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Abstract Hydrogenated multilayers (MLs) of a-Si/a-Ge have been analysed to establish the reasons of H release during annealing that has been seen to bring about structural modifications even up to well-detectable surface degradation. Analyses carried out on single layers of a-Si and a-Ge show that H is released from its bond to the host lattice atom and that it escapes from the layer much more efficiently in a-Ge than in a-Si because of the smaller binding energy of the H-Ge bond and probably of a greater weakness of the Ge lattice. This should support the previous hypothesis that the structural degradation of a-Si/a-Ge MLs primary starts with the formation of H bubbles in the Ge layers.

We have realized perpendicular hard/soft bilayers with exchange-spring behavior, based on FePt-[L1.sub.0] and Fe. Studying the magnetization process as a function of the soft-layer thickness, two different coupling regimes have been identified, i.e., the rigid-magnet and exchange-spring regimes. High values of the maximum energy product (12.4 MGOe) and remanent magnetization (750 emu/[cm.sup.3]) have been found in the exchange-coupled bilayers. Index Terms--Iron alloys, permanent magnets, perpendicular magnetic anisotropy, thin films.

The magnetic and structural properties of [Fe.sub.53] [Pt.sub.47] deposited by alternated-layer sputtering on MgO (100), heated at temperatures up to T = 550 [degrees]C, were investigated. The effect of a subsequent thermal annealing performed at the same temperature was found to be essential for obtaining 10-nm FePt thin films with a high degree of ordering and high squareness. Index Terms--FePt L[1.sub.0], perpendicular recording media, permanent magnets, thin films.

Energy-loss magnetic chiral dichroism (EMCD) is a versatile method for measuring magnetism down to the atomic scale in transmission electron microscopy (TEM). As the magnetic signal is encoded in the phase of the electron wave, any process distorting this characteristic phase is detrimental for EMCD. For example, elastic scattering gives rise to a complex thickness dependence of the signal. Since the details of elastic scattering depend on the electron's energy, EMCD strongly depends on the acceleration voltage. Here, we quantitatively investigate this dependence in detail, using a combination of theory, numerical simulations, and experimental data. Our formulas enable scientists to optimize the acceleration voltage when performing EMCD experiments. [ABSTRACT FROM AUTHOR]

Organo-halide perovskite solar cells (PSCs) have emerged as next-generation photovoltaics, owing to their high power-conversion efficiency (PCE), lower production cost, and high flexibility. ABX3-structured methylammonium lead triiodide (CH3NH3PbI3 or MAPbI3) perovskite is a widely studied light-absorbing material in PSCs. Interestingly, a small amount of chlorine incorporation into MAPbI3 increases charge carrier diffusion lengths (from 129 nm to 1069 nm), which enables planar structured PSCs with high PCEs. However, existence of chloride ions in the final perovskite film is still under debate. Contrastingly, few studies reported a negligible amount or absence of chloride ions in the final film, while others reported detection of chloride ions in the final film. Herein, we observed the microstructure and chlorine content of MAPbI3−xClx thin films with increasing temperature via an in-situ nano-Auger spectroscopy and in-situ scanning electron microscopic analysis. The relative precipitation of MAPbI3−xClx films occur at lower temperature and MAPbI3−xClx grains grow faster than those of MAPbI3 grains. Local concentrations of chlorine at intragrain and the vicinity of grain boundary were analyzed to understand the behavior and role of the chloride ions during the microstructural evolution of the MAPbI3−xClx films. [ABSTRACT FROM AUTHOR]

Extended abstract of a paper presented at Microscopy and Microanalysis 2010 in Portland, Oregon, USA, August 1 – August 5, 2010. [ABSTRACT FROM PUBLISHER]

Antimony telluride (Sb 2 Te 3 ) thin films were prepared by a room temperature Metal-Organic Chemical Vapor Deposition (MOCVD) process using antimony chloride (SbCl 3 ) and bis(trimethylsilyl)telluride (Te(SiMe 3 ) 2 ) as precursors. Pre-growth and post-growth treatments were found to be pivotal in favoring out-of-plane and in-plane alignment of the crystallites composing the films. A comprehensive suite of characterization techniques were used to evaluate their composition, surface roughness, as well as to assess their morphology, crystallinity, and structural features, revealing that a quick post-growth annealing triggers the formation of epitaxial-quality Sb 2 Te 3 films on Si(111)., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Hybrid organo-lead halide perovskites are becoming the benchmark material for next generation photovoltaics and a very important player for other applications such as photodetectors and light emitting diodes. Nevertheless, the most important issue hindering the large-scale application of these materials remains their intrinsic instability due to the organic cation. Although the substitution with inorganic cesium (Cs) enhances stability, in most cases solution deposition methods of fully inorganic perovskites result in high surface roughness and poor surface coverage. This work reports on the evaporation of the CsPbBr 3 precursor by Single Source Thermal Ablation, showing that just after deposition films consist of a mixture of CsPbBr 3 , CsPb 2 Br 5 , and Cs 4 PbBr 6 due to a vertical composition gradient. We point out that mild post deposition treatments lead to the conversion of CsPb 2 Br 5 and Cs 4 PbBr 6 into CsPbBr 3 due to its higher thermodynamic stability. Conversion results into smooth and pinhole-free CsPbBr 3 films with good light absorption and emission properties. We demonstrate the suitability of obtained films for planar devices by preparing perovskite-based pure-green light emitting diodes, thus promoting Single Source Thermal Ablation as a promising alternative deposition technique for all-inorganic perovskite-based devices., (Copyright © 2020 Nasi, Calestani, Mezzadri, Mariano, Listorti, Ferro, Mazzeo and Mosca.)