A short review of electron-energy-loss spectroscopy (EELS) experiments of carbon nanotubes and onions is presented. The dielectric response function of these nanostructures is derived from electrodynamics. Loss spectra computed with the dielectric theory are compared with spatially-resolved experimental spectra. The main features of the loss spectra obtained with non-penetrating electrons can be attributed to surface plasmon excitations (π plasmon at 6 eV and π + σ plasmon at 15 and 17-18 eV).

The talk presents an overview of theoretical results on electrodynamics and transport properties of carbon nanotubes (CNs). Consideration is given in the microwave, the infrared and the visible regimes. The talk comprises linear electrodynamics of isolated CNs with the emphasis given to waveguiding properties, nonlinear transport and nonlinear optics of CNs, electromagnetic response properties of CN-based composites. Effective boundary conditions for the electromagnetic field and the electrostatic potential in CNs are stated on the nanotube surface providing thereby the most appropriate tool for solving electrodynamic problems involving CNs. A detailed analysis of the waveguiding in a single homogeneous CN is presented allowing the concept of nanotubes as nanowaveguides. Scattering of electromagnetic cylindrical waves by an isolated semi-infinite CN is considered by the Wiener-Hopf technique. The differences between the scattering responses of metallic and semiconducting CNs are discussed. The high harmonic generation by an isolated metallic CN exposed to an intense ultrashort pulse is discussed and the phase matching for different harmonics in a rope of parallel aligned CNs in dependence on the angle of incidence is considered. The talk also discuss a foundation of quantum electrodynamics of nanotubes. The last issue is of interest in relation to recent idea to use nanoobjects in quantum networks that store and process quantum information being transmitted by entangled states of photons. The talk stresses the tight relation between traditional problems of classical macroscopic electrodynamics and electrodynamic problems of quasi-one-dimensional nanostructures. That allows extension to nanostructures of well-developed mathematical approaches and rich experience accumulated in the traditional electrodynamics. On the other hand, complicated conductivity low and pronounced nanoscale field inhomogeneity provide peculiar electromagnetic response of CNs irreducible to the response of macroscopic samples.

One of the most versatile formalism for the study of the electrodynamic response of solids, surfaces and interfaces or nanoparticles is the continuum dielectric model. In this contribution, we develop an application of this dielectric approach to nanocylinders and more particularly to the simulation of near-field electron energy loss (EEL)spectra of nanotube bundles. On the experimental side, EELS in a Scanning Transmission Electron Microscope (STEM) combines both spatial and energy resolutions in the plasmonic energy range and then permits the spectroscopic analysis of the surface and volume excitations of nanoparticles. Amongst the challenges brought about by the discovery of carbon nanotubes, one can cite the understanding of their optical properties. In this contribution, pursuing this goal within a dielectric continuum model, we focus on the dispersion and coupling of surface plasmon excitations of hollow nanocylinders and on the near-field EELS of nanotube nanocrystals (bundles). Experimental EELS in a STEM have also been obtained on bundles of carbon nanotubes. The interpretation in terms of effectif medium theory is successfuly performed both for surface and bulk losses associated with the σ plasmon.

Density Functional theory calculations combined with non-equilibrium Green's function technique have been used to compute electronic transport in organic molecules. In our approach the system Hamiltonian is obtained by means of a self-consistent density-functional tight-binding (DFTB) method. This approach allows a first- principle treatment of systems comprising a large number of atoms. The implementation of the non-equilibrium Green's function technique on the DFTB code allows us to perform computations of the electronic transport properties of organic and inorganic molecular-scale devices. The non-equilibrium Green's functions are used to compute the electronic density self-consistently with the the open-boundary conditions naturally encountered in transport problems and the boundary conditions imposed by the potentials at the contacts. The Hartree potential of the density-functional Hamiltonian is obtained by solving the three-dimensional Poisson's equation involving the non-equilibrium charge density.

The nonlinear optical response of a ingle-wall carbon nanotube (CNT)due to the interaction with femtosecond laser pulses is investigated. The analysis utilizes the quantum kinetic equations for π-electrons with both intra-band and inter-band transitions accounted. In the regime of weak driving fields the kinetic equations have been solved by the perturbation method and the third-order nonlinear usceptibility of different achiral CNTs has been calculated. In the strong driving field regime,a non-perturbative approach using the numerical solution of the quantum kinetic equations in the time domain has been developed and the density of the axial electric current in CNT has been calculated. The amplitude of this current and the conversion efficiency in dependence on the number of the high-order harmonics, the CNT type, the frequency and the intensity of the driving field have been predicted.

