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Abstract: In this paper the microstructural characterisation of yttria-stabilised zirconia (YSZ) thin films deposited by laser ablation is reported for the as-deposited sample as well as for samples submitted to thermal treatments in different atmospheres (vacuum, N2 and O2) at a moderate temperature (500 °C). Results obtained by different characterisation techniques such as grazing incidence X-ray diffraction, X-ray reflectivity and transmission electron microscopy evidenced the formation of the cubic YSZ phase after the annealing treatments. On the contrary, the as-deposited sample is amorphous with nanocrystals of the cubic YSZ phase dispersed inside. It also exhibits a difference between the density of the surface region and the region of the interface with the substrate. This latter effect has been attributed to the loss of oxygen atoms during the deposition. The annealing treatments are able to recover the density unhomogeneity present inside the as-deposited sample, the degree of recovering depends on the ambient atmosphere. [Copyright &y& Elsevier]

Hydrogenated silicon–carbon films have been grown in a PECVD system over a wide range of RF power by silane+methane gas mixtures highly diluted in hydrogen. The effect of RF power on the properties of the deposited films has been explored. The RF power appears to control the transition from microcrystalline to amorphous phase. The increase in RF power modifies the hydrogenated microcrystalline silicon–carbon (μc-Si1 - xCx:H) growth from columnar silicon crystals to crystallites uniformly dispersed in an amorphous matrix and enhances the carbon content in the films increasing their energy gap. μc-Si1 - xCx:H samples with higher dark conductivity are deposited at lower RF power and those having carbon content x⩾0.074 exhibit photoluminescence in the visible region at room temperature. [Copyright &y& Elsevier]

In the framework of a research aimed to superconductor/semiconductor integrated electronics, we have grown a-axis oriented YBa[SUB2]Cu[SUB3]O[SUB7-δ] (YBCO) thin films on silicon (100) substrates with (111) oriented insulating buffer layers of cerium dioxide (CeO[SUB2]), using magnetron sputtering deposition techniques. The properties of the cerium dioxide layer have been preliminary optimized by means of several layout and by monitoring the growing procedures through X-ray diffraction, AFM and TEM techniques. The lattice matching between CeO[SUB2] and YBCO resulted to be worsened by an amorphous thin SiO[SUB2] layer at the Si/CeO[SUB2] interface, that decouples the buffer orientation from the seed orientation. However, it was possible to grow a relatively thick, optimally textured layer of CeO[SUB2] without spurious orientations. The YBCO films deposited on top of this layer result preferentially aaxis oriented. The transition widths are very large, jet well controllable and reproducible. Some technological applications can be already envisaged. [ABSTRACT FROM AUTHOR]

Abstract: In the present work we focus our attention on the structural modifications induced by repeated absorption/desorption cycles on Mg–Nb layers. Samples consisting of a 30μm thick pure Mg or Mg–5at.% Nb doped films, coated with a 20nm thick Pd layer were submitted to repeated H2 sorption cycles in a volumetric apparatus. Isothermal desorption analysis at 350°C was performed to evaluate the amount of absorbed hydrogen. X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and electron microscopy techniques (SEM and TEM) were used for the structural characterisation of the samples. Analyses show a deep modification of the material upon cycling. The presence of Nb enhances the structural modifications and induces an initial lattice contraction of the Mg matrix that tends to decrease on cycling via the formation of Nb nanoparticles (with average size of ∼10nm). SEM and TEM observations performed in cross section evidenced the formation of a porous structure. [Copyright &y& Elsevier]

• We report a new chemical route to prepare single-layer bi-magnetic composite films. • We prepared a composite LaFeO 3 -CoFe 2 O 4 film to demonstrate the synthesis technique. • The film is homogeneous and highly crystalline in nature with no impurity phases. • High coercivity value is found despite a large fraction of antiferromagnetic phase. • This new synthesis technique for composite films is low cost as well as scalable. Bi-phasic composite films are generally grown as multilayers that result in layer-by-layer morphology with each layer having a distinct chemical composition. In this work, we report an all-in-one chemical synthesis technique combined with spin-coating to prepare single-layer bi-magnetic LaFeO 3 (LFO)-CoFe 2 O 4 (CFO) composite thin films with both phases co-existing in the same layer. The films have been characterized using X-ray diffraction (XRD) and transmission electron microscopy (TEM), and the magnetic properties have been probed using dc magnetometry at room and low temperature. The unique synthesis technique followed ensures homogeneity of the two phases on the nanoscale with grain sizes ~10 nm for CFO and few tens of nm for LFO, as observed from TEM images. XRD confirms the presence of only the desired LFO and CFO phases in the films without any undesired secondary phases. Magnetic hysteresis loops reveal a coercivity of ~0.2 T at room temperature that increases by nearly one order of magnitude at T = 5 K. The all-in-one synthesis technique reported here can be used to prepare different bi-phasic composites in the form of single-layer two-dimensional films as well as zero-dimensional nanoparticles by a suitable modification of the precursors, solvents, and chelating agents. [ABSTRACT FROM AUTHOR]

Abstract: The structure and morphology of chromium disilicide (CrSi2) nanometric films grown on 〈100〉 silicon substrates both at room temperature (RT) and at 740K by pulsed laser ablation are reported. A pure CrSi2 crystal target was ablated with a KrF excimer laser in vacuum (∼3×10−5 Pa). Morphological and structural properties of the deposited films were investigated using Rutherford backscattering spectrometry (RBS), grazing incidence X-ray diffraction (GID), X-ray reflectivity (XRR), scanning (SEM) and transmission electron microscopy (TEM). From RBS analysis, the films’ thickness resulted of ∼40nm. This value is in agreement with the value obtained from XRR and TEM analysis (∼42 and ∼38nm, respectively). The films’ composition, as inferred from Rutherford Universal Manipulation Program simulation of experimental spectra, is close to stoichiometric CrSi2. GID analysis showed that the film deposited at 740K is composed only by the CrSi2 phase. The RT deposited sample is amorphous, while GID and TEM analyses evidenced that the film deposited at 740K is poorly crystallised. The RT deposited film exhibited a metallic behaviour, while that one deposited at 740K showed a semiconductor behaviour down to 227K. [Copyright &y& Elsevier]

Abstract: Polycrystalline 3C–SiC thin films grown by LPCVD on different substrates were characterized by vibrational and electronic spectroscopies and electron diffraction measurements aimed at studying the samples microstructure. Raman spectra evidence the coexistence of crystallites, whose size distribution depends on the deposition conditions, and of a disordered matrix. On the other side, IR reflectivity measurements show spectra which are strongly influenced by the surface morphology. [Copyright &y& Elsevier]

Abstract: Due to its outstanding electrical and mechanical properties, silicon carbide (SiC) is considered a leading semiconducting material for high temperature sensors. Since the piezoresistive effect in SiC is highly anisotropic and exhibits a dependence on the crystal orientation, the role of the substrate on the residual stress must be investigated. This paper presents the structural and morphological characterisation of polycrystalline 3C–SiC films using two-dimensional X-Ray Diffraction (XRD2) and Transmission Electron Microscopy (TEM) techniques. 3C–SiC thin films were grown on single crystalline Si and on SiO2/Si substrates under the same deposition conditions. The influence of the two substrates on the structural and microstructral properties of the films was investigated. By means of XRD2 technique, particular attention was devoted to the stress calculation and in particular to the stress release by the formation of extended defects. [Copyright &y& Elsevier]