Patterned mesoporous DAM-1 thin films were prepared on flexible transparent film utilizing the pulsed laser deposition and a line patterning technique. The patterned lines are transferred to the transparent film using a laser printer or copy machine. Laser ablation of DAM-1 onto the patterned substrate followed by a hydrothermal treatment resulted in a densely packed mesoporous film. Upon removal of the patterned lines (i.e. the underlying toner) by ultrasonic treatment in toluene, patterned DAM-1 films were produced.

Using the Discrete Dipole Approximation we have studied the optical properties of different isolated nanoparticles with arbitrary shapes. We have investigated the main features in the optical spectra, depending of the geometry and size of such nanoparticles. We present and discuss our results in terms of the scattering, extinction and absorption optical coefficients, which can be directly compared with experiments. The results are discussed in terms of the optical signature of each nanoparticle depending of its size and shape.

Nanoparticulates of aluminum nitride (AlN) have been synthesized by novel dry process, namely pulsed wire discharge where aluminum wire is exploded by an intense pulsed current (10-20 kA at the peak, half cycle of 10 μs) in NH3/N2 gas. The average size of the nanoparticulates was found to be 28 nm. Furthermore, narrow particle distribution of the particulates was observed, where geometric standard deviation was 1.29. Increasing charging energy enhances the nitridation of aluminum. The maximum content of AlN in synthesized particulates was ∼95 %. The sintered body with 80 % of density has been obtained by sintering at 1, 600°C for one hour.

ZnS:Ag phosphor particles were encapsulated with nano-meter thick films of indium tin oxide (ITO) in order to slow the degradation process of the phosphor as well as to reduce the amount of sulfur species out-gassing from the phosphor. Cathodoluminescent (CL) degradation measurements were performed at two different vacuum conditions (6.1–10-7 Torr and 1–10-5 Torr). The CL degradation curves showed that the ITO coating improved the brightness lifetime. X-ray photoelectron spectroscopy was used to determine the chemical changes on the coated and uncoated degraded particle surfaces. CL images were used to show the loss of brightness from the surface of the phosphor particles. Then energy dispersive x-ray spectroscopy was used to measure the ratio of the area under the zinc and sulfur peaks on an atomic weight %, which showed a loss in sulfur during the degradation experiments.

The Mn deposited clean Si (111) substrates were examined with UHV-TEM and STM that are part of an UHV-TEM/STM integrated characterization system. The Mn deposition with coverages of 5-20 ML followed by annealing at 673 K formed MnSi islands with Moire fringes. They showed metallic character. Subsequent annealing at 873 K dissipated the islands instead of transforming them into MnSi1.7. The re-deposition of Mn and re-annealing at 473 K succeeded to transform MnSi islands into MnSi1.7. The islands had several orientation relationships with substrate Si, and were semiconducting. The growth mechanism of MnSi1.7 is inferred.

Octanethiol-stabilized Si nanocrystals, ranging from 2 to 8 nm in diameter, were synthesized in cyclohexane heated and pressurized above its critical point at temperatures ranging from 400°C to 500°C. The nanocrystals exhibit crystalline cores and photoluminesce with relatively high efficiencies. These nanocrystals are suitable for single particle spectroscopic measurements that reveal optical information about the individual chromophores that are buried in ensemble measurements. The sterically-stabilized Si nanocrystals emit with relatively narrow emission spectra at room temperature, characteristic of molecules.

The synthesis and characterisation of gold-coated cobalt nanoparticles, as well as their chemically- and magnetically-induced self-organisation have been studied. Metallic core-shell nanoparticles were prepared using two different experimental techniques: bulk reductive precipitation, with average particles size ∼15 nm, and microemulsion confining method, with average particle size of ∼6 nm. The self-assembly of prepared nanoparticles on flat substrates was achieved by derivatising the substrate and particle surfaces with bifunctional organic molecules that attaches to both particles and substrates.

Examination of the self-assembled systems was carried out by a number of characterisation techniques including transmission electron microscopy (TEM), UV-visible spectrophotometry (UV-VIS), and atomic force microscopy (AFM).

The spark plasma sintering (SPS) of L12 phase Al3Zr and (Al+12.5at.%Cu)3Zr powders with a nanocrystalline microstructure has been studied to produce bulk intermetallic compounds which maintain metastable structures such as L12 structure and nanocrystalline microstructure. The powders were prepared by 10 h planetary ball milling (PBM). Full-density L12 (Al+12.5at.%Cu)3 Zr intermetallic compounds were obtained by SPS for 0 min. at 600°C. The smallest grain size was obtained in the specimen prepared at 600°C for 0 min., which was 20-30 nm as confirmed by TEM observation. Accordingly, the highest micro-hardness, 989.5 HV, was obtained in the specimen and this value was three times higher than those of the specimens with micro grain sizes. Full density Al3Zr intermetallics were prepared by SPS at 700°C for 0 min.. However, their crystal structure was D023 and micro-hardness was 778.1 HV. By using SPS, the sintering time can be reduced within 10 min.

