This PDF file contains the front matter associated with SPIE Proceedings Volume 7030, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

There has been significant interest in the development of multicomponent nanocrystals formed by the assembly of two or more different materials with control over size, shape, composition, and spatial orientation. In particular, the selective growth of metals on the tips of semiconductor nanorods and wires can act to couple the electrical and optical properties of semiconductors with the unique properties of various metals. Here, we outline our progress on the solution-phase synthesis of metal-semiconductor heterojunctions formed by the growth of Au, Pt, or other binary catalytic metal systems on Cd- and Pb-calcogenide nanocrystals.

Silica xerogels doped with Ge(IV), substituting for Si(IV) in the oxide network, are prepared from tetraethylorthosilicate and germanium-tetraethoxide. The sintering process is carried out in reducing atmosphere at 700 - 900° C by reaction with H₂. Raman spectroscopy and high resolution transmission electron microscopy (TEM) show that reactions with H₂ give rise, in the porous silica network, to uncontrolled islands of crystallites of elemental cubic germanium with average size of 50 nm. Sintering process in reducing H₂ atmosphere at temperatures just below the phase separation, at about 610°C, gives materials where Ge atoms are dispersed in the matrix in conditions of incipient clustering. Evidences of segregation of germanium nanocrystals are observed with electron irradiation during TEM analysis. Furthermore, the electron beam induced precipitation leads to the formation of isolated quantum dots-like nanocrystals (5-6 nm in diameter) and with narrower size dispersion. The ranges of suitable temperature and germanium concentration are analysed, as well as the size dispersion of the resulting Ge nanophases.

The present investigators have previously reported on strong room-temperature luminescence at 1540 nm from erbium-doped amorphous silicon oxycarbide (a-SiC_xO_y:Er) thin films. An enhancement of ~20 times was found for asgrown SiC_0.5O_1.0:Er compared to SiO₂:Er control samples under continuous wavelength (cw) pumping at 496.5 nm. Here, we report the effects of post-deposition annealing on the photoluminescence (PL) properties of Er-doped silicon oxycarbide. The amorphous SiC_xO_y films were grown by thermal chemical vapor deposition (TCVD) at 800°C and postdeposition annealing was conducted in the temperature range 500-1100°C. The thin films were then implanted with 260keV Er ions and subsequently annealed at 900°C. Strong room-temperature photoluminescence around 1540 nm was observed, with efficient Er⁺³ ion excitation occurring for pumping wavelengths ranging from 460 nm to 600 nm. Modeling of the power dependence of Er luminescence yielded an effective Er excitation cross-section about four orders of magnitude larger than that for a direct optical excitation of Er⁺³ ions. Additionally, Fourier transform infrared spectroscopy (FTIR) studies of post-deposition annealed samples revealed a strong correlation between the Er PL intensity and the C-O bond concentration in the materials. The work suggests a novel method for achieving efficient Er luminescence in Si-based materials through controlled engineering of the Si-C-O system.

A sol-gel method was successfully used to synthesize Y₂O₃-MgO composite powder with a grain size below 30nm. Results from X-ray diffraction revealed how the microstructure evolved with increasing heat treating temperature. Taking advantage of high heating rate, spark plasma sintering (SPS) technique was used to sinter the nanopowder, resulting in a fully dense nanocomposite with grain size below 100nm. The transmittance can be enhanced by optimizing sintering parameters as well as appropriate post-sinter annealing. The fully consolidated nanocomposite exhibits an optical transmittance between 75% and 84% over infrared wavelength range between 3μm and 6μm. This kind of nanocomposite has a great potential to be used as infrared transparent material.

Frequency Selective Surfaces (FSS) are comprised of periodic, geometric, metallic patterns that act like an array of horizontal antennas. They were originally designed as band-pass/band-block filters. Nanofabrication techniques allow for the realization of FSS structures that operate in the near infrared (NIR) and visible portions of the electromagnetic spectrum. Thus it is possible to create arrays of light antenna filters possessing optical properties that are unlike those of dye, dielectric, or holographic filters that are in common use today. Recent studies of arrays of gold, dipole nanoantennas by our group and others offer an opportunity to compare modeled FSS response with experimental results elucidating the unique, off-normal reflectance stability of frequency selective surfaces operating in the NIR/visible portion of the spectrum.

