Search results for "Chalcogenide"
showing 10 items of 141 documents
Chemical modification of carbon nanomaterials (SWCNTs, DWCNTs, MWCNTs and SWCNHs) with diphenyl dichalcogenides
2015
Control over chemical functionalization is a crucial point in the field of nanotechnology. Herein, we present the covalent functionalization of several carbon nanoforms (single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes and carbon nanohorns) by means of diphenyl dichalcogenides. These ones show different reactivity to the nanomaterials and are able to modify their electronic properties depending on the electronegativity of the functionalizing heteroatom. Theoretical calculations were also performed to support the experimental results. All the modified structured nanocarbons were thoroughly characterized by TGA Raman, XPS, UV/Vis/nIR, IR and TEM te…
ChemInform Abstract: Modular Metal Chalcogenide Chemistry: Secondary Building Blocks as a Basis of the Silicate-Type Framework Structure of CsLiU(PS4…
2012
The new title compound is synthesized from a mixture of U, P2S5, Li2S, Cs2S, and S in the molar ratio 2:2:1:1:4 (sealed silica tube, 700 °C, 3 d).
Recent advances in the development of holey optical fibers based on sulfide glasses
2006
International audience; Microstructured optical fibers as new optical objects have been developed in the recent past years, firstly from silica glass and then from other oxide glasses such as tellurite or different heavy cations oxide glasses. However very few results have been reported concerning non-oxide glasses and more particularly chalcogenide glasses. In a photonic crystal fiber the arrangement of air holes along the transverse section of the fiber around a solid glassy core leads to unique optical properties, such as for example broadband single-mode guidance, adjustable dispersion, nonlinear properties. Since the effective modal area is adjustable thanks to geometrical parameters, …
Towards metal chalcogenide nanowire-based colour-sensitive photodetectors
2018
Financial support provided by Scientific Research Project for Students and Young Researchers Nr. SJZ/2016/6 realized at the Institute of Solid State Physics, University of Latvia is greatly acknowledged. Authors are grateful to Reinis Ignatans for XRD measurements.
Zinc Chalcogenide Seed-Mediated Synthesis of CdSe Nanocrystals: Nails, Chesses and Tetrahedrons
2015
Systematically shape-controlled synthesis of colloidal semiconductor nanocrystals (NCs) has attracted increasing attention recently for both fundamental and technological interest. The study on the synthesis of colloidal CdSe NCs has given rise to well-developed methods for producing diverse shapes such as rods, wires, cubs and discs. In the current study, we demonstrate the shape evolution of CdSe NCs by using a seed-mediated approach by control reaction temperature and injection methods. The synthesis utilizes small (2.0–3.0 nm) zinc chalcogenide NCs with zincblende structure as seeds for subsequent growth, which results in distinct shapes of nail-shaped, tetrahedron-shaped, chess piece-s…
Holographic recording optimization in amorphous As-Se-S films
2003
The holographic recording parameters of amorphous chalcogenide semiconductor (AChS) thin films under optimization depend on hologram type. So, using self-enhancement effect during recording and wet etching after recording enable possibility to decrease recording energy and increase of signal/noise ratio for embossed holograms. Choosing the appropriate light exposure permit us to achieve equal values of diffraction efficiency (DE) for different diffraction orders during fabrication of light splitting holographic optical elements (HOE). Changing film thickness and recording wavelength it is possible to find optimal conditions for high DE holographic gratings readable at infrared region of lig…
<title>Mechanisms of holographic recording in amorphous semiconductor films</title>
1998
The mechanisms of holographic recording in (mainly chalcogenide) amorphous semiconductor films are reviewed including photoinduced structural changes, relaxational structural changes, recharging of localized states in the band gap, and photoinduced anisotropy. The holographic properties in these cases are compared. Different effects of hologram self-enhancement are also considered.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
<title>Holographic recording in amorphous chalcogenide semiconductor photoresists</title>
1998
The properties and mechanism of relaxation processes of holographic gratings in amorphous chalcogenide semiconductor films have been studied. The possibilities of the practical applications of these materials as the photoresists for the production of the relief holograms and holographic optical elements are discussed. It is shown that the self- enhancement phenomenon of holographic recording in amorphous chalcogenide semiconductor films by light or thermal treatment can be used to increase the diffraction efficiency of the holograms.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
<title>Investigation of As<formula><inf><roman>2</roman></inf></formula>S<formula><inf><roma…
2008
We have performed the investigation of dot matrix holographic recording in amorphous As2S3 chalcogenide films with different thickness on Al coated glass substrates. The control over the interference minimum of reflection during the evaporation process allowed obtaining As2S3-Al system with a minimum value of initial reflection in defined spectral region. The investigation of dependence of diffraction efficiency of holographic recording on both film thickness and initial conditions of reflectivity in the system was performed. The main advantage of this type of system is the possibility to increase optical sensitivity of material in predefined spectrum region for phase hologram recording.© (…
<title>Relaxation processes in amorphous As-S and As-Se films</title>
1997
The relaxation of optical, mechanical and chemical properties of as-evaporated amorphous As-S and As-Se films while storing them at room temperature is investigated. The AsxS1-x films with arsenic content 0.3 less than x less than 0.4 are found to undergo maximal changes. It is shown that the phenomenon of dark self-enhancement of holograms (an increase of diffraction efficiency over time without any special treatment) can be used as an efficient method for investigation of relaxation processes in the amorphous chalcogenide films. The changes of diffraction efficiency in amorphous As2S3 films have been measured as a function of aging time and recording light intensity. The relaxation proces…