Novel arrays of gold nanoparticles with sulfur containing fullerene nanoparticles were self-assembled through the formation of Au-S covalent bonds. Disulfide functional groups were introduced into C60 molecule by reacting propyl 2-aminoethyl disulfide with C60. The two dimensional(2D) arrays were formed at the interface of aqueous phase of gold particles and organic phase of fullerene particles as a blue transparent film. TEM images showed that the fullerene spacing between adjacent Au(~10 nm) particles was about 2.1±0.4 nm, which was consistent with the result of 2.18 nm by molecular molding calculations(MM+). The arrays were deposited on the top of pairs of gold electrodes to form 2D colloidal single electron devices. The electrode pairs were made by electron beam lithography techniques, and the separation between tips of the two electrodes in a pair was less then 100 nm. Transport measurements at low temperatures exhibited Coulomb-Blockade type current-voltage characteristics, the lower the temperature the more pronounced the Coulomb gap. Also, step-by-step method was used to assemble one-dimensional(1D) array of gold nanoparticles with fullerene derivative between two electrodes spaced with 15 nm. The Coulomb blockade behavior of 1D arrays was clearer than that of 2D arrays.

Two types of iron (Fe) nanoparticles, carbon-coated Fe nanoparticles (Fe(C)) and pure α-Fe nanoparticles that coated with oxide layers (Fe(O)), have been successfully synthesized using modified graphite arc-discharge method. X-ray diffraction (XRD), high-resolution transmission electron microscopy (HREM) and electron diffraction (SAED) analysis have been used to characterize these distinct structural morphologies. It is indicated that those two Fe nanoparticles have an average grain size of 15-20nm. The presence of carbon encapsulated α-Fe, γ-Fe and Fe3C phases are clearly identified by X-ray diffraction and SAED patterns in those Fe(C) particles. However, the evidence of pure α-Fe nanocrystal coated with oxide layer is also revealed by HR-TEM images and SAED patterns in these Fe(O) particles.

Mössbauer spectra and hyperfine magnetic fields at room temperature for the assemblies of Fe(C) and Fe(O) nanoparticles further confirm their distinct nanophases that detected by XRD analysis and HRTEM observation. Specially, the assemblies of Fe(O) nanoparticles exhibit ferromagnetic properties at room temperature due to the stronger interparticle interaction and bigger magnetocrystalline anisotropy effects among these Fe(O) nanoparticles. Moreover, modified superparamagnetic relaxation is observed in the assemblies of Fe(C) nanoparticles, which is attributed to the nanocrystalline nature of the carbon-coated nanoparticles.

Cr1-xMnx (x < 6.3 %) alloy in the bulk form is an interesting complex system that behaves in many but not all respects like a spin-glass system. In this study, 14 nm-size CrMn nanoparticles with 5% Mn, were synthesized by ball milling of Cr and Mn particles in Ar atmosphere. After 50 hours of milling, the x-ray diffraction pattern indicated alloying of the two metals Cr and Mn. However XPS data indicated the formation of MnO2 and Cr2O3oxides on the surface of the chromium core in the nanoparticle. These oxides on the surface, like the Cr core, are antiferromagnets. Magnetization (M) measurement at 200 G as a function of temperature (T), after zero-field-cooling, showed that M increased as T increased from 5 K all the way to 330 K, beyond the Neel temperatures of the Cr and the oxides. Even though the magnetization value is in the range of a typical antiferromagnet at all temperatures from 5 to 330 K, the shape of M versus T curve is neither that of an antiferromagnet nor of a spin-glass. It appears that the behavior of the magnetization curve is due to the frustration of the spins by weak fields associated with spin-density-wave and by the existence of the oxides. This frustration should be different from the frustration of the spins due to the ferromagnetic-antiferromagnetic competition in spin-glass systems.

Two kinds of nanocrystalline Tin doped indium oxide (or indium tin oxide: denoted ITO hereafter) powders with different crystal structures – rhombohedral and cubic – were prepared using a coprecipitation method through the control of pH of a mixing solution and aging time after coprecipitation. The two powders have the same particle size of 15 nm in diameter but different morphologies (spherical for rhomboheral and rectangular for cubic). The gaseous ethanol sensing characteristics of the sensors prepared by the two ITO powders were quite different. The sensitivity of rhombohedral ITO sensor was high compared to that of the cubic ITO sensor across all temperatures. The reason for this is explained through the viewpoint of the binding energy of XPS and the surface structure relating to the crystal structure.

Chemical modifications of Superparamagnetic Iron Oxide Nanoparticles (SPION) surfaces by attachment of functional groups and further covalent coupling with biodegradable substances have been studied. Based on computer-assisted chemical equilibrium calculations, several optimum operation conditions for a coprecipitation process of magnetite nanoparticles were predicted. These particles were immobilized by ultra-thin films of PVA, Dextran, Dextrin, PEG and MPEG to obtain a biocompatible particle surface for further functionalization purposes. The effect of surface modification of the superparamagnetic nanoparticles in terms of chemical and physical properties of the samples was investigated with several techniques, including microelectrophoresis measurement. The feasibility of using SPION in biomedical applications was investigated by in-vivo treatment in rat brains.