Metal oxide nanoparticles can be used in thin film polymer systems to engineer specific material properties while maintaining visible transparency. High loadings of nanoparticles in a polymer can manipulate refractive index, modulus, and UV absorption over a wide range. Because the polymer binders can be allowed to dominate the physical properties, these systems are ideal where materials undergo large strains. While stable dispersions of sub-100nm diameter CeO2, ZnO, and SiO2 are well understood and commercially available, our group also developed a stable dispersion of TiO2 nanoparticles. These metal oxides are significantly harder than the host polymer, have high UV absorption, and cover a large refractive index range. Our group has successfully incorporated these materials into PMMA thin films with loadings up to 60% by volume (approaching the theoretical close packing of spheres). These thin film nanocomposites have been successfully incorporated into 30 layer, sharp cut optical filters that easily withstand large strains induced by mechanical loading and thermal cycling. In these films we have adhered to the rule that nanoparticle diameter should be one-tenth the wavelength of visible light. As the thickness of the overall filter stack increases, light scattering is intensified, so the dimensions and refractive indices of the nanoparticles become critical for highly transparent systems. We study here the interactions of particle dimensions, refractive index, loading, thickness, and transparency in nanocomposites.

Semiconductor colloidal quantum dots have been, for the past two decades, incorporated in a wide range of applications from catalysis and optical sensors to biolabels. For this reason, simple, cheap and reproducible routes of synthesis are the main goal of many research groups around the world. They seek the production of a very stable and extremely quantum efficient nanocrystal that can afford rough changes in the external environment. Silica capping is becoming a very common tool in the quest for a stable quantum dot, because of its strong and stable structure, this material provides a great insulator to the nanocrystal from the outside. The nanocrystal surface is not chemically favorable to the deposition of the bare silica shell, what demands a bifunctional molecule that provides the linkage between the core and the shell. In this work we present a comparison between several silanization methods of thiol capped CdSe and CdTe quantum dots, showing some simplifications of the routes and an application of the quantum dots produced as fluorescent cell markers in acquisition of confocal microscopy images.

Metallic nanoparticles embedded in dielectrics permit enhanced capture absorption and/or scattering of light at specific wavelengths through excitation of plasmons, i.e. the quanta of coherent and collective oscillations of large concentrations of nearly free electrons. In order to maximize the potential of such enhanced absorption in useful tasks, such as the generation of carriers in photocatalysts and semiconductors, it is important to be able to predict and design plasmonic nanocomposites with desired wavelength-dependent optical absorption. Recently, a mixing approach formulated by Garcia and co-workers [Phys. Rev. B, 75, 045439 (2007)] has been successfully applied to model the experimentally measured broadband optical absorption for ternary nanocomposites containing alloys or mixtures of two metals (from Ag, Au or Cu) in SiO₂ dielectric. In this work we present the broadband optical behavior of an important an optical coating dielectric, Si₃N₄, containing various configuration of nanoparticles of Al, Au, Ag, or Cu. The spectral behavior of various combinations of the metallic species in the dielectrics was optimized to show either broadband solar absorption or strong multiple plasmonic absorption peaks. The applications of such nanocomposite materials in solar energy harvesting and spectral sensing are also presented and discussed.

Stimulated emission depletion (STED) and single molecule fluorescence correlation spectroscopy (FCS) are used to determine stimulated emission cross-sections and investigate non-radiative relaxation in a branched quadrupolar chromophore (OM77). The results are used as inputs to simulations of single molecule STED by which the feasibility of STED control of the single molecule fluorescence cycle can be assessed. Single molecule STED in OM77 is shown to be readily achievable; however its effectiveness in reducing triplet trapping is apparently mediated by fast non-radiative relaxation processes other than intersystem crossing and rapid quenching of the triplet state in a non-deoxygenated environment.

