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Fluorine doped tin oxide thin films (SnO2:F) are widely used as transparent conductive oxide electrodes in thin-film solar cells because of their good electrical and optical properties. Thus, the surface morphology has an important influence on the optical properties of SnO 2 thin films. On a rough surface light is diffusely scattered, which extends the optical path of light inside the active layer of the solar cell and in that way improves light absorption and solar cell conversion efficiency. In this work, we investigated the surface morphology of undoped and doped SnO 2 thin films and its influence on the optical properties of the films. We have compared and analysed the results obtained by several complementary methods for thin film surface morphology investigation: atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and grazing-incidence small-angle X-ray scattering (GISAXS). Based on the AFM, SEM and TEM results, we propose a theoretical model that reproduces well the GISAXS scattering patterns.

Self-supporting thin films containing nanopores are very promising materials to be used for multiple applications. Here we present a method for the production of nanomembranes containing a 3D ordered network of nanopores in an alumina matrix, with a diameter of about 1 nm, and body centered tetragonal structure of the network nodes [1]. The material is produced by magnetron sputtering deposition of a 3D ordered network of Ge nanowires in alumina matrix, followed by a specific annealing process resulting in the evaporation of Ge. We demonstrate that the films can be easily grown on different substrates, including porous ones. We believe that these films have a potential for applications in the fields of filtration, separation and sensing.

Large effective surface area and superior electron transport properties are required characteristics for photoanode material in dye sensitised and perovskite solar cells. Nanostructured TiO2 thin films with various shape forms (porous layer, nanoparticles, nanorods, nanotubes) are widely used for that purpose. In this work, we will examine vertically aligned TiO2 nanotube array thin films as possible photoanode material. TiO2 nanotube arrays usually are prepared by anodization of titanium metal foil. TiO2 nanotube arrays structural properties (nanotube diameter, wall thickness) are influenced by anodization parameters (applied voltage, Flour ions concentration in the electrolyte) and surface morphology of starting Ti layer. Instead of thick Ti foil, in this work Ti thin films prepared by DC magnetron sputtering will be used as a substrate for anodization process. SnO and ZnO coated glass will be used as a substrate for magnetron sputtering. Ar working gas pressure and substrate temperature will be varied in order to obtain Ti thin films with different surface morphology. It will be presented and discussed structural properties of starting Ti thin films and TiO2 nanotubes arrays be examined by using simultaneous small and wide angle X-ray scattering under grazing incidence geometry, X-ray reflectivity, scanning electron microscopy and Raman spectroscopy.

TiO2 is material considered as a prominent electrode material in solar cells. Nano forms of TiO2 such as nanoparticles, nanorods, nanowires and, in particular nanotubes may allow obtaining high efficiency photosensitive devices and solar cells. In order to be widely used, the method of producing large areas should be established. The formation of nanotubes perpendicular to the surface, on thin TCO film and decoration with dye molecules or perovskites looks as good first steps. In order to control the properties averaged on relatively large area, the suitable method should be established as well and grazing incidence x-ray scattering GISAXS, looks promising in that sense. The TiO2 nano porous thin films were prepared by electro chemical etching of thin Ti films prepared by magnetron sputtering. The as deposited films were etched using various concentrations of acid and under various voltage and current densities. The properties were estimated upon small and wide angle x-ray scattering under grazing incidence angles and scanning electron microscopy and correlated with condition of formation. The nanostructures estimated upon X-ray scattering were correlated with results obtained by high resolution electron microscopy and advantages and disadvantages of these methods were discussed. In second step, the nanotubes were decorated with active organic materials and finalized in typical solar cells. For each step, the structural, optical and electrical properties of obtained multilayer structures were measured and compared with properties of identical ones formed on other nanostructures formed with chemical methods and on near flat surfaces. Acknowledgments Research was supported by project: “Titanium dioxide nanostructures for photovoltaic solar cell: professional development of young researchers/postdoctorands” financed by the European Union from the European Social Fund and in part by the Croatian Science Foundation under the projects IP-2014-09-9419 and IP-11-2013-2753.

