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Abstract: X-ray induced structural changes at the Ag/As2S3 interface are investigated using X-ray photoelectron spectroscopy on the samples prepared within the spectrometer. The as-prepared film consists of stable heteropolar As–S bonds as well as ∼16% S (and As) atoms in lower (higher) electron density configurations such as the –S–S– (–As–As–) segments with ‘wrong’ homopolar bonds. Two distinct stages of the X-ray induced diffusion are revealed. At first, silver reacts with atoms within –S–S– like segments to form Ag–S bonds. In the second stage, the Ag–S bonds decompose due to the reaction of S with As atoms within the –As–As– ‘wrong’ segments to form As–S heteropolar bonds, and silver diffuses away from the interface into the film. The results provide guideline for enhancing silver photodiffusion in chalcogenide glass. The irradiation of the (Ag–Te)/As2S3 sample with X-rays shows that not only Ag, but Te also diffuses away from the surface. [Copyright &y& Elsevier]

Abstract: Changes of electronic and atomic structure during silver photodissolution in As2S3 thin film are studied using a combination of high-resolution X-ray photoelectron spectroscopy (XPS) and extended X-ray absorption fine structure (EXAFS) methods. It is shown that the photodiffusion process starts already under the influence of Al Kα and synchrotron X-ray probe radiations, forming a highly disordered metastable structure. Concurrent irradiation with UV/VIS light leads to the formation of a stable uniform ternary phase. The mechanisms of structural transformations and final chemical products are proposed. The influence of surface oxidation on the structure of Ag/As2S3 bilayer is also investigated. [Copyright &y& Elsevier]

Abstract: The as-quenched samples in the system (100− x) TeO2-(x) Ba5Li2Ti2Nb8O30 (2⩽ x ⩽8) were found to be embedded with 10–20μm sized crystallites of the polar phase Ba5Li2Ti2Nb8O30 (BLTN). Blue (400nm) second harmonic generation (SHG) was observed in transmission mode when 800nm laser light was allowed to pass through the individual crystallites. The blue SHG signal was temperature dependent and its intensity was maximum at ∼175°C which was tentatively attributed to the concomitant changes associated with the refractive indices of the BLTN crystallites. The SHG intensity attained a minimum value around the Curie temperature of BLTN crystals. [Copyright &y& Elsevier]

Abstract: We have investigated and compared vibrational modes of SiO2 and LaBGeO5 in the glass and crystalline phases based on terahertz (THz) spectroscopy. This is made possible by frequency-tuning a THz source developed by us recently. The THz absorption spectra are significantly different between the two phases of the same composition. In particular, we have identified the transition peak at 78.0μm for the SiO2 crystal (i.e. quartz). Moreover, we have observed an evidence for a boson peak in the spectrum for LaBGeO5 glass. [Copyright &y& Elsevier]