The wide band gap and unique photoluminescence (PL) spectrum of nanocrystalline zinc oxide (nano-ZnO) make it attractive for a variety of photonics and sensor applications. Toward the goal of modifying the electronic structure and optical properties of nano-ZnO, the adsorption of 3-mercaptopropyltriethoxysilane (MPTES) has been investigated. Nano-ZnO rods having widths of 10-20 nm and lengths of 100-300 nm were functionalized by ultrasonicating them in a hot ethanol/water solution and adding MPTES. FTIR and X-ray photoelectron spectroscopy (XPS) of the modified nano- ZnO confirm silane functionalization. The presence of hydroxyl groups prior to functionalization suggests that adsorption to ZnO occurs primarily via a condensation reaction and the formation of Zn-O-Si bonds. Comparison has been made to 3-mercaptopropyltrimethoxysilane (MPTMS) adsorbed in ultrahigh vacuum onto sputter-cleaned single crystal ZnO(0001) in which MPTMS vapor is leaked into the vacuum chamber. In this case, bonding occurs via the thiol groups, as indicated by angle-resolved XPS studies. Similar experiments in which sputter-cleaned ZnO(0001) is dosed with dodecanethiol (DDT) confirm adsorption via S-Zn bond formation. Photoluminescence measurements of MPTES-functionalized nano-ZnO show an increase in intensity of the UV emission peak and a decrease in the visible peak relative to the unfunctionalized particles. The reduction of the visible emission peak is believed to be due to passivation of surface defects.

We present a new formulation of the Finite Element Method (FEM) dedicated to the 2D rigorous solving of Maxwell equations adapted to the calculation of the diffracted field in optoelectronic subwavelength structures. The advantage of this method is that its implementation remains independent of the number of layers in the structure, of the number of diffractive patterns, of the geometry of the diffractive object and of the properties of the materials. The spectral response of large test photodiodes that can legitimately be represented in 2D has been measured on a dedicated optical bench and confronted to the theory. The representativeness of the model as well as the possibility of conceiving this way simply processable diffractive spectral filters are discussed.

CdSe and ZnS core-shell nanoparticles made by LAM (Laser Ablation of Microparticles) show photoluminesence (PL) peaks in a region of wavelengths around 400 nm. Control over the size and PL peak position is obtained by irradiating the nanoparticles multiple times. In LAM, micropaticle powder passes through an aerosol generator and then into a laser ablation glass cell, where a laser pulse (high energy excimer laser) ablates the microparticle aerosol. Nanoparticles are formed after condensation. At this stage the nanoparticles can be covered with a second material or irradiated multiple times to change their size. The size distribution of these particles is successfully investigated with TEM (Transmission Electron Microscopy). PL blue shifts are seen as the mean size decreases.

This study focuses on ultraviolet cross-link process using spin-coating materials for advanced planarization and sublimate defect reduction in the advanced process techniques of semiconductor, display, and new electronic devises. The ultraviolet cross-link process and spin-coating material have been optimized and studied for excellent global planarization property. The newest approach by excellent collaborations from both process and material has the planarization property on an irregular substrate such as the patterned steps, holes and trenches to increase the depth of focus and pattering resolution. After planarizing the substrate surface, the ultraviolet planar materials are used to provide the dry or wet etching selectivities against the under-layer, and specially, avoid the dry or wet etching damage as an etch protecting layer. In addition, we reported the newest process using developed ultraviolet irradiation tool on in-line system in an coater equipment (TOKYO ELECTRON LTD CLEAN TRACK^TM) for manufactability with higher throughput (Spin-coating time: less than 30 sec., ultraviolet irradiation time: less than 5 sec, low temperature baking time: less than 60 sec.) Using this technique, a remarkable reduction in via topography with 1.1 μm as a depth and 0.9-1.0 μm as a diameter has been achieved excellent thickness bias less than 20 nm. And, the sublimate amount of the film obtained from the developed ultraviolet planar material was very low as compared with that of the film obtained from current standard thermal cross-link material as the reference.

