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81.
82.
F. Kober 《无机化学与普通化学杂志》1973,398(2):115-118
Reactions of Dialkyl Aminodifluoroarsines with Hydrogen Halides. Diethylaminodifluorarsines react with hydrogen halides and CH3J under formation of AsF2X and AsFX2. Under various conditions rearrangements occur resulting in AsX3 and AsF3. 相似文献
83.
Friedhelm Erwe 《Archiv der Mathematik》1958,9(3):197-201
Ohne ZusammenfassungHerrn Professor Dr. H.Kneser zum 60. Geburtstag gewidmet 相似文献
84.
85.
Christoph Meier Christian Teutloff Oleksandr Astakhov Friedhelm Finger Robert Bittl Jan Behrends 《Applied magnetic resonance》2014,45(10):1075-1086
Electrically detected hyperfine sublevel correlation (ED-HYSCORE) measurements are presented and employed to study spin-dependent transport in thin-film microcrystalline silicon solar cells. We explore the hyperfine coupling between paramagnetic conduction band tail states involved in hopping transport and neighboring 29Si nuclei at low temperature ( \(T = 5\) K). ED-HYSCORE measurements performed on solar cells with 29Si-enriched absorber layers reveal that the hyperfine interaction between these current-influencing centers and 29Si nuclei in the surroundings is dominated by isotropic couplings up to \(\sim\) 4 MHz, whereas the anisotropic contributions are small. This indicates that the wave function of the conduction band tail states is distributed over several nuclei. Our results demonstrate that the ED-HYSCORE technique can provide helpful insight into the microscopic structure of transport-relevant paramagnetic states and thus usefully complement the toolbox of electrically detected magnetic resonance spectroscopy. 相似文献
86.
Electron doping turns semiconductors conductive even when they have wide fundamental band gaps. The degenerate electron gas in the lowest conduction-band states, e.g., of a transparent conducting oxide, drastically modifies the Coulomb interaction between the electrons and, hence, the optical properties close to the absorption edge. We describe these effects by developing an ab initio technique which captures also the Pauli blocking and the Fermi-edge singularity at the optical-absorption onset, that occur in addition to quasiparticle and excitonic effects. We answer the question whether free carriers induce an excitonic Mott transition or trigger the evolution of Wannier-Mott excitons into Mahan excitons. The prototypical n-type zinc oxide is studied as an example. 相似文献
87.
Nanoimprint texturing of transparent flexible substrates for improved light management in thin‐film solar cells 下载免费PDF全文
Karen Wilken Ulrich W. Paetzold Matthias Meier Nicole Prager Matthias Fahland Friedhelm Finger Vladimir Smirnov 《固体物理学:研究快报》2015,9(4):215-219
We present a nanoimprint based approach to achieve efficient light management for solar cells on low temperature transparent polymer films. These films are particularly low‐priced, though sensitive to temperature, and therefore limiting the range of deposition temperatures of subsequent solar cell layers. By using nanoimprint technology, we successfully replicated optimized light trapping textures of etched high temperature ZnO:Al on a low temperature PET film without deterioration of optical properties of the substrate. The imprint‐textured PET substrates show excellent light scattering properties and lead to significantly improved incoupling and trapping of light in the solar cell, resulting in a current density of 12.9 mA/cm2, similar to that on a glass substrate. An overall efficiency of 6.9% was achieved for a flexible thin‐film silicon solar cell on low cost PET substrate. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) 相似文献
88.
Hubertus Rimke Günter Herrmann Marita Mang Christoph Mühleck Joachim Riegel Peter Sattelberger Norbert Trautmann Friedhelm Ames Hans -Jürgen Kluge Ernst -Wilhelm Otten Dieter Rehklau Wolfgang Ruster Franz Scheerer 《Mikrochimica acta》1989,99(3-6):223-230
Resonance ionization mass spectrometry (RIMS) is a very sensitive analytical technique for the detection of trace elements. This method is based on the excitation and ionization of atoms with resonant laser light followed by mass analysis. It allows element and, in some cases, isotope selective ionization and is applicable to most of the elements of the periodic table. A high selectivity can be achieved by applying three step photoionization of the elements under investigation and an additional mass separation for an unambiguous isotope assignment.An effective facility for resonance ionization mass spectrometry consists of three dye lasers which are pumped by two copper vapor lasers and of a linear time-of-flight spectrometer with a resolution better than 2500. Each copper vapor laser has a pulse repetition rate of 6.5 kHz and an average output power of 30 W.With such an apparatus measurements with lanthanide-, actinide-, and technetium-samples have been performed. By saturating the excitation steps and by using autoionizing states for the ionization step a detection efficiency of 4 × 10–6 and 2.5 × 10–6 has been reached for plutonium and technetium, respectively, leading to a detection limit of less than 107 atoms in the sample. Measurements of isotope ratios of plutonium samples were in good agreement with mass-spectrometric data. The high elemental selectivity of the resonance ionization spectrometry could be demonstrated.Presented in part at the 1989 European Winter Conference on Plasma Spectrochemistry, Reutte, Austria 相似文献
89.
L. Alff G.M. Fischer R. Gross F. Kober A. Beck K.D. Husemann T. Nissel F. Schmidl C. Burckhardt 《Physica C: Superconductivity and its Applications》1992,200(3-4):277-286
Patterning of thin films and multilevel structures of high-temperature superconductors is a key technology for microelectronic applications. We performed a comparative study of Ion Beam Etching (IBE) and Reactive Ion Etching (RIE) processes for YBa2Cu3O7−δ thin films. The RIE process with a pure chlorine plasma yielded small etching rates, caused by chemical modifications of the sample surface which result in a passivation layer reducing the chemical etching rate. Using IBE, microstructures down to the 1 μm regime could be fabricated without reducing the critical temperature Tc and the critical current density Jc of the material. Etching rates up to 40 nm/min could be achieved without deteriorating the properties of the superconducting film by cooling the sample effectively during the etching process. The influence of the etching process on Jc was investigated by imaging the spatial distribution of the critical current along the patterned microstructures using Low-Temperature Scanning Electron Microscopy (LTSEM). 相似文献
90.
Friedhelm Schönfeld Arno P. Kampf Erwin Müller-Hartmann 《Zeitschrift für Physik B Condensed Matter》1996,102(1):25-35
We present the results for a model calculation of resonant two-magnon Raman scattering in a spin density wave (SDW) antiferromagnet. The resonant enhancement of the two-magnon intensity is obtained from a microscopic analysis of the photon-magnon coupling vertex. By combining magnon-magnon interactions with ‘triple resonance’ phenomena in the vertex function the resulting intensity line shape is found to closely resemble the measured two-magnon Raman signal in antiferromagnetic cuprates. Both, resonant and non-resonant Raman scattering are discussed for the SDW antiferromagnet and a comparison is made to the conventional Loudon-Fleury theory of two-magnon light scattering. 相似文献