For the correct interpretation of Raman spectra it is important to realize that the scattering process in carbon nanotubes is doubly resonant, a feature which - although known from semiconductors - is greatly enhanced by the peculiar bandstructure of graphene near the K-point. We discuss the double-resonant process and, as examples of its importance, show how the relative defect concentration in a set of boron-doped multiwalled tubes can be measured and how the determination of the diameter through the radial breathing mode (RBM) is affected by double resonance.

In this work, we report a simple method for mass production of ZnO tetrapod nanorods. A mixture of Zn and graphite powders (ratio 2:1) was placed in a quartz tube. The quartz tube was placed in a horizontal tube furnace and heated up to 950°C. The tube was then removed from the furnance and quenched to room temperature. Fluffy products white in color were formed on the walls of the tube. Obtained products were characterized by X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoluminescence. SEM images showed tetrapod-like ZnO nanorods. The four tetrapod legs were approximately equal in length, and the length of tetrapod legs was in the range ~1-3 μm. We investigated influence of the growth temperature (in the range from 700°C to 1100°C) and Zn to catalyst ratio to the properties of obtained products. Fabrication is different atmospheres (air, argon, nitrogen, humid argon, and humid nitrogen) was also performed. The influence of growth conditions (temperature, atmosphere, and catalyst concentration) to the formation and properties of ZnO nanorods is discussed.

Three-dimensional nanostructures can be fabricated by the glancing angle deposition technique. By rotating the substrate in both polar and azimuthal directions, one can fabricate desired nanostructures, such as nano-rod arrays with different shapes, nano-spring arrays, and even multilayer nanostructures. This method offers a fully three-dimensional control of the nanostructure with additional capability of self-alignment. There is almost no limitation on materials that can be fabricated into desired nanostructures. In this presentation, we will discuss the current status of the glancing angle deposition technology, its potential applications, and its future challenges.

Sculptured thin films (STFs) comprise parallel bent nanowires that are 30-100 nm in diameter. Using a finite-difference algorithm, we solved the time-domain Maxwell equations to investigate the reflection of optical narrow-extent pulses from both linear and nonlinear chiral STFs. Although he axial component of the Poynting vector -- the pulse shape -- is invariant to changes of carrier wave phase in the incident pulse, we determined that the reflected pulse shape is affected by those changes.

Optical properties of metal nanowires and nanowire composite materials are studied experimentally and theoretically. We suggest that a nanowire composite, constructed from parallel pairs of nanowires has both effective magnetic permeability and dielectric permittivity negative in the visible and near-infrared spectral ranges due to resonant excitation of surface plasmon polaritons. Experimental results confirm excitation of surface plasmons polaritons in periodical array of nanowires.

A variety of novel ZnO nanostructures such as nanowires, nanowalls, hierarchical nanostructures with 6-, 4-, and 2-fold symmetries, nanobridges, nanonails have been successfully grown by a vapor transport and condensation technique. Doping both In and Sn into ZnO hierarchical nanostructures can be created. The 2-fold eutectic ZnO structures can also be created without any doping in the source. It was found that the hierarchical nanostructures can be divided into two categories: homoepitaxial and heteroepitaxial where heteroepitaxy creates the multifold nanostructures. The novel ZnO nanowalls and aligned nanowires on a-plane of sapphire substrate have also been synthesized and the photoluminescence is studied. The ZnO nanowires also demonstrated very good field emission properties, comparable to carbon nanotubes. These nanostructures may find applications in a variety of fields such as field emission, photovoltaics, transparent EMI shielding, supercapacitors, fuel cells, high strength and multifunctional nanocomposites, etc. that require not only high surface area but also structural integrity.

In the present work we investigate the influence of molecular vibrations on the tunneling of electrons through a molecule sandwiched between two metal contacts. The study is confined to the elastic scattering only, but beyond the harmonic approximation. The problem is tackled both from a classical and a quantum-mechanical point of view. The classical approach consists in the computation of the time-dependent current uctuations calculated at each step of a molecular dynamics (MD) simulation. On the other hand, the vibrational modes are treated quantum-mechanically and the tunneling current is computed as an ensemble average over the distribution of the atomic configurations obtained by a suitable approximation of the density matrix for the normal mode oscillators. We show that the lattice fluctuations modify the electron transmission. At low temperatures the quantum-mechanical treatment is necessary in order to correctly include the zero-point fluctuations. However, for temperatures higher than few hundreds Kelvin the simple harmonic approximation which leads to the phonon modes breaks because the oscillation amplitudes of the lowest energy modes become large.