Sonoluminescence (SL) involves the conversion of mechanical [ultra]sound energy into light. Whilst the phenomenon is invariably inefficient, typically converting just 10^-4 of the incident acoustic energy into photons, it is nonetheless extraordinary, as the resultant energy density of the emergent photons exceeds that of the ultrasonic driving field by a factor of some 10¹². Sonoluminescence has specific [as yet untapped] advantages in that it can be effected at remote locations in an essentially wireless format. The only [usual] requirement is energy transduction via the violent oscillation of microscopic bubbles within the propagating medium. The dependence of sonoluminescent output on the generating sound field's parameters, such as pulse duration, duty cycle, and position within the field, have been observed and measured previously, and several relevant aspects are discussed presently. We also extrapolate the logic from a recently published analysis relating to the ensuing dynamics of bubble 'clouds' that have been stimulated by ultrasound. Here, the intention was to develop a relevant [yet computationally simplistic] model that captured the essential physical qualities expected from real sonoluminescent microbubble clouds. We focused on the inferred temporal characteristics of SL light output from a population of such bubbles, subjected to intermediate [0.5-2MPa] ultrasonic pressures. Finally, whilst direct applications for sonoluminescent light output are thought unlikely in the main, we proceed to frame the state-of-the- art against several presently existing technologies that could form adjunct approaches with distinct potential for enhancing present sonoluminescent light output that may prove useful in real world [biomedical] applications.

Self-assembled interfaces in nanoscale structure made of metal; oxides and mixed composites have drawn a lot of attention due to its application in from photonics to sensor application. Here we report that for low melting point metals like aluminum, can self-assembly into well separated nanodots even with very high thickness (<150nm) when interface in driven close to their melting point. When electrochemical oxidized the stress causes discrete cross plastic slip without continuous deformation and forms stepped porous oxide nanostructure. The process is a very efficient way to make large-scale oxide or composite nanostructure for wide variety of application ranging from efficient solar cell to photonic devices.

We studied nonlinear absorption of three kinds of porphyrin covalently functionalized SWNTs using Z-scan technique with nanosecond pulses at 440 nm, 460nm, 480nm, 500nm, and 532nm. The large enhancement of nonlinear absorption in porphyrin covalently functionalized SWNTs were found at 532 nm. This nonlinear behavior of SWNTs has been shown to arise from strong nonlinear scattering, and porphyrin exhibits strong reverse saturable absorption at 532 nm. The porphyrins covalently functionalized SWNTs offer superior performance to the individual SWNTs and porphyrins by combination of nonlinear mechanism and the photoinduced electron or energy transfer between porphyrin moiety and SWNTs.

Using transfer matrix method transmission spectra for the layered ordered structures of (Si/a - SiO₂)_m with defect were investigated as in constant inductivity as with the account of dispersion of refraction index. It was found that the account of the refraction index in silicon has a relatively weak effect on position of the stop-bands in the considered photon-crystalline but considerably changes location and the value of peaks in the transmission spectrum connected with the presence of defect in the structure. Moreover, the propagation of electromagnetic waves through one-dimensional defect photon-crystalline structure was investigated by numeric solution of Maxwell equations by the FDTD method. The cases of transmitted wave and spontaneous emission were simulated. Localization of electrons and photons in the defect ordered structures were shown to be explicitly different.

In recent years the application of nano-porous templates, such as anodic alumina and PTFE, in the production of cylindrical nanostructures has been vast. In our work we used porous alumina membranes to produce luminescent nanowires from polystyrene and silica. The silica wires were fabricated by infiltration of a TEOS derived sol-gel into 200 nm diameter porous alumina membranes with vacuum assistance followed by annealing at 400 °C. Polystyrene luminescent, magnetic nanowires have been fabricated using a similar technique. The wires were studied by optical, confocal and transmission electron microscopy. Silica nanowires demonstrated a broad luminescence spectrum due to interstitial carbon defect emission. Polystyrene nanowires have demonstrated strong emission and interesting magnetic behaviour. Both polystyrene and silica maghemite loaded nanowires show alignment to an external magnetic field. We believe that these silica and polystyrene nanowires might find potential applications in photonics, bio-sensing and biological imaging.