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.

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.

White Light Emission from Thin-Film Samples of ZnO Nanocrystals, Eu3+ and Tb3+ Ions Embedded in an SiO2 Matrix

In this work, a method was developed to determine the concentration of Eu3+ and Tb3+ ions in a thin-film sample of SiO2, co-doped with ZnO-nanocrystals (ZnO-nc), to produce a sample of any desired colour in the International Commission on Illumination (CIE) colour space. Using this method, a white light emitting sample was fabricated. The thin-film sample combines red, green and blue emissions from the Eu3+ ions, Tb3+ ions and ZnO-nc, respectively, to create white light or light of any desired colour. The emissions at 614 nm and 545 nm from Eu3+ and Tb3+ ions, respectively, is due to the energy transfer from the excited ZnO-nc to the rare-earth (RE) ions. In this way, only a single excitation wavelength is needed to excite the ZnO-nc, Eu3+ and Tb3+ ions in the sample to produce emission of a desired colour from the sample. We developed an empirical 4th-degree polynomial equation to determine the concentrations of Eu3+ and Tb3+ ions to produce light of any desired colour in the CIE colour space. Based on the above empirical equation, the concentration of Eu3+ and Tb3+ ions for a white light emitting sample was found to be 0.012 and 0.024 molar fractions, respectively. The white light emission from the sample was confirmed by fabricating the sample using the low-cost sol–gel process. The stimulated emission spectra and the experimental emission spectra of the white light sample fit very well. The results presented in this work are important to develop energy efficient solid state lighting devices.

Инверсия типа проводимости тонких пленок n-InSe под действием лазерного излучения

Conductivity inversion in thin n -InSe films under intense pulsed laser irradiation was obser. A p – n structure based on indium selenide formed between irradiated and nonirradiated regions of a thin-film sample. It was confirmed by EDAX analysis that the composition of the sample remained the same after irradiation. The conductivity inversion is attributed to a change in the dynamics of lattice defects under heating.

Omega–Phi compensated GID in side inclination mode for measurement of residual stress in polycrystalline thin films

The grazing incidence diffraction (GID) method in side inclination mode, described by Ma et al. in 2002, of polycrystalline thin-film residual stress was revisited and explained using simple geometric relations. To overcome the issue of decreasing peak intensity of this method, which is induced by the decreasing incident angle because of the Eulerian cradle Chi-tilt, an improvement of Omega (ω)–Phi (φ) compensation was devised and applied to a NiFe thin-film sample. The geometry of this improved ω–φ compensated GID method in side inclination mode is detailed in this paper. This improvement guarantees a constant incident angle on the sample surface and a fixed sample illumination volume during measurement. The measured data were analysed using parametric refinement in DIFFRAC.TOPAS v6 software in Launch Mode, and details of the input file (.INP) are explained in this paper. The tensile stress of the NiFe thin-film sample was measured to be 1181 ± 85 MPa using this improved method.