Oxygen Hole Character and Lateral Homogeneity in PrNiO2+δ Thin Films

Using x-ray absorption spectroscopy with lateral resolution from the submillimeter to submicrometer range, we investigate the homogeneity, the chemical composition, and the nickel 3d- oxygen 2p charge transfer in topotactically reduced epitaxial PrNiO2+δ thin films. To this end, we use x-ray absorption spectroscopy in a standard experimental setup and in a soft x-ray microscope to probe the element and spatially resolved electronic structure modifications through changes of the nickel-2p and oxygen-1s absorption spectrum upon soft-chemistry reduction. We find that the reduction process is laterally homogeneous across a partially reduced PrNiO2+δ thin film sample for length scales down to 50 nm.

Simultaneous measurement of pole figure and residual stress for polycrystalline thin films: ω–φ′ compensated grazing-incidence diffraction in side-inclination mode

A new grazing-incidence diffraction (GID) measurement geometry between in plane and out of plane is proposed. It is improved from the previous ω–φ compensated GID in side-inclination mode for measurement of residual stress in polycrystalline thin films [Wang & van Riessen (2017). Powder Diffr. 32, S9–S15]. Instead of keeping a constant azimuthal direction of the incident beam on the thin film sample, the current proposed variation maintains a constant azimuthal direction of the scattering vector projection on the thin film sample. The variation is named `ω–φ′ compensated GID in side-inclination mode' and enables d-spacing measurements along the same azimuthal direction. An Excel spreadsheet is included for readers to plan the measurement and to calculate the residual stress for the planned sample azimuthal direction. Anisotropic residual stresses of a polycrystalline NiFe thin film on an Si 001 substrate are measured by combining this method with phi rotations. Highly automated data analysis templates are developed using DIFFRAC.TOPAS v7 launch mode to calculate residual stress for all planned azimuthal directions sequentially. A pole figure file in simple text format is also generated from the same data set using DIFFRAC.TOPAS v7 launch mode, and can be directly imported into DIFFRAC.TEXTURE v4.1 for further texture analysis. Corrections for the incident-beam refraction have been implemented in both data analysis models.

Effect of the essential oils addition on the rate of bacterial cellulose surface overgrowth by mold fungi

Effect of the essential oils addition on the rate of bacterial cellulose surface overgrowth by mold fungi. The aim of this study was to determine the effectiveness of protecting films made of bacterial cellulose with essential oils against overgrowth by mold fungi. The cellulose film produced by microorganisms forming a pellicle called SCOBY was modified by introducing into the cellulose pulp essential oils: cinnamon and manuka. Samples of the protected film were treated with mold fungi: Chaetomium globosum, Aspergillus niger and Trichoderma viride. On the basis of the tests conducted, the rate of film overgrowth by mold fungi and the effectiveness criteria of cellulose film protection with essential oils were determined. The addition of cinnamon oil protected the film against the growth of Aspergillus niger and Chaetomium globosum fungi. Manuka oil slowed down the growth of Chaetomium globosum microorganisms on the surface of the bacterial cellulose film sample, but did not protect the samples from overgrowth. The essential oils tested were ineffective against the fungus Trichoderma viride.

Fabrication of monoclinic BiVO4 photocatalyst film and its photocatalytic activity for organic pollutant removal

Monoclinic BiVO4 photocatalyst films decorated on glass substrates were successfully fabricated via a dip-coating technique with different annealing temperatures of 400 °C, 450 °C, 500°C, and 550 °C. All of the physical and chemical properties of as-prepared BiVO4 photocatalyst film samples were investigated using X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and UV–vis diffuse reflectance spectra techniques. The results revealed that the as-prepared BiVO4 photocatalyst film samples retained a monoclinic phase with an average particle size of about 50 – 100 nm. Moreover, the BiVO4 photocatalyst film samples showed a strong photoabsorption edge in the range of visible light with the band gap energy of 2.46 eV. The photocatalytic activities of all the film samples were tested by the degradation of model acid orange 7 under visible light irradiation. The BiVO4 photocatalyst film sample annealed at a temperature of 500 °C showed the highest photoactivity efficiency compared with other film samples, reaching up to 51%within 180 min. In addition, the stability and reusability of BiVO4 photocatalyst film sample made with an annealing temperature of 500 °C did not show loss of photodegradation efficiency of acid orange 7 after ten recycles. A likely mechanism of the photocatalytic process was established by trapping experiments, indicating that the hydroxyl radical scavenger species can be considered to play a key role for acid orange 7 degradation under visible light irradiation.

Формирование интерметаллида Cu-=SUB=-6-=/SUB=-Sn-=SUB=-5-=/SUB=- в тонких пленках Cu/Sn

The study of the formation of the Cu6Sn5 intermetallic compound in Sn(55nm)/Cu(30nm) thin bilayer films was carried out directly in the column of a transmission electron microscope (electron diffraction mode) by heating the film sample from room temperature to 300 °C and recording the electron diffraction patterns. The thin films formed as a result of a solid state reaction were monophase and consisted of the η-Cu6Sn5 hexagonal phase. The temperature range for the formation of the η-Cu6Sn5 phase was determined. The estimate of the effective interdiffusion coefficient of the reaction suggests that the main mechanism for the formation of the Cu6Sn5 intermetallic is diffusion along the grain boundaries and dislocations.

Drastic improvement in detection limits in energy dispersive X-ray fluorescence geometry utilizing micro-focused bremsstrahlung excitation in thin-film sample specimen

Lowest detection limit achieved down to 0.4–4 ng mL−1 till date in a lab based XRF instrument.

Study of Structural and Optoelectronic Properties of Thin Films Made of a Few Layered WS2 Flakes

We report a surfactant-free exfoliation method of WS2 flakes combined with a vacuum filtration method to fabricate thin (<50 nm) WS2 films, that can be transferred on any arbitrary substrate. Films are composed of thin (<4 nm) single flakes, forming a large size uniform film, verified by AFM and SEM. Using statistical phonons investigation, we demonstrate structural quality and uniformity of the film sample and we provide first-order temperature coefficient χ, which shows linear dependence over 300–450 K temperature range. Electrical measurements show film sheet resistance RS = 48 MΩ/Υ and also reveal two energy band gaps related to the intrinsic architecture of the thin film. Finally, we show that optical transmission/absorption is rich above the bandgap exhibiting several excitonic resonances, and nearly feature-less below the bandgap.

Investigation of Ni-Al Intermetallic Thin Films

The article describes the results of studies of Ni-Al ultrathin films obtained by the resistive thermal evaporation method and having the characteristic dimensions of islands of 700-1000 nm with a film thickness of about 500 nm. This paper presents a method of obtaining a film using a unit for creating high vacuum and the subsequent deposition of the film. The obtained film sample was studied using an optical microscope, a scanning probe microscope and a Fourier analyzer. The kinetic characteristics of the film, the film relief, and the characteristic dimensions of the islands were established; the search for regularities in the island structure of films was carried out and its electrical conductivity was determined.