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  • 1
    Electronic Resource
    Electronic Resource
    Wafer and epilayer improvement for integrated optics devices on InP: the ESPRIT project 2518 (1991)
    Springer
    Optical and quantum electronics 23 (1991), S. 391-404 
    Details
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract Ga x In1−x As y P1−y alloys lattice matched to InP substrates are currently used to fabricate optoelectronic and integrated optics devices. To achieve devices with high performances and high fabrication yield, the uniformity and reproducibility of the Ga x In1−x As y P1−y epitaxial layers (composition, thickness, doping, etc.) have become key parameters. These problems have been addressed in the frame of ESPRIT project 2518 and are presented in this paper. Several aspects have been considered starting from the optimization of InP substrates, the MOVPE growth of uniform GalnAsP layers, the material characterization to the validation of material uniformity on passive optical waveguides. Both scanning photoluminescence analysis and waveguide losses measurements performed on 2 inch wafers with a high lateral resolution have shown that high quality uniform GalnAsP layers can be obtained reproducibly on 2″ InP substrates using a commercially available LP-MOCVD growth process. In particular, more than 60% of 36 mm long, 3μm wide and 100μm spaced rib waveguides exhibit losses below 0.8dBcm−1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00619612
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  • 2
    Electronic Resource
    Electronic Resource
    Cs4Re6S13 und Cs4Re6S13,5 - zwei Verbindungen mit [Re6S8]-Baueinheiten in geringfügig variierten GerüststrukturenProfessor Dirk Reinen zum 60. Geburtstage gewidmet (1990)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 587 (1990), S. 91-102 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cs4Re6S13 and Cs4Re6S13.5  -  Two Compounds with [Re6S8] Clusters Slightly Differing as to their Framework StructuresCs4Re6S13 was synthesized by the reaction of cesium carbonate with rhenium at 800°C in an argon atmosphere charged with sulphur. The preparation of Cs4Re6S13.5 succeeded by an analogous procedure using a stream of H2S.Structural investigations on single crystals revealed atomic arrangements in which [Re6S8] clusters are linked threedimensionally by Sn2- bridges. In the compound Cs4Re6S13 \documentclass{article}\pagestyle{empty}\begin{document}$\buildrel \wedge \over =$\end{document} Cs4[Re6S8]S2/2(S2)4/2 the rhenium atoms of adjacent Re6-octahedra are connected by sulphide and disulphide bridges in a ratio of 1:2. In the compound Cs4Re6S13.5 \documentclass{article}\pagestyle{empty}\begin{document}$\buildrel \wedge \over =$\end{document} Cs4[Re6S8]S2/2(S2)3/2(S3)1/2 one disulphide bridge is replaced by one trisulphide bridge.The nearly regular Re6-octahedra correspond with a diamagnetic 24-electron configuration.
    Notes: Cs4Re6S13 wurde durch Umsetzung von Caesiumcarbonat mit Rhenium in einem mit Schwefel beladenen Argonstrom bei 800°C erhalten. Cs4Re6S13,5 konnte nach einem analogen Verfahren im Schwefelwasserstoffstrom synthetisiert werden.Strukturuntersuchungen an Einkristallen führten zu Atomanordnungen, in denen [Re6S8]-Baueinheiten über Sn2--Brücken dreidimensional zu Gerüststrukturen verknüpft sind. Im Cs4Re6S13 \documentclass{article}\pagestyle{empty}\begin{document}$\buildrel \wedge \over =$\end{document} Cs4[Re6S8]S2/2(S2)4/2 werden die Rheniumatome benachbarter Re6-Oktaeder über Sulfid- und Disulfidbrücken im Verhältnis 1:2 miteinander verbunden, im Cs4Re6S13,5 \documentclass{article}\pagestyle{empty}\begin{document}$\buildrel \wedge \over =$\end{document} Cs4[Re6S8]S2/2(S2)3/2(S3)1/2 ist eine Disulfidbrücke durch eine Trisulfidbrücke ersetzt.Die nahezu regulären Re6-Oktaeder sind in Übereinstimmung mit dem unmagnetischen 24-Valenzelektronenzustand.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19905870111
