Fyzikální ústav Akademie věd ČR

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Research at Department 27

Luminescence and scintillation materials (M. Nikl)Research subjects

  • Optical, luminescence and EPR spectroscopy of wide band-gap solids in the form of single crystals, thin films, glasses, pwders, optical ceramics and composite materials.
  • Scintillation characteristics under high energy excitation.
  • Spectroscopy of point defects, trap states in the forbidden gap, energy transfer processes in the luminescence and scintillation mechanisms.
  • Modification of the optical properties of solid states due to quantum size effect.
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Photovoltaics (and nanotechnology) group (M. Vaněček)Research subjects

Optical and photoelectrical spectroscopy of solar cells materials (amorphous silicon, nanocrystalline silicon, microcrystalline silicon, recrystalized silicon, silicon carbides, ZnO, SnO2).

Optical model CELL – Monte Carlo modeling of quantum efficiency spectra of thin film silicon solar cells (single or multiple junctions). Study of light trapping in thin film silicon solar cells.

Transparent conductive oxides (TCO) for solar cells.  Celý text >>

CVD diamond (A. Kromka)Research subjects

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Theory of phase transition (P. Demo)Research subjects

  • Modeling of formation of new stable phase from the supersaturated vapor, solution or supercooled melt by homogeneous or heterogeneous nucleation proces.
  • Kinetic of formation of new phase nuclei in closed systems.
  • Nucleation on active centers.
  • Controlled nucleation on nanofibers.

Řešitelský tým: Pavel Demo, Zdeněk Kožíšek, Alexej Sveshnikov, Petra Tichá, Marina Davydova, Jan Kulveit (diplomant)

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Electron spectroscopy (J. Zemek)Research subjects

  • Measurement of the hydrogen content at solid surfaces by elastic peak electron spectroscopy. Determination of the attenuation length at the solid surfaces.
  • Assesment of the atomic structure of solid surfaces by photoelectron diffraction and low energy electron diffraction.
  • Characterization of solid surfaces by UV and X-ray induced photoelectron spectroscopy and electron energy loss spectroscopy.
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Preparation and characterisation of optical materials (K. Nitsch)Research subjects

  • Searching for and preparation of materials - crystals, epitaxial layers, nanostructures and glasses - of high quality and purity with interesting optical properties and with their possible application in laser hosts in near IR range, as neutrons, gama and X-rays radiations detectors in industrial and medical application.
  • Preparation of model crystalline systems for luminescence mechanism study.
  • Thermal analysis study of properties of solids and glasses prepared by rapid cooling.
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Nature and role of defects in the scintillation mechanism of complex oxide- based materialsSelected results

In the field of complex oxide scintillators the tungstates and doped aluminum perovskites (REAlO3), garnets (RE3Al5O12) and orthosilicates (RE2SiO5) are systematically studied in the form of single crystals, optical ceramics or thin films prepared by the liquid phase epitaxy (LPE), Fig. 1. We focus on the point defects which give rise to trapping levels in the material forbidden gap. Understanding the nature and role of such defects in the scintillation mechanism and their relation to the manufacturing technology enables further optimization of these materials.  Celý text >>

New 3-dimensional design of thin film silicon solar cellsSelected results

At 24th European Photovoltaic Solar Energy Conference we reported on a new 3-dimensional design of „folded“ thin film silicon solar cells. It is based on nanostructured substrate glass/ZnO, where ZnO nanocollumns are organized approximately in hexagonal arrangement and amorphous and/or nanocrystalline silicon p-i-n cells are deposited conformally over this nanostructured substrate. We experimentally measured a high quality of the Si absorber layer deposited over the ZnO nanocollumns and calculated potential for the record stable efficiency of such amorphous and “micromorph” solar cells. M.  Celý text >>

Diamond thin films and carbon nanostructuresSelected results

In the laboratory of Diamond thin films and carbon nanostructures we have achieved a technological progress in the fabrication of diamond nanostructures. Diamond nanorods and/or nano-needles are fabrucated by dry plasma etching using a metal mask (Fig. 1). All these geometrically ordered nano-patterns suddenly found applications in multidisciplinary scientific fields like a sensing part in chemical sensors (phosgene gas sensor) or realization of artificial substrates for regenerative medicine.  Celý text >>

Modeling of nanophase formationSelected results

Kinetics of formation of a new phase nuclei in confined systems is complex process due to depletion of a parent phase. As a consequence the critical size of clusters increases similarly as a nucleation barrier. Supercritical clusters (formed during phase transition process) can become undercritical, which has impact on nucleation.  Celý text >>

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