudopotential calculations on the most likely nitride stoichiometry, Au3N, and identified a novel triclinic crystal structure of a significantly lower energy than the anti-ReO3 expected from a simple consideration of the periodic table, although the latter structure is also found to be stable. The triclinic structure is determined to be metallic, of importance to possible applications.

Published
2004

20. Final-state interference effects in valence band photoemission of (C59N)2

Author

Hunt, M. R. C., Pichler, T., Šiller, L., Brühwiler, P. A., Golden, M. S., Nikos Tagmatarchis, Prassides, K., Rudolf, P., Zernike Institute for Advanced Materials, and WZI (IoP, FNWI)

Subjects
Azafullerene, Oscillations, Heterofullerene C59Nn, Physics::Atomic and Molecular Clusters, Photoionization Cross-sections, C-60, Spectroscopy, Electronic-structure
Abstract

Oscillatory behavior of photoemission intensity with incident photon energy has been observed for several fullerenes and fullerene derivatives. However, until now it has been unclear if these effects arise from interference associated with the spatial distribution of the initial state within the molecule or are due to scattering of the outgoing photoelectron. In order to resolve this issue we performed synchrotron radiation excited valence band photoemission measurements on multilayer (C59N)2 films. The highest occupied molecular orbital (HOMO) of the (C59N)2 dimer is spatially localized, while each half of the dimer remains approximately spherical. Careful normalization and fitting of the measured spectra clearly show that the intensity of the HOMO also displays a periodic variation of intensity with photon energy indicating that scattering of the photoemitted electron and consequent interference effects lead to the observed intensity changes.

Published
2002

21. Nitrogen ion irradiation of Au(110): formation of gold nitride

Author

Šiller, L., Hunt, M.R.C., Brown, J.W., Coquel, J-M., Rudolf, P., Zernike Institute for Advanced Materials, and Surfaces and Thin Films

Abstract

Often metal nitrides posses unique properties for applications, such as great hardness, high melting points, chemical stability, novel electrical and magnetic properties. One route to the formation of metal nitride films is through ion irradiation of metal surfaces. In this report, the results of irradiation of Au(110) surfaces by nitrogen ions with kinetic energies of 0.5 and 2 keV are studied with high resolution X-ray photoemission spectroscopy. N1s core level spectra show clear evidence for the formation of a gold nitride at, or in close vicinity to, the surface–the first direct observation of nitride formation by this element. Subsurface molecular nitrogen is also observed, the relative concentration of which increases with irradiation energy. We suggest that the subsurface molecular nitrogen is most likely present in the form of trapped bubbles.