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  • 3
    Electronic Resource
    Electronic Resource
    Schichtstrukturen ternärer Chalkogenide A2M3X4 (A ≙ K, Rb, Cs; M ≙ Ni, Pd, Pt; X ≙ S, Se)Professor Hanskarl Müller-Buschbaum zum 60. Geburtstage gewidmet (1991)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 597 (1991), S. 27-32 
    Details
    ISSN: 0044-2313
    Keywords: Ternary chalcogenides A2M3X4 (A ≙ alkali metal; M ≙ Ni, Pt, Pd; X ≙ S, Se) crystal structures ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Layered Structures of Ternary Chalcogenides A2M3X4 (A ≙ K, Rb, Cs; M ≙ Ni, Pd, Pt; X ≙ S, Se)The ternary chalcogenides A2M3X4 have been prepared by fusion reactions of alkali carbonates with metals M ≙ Ni, Pd or Pt and the chalcogens X ≙ S or Se. Alternatively, the chalcogenides could be synthesized from alkali carbonates and M in a stream of hydrogen charged with chalcogen. X-ray investigations on powdered samples and single crystals reveal layered structures in which neutral A2M3X4-slabs from stacking variants.
    Notes: Die Synthese ternärer Chalkogenide A2M3X4 gelang über Schmelzreaktionen durch Umsetzungen von Alkalimetallcarbonaten mit den Metallen M ≙ Ni, Pd oder Pt und den Chalkogenen X ≙ S oder Se oder über eine Reaktion der beiden erstgenannten Komponenten in einem mit Chalkogen beladenen Wasserstoffstrom.Röntgenographische Untersuchungen an pulverförmigen Proben sowie an Einkristallen führten zu Schichtstrukturen, in denen neutrale A2M3X4-Schichtpakete Stapelvarianten erzeugen.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19915970105
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  • 4
    Electronic Resource
    Electronic Resource
    Neue Alkalimetallchromchalkogenide und ihre StruktursystematikProfessor Hartmut Bärnighausen zum 60. Geburtstage gewidmet (1993)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 619 (1993), S. 243-252 
    Details
    ISSN: 0044-2313
    Keywords: Alkali metal chromium chalcogenides ; crystal structures ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: New Alkali Metal Chromium Chalcogenides and their Structural ClassificationThe compounds RbCr3S5, K3Cr11S18, RbCr5Se8 and CsCr5Se8 could be obtained in the form of wellshaped crystals via fusion reactions of the alkali metal carbonates with chromium and the corresponding chalcogen. The compounds crystallize in the monoclinic space groups C2/m (RbCr3S5: a = 19.372(3) Å, b = 3.498(1) Å, c = 12.119(2) Å, β = 122.78(1)°, Z = 4; K3Cr11S18: a = 41.876(3) Å, b = 3.463(1) Å, c = 16.315(3) Å, β = 150.07(1)°, Z = 2; RbCr5Se8: a = 18.737(2) Å, b = 3.623(1) Å; c = 9.016(1) Å, β = 104.65(1)°, Z = 2; CsCr5Se8: a = 18.795(2) Å, b = 3.637(1) Å, c = 9.104(1) Å, β = 104.52(1)°, Z = 2).We propose a structure classification from group-subgroup-relations.MAPLE calculations reveal that the reactions of the binary chalcogenides to yield the ternary compounds are exothermic in each case and are dependent on the chromium/alkali metal ratio in the ternary chalcogenides.
