Four-Particle Recombination Luminescence of Electron-Hole Liquid and Biexcitons in SiGe Quasi-Ttwo-Dimensional Layers of Silicon Heterostructures in the Visible Spectrum

In this study, we investigate the energy spectrum and collective effects in the system of excitons in strained SiGe layers in a series of Si/Si1-xGex/Si heterostructures with 0.05 x 0.25 and the layer thickness d 2 5 nm. We use the low-temperature photoluminescence spectroscopy both in the near-infrared and the visible spectral regions. In the latter case, the luminescence originates from simultaneous recombination of two electrons with two holes. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3487

Four-Particle Recombination Luminescence of Electron-Hole Liquid and Biexcitons in SiGe Quasi-Ttwo-Dimensional Layers of Silicon Heterostructures in the Visible Spectrum

In this study, we investigate the energy spectrum and collective effects in the system of excitons in strained SiGe layers in a series of Si/Si1-xGex/Si heterostructures with 0.05 x 0.25 and the layer thickness d 2 5 nm. We use the low-temperature photoluminescence spectroscopy both in the near-infrared and the visible spectral regions. In the latter case, the luminescence originates from simultaneous recombination of two electrons with two holes. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3487

Choosing systems of ionic radii for crystal-chemical laws in lanthanide oxobromotungstates

The unit cell parameters in LnWO4Br compounds (Ln = La, Pr, Nd, Sm, Eu, Gd, Dy, Er, or Yb) are studied as functions of ionic radii in various systems. The best systems of ionic radii for the description of crystal-chemical laws in lanthanide oxobromotungstates are determined. Crystal-chemical plots are constructed for the unit cell parameters versus lanthanide ionic radius for the specified compounds, as well as the plot of the parameter c for the monoclinic crystal system that accounts for the monoclinic angle β. © 2008 Pleiades Publishing, Ltd

Crystal chemistry of lanthanide oxochlorotungstates

Crystal chemical properties of lanthanide oxochlorotungstates of composition LnWO4Cl (Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm) are reported. The unit cell parameters a, b, c, c', and V of the LnWO 4Cl compounds are correlated with lanthanide ionic radii from different radius systems and with the lanthanide atomic number. The ionic radius systems most suitable for describing the crystal chemical properties of the lanthanide oxochlorotungstates are determined. © 2008 Pleiades Publishing, Ltd

Choosing systems of ionic radii for crystal-chemical laws in lanthanide oxobromotungstates

The unit cell parameters in LnWO4Br compounds (Ln = La, Pr, Nd, Sm, Eu, Gd, Dy, Er, or Yb) are studied as functions of ionic radii in various systems. The best systems of ionic radii for the description of crystal-chemical laws in lanthanide oxobromotungstates are determined. Crystal-chemical plots are constructed for the unit cell parameters versus lanthanide ionic radius for the specified compounds, as well as the plot of the parameter c for the monoclinic crystal system that accounts for the monoclinic angle β. © 2008 Pleiades Publishing, Ltd

Crystal chemistry of lanthanide oxochlorotungstates

Crystal chemical properties of lanthanide oxochlorotungstates of composition LnWO4Cl (Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm) are reported. The unit cell parameters a, b, c, c', and V of the LnWO 4Cl compounds are correlated with lanthanide ionic radii from different radius systems and with the lanthanide atomic number. The ionic radius systems most suitable for describing the crystal chemical properties of the lanthanide oxochlorotungstates are determined. © 2008 Pleiades Publishing, Ltd

Crystal-chemical features of monoclinic lanthanide oxobromotungstates of composition LnWO4Br (Ln = Eu, Gd, Dy, Er, Yb)

The crystal-chemical properties of lanthanide oxobromotungstates of composition LnWO4Br (Ln = Eu, Gd, Dy, Er, Yb) are studied. The crystal system and space group for the oxobromotungstates are determined. The unit cell parameters are refined. The parameters a, b, c, and V of the LnWO 4Br compounds are studied as functions of the atomic number of the lanthanide. Analytical equations are derived to predict unit cell parameters for unsynthesized lanthanide oxobromotungstates of the class in question. © Pleiades Publishing, Inc., 2006

PRECISION X-RAY-DIFFRACTION STUDY OF THE GARNETS NA3SC2V3O12 AND NA0.90CA2.38MN1.72V3O12

The distribution of electron density and electrostatic potential in the compounds Na3Sc2V3O12 (ScVG) and Na0.90Ca2.38Mn1.72V3O12 (MnVG) with garnet structure was studied by precision x-ray diffraction. Refinement of the structure using reflections chosen by a special method from the outer region of reciprocal space led to R = 0.0085, R(w) = 0.0071, S = 1.006 (ScVG) and R = 0.0058, R(w) = 0.0049, S = 1.079 (MnVG). Maps of deformed electron density and deformed electrostatic potential were constructed and their interpretation given in terms of MO. Features of the electronic structure in the crystals studied have a confidence level not lower than 95%

Crystal chemistry of orthorhombic lanthanide oxobromotungstates of composition LnWO4Br

The crystal-chemical properties of lanthanide oxobromotungstates of composition LnWO4Br(Ln = La, Pr, Nd, Sm) were studied: the crystal system and space group were determined, and the unit cell parameters were refined. The dependence of the unit cell parameters a, b, c, and V of the LnWO4Br compounds on the lanthanide atomic number was analyzed. The analytical equations derived make it possible to predict the unit cell parameters for lanthanide oxobromotungstates that have not been synthesized yet. © Pleiades Publishing, Inc., 2006