Temperature dependent infrared (IR) and optical spectroscopic ellipsometry methods are used to investigate peculiarities of the transitions from the ionic conductivity to the superionic conductivity states in Ag2S and Ag2Se compounds. The structural phase transitions (SPTs), known as β→α transition in these semiconductors, are investigated also with spectroscopic ellipsometry methods. The electronic band structure of Ag2S at the SPT changes sharply from the monoclinic to the bcc phase, which occurs at T = 453 K in the super ionic conductivity state, where all the interband transitions in optic region, corresponding to the monoclinic structure of β‐phase, disappear. The α‐phase of Ag2S is characterised with new lines in the dielectric functions ε1 and ε2, which arise at 5‐6.5 eV. The interband transitions do not change in the SPT from the orthorhombic to the bcc in Ag2Se, which occurs at T > 406 K. In IR ellipsometry for the degenerated Ag2Se, the free carriers' plasma energy is displaced abruptly from ħω=0.075 eV at T=300 K to ħω=0.125 eV at T=338 K. The same effect is seen in the IR ellipsometry for Ag2S, where negative ε1 appears at T=434‐440 K. These facts indicate a drastic increase of the free carriers concentrations in both of the semiconductors at temperatures before the β→α SPT. In Ag2S the second abrupt shift of the free carriers plasma energy from 0.035eV to 0.1 eV occurs at T=453 K, corresponding to β→ α SPT. The second shift is due to the electronic band structure change of Ag2S. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
In this work, the concept of mass-energy equivalence in left-handed metamaterials is discussed by following Einstein's box thought experiment. Left-handed metamaterials are artificial composite structures that exhibit unusual properties, especially negative refractive index, in which phase and group velocities are directed oppositely. Equation E = mc2 assumes that, in vacuum, the propagation of an electromagnetic radiation from emitter to receiver is accompanied by the transfer of mass. It was hypothesized previously that if the space between emitter and receiver is medium with a negative refractive index, then radiation transfers the mass not from the emitter to receiver as expected, but rather from the receiver to the emitter due to the opposite directions of phase and group velocities. In this paper, it is shown that even though one radiating atom is taken, the negative mass transferring must be in force. In particular, it means that, if the atom radiates a photon in a medium with negative refractive index, photon transfers the mass not from the atom, but to the atom.
Infrared spectroscopic ellipsometry (IRSE) is a powerful tool for the characterization of various types of organic and inorganic films. In application to protein films, IRSE can be utilized to detect structural changes, orientation of specific group, etc. Because of sensitivity, enhanced IRSE will be very useful to study protein thin films. Here we show that fibroin films on Al mirror display surface‐enhanced infrared spectroscopic ellipsometry (SEIRSE). AFM data indicate that nanoislands on the Al mirror are responsible for the plasmon‐enhanced mechanism. SEIRSE for fibroin films shows non‐uniform enhancement across the spectrum. Possible mechanisms of such enhancement are provided. Evidently, as proposed previously, at least two mechanisms, the electromagnetic (EM) and chemical, are expected to contribute to the enhancement. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
ZnO and ZnO: Al thin films of about 100 nm thicknesses were deposited by magnetron sputtering method at 200‐400 °C substrate temperatures under oxygen/argon gas mixture with different O/Ar ratio (0‐6%O2). The higher crystallinities for ZnO: Al and ZnO films are achieved at 400 °C substrate temperature under 0% and 4% (O/Ar) mixture ratios, respectively. The films were characterized by X‐ray diffraction (XRD), spectroscopic ellipsometery (SE), photoluminescence spectroscopy, and atomic force microscopy (AFM) methods. Electrical, optical, and luminescent properties depending on crystallinities of the obtained films were studied. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The 200 to 300 nm thick, Er and Er,Yb doped Y2O3 films deposited onto silicon substrate by spin coating have been studied by spectroscopic ellipsometry over the 192‐1680 nm spectral range at room temperature. All samples have been found to be strongly depolarizing in the blue and UV part of the spectrum. Complimentary examination of the sample surfaces, using confocal photoluminescence microscopy has disclosed the non‐uniform distribution of the rare‐earth dopants. The depolarization effects have then been modeled and found to be best reproduced by taking the thickness non‐uniformity as the main source of depolarization. The optical constants of the studied films have been determined after four‐step modeling with sequential decrease of the mean square error. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
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