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Photonic structures and their preparation
Varga, Marián ; Ondič, Lukáš ; Hruška, Karel ; Potměšil, Jiří ; Libertínová, Jitka ; Kromka, Alexander ; Remeš, Zdeněk
Photonic crystals are periodically structured electromagnetic media, generally possessing photonic band gaps: ranges of frequency in which light cannot propagate through the structure. This periodicity, which length scale is proportional to the wavelength of light in the band gap, is the electromagnetic analogue of a crystalline atomic lattice, where the latter acts on the electron wavefunction to produce the familiar band gaps of semiconductors, and so on, in solid-state physics. Several examples of organisms and structures possessing photonic crystals and iridescence are visible all around us (Morpho didius, Pavo cristatus, Chrysochroa vittata, Chrysina resplendens, …).
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High resolution ATR FTIR spectroscopy of hydrogenated diamond nanoparticles using NCD-coated prism
Remeš, Zdeněk ; Kozak, Halyna ; Rezek, Bohuslav ; Babchenko, Oleg ; Kromka, Alexander ; Girard, H. ; Petit, T. ; Arnault, J. ; Bergonzo, P.
Crucial part of successful ATR - linear antenna CVD NCD. ATR IR spectroscopy compared to transmittance FTIR spectroscopy. IR spectra of diamant nanoparticles adsorbed on NCD surface. Advances of ATR FTIR - higher sensitivity, better resolution, reproducibility.
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Photothermal and photocurrent spectroscopy of wide band gap nanocrystalline semiconductors
Remeš, Zdeněk ; Babchenko, Oleg ; Neykova, Neda ; Varga, Marián
Optical spectroscopy belongs to the most important methods applied to characterize thin films. Photothermal deflection spectroscopy (PDS) as well as the dual beam photocurrent (DBP) spectroscopy in near ultraviolet (200-400 nm), visible (400-700 nm) and near infrared regions (700-2000 nm) are particularly useful for study of the wide band gap semiconductors deposited as thin layers on glass substrates. In our laboratory we focus on optically transparent thin films such as nanocrystalline diamond (NCD) or ZnO nanostructures with size too small to be visualized in optical microscope and the optical absorption edge in the ultraviolet region. In this contribution we summarize how to evaluate the optical absorption edge and the defects in the band gap of these wide band gap nanocrystalline semiconductors.
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Pulsed linear antenna microwave plasma – a step ahead in large area material depositions and surface functionalization
Kromka, Alexander ; Babchenko, Oleg ; Ižák, Tibor ; Potocký, Štěpán ; Davydova, Marina ; Neykova, Neda ; Kozak, Halyna ; Remeš, Zdeněk ; Hruška, Karel ; Rezek, Bohuslav
A technological progress in the large area growth of diamond films and carbon nanotubes by the modified linear antenna MW system is presented. We show a correlation between process parameters and nano- or poly-crystalline film character. A challenging part, diamond coated mirrors or ATR prisms, are shown as multifunctional optical elements suitable for detection of absorbed molecules. Additional positive feature of the presented plasma system is low temperature hydrogen functionalization of diamond films. Finally, we present that combination of pulsed MW plasma with radiofrequency substrate biasing results in growth of oriented CNTs over large area.
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Optické charakterizační metody ve výzkumu solárních článků
Remeš, Zdeněk ; Vaněček, Milan ; Poruba, A.
Optická spektroskopie patří k nejdůležitějším technikám používaným k charakterizaci tenkých vrstev a solárních článků. Na našem pracovišti se zabýváme především následujícími metodami: Fotoproudová spektroskopie (CPM), Fourier Transform Photocurrent Spectroscopy (FTPS), Fototermální spektroskopie (PDS), infračervená spektroskopie (FTIR) and optical spektroscopie with mikrometric resolution.
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Zkušenosti s měřením optických spekter tenkých vrstev
Remeš, Zdeněk
V tomto článku shrnuji některé své zkušeností s měřením optických spekter tenkých vrstev. První část je zaměřena na měření optických spekter ve střední infračervené oblasti, v druhé části jsou diskutovány měření optických spekter tenkých vrstev v blízké ultrafialové, viditelné a blízké infračervené oblasti a ve třetí části se zabývám možnostmi měření optických spekter v optickém mikroskopu.
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