    Notes: Durch Umsetzungen der Alkalimetallcarbonate mit Chrom und dem entsprechenden Chalkogen in der Schmelze konnten die Verbindungen RbCr3S5, K3Cr11S18, RbCr5Se8 und CsCr5Se8 als gut ausgebildete Kristalle erhalten werden. Die Verbindungen kristallisieren monoklin im Raumgruppentyp C2/m (RbCr3S5: a = 19,372(3) Å, b = 3,498(1) Å, c = 12,119(2) Å, β = 122,78(1)°, Z = 4; K3Cr11S18: a = 41,876(3) Å, b = 3,463(1) Å, c = 16,315(3) Å, β = 150,07(1)°, Z = 2; RbCr5Se8: a = 18,737(2) Å, b = 3,623(1) Å; c = 9,016(1) Å, β = 104,65(1)°, Z = 2; CsCr5Se8: a = 18,795(2) Å, b = 3,637(1) Å, c = 9,104(1) Å, β = 104,52(1)°, Z = 2).Über Gruppe-Untergruppe-Beziehungen wird eine Struktursystematik vorgeschlagen.MAPLE-Rechnungen zeigen, daß die Reaktionen der binären Chalkogenide zu den ternären Verbindungen jeweils exotherm sind und vom Verhältnis Chrom/Alkalimetall in den ternären Chalkogeniden abhängen.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19936190205
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  • 5
    Electronic Resource
    Electronic Resource
    Isolierte [M6S14]-Baueinheiten in ternären Sulfiden des Technetiums und RheniumsProfessor Heinrich Nöth zum 65. Geburtstage gewidmet (1993)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 619 (1993), S. 2015-2020 
    Details
    ISSN: 0044-2313
    Keywords: Cluster compounds ; technetium ; rhenium ; preparation ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Isolated [M6S14] Units in Ternary Sulfides of Technetium and RheniumWe have successfully prepared the ternary sulfides Rb10Tc6S14, Cs10Tc6S14, Rb10Re6S14, and Cs10Re6S14 by heating alkali carbonate with elemental technetium or rhenium in a hydrogen stream charged with sulfur.Structural investigations on single crystals revealed that these compounds crystallize in the space group Fm3m. [M6S14] cluster units (M \documentclass{article}\pagestyle{empty}\begin{document}$ \hat = $\end{document} Tc, Re) are found as the characteristic structural features, in which regular M6 octahedra are coordinated by sulfur atoms over their eight faces and six vertices. Other than in the case of the previously investigated ternary technetium and rhenium chalcogenides, these units are not linked to one another, but occur as isolated complex anions which form a cubic close packed array. The alkali ions, whose sites are partly statistically occupied, are found on the corners, the edges and the longer face diagonals of a rhombic dodecahedron surrounding each of these units. The dodecahedra share all their faces with one another.The diamagnetic behaviour which was measured on Cs10Tc6S14 in the temperature range from 10 to 295 K is in accordance with a 24-electron-configuration of the regular M6 octahedra.
    Notes: Durch Schmelzreaktionen von Alkalicarbonat mit elementarem Technetium oder Rhenium in einem mit Schwefel beladenen Wasserstoffstrom gelang die Darstellung der ternären Sulfide Rb10Tc6S14, Cs10Tc6S14, Rb10Re6S14 und Cs10Re6S14.Strukturuntersuchungen an Einkristallen ergaben, daß diese Verbindungen isotyp in der Raumgruppe Fm3m kristallisieren. Als charakteristische Strukturelemente treten [M6S14]-Baueinheiten (M \documentclass{article}\pagestyle{empty}\begin{document}$ \hat = $\end{document} Tc, Re) auf, in denen die unverzerrten M6-Oktaeder über den acht Flächen und sechs Ecken von Schwefelatomen koordiniert sind. Diese Einheiten sind, anders als bei den bisher untersuchten ternären Technetium- und Rheniumchalcogeniden, nicht untereinander verknüpft, sondern liegen als isolierte komplexe Anionen vor, die sich entsprechend einer kubisch dichten Kugelpackung anordnen. Die Alkalimetallionen befinden sich mit teilweise statistischer Besetzung ihrer Punktlagen auf den Ecken, den Kanten und den längeren Flächendiagonalen eines jede dieser Einheiten umgebenden Rhombendodekaeders. Die Dodekaeder sind untereinander allseitig flächenverknüpft.Der an Cs10Tc6S14 im Temperaturbereich zwischen 10 und 295 K gemessene Diamagnetismus stimmt mit der Annahme einer 24-Elektronenkonfiguration der regulären M6-Oktaeder überein.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19936191209
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