TiO2 is material considered as a prominent cathode electrode material in solar cells. Among all the different shapes of this material the nanostructure thin films have raised a lot of interest in the last decade. TiO2 is one of the most intensively investigated compounds in material science due to its essential properties. It is a wide band gap semiconductor having band-edge positions appropriate for solar cell applications and for hydrogen generation by water splitting. It is also known as a non-toxic, environment friendly, corrosion-resistant material. In particular, TiO2 nanocrystal is a very active photocatalytic material that has many powerful applications in biomedicine, environment technology and photochemistry. Nano forms of TiO2 such as nanoparticles, nanorods, nanowires and, in particular nanotubes may allow obtaining high efficiency photoelectrochemical devices. The TiO2 nano porous and meso porous thin films were prepared by chemical and plasma etching of thin Ti films prepared by evaporation and magnetron sputtering. The parameters of initial film growth were varied in order to obtain various initial structures in particularly the crystal orientation, crystallinity, grain size, and porosity. The as deposited films were etching using various concentrations of acid and under various voltage and current densities. The properties were estimated upon small and wide angle x-ray scattering under grazing incidence angles and by X-ray reflectivity and correlated with condition of formation. The nanostructures estimated upon X-ray scattering were correlated with results obtained by high resolution electron microscopy and advantages and disadvantages of these methods were discussed.

Tantalum nitrides (Ta-N) are used in a wide variety of applications such as diffusion barrier in magnetoresistive random access memory, wear and corrosion-resistant materials, high-speed thermal printing head, as well as thin film resistors. Structural properties of magnetron-sputter-deposited Ta-N thin layers were investigated in correlation with electrical properties. We focused on the impact of varying nitrogen content in the deposition chamber during synthesis as well as post-deposition annealing in the temperature range up to 950°C. Thin Ta-N films were grown on silicon wafers, pre-deposited with 100 nm SiO2 buffer layer, kept at room temperature (RT) or at 550°C during deposition. The films were structurally and morphologically characterized with grazing incidence X-ray techniques: specular reflectivity (XRR), diffraction (GIXRD) and small angle scattering (GISAXS). Structural features in films deposited at RT strongly depend on the Nitrogen partial flow rate (pN2) ; as pN2 increases the crystal structure changes: from amorphous Ta-rich (pN2 =10%), to fcc-TaN (pN2 =20-40%), to amorphous N-rich (pN2 >60%) ; the density of the films are correspondingly affected. Upon annealing, amorphous films crystallize into fcc-TaN (pN2=10%) and Ta4N5 or Ta3N5 (pN2>60%), while as deposited fcc-TaN films are stable up to 950°C with releasing stacking fault deformations. The loose homogenous structure of the films deposited at high pN2>60% anneals into particulate nanostructure with the average grain size increasing from 3nm (annealing @550°C) to 15 nm (annealing @950°C). All these findings are evaluated in relation with electrical measurements of the film resistivity to gain deeper insight into material parameters relevant for electronic devices.

Beside being already used in microelectronics, the TaxN thin films hold promise to be applied in certain superconducting devices, as well. The TaxN thin films for that purpose are usually deposited on sapphire, or on SiO2 in order to decrease the cost of a final product. Here we report an interim investigation of the thin TaxN films prepared by reactive magnetron deposition in a wide range of composition deposited on SiO2. Pure tantalum target and Ar + N2 working gas were used. Films (cca 100 nm) were deposited at room temperature and 550 degC, respectively. A selected samples deposited at room temperature were subsequently annealed at intermediate temperatures in a protective atmosphere. The chemical composition of the films was determined by ERDA (0.5

