High-resolution SAXS setup with tuneable resolution in direct and reciprocal space: a new tool to study ordered nanostructures

A novel compact small-angle X-ray scattering (SAXS) setup with tuneable resolution in both direct and reciprocal space has been designed and tested for the study of nanostructured materials with a hierarchical structure. The setup exploits a set of compound refractive lenses that focus the X-ray beam at the detector position. Anodic alumina membranes with a self-ordered porous structure were chosen as test samples. The setup allows patterns to be collected with a minimum scattering vector value of 0.001 nm−1 and gives the possibility for an easy continuous switch between taking high-resolution statistically averaged diffraction data of macroscopically large sample volumes and lower-resolution diffraction on a small single domain of the anodic aluminium oxide film. It is revealed that the pores are longitudinal and their ordering within each domain tends towards the ideal hexagonal structure, whereas the in-plane orientation of the pore arrays changes from domain to domain. The possible advantages and disadvantages of the proposed compact SAXS scheme are discussed.

Morphology and Wettability of Nanoporous Aluminium Oxide Film Prepared by Anodization

Anodic aluminium oxide (AAO) is a well-known material for nanofabrication. To obtain highly ordered nanoporous array, there is anodization process. AAO were fabricated by anodization method utilizing high purity aluminium foil as the substrate. The substrate was degreased with ultrasonic cleaner for 15 minutes. Then the substrate was anodized in an electrolyte of 0.3 M oxalic acid with various potentials: 10, 20, 30, and 40 V and various durations: 10, 30, 60, 120, and 180 minutes at room temperature. Field emission scanning electron microscope (FE-SEM) was used to investigate surface morphology of nanoporous aluminium oxide film. The wettability of nanoporous aluminium oxide surface was estimated by measuring water contact angle (WCA) of water droplets on the nanoporous aluminium oxide surface. The FE-SEM images showed that the pore size was in the range of 12 - 81 nm. This result can indicated that nanopore size of AAO film increased with the increasing of anodization potentials and anodization time. The water contact angle of AAO samples were approximately 90.55 - 44.33 degrees. The result of measurement proved that super hydrophilic surface obtained with the increasing of nanopore size and high porosity of AAO.

INFLUENCE OF NANOWIRE DIAMETER ON STRUCTURAL AND OPTICAL PROPERTIES OF Cu NANOWIRE SYNTHESIZED IN ANODIC ALUMINIUM OXIDE FILM

Copper (Cu) nanowire arrays embedded in anodic aluminium oxide films (AAO) on aluminium substrate have been synthesized by alternating current electrochemical deposition. Two-step anodization process has been performed to get the through-hole AAO with ordered nanochannels in 0.3[Formula: see text]M oxalic acids at DC voltages 30, 40, 50 and 60[Formula: see text]V, respectively. Structural characterization of the Cu nanowires has been analyzed by scanning electron microscopy (SEM) and X-ray diffraction (or) X-ray diffractometer (XRD). Our SEM analysis has revealed that the diameters of vertically oriented Cu nanowires are 15, 25, 45 and 60[Formula: see text]nm and the length of Cu nanowires having high packing density is about 15[Formula: see text][Formula: see text]m. XRD measurement has indicated that polycrystalline Cu nanowires prefer growth orientation along the (111) direction. Optical measurements show that reflection of the Cu nanowires/AAO on aluminium reduces with decreasing diameter of the Cu nanowires. This effect can be associated with increased light scattering from metal nanoparticles near their localized plasmon resonance frequency depending on the size and shape of the nanoparticles.

Subnanometer Aluminium Oxide Film as a Model Photochemical Sensor

The growth and the atomic structure of alumina films of submonolayer to multilayer thickness evaporated onto the surface of Mo (110) crystal have been studied by Auger electron spectroscopy, high resolution electron energy loss spectroscopy and scanning tunneling microscopy. It is shown that the stoichiometry of the submonolayer film corresponds to that of the bulk oxide, and after achieving two monolayers the properties of the film largely resemble the properties of massive alumina. Deposition of the oxide at a substrate temperature of 1100 K results in the film structure corresponding to α-Al2O3. Such ultrathin oxide film is of considerable potential application in sensor physics and technology.

Morphology and chemical states of size-selected Ptnclusters on an aluminium oxide film on NiAl(110)

Size-selected Ptnclusters on the Al2O3surface form two-dimensional planar structures atn≤ 18 and three-dimensional two-layer structures start to appear atn≥ 19. They are composed of neutral and cationic Pt atoms.