Published
2002

22. The Science Case for 4GLS

Author

Allan, R.J., Allen, M.P., Alexandrov, A.S., Ashfold, M.N.R., Atkinson, R., Avaldi, L., Bain, C.D., Bancroft, J., Barrett, S.D., Barron, L.D., Bayliss, S., Becker, U., Benning, L.G., Berrah, N., Binns, C., Bisby, R.H., Bizau, J.M., Blake, R.J., Bowler, M.A., Bowyer, J., Brettle, J., Briggs, D., Brown, L.M., Brown, W.A., Burke, P.G., Cacho, C., Carter, R., Catlow, R., Cernik, R.J., Chesters, M., Clark, S.A., Clarke, D.T., Clarke, J.A., Codling, K., Cogdell, R., Connaughton, D., Connerade, J.P., Costello, J.T., Crapper, M.D., Creaser, C., Currell, F.J., Davies, P.B., de Jong, M., Dessent, C., Dhanak, V.R., Dobson, D.M., Dobson, P.J., Doig, A.J., Donovan, R.J., Dumas, P., Dunn, K., Dutuit, O., Dyke, J.M., Eastham, D.A., Egdell, R.G., Eland, J.H.D., Emerson, D.R., Eriksson, M., Erman, P., Evans, A., Evans, H., Evans, S., Field, T., Fielding, H., Fisher, A., Flavell, W.R., Ford, R., Frasinski, L.J., Freeman, N., Galayda, J.N., Gardner, P., Garside, J., Gay, N.J., Gejo, T., George, M., Gray, M.D., Greenshaw, T.J., Greig, D., Halsall, M.P., Hamilton, B., Harrison, N.M., Hasnain, S.S., Hatherly, P.A., Heathcote, P., Helliwell, J.R., Henderson, C.M.B, Hepburn, J., Hill, J., Hirst, G., Hirst, J.D., Holland, D.M.P., Horn, A.B., Horton, P., Hunt, M.R.C., Hutchinson, H., Inglesfield, J.E., Ivanov, V.K., Johnson, C.A.F., Johnson, L.N., Jones, D., Jones, F.H., Jones, G.R., Jones, L., Kadodwala, M., Karlsson, L., Kennedy, E.T., King, G.C., King, M.R.F., Kirkman, I.W., Kleese, K., Knight, P.L., Kylstra, N., Larkins, F.P., Latimer, C., Lawley, K.P., Leggett, G.J., Lewis, R.A., Lindsey, K., Lu, J.R., Lyng, F.M., Macdonald, M.A., Malins, A., Marangos, J.P., Margaritondo, G., Marsi, M., Marston, G., Martin, S.R., Martin-Fernandez, M.L., Mason, N.J., Matthew, J.A.D., McCoustra, M.R.S., McGilp, J., McGovern, I.T., McGrath, R., Meldrum, R.A., Meyer, M., Millar, T.J., Mitchell, D., Møller, S.P., Molster, F.J., Moriarty, P., Morin, P., Munro, I.H., Murdin, B.N., Nahon, L., Newell, W.R., Noble, C.J., Nordgren, E.J., Norman, P.R., O'Brien, P., O'Neill, P., O'Shea, P., Owen, H., Pain, R., Papiz, M., Parker, A., Parker, J., Parr, A., Pattrick, R., Pemble, M.E., Picardo, M., Pidgeon, C.R., Pinheiro, T.J.T., Poliakoff, E.D., Poole, M.W., Potts, A., Potvliege, R., Powis, I., Price, S.D., Quinn, F.M., Radford, S., Rachlew-Källne, E., Raval, R., Read, F.H., Reddish, T.J., Ridley, P.A., Roberts, G., Russell, A.E., Ryan, A.J., Sapelkin, A., Sato, S., Schneider, A., Seddon, E.A., Shaw, E.A., Shen, T., Sherwood, P., Šiller, L., Smith, A.D., Smith, D.A., Smith, I., Smith, S.L., Snowdon, K., Softley, T.P., Sokell, E., Southworth, S.H., Srivistava, G.P., Stankiewicz, M., Sule-Suso, J., Sutherland, J.C., Surman, M., Svensson, S., Taylor, A.O., Temmerman, W.M., Thomas, A., Tiddy, G.J., Tobin, M., Towns-Andrews, Elizabeth, Towrie, M., Truscott, G., Tuckett, R.P., Turner, Tracy, Twigg, M.V., Vagdama, P., van der Hart, H.W., Volk, M., Vrakkring, M.J.J., Walker, I.C., Wander, A., Wasserman, S.P., Watanabe, M., Weightman, P., Welton, T., West, J.B., Wharton, C.W., Whitehead, J.C., Williams, G.P., Winick, H., Withnall, R., Woodruff, D.P., and Zayats, A.

Subjects
Q1
Published
2001

34. Rapid thermal oxidation of Ge-rich Si1−xGex heterolayers

Author

Bera, M. K., primary, Chakraborty, S., additional, Das, R., additional, Dalapati, G. K., additional, Chattopadhyay, S., additional, Samanta, S. K., additional, Yoo, W. J., additional, Chakraborty, A. K., additional, Butenko, Y., additional, Šiller, L., additional, Hunt, M. R. C., additional, Saha, S., additional, and Maiti, C. K., additional

Published
2006
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results