STRUCTURAL STUDY OF Ni-Nb THIN FILMS Radić, N1, Dubček, P1, Bernstorff, S3, Skoko, Ž 2, Ristić, M1, Siketić, Z1 1 Rudjer Boskovic Institute, Bijenicka 54, 10000 Zagreb, Croatia 2 Faculty of Sciences, Physics Department, Bijenicka 32, 10000 Zagreb, Croatia 3 Sincrotrone Trieste, Strada Statale 14, km163.5, 34149 Basovizza, Italy Ni-Nb thin films (500 nm) have been prepared in a full range of compositions (pure Ni - pure Nb) by magnetron codeposition onto various substrates. The chemical compositions of the alloys have been determined by time-of-flight elastic recoil detection analysis (TOF-ERDA), while the structure of the as-deposited films has been determined by X-Ray Diffraction. It has been found that the glass-forming range (25-85 at.% Ni) conforms very well with the glass forming ability estimated from molecular dynamics simulations and Miedema's theory. Below 10 at.% Nb content, the prepared films are fcc crystalline Ni(Nb) solid solutions. The Ni(Nb) (nano)crystallites (20-30 nm) are preferentially (111) oriented in the direction perpendicular to the film plane. Grazing incidence small angle x-ray scattering (GISAXS) results indicate that the surface contributions dominate in the GISAXS patterns from the nickel rich samples. Upon increasing the Nb content of the samples, the sample surfaces become smoother, and the GISAXS patterns become better defined. In the glass-forming range, the surface structure becomes island-like, with a narrow size distribution both vertically and horizontally. When scattering pattern taken at wider angles are compared to those taken at the critical angle, the bulk contribution scattering can also be deduced. The sizes of bulk features are fairly similar for most concentrations. However, the values that stand out are in the glass-forming range, as well as with 90%Ni content, where the bulk features appear to be 50% bigger. The GISAXS findings have also been confronted with the images obtained by scanning electron microscopy from selected samples.

Lateral continuity of ultrathin tungsten layers

Transition metals carbides, and tungsten carbides in particular, exhibit many properties of interest to technology - high metling point, extreme hardness, low friction coefficient, chemical inertness, oxidation resistance, and good electric conductivity. The surface conditions of these materials are critical for some applications, and preparation processes are optimized to meet such requirements. Surface layer of W-C thin films prepared by reactive magnetron sputtering (argon + benzene) on monosilicon substrates has been examined by GISAXS, AFM and SEM methods. Preparation conditions have been varied in a wide range of deposition parameter values: benzene partial pressure in the 1-10% range, substrate temperature in steps RT, 200°C, and 400°C, and beside deposition onto substrates at floating potential a substrate bias of -70 V has been applied . It was found that WC1-x is a dominant carbide in all prepared films, with (111) preferential orientation in films deposited at room temperature. The surplus/unreacted carbon forms a fine dispersion of graphitic nanoparticles imbedded in the intergranular space. The W-C grainsize is determined at about 3 nm by the GISAXS method, with a very smooth surface - roughness about 0, 5 nm - and a very short height-height correlation length at the surface. The AFM examination show roughness depending upon the preparation conditions - from about 0, 5 nm on films prepared at low benzene partial pressure increasing towards a few nanometers when high benzene partial pressure was used. A corresponding average lateral grainsize has been estimated at 10-20 nm, revealing a scale-like morphology of the film surface. The SEM results corroborate the surface morphology, but reveal the subsurface film structure: at the top of the film there is a 10-20 nm thick layer which clearly differs from the main body of the film beneath. The "bulk" of the W-C films (about 200 nm thick) consist of columns 50-100 nm in diameter, atop of which there is a continuous segregated fine-structured layer. The observed structural discontinuity in the prepared W-C films inevitably influence their mechanical properties.

The amorphous Nb-Ge thin films are well-known model system for experiments on fundamental properties of vortex transport. Vortex dynamics has also been studied in Ta-Ge films with columnar structure, and other refractory metal-germanium alloys are interesting in that respect, as well. We have prepared a series of Ge30-refractory metals (Nb, Mo, Ta, W)70 thin films by magnetron codeposition. The structure of the films was examined by GISAXS, and the effects of substrate type and film thickness were investigated. In addition to the film contribution to the scattering (fringes of intensity), Mo and Nb films show strong scattering from island like structures on top of the film. These island sizes are 5 to 10 nm, and they are 10 to 20 nm apart. Furthermore, Nb films have a distinctive signal suggesting a very uniform island height (about 8nm). Ta and W films exhibit more complex scattering patterns which could be ascribed to top few nanometers of the film having different density than the rest below. The samples grown on amorphous substrates have more regular fringes in the scattering intensity than those grown on monocrystalline silicon and sapphire substrates. It seems that flat, monocrystalline substrate surface favours island formation during the deposition, the tendency that is conserved at least up to the film thickness of 20nm. For the films whose thickness exceeds 80 nm, the substrate influence diminishes, and the scattering from films of different composition grown on different substrate tends to reflect mainly the metal component of the alloy.

