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GaSb and InSb epilayers grown on GaAs (001) vicinal substrates misoriented toward (111) plane were studied using high resolution x-ray diffraction. The results show that GaSb and InSb epilayers take on positive crystallographic tilt, and the asymmetric distribution of 60° misfit dislocations in {111} glide planes have an effect on the tilt. In addition, the vicinal substrate influences the distribution of the threading dislocations in {111} glide planes, and the density of dislocation in the (111) plane is higher than in the [formula] plane. A model was proposed to interpret the distribution of full width at half maximum, which can help us understand the formation and glide process of the dislocations. [ABSTRACT FROM AUTHOR]

Presents a study that investigated gallium arsenide epilayer films on silicon substrates grown by molecular-beam epitaxy by the x-ray double-crystal diffraction method. Growth process of the epilayers; Function of SLS in improving the quality of gallium arsenide epilayers; Relative perfection of epilayers at different depths.

We demonstrated the synthesis of Pt-GO/MOF (Metal-organic framework) materials via a facile three-step procedure. The hybrid materials were characterized by powder X-ray diffraction, infrared spectrum, and thermo-gravimetric analysis. The adsorption experiments of the Pt-GO/MOF on CO2were investigated at 273 K. To be interested, all of the hybrid materials show enhanced adsorption ability on CO2, which is higher than parent MOF materials under the same conditions. As the ratios of Pt-GO increase, the adsorption amount increase first and then decrease, which is ascribed to the interaction among Pt-GO, ligands, and metal sites. [ABSTRACT FROM PUBLISHER]

Abstract: Reaction of Ag2CO3 with four methyl-substituted derivatives of benzoic acid afforded silver benzoates; no additional anions are involved in these solids. One of the silver carboxylates was studied by X-ray diffraction: in the crystal, silver 3,5-dimethylbenzoate monohydrate consists of carboxylato-bridged discrete dinuclear molecules with a short Ag⋯Ag separation of 2.7719(5)Å and one weakly bonded hydrate water molecule per cation. The binary silver carboxylates were combined with either racemic or enantiopure trans-1,2-diaminocyclohexane and resulted in four homochiral and four heterochiral crystalline solids. All eight structures feature cationic chain polymers, carboxylate anions and hydrate water. In three of the solids derived from the racemic ligand, the individual cationic chains are homochiral. In all structures, the primary coordination of the Ag(I) centers by nitrogen is essentially linear. Despite the chemical similarity in the anions, the backbone of the polymers proved to be conformationally soft with variable Ag–N–C–C torsion angles. In the resulting structures, the diamine ligand may bridge two cations in a wide distance range between ca. 3.0 and ca. 7.2Å. Both the chirality of the trans-1,2-diaminocyclohexane ligand and the substitution pattern of the benzoate anion have strong impact on the nature of secondary interactions perpendicular to the polymer strands: either weak coordination by carboxylato or hydrate water oxygen atoms or argentophilic interactions are encountered. The Ag⋯Ag contacts increase the dimensionality of the solids from chain polymers to layer structures. [ABSTRACT FROM AUTHOR]

Abstract: The self-assembly of ω-ferrocenylalkanethiols (FcCnSH) with different alkyl-spacer lengths on Au(111) substrates has been studied by scanning tunneling microscopy (STM). Upon deposition at room temperature FcCnSH molecules tend to form multilayers, while by thermal treatment monolayer formation, a rearrangement of the molecules and the formation of ordered domains is achieved. The surface structure of the resulting full coverage self-assembled monolayers is resolved with molecular resolution by STM. The ordered monolayer structure of ω-ferrocenylpropanethiol is discussed in comparison with its bulk crystal structure, derived from single crystal X-ray analysis. Based on these results a monolayer structure of ω-ferrocenylalkanethiols with longer alkyl chains closely related to the bulk crystal structure of the shorter alkyl-spacer derivates is suggested. Our results provide detailed insight into the self-assembly of FcCnSH on gold substrates. [Copyright &y& Elsevier]