Advanced nano and micro particulate thin films of 3d transition and post-transition metal oxides consisting of nanorods and microrods with parallel and perpendicular orientation with respect to the substrate normal, have been successfully grown onto various substrates by heteronucleation, without template and/or surfactant, from the aqueous condensation of solution of metal salts or metal complexes (aqueous chemical growth). Three-dimensional arrays of iron oxide nanorods and zinc oxide nanorods with parallel and perpendicular orientation are presented as well as the oxygen K-edge polarization dependent x-ray absorption spectroscopy (XAS) study of anisotropic perpendicularly oriented microrod array of ZnO performed at synchrotron radiation source facility.

Cu-nanoclusters can be produced in an electrochemical environment by tip-induced metal deposition using an electrochemical scanning tunneling microscope (EC-STM). These clusters, consisting of 100-1000 atoms only, show a surprising stability against anodic oxidation. The clusters, which are 2-3 atomic layers in height dissolve slowly when the applied potential is increased step by step to 200 mV positive of the reversible Nernst potential for “normal” copper dissolution. The presented work gives evidence that the unusual stability of the clusters could be a consequence of interfacial alloying between the cluster and the underlying substrate. In order to study these effects Cu-nanoclusters have been produced on pure gold substrates and on carefully prepared Au3Cu(111)-substrates. This work compares the results obtained on both substrates.

Nanostructured thin films were assembled as metal-responsive electrode materials from monolayer-capped gold nanoparticles (2 nm) and carboxylic acid functionalized alkyl thiol linkers via an exchange-crosslinking-precipitation reaction pathway. The network assemblies have open frameworks in which void space forms channels or chambers with the nanometer sized cores defining its size and the shell structures defining its chemical specificity. Such nanostructures were investigated as responsive materials for the detection of metal ion fluxes. Cyclic voltammetry, in-situ electrochemical quartz-crystal nanobalance, and surface infrared reflection spectroscopy techniques were used to characterize the interfacial redox reactivity and mass fluxes at the nanostructured electrode materials. The system showed remarkable reversible mass loading arising from incorporation of ionic species into the film. The diagnostic stretching bands of the carboxylic and carboxylate groups at the shell allowed the identification and assessment of the interfacial carboxylate-metal ion reactivity.

We report electron microscopy studies of nanoparticles ( 500 ≤ n ≤ 104, where n is the number of atoms in a given cluster) that are sputtered from the surface by high-energy ion impacts. Measurements of the sizes of these clusters yielded an inverse power-law distribution with an exponent of –2 that is independent of irradiating ion species and total sputtering yield. This inverse-square dependence indicates that these nanoclusters are produced when shock waves, generated by sub-surface displacement cascades, impact and ablate the surface. Such nanoparticles consist of simple fragments of the original surface, i.e., ones that have not undergone any large thermal excursion. As discussed below, this “ion ablation” technique should therefore be useful for synthesizing nanoparticles of a wide variety of alloy compositions and phases.

Nano-sized Fe particles were synthesized by Chemical Vapor Condensation (CVC) Process using the precursor of iron carbonyl (Fe(CO)5) as the source. We investigated the microstructures, magnetic properties of the Fe nanoparticles and their oxidation behavior during annealing systematically by means of HRTEM, DTA-TG, Mössbauer spectroscopy. The prepared particle was nearly spherical shape and core-shell type structure. The magnetic states of Fe nanoparticles changed from superparamagnetism to ferromagnetism with the particle size and microstructure. Oxidation heat treatment leads to the successive appearance of oxide phases.

Monodispersed gold coated Superparamagnetic Iron Oxide Nanoparticles (SPION) were prepared in water-in-oil reverse microemulsion (μE) of CTAB (cetyltrimethyl -ammonium bromide)/octane/butanol/water and Brij@97/cyclohexane/water. Gold coated SPION were obtained in the μE system by coprecipitation of magnetite and subsequent reduction of Au on the surface of the magnetite using NaBH4. The SPION were characterized by TEM with EDX, AFM, TGA, ESA, UV-Vis spectroscopy, and SQUID at intermediate and final stages.

Red light emitting Eu3+ doped Y2O3 phosphor nano-particles were synthesized by a solgel method combined with a furnace firing. The particle size, measured using dynamic light scattering (DLS), was between36nm and 1 micron depending on the conditions. Final dopant concentrations were measured through inductively coupled plasma (ICP). The ICP results show a dopant loss of 58% during the processing for the europium doped yttria. Red photoluminescence (PL) and cathodoluminescence (CL), at 614nm was observed from the phosphor particles under UV excitation and electron bombardment. Results show that the samples with a mean diameter of 30nm displayed a significant increase in PL brightness over the samples whose mean diameter was 215nm. The lag in PL, and CL intensity behind the commercial reference samples is attributed to the significantly lower dopant levels present in the experimental phosphors. Results also indicate that these processing methods and nanophosphors may be a useful alternative to current materials and methods.