Journal of Surface Investigation. X-Ray, Synchrotron and Neutron Techniques

The potential of using the method of high-frequency cathode sputtering in an oxygen atmosphere for the synthesis of thin-film lead-containing antiferroelectric materials is investigated. Two films with the chemical composition of the PbHfO₃ target were synthesized on Si(001) and SrRuO₃/SrTiO₃/MgO(001) substrates. The formed films were characterized by single-crystal X-ray diffraction, including reverse space mapping, and energy dispersive spectroscopy. It has been demonstrated that this synthesis method makes it possible to grow polycrystalline films based on materials with a perovskite structure. In this case, an epitaxial film with rhombic syngony and a new crystal lattice, different from the one known for PbHfO3, was obtained on a heterophase substrate. The revealed ratio of the parameters of the film cells and the intermediate layer is 7 to 6, i.e. the coincidence of the nodes of the film and substrate structure occurs when 7 film cells and 6 cells of the SrRuO3 layer are superimposed. This indicates the complex nature of the orientation. The morphology analysis showed significant differences between the samples in terms of grain size and distribution. The data obtained confirm the high sensitivity of the phase composition to the type of substrate and demonstrate the promise of the high-frequency cathode sputtering method for creating new functional oxide films suitable for use in microelectronics, sensors and energy-efficient devices.

Detectors based on CMOS matrices (CMOS is a complementary metal–oxide–semiconductor structure) are widely used to solve a wide range of problems that require imaging. In addition to their widespread use in conventional cameras, including mobile phones, today they are increasingly used in various fields of science and technology: dosimetry, imaging neutron and X-ray spectroscopy. On the basis of such devices, both X-ray microscopy devices and X-ray telescopes can be built, for example, for studying various astrophysical objects. The possibility of using two CMOS matrices from Sony IMX265LLR-C and IMX226CLJ-C for simultaneous imaging and spectral acquisition in the soft X-ray range is considered. It is shown that in the range from 1 to 22 keV, the detectors have a high energy resolution. A comparison of two matrices is carried out, and their features for use in recording radiation in various energy ranges are considered.

Thin films of tin (II) phthalocyanine (SnPc) have been thermally evaporated in vacuum on substrates at different temperature (T_g). Their transmission spectra in the UV, visible and near IR ranges have been measured. It is shown that a 100 nm thick SnPc films becomes almost panchromatic photoabsorbers: the “green gap” characteristic of porphyrinoids can narrow to the range 410–490 nm, and the long-wavelength edge of the Q-band can reach 1100–1200 nm, depending on the growth conditions. At T_g below room temperature, the films are X-ray-amorphous, and at T_g > 25°C, the triclinic polymorph accumulates. The structure of the films is always granular, but the size, shape and packing of grains largely depend on T_g. The specific conductivity of SnPc thin films has been measured in the dark and under continuous white light (solar simulator) or filtered near-infrared light. It is found that for SnPc films grown at elevated Tg, the photo-to-dark current ratio exceeds an order of magnitude under residual illumination at wavelengths longer than 1 µm.

In this paper, the formation process and time evolution of the crystal structure of thin films of yttriastabilized zirconia ZrO₂:Y₂O₃ (YSZ) and gadolinia-doped ceria Ce_0.9Gd_0.1O₂, (GDC) were investigated. YSZ and GDC films for use as an electrolyte layer in microtubular solid oxide fuel cells were formed by reactive mid-frequency magnetron sputtering on WC-Co alloy substrates. The films were deposited in a vacuum setup specially designed for in situ X-ray diffraction studies of thin film growth using synchrotron radiation. It is shown that the texture of the formed films is determined by the substrate temperature. At a substrate temperature of 100‒187°C, YSZ and GDC films with a cubic crystal lattice are formed. Under such deposition conditions, YSZ films have a preferred orientation of (200), whereas for GDC films the preferred orientation changes from (111) to (220) during growth. To obtain YSZ and GDC films with a preferred orientation (111), which have the highest ionic conductivity, it is necessary to increase the mobility of adsorbed atoms by increasing the substrate temperature or applying a bias voltage to it. It is also shown that with the deposition parameters used, compressive residual stresses are formed in both films, which decrease slightly in amplitude with increasing film thickness due to the increase in grain size.

The paper examines the influence of the decay process of plasmonic (Langmuir) excitations on secondary electron emission processes. An assessment of the lifetime of the plasmon excitations decay process is carried out. A connection is established between the relaxation process of plasmon excitations and electron-photon emission yield. The electron-ion plasma of a solid body, interacting with an electron beam whose energy substantially exceeds the Fermi energy, is considered based on quantum electrodynamics. It is shown that the quantum description of plasmons leads to the concept of the electromagnetic vacuum of longitudinal Langmuir waves. The vacuum of longitudinal waves significantly alters the dielectric permeability of the solid-body plasma, resulting in the broadening and shifting of peaks associated with energy losses of fast electrons scattered by the solid. The interaction of plasmons with the plasmonics vacuum leads to the relaxation of plasma excitations and the generation of longitudinal photons. The relaxation mechanism of plasmons presented in this work helps to explain a number of seemingly anomalous phenomena, namely the polarization of electron-photon emission observed at plasmonic frequencies and the features in the spectra of secondary electron emission at plasmonic energies observed during ion and electron bombardments. The paper presents a comparison of the spectra of electron-photon emission with the differential cross-sections of inelastic energy losses of fast electrons due to plasmon excitation. Possible practical applications of the phenomena observed during the relaxation of collective excitations of solid-body plasma are discussed.

A dynamic theory of coherent X-ray radiation generated by a beam of relativistic electrons in a composite target “amorphous layer-vacuum-periodic layered medium” has been developed. A periodic layered medium consists of three different layers arranged periodically, with the layers located at an arbitrary angle to the target surface. Coherent X-ray radiation exits through the rear surface of the target, that is, radiation in a periodic layered medium occurs in the Laue scattering geometry. Within the framework of the two-wave approximation of the dynamic theory of diffraction, expressions describing the spectral-angular densities of parametric X-ray radiation (PXR) in a periodic layered medium and diffracted transition radiation (DTR) are obtained and studied.