Crystalline fullerine-fullerite- is a molecular crystal and therefore possesses a number of dynamical modes: librational, orientational-diffusive, tunnelling and optical in addition to the usual anisotropic translational modes. Making use of these dynamical modes a thermal neutron scattering kernel for fullerite has been developed. The total neutron scattering cross-section of thermal neutrons have been computed in the energy range 10^-4 - 0.3 eV. For inelastic scattering while one phonon and two phonon processes are sufficient, for libron exchanges as many as thirteen libron quanta exchanges have to be considered. Using the thermal neutron scattering kernel the multigroup Boltzmann transport equation has been diagonalized, to obtain its eigenvalue and corresponding eigenfunctions of a neutron pulse propagating in the medium. The variation of lowest eigenvalue with the size of the assembly is compared with the corresponding measured values in graphite and it turns out to be slower in smaller assemblies of fullerite. The time dependent thermalization of the neutron pulse, introduced in the assembly at time t=0, has also been computed. While for large assembly (B²=0.0006 /cm^-2) the high energy neutron pulse gets thermalised in about 1500 μs, it takes as long as 5000 μs for smaller assemblies ( B²=0.005 /cm^-2).

Spontaneous decay process of an excited two-level atom placed inside or outside a single-wall carbon nanotube is analyzed for both weak and strong atom-radiation-field coupling regime. In the weak coupling regime, the effect of the nanotube surface has been demonstrated to dramatically increase the spontaneous decay rate -- by 4 to 5 orders of magnitude compared with that of the same atom in vacuum. Such an increase is associated with the nonradiative decay via surface quasiparticle excitations in the nanotube. In the strong coupling regime, the decay of the upper atomic state proceeds via damped Rabi oscillations with the frequency assigned by the density of final photonic states of the system. Possible applications of the effect predicted are discussed.

The long-range charge transfer correlated with the existence of fractal nanostructure for thin Fe-containing Langmuir-Blodgett (LB) films of thiophene derivatives has been experimentally observed. Band structure of the film with hexagon crystal structure has been simulated assuming 26 carbon atoms and one(or two) Fe atom in cluster in elementar cell and validity of adiabatic approximation. The simulations display, that the energy of the structure is reduced when taking into account the ferromagnetic ordering. This leads to the stabilization of the structure. Dynamically invertible instability of band structure at changes of spin polarization is considered as appearance of photo-induced quasi-steady states of nanostructured LB-films. Temperature Green function method has been proposed to examine relativistic corrections for Fermi system which are caused by non-sphericity of atom potential in leaky packed solids. The origin of quasi-stationary modes in Dirac problem is considered for an electron in the vicinity of the ionization threshold in a strong oscillating magnetic field.

Alumina nanotemplates integrated on silicon substrate with pore diameters of 12 nm to 100 nm were prepared by galvanostatic anodization. High current density (e.g. 100 mA.cm-2) promoted a highly ordered hexagonal pore structure with fast formation rate independent of anodizing solutions, where 2000 nm/min, 1000 nm/min were achieved at current densities of 100 mA.cm^-2 and 50 mA.cm^-2, respectively. These rates were approximately two orders of magnitude greater than other reports in the literature. Different electrolytes of sulfuric acid (1.8 to 7.2 M), oxalic acid (0.3 M) and mixed solutions of sulfuric and oxalic acid were evaluated as anodizing solutions. Sulfuric acid promoted smaller pore diameter with lower porosity than mixed acids and oxalic acid. The I-V characteristics strongly depend on solution composition, temperature, and bath agitation. In the case of sulfuric acid, the breakdown voltage (U_B) varied linearly with logarithmic of sulfuric acid concentration (U_B = 24.5-11 log [H₂SO₄]) and it decreased at higher temperature. The pore diameter of silicon-integrated alumina nanotemplate varied linearly with measured voltage with a slope of 2.1 nm/V, which is slightly smaller than reported data on bulk aluminum (2.2 nm/V and 2.77 nm/V). Thermoelectric Bi₂Te₃ nanowires with diameter of 43 nm were electrodeposited.

The generation of electron drift velocity oscillations in GaAs-quantum wires with finite length at temperature T=77 K in uniform as well as nonuniform field is studied. The influence of wire length and dominant scattering processes on the amplitude, frequency and attenuation of the oscillations is investigated. The average time of electron drift in the various regions of the quantum wire is calculated.

Sculptured thin films (STFs) are nanoengineered materials with columnar morphology tailored to elicit desired optical responses upon excitation. The identical nanowires comprising a STF are oriented (nominally) parallel to each other, and possess two-- and/or three--dimensional shapes. Two canonical forms of STFs have been formalized. Linear constitutive relations for general STFs as unidirectionally nonhomogeneous (continuously or piecewise uniformly) and locally bianisotropic continuums are presented, along with a 4 x 4 matrix ordinary differential equation for wave propagation therein. A nominal model for the macroscopic properties of linear STFs has been devised from using local homogenization. Several advanced as well as emerging applications of STFs are also discussed.