Thin films of completely immiscible Ag-W system have been prepared in a wide range of composition by codeposition of pure silver and pure tungsten sputtered by two independently controlled magnetron sources. Deposition rate onto substrates (glass, alumina, sapphire, mono-Si) at room temperature was about 0, 33 nm/s, and the final film thickness was about 0, 5  m. The effects of working gas pressure, and of oxygen or aluminum incorporation upon the film structure have been examined. The chemical composition of the prepared films has been determined by the RBS technique. The structure of prepared films was examined by the XRD, GISAXS and SEM methods. No completely amorphous films have been obtained in the composition range Ag94W6-Ag12W88. A supersaturated solid solution Al(W) with the fcc structure is formed with

Nanocrystalline nickel thin films were deposited by magnetron sputtering onto monocrystalline silicon and sapphire, as well as onto fused silica and glass, at room temperature. The film thickness was ranged from 15 to 325 nm, and the deposition time was doubled in each step. The film structure has been studied using grazing incidence small angle X-ray scattering (GISAXS). In thinner films (nominal thickness up to 35nm) island-like structure atop flat film layer is detected for all substrate types, with the island sizes ranging from 4 to 7 nm and inter-island distances varying from 10 to 35 nm. Both the size and inter-island distances sizes varied slightly with the type of the substrate. The flat film contribution to the scattering is also present in the form of fringes, and it is strongest on (amorphous) fused silica substrate, while the film thickness is similar for all the substrate types. In the thicker films (above 35 nm nominal thickness) film to substrate surface correlation is absent. Apart from Porod type scattering, due to the grain agglomeration, additional contribution from few nm sized inhomogeneities, attributed to grain boundaries, was detected.

Nanocrystalline nickel (nc-Ni) is a very interesting material due to its enhanced mechanical and corrosion properties. However, being metastable, it transforms into large-grain nickel upon heating. Here we present the results of a GISAXS study of the structure of nc-Ni thin films deposited onto substrates at elevated temperatures. Nickel thin films were deposited by dc magnetron sputtering onto fused silica substrates. The base pressure in the process chamber was 10-6 – 10-5 Pa, and the working gas was argon at 1.3 Pa. The deposition rate was about 7-8 nm/min, and the film thickness was about 400 nm. In order to examine the effects upon the film structure, the substrate temperature was varied in the room temperature (RT) - 700  C range. The film structure has been investigated using Grazing incidence small angle X-ray scattering (GISAXS) and the XRD method. 2D GISAXS patterns were recorded with a two-dimensional CCD-detector, placed perpendicular to the incident beam. The scattering intensities along a line parallel to the specular plane, (and distanced enough to minimize the surface roughness contribution) are shown in Fig. 1 for different substrate temperatures. We have found that the nc-Ni films deposited onto substrates held at temperatures up to 80º C contain inhomogenities up to 8 nm in size. Above 80º C their size is gradually reduced to about 6 nm. Only at 700º C there is a strong SAXS signal from about 2nm large inhomogenities. These inhomogenities are ascribed to intergranular matter/ grain boundaries, since the grain size (as determined from the XRD patterns) of the examined sample was found to increases from 12 nm in samples deposited at room temperature to about 90 nm in samples deposited at 150 C, or higher temperature.The change of ratio between the two phases as observed by GISAXS and XRD, respectively, corresponds well to the variation of the electric resistance of the nc-Ni samples deposited at different temperatures.

Nanocrystalline TiO2 thin films, deposited on the flat glass substrate using various techniques, have been investigated by GISAXS. In data interpretation it is assumed that the surface roughness correspond to the bulk structure of the film, which is porous. Therefore, both contributions should indicate the same average particle sizes and film porosity. So obtained film parameters are correlated to photo cell efficiency.