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551.
The properties of ZnSiP2 crystals prepared by adding of Ga and In to the melt differ essentially from that of undoped samples. Especially the activation energies determined from the temperature dependence of the Hall coefficient prove that in both cases a real doping with shallow impurities has taken place. Ga and In act as donors suggesting the conclusion that Ga and In atoms substitute Zn atoms. The existence of strong electrical inhomogenities in a part of the samples is discussed. 相似文献
552.
W. Siegel H. Boudriot H. Koi K. Deus O. Oettel H. A. Schneider 《Crystal Research and Technology》1989,24(10):999-1002
GaAs: Si with different doping level was grown by the gradient freeze method. The crystals were characterized by structural, electrical and optical methods concerning especially the dependence of the epd and the compensation degree on the carrier concentration. 相似文献
553.
Bastian Achenbach Erik Svensson Grape Dr. Mohammad Wahiduzzaman Sandra K. Pappler Marcel Meinhart Dr. Renée Siegel Prof. Dr. Guillaume Maurin Prof. Dr. Jürgen Senker Dr. A. Ken Inge Prof. Dr. Norbert Stock 《Angewandte Chemie (International ed. in English)》2023,62(29):e202218679
The solution chemistry of aluminum is highly complex and various polyoxocations are known. Here we report on the facile synthesis of a cationic Al24 cluster that forms porous salts of composition [Al24(OH)56(CH3COO)12]X4, denoted CAU-55-X, with X=Cl−, Br−, I−, HSO4−. Three-dimensional electron diffraction was employed to determine the crystal structures. Various robust and mild synthesis routes for the chloride salt [Al24(OH)56(CH3COO)12]Cl4 in water were established resulting in high yields (>95 %, 215 g per batch) within minutes. Specific surface areas and H2O capacities with maximum values of up to 930 m2 g−1 and 430 mg g−1 are observed. The particle size of CAU-55-X can be tuned between 140 nm and 1250 nm, permitting its synthesis as stable dispersions or as highly crystalline powders. The positive surface charge of the particles, allow fast and effective adsorption of anionic dye molecules and adsorption of poly- and perfluoroalkyl substances (PFAS). 相似文献
554.
Hydrogels based on lightly crosslinked poly(methacrylamidophenylboronic acid-co-acylamide) swell monototically at pH 7.4 with exposure to increasing concentrations of glucose. At pH 10 these hydrogels first shrink and then reswell with increasing glucose concentration. A mechanism for these disctinct behaviors is proposed and preliminary results validating this mechanism are presented. A simple microfabricated glucose-sensitive valve based on this hydrogel is described. 相似文献
555.
H. Becherer E. Buhrig K. Hein M. John P. Kirsten H. A. Schneider W. Siegel K. Winkler 《Crystal Research and Technology》1978,13(9):1053-1057
Undoped ZnSiP2 crystals grown by different methods (vapour phase transport, solution growth) show in part considerable differences in their physical properties. The connections between growth, quality of the basic materials and the physical properties of ZnSiP2 will be shown. Measurements of Hall effect, resistivity, luminescence and backscattering of protons yielded informations about the perfection and homogenity of the crystals and about the impurities and recombination centres characteristically for the various growth methods. The influence of doping by different elements on the properties of solution grown ZnSiP2 crystals was investigated. 相似文献
556.