Ultrasonic spray-assisted mist deposition techniques have been developed as a cost-effective and environmental friendly deposition method for oxide and organic thin films. The chemical vapor deposition (CVD) of a variety of oxide thin films having unique functions, such as Cr2O3, Cu2O, Fe3O4, and Al2O3 thin films, has been demonstrated as well as high-quality ZnO and Ga2O3 films ever reported. In addition to the films deposition by the CVD process, the deposition of organic material thin films from the source solution has also been achieved; as examples we have shown the patterned deposition of water-soluble fluorescent polymers with a metal mask. This may substitute the spin-coating technique and contribute to increase the source consumption efficiency in the thin film deposition. We appeal that the mist deposition is a unique and promising technique as a green chemical route for film deposition.

HfO2-based layers prepared by RF magnetron sputtering were studied by X-ray diffraction, infrared absorption spectroscopy and transmission electron microscopy techniques. The effect of the deposition parameters and post-deposition annealing treatment on the properties of the layers was investigated. The amorphous-crystalline transformation of pure HfO2 layers is observed to be stimulated by annealing treatment at 800 ° C. It was found that the incorporation of silicon in HfO2 matrix allows to prevent crystallization of the layers and to shift the crystallization temperature to values up to 900 °C.

Nanoparticles, nanowires, nanorods and other kinds of nanostructures have been of great interest to scientific field. Semiconducting nanowires have attracted much attention due to the fact that reduced dimensional confinement of electrons, holes and photons make them particularly attractive as potential building blocks for nanoscale optoelectronic devices, highly quantum efficient lasers and non-linear optical converters. It is generally accepted that the low dimensional structures (where the size in one direction is equivalent to or smaller than the de Broglie wavelength) are useful materials for investigating the dependence of electrical and thermal transport or mechanical properties on the dimensionality and quantum confinement. Nanomaterials also play an important role as functional units in fabricating the electromechanical devices. Semiconductor nanostructures of different materials and shapes are investigated due to their size dependent electronic properties observable at dimensions comparable to or less than Bohr radius of exciton in these materials. Especially various oxides and sulphides have generated interests in variety of applications. In this paper, the recent progress in various nanostructures, paradigms in implementation and technology hurdles in implementing nanostructures are discussed

The collinear generation of sub-4 fs ultraviolet (UV) and attosecond extreme ultraviolet (XUV) pulses via subsequent third-harmonic and high harmonic generation in noble gases is demonstrated. The ultrashort coherent light bursts are produced by focusing a sub-1.5 cycle near-infrared/visible (NIR) laser pulse in two subsequent quasi-static noble gas targets. With this simple approach, inherently synchronized UV pulsed radiation with a photon energy of ˜5 eV and a pulse energy of ˜1 μJ, and XUV pulses with a cut-off photon energy of more than 120 eV and up to ˜107 XUV photons can be generated. This source represents a novel tool for future UV pump/XUV probe experiments with unprecedented time-resolution.

Recently a collaboration of LLNL and LBNL has constructed a second generation Compton coincidence instrument to study the non-proportionality of scintillators [1]. This device, known as SLYNCI (Scintillator Light-Yield Non-proportionality Characterization Instrument), has an over 30 time higher data collection rate than previous devices enabling complete characterization of a sample with less 24 hours of running time. Thus, SLYNCI enables a number of systematic studies of scintillators as many samples can be processed in a reasonable length of time. The studies include difference in non-proportionality between different types of scintillators, different members of the same family of scintillators, and impact of different doping levels. The results of such recent studies are presented here, including a study on of various alkali halides, and the impact of europium doping level in strontium iodide. Directions of future work will also be discussed.

The mechanics of systems of non-cross-linked fiber networks is studied in this work using a computational model inspired from the bead-spring models of polymeric melts. The fibers have random orientation and distribution in space, interact via stiff repulsive potentials and are characterized by their axial and bending stiffness. Fiber-fiber Coulombian friction is considered. The system is subjected to isostatic compression (strain control) and various statistical measures are evaluated. As the system is compacted, a critical density is reached at which stiffness develops. At this stage there is in average one fiber-fiber contact per fiber and the fiber free segment length has a uniform probability distribution function. Upon further compaction, the number of contacts per fiber increases and the segment length distribution becomes exponential. The respective cross-over densities depend on the fiber length and the friction coefficient. Significant hysteresis is observed upon loading-unloading in the total energy and the number of contacts per fiber. It is also observed that the distribution of contact energies in the range of densities where the system forms a topological network is a power law.

NiO is a typical material for new p-type oxide semiconductors. Conductivity of NiO can be raised with Li+ doping. In case of Li-heavy doping, we can obtain LixNiO2(0.5< × <1.0). Recently the importance of LiNiO2 has been increased as an electrode material for rechargeable lithium cells.

In this work, we tried to fabricate a novel NiO material with Li+-heavily doped by applying the pulsed laser-induced room temperature (R.T.) film process. Previously, we have succeeded in the epitaxial growth of various oxide thin films at R.T. such as Sn-doped In2O3 transparent electrodes [1]. Although the many studies have been made on the deposition of NiO epitaxial thin film at low temperatures [2], there are few reports on fabrication and the conductive characteristic for Li-heavily doped NiO epitaxial films. The film deposition at R.T., which is the unequilibrium vapor phase process, is expected to result in different crystal structure and characteristics from the films grown at high-temperatures.

A composition-adjusted thin film of LixNi1-xO(0.10< × <0.40) was deposited on a sapphire (α-Al2O3)(0001) or MgO(100) substrates by pulsed laser deposition (PLD) technique in 10−6 Torr of oxygen at R.T. and the high temperatures of 350 and 515°C. Crystalline properties of thin films deposited at R.T. or high temperatures were examined using reflection high energy electron diffraction (RHEED) and X-ray diffraction. For the Li-heavily doped NiO films(x>0.30) grown at R.T., a clear streak RHEED pattern showing epitaxial growth was observed. But the Li-heavily doped NiO films grown at high temperatures, exhibited the ring RHEED pattern, which indicates the policrystal growth of films. Electric conductivity of various Li-doped NiO thin films deposited at R.T. or high temperatures on sapphire (0001) substrates were measured by two-probe method. The interesting results were obtained that conductivity of the film was increased remarkably with an increase of Li-doping for R.T. deposition, but was not changed so much regardless of Li-doping for high-temperature depositions.

Nanocrystalline silicon microwires are self-heated through microsecond voltage pulses. Nonlinear changes in current level are observed during the voltage pulse, which end with melting of the microwires. Liquid silicon resistivity is extracted as 65.9 ± 6.1 μΩ.cm from the minimum resistance of the wire during the voltage pulse. The extracted resistivity is in good agreement with previously reported values.

We study the optical gain for various doping concentrations in a dye doped polymer (poly-[9,9-dioctylfluorene] with 6,6'-[2,2'-octyloxy-1,1'-binaphthyl] spacer groups (BN-PFO) doped by the stilbene dye 1,4-bis[2-[4-[N,N-di[p-tolyl]amino]phenyl]vinyl-benzene] (DPAVB)). In such a guest-host-system (GHS) the occupation of the upper laser level (dopant site) is due to Förster energy transfer (FET), which strongly depends on the donor acceptor distance and hence on the concentration of the laser dye. Therefore, the doping concentration is varied over a wide range and the gain coefficients are measured at various excitation densities to analyze the stimulated emission cross section.

For the investigated GHS maximum gain coefficients up to ∼340 1/cm were found at absorbed pump energy densities of around 50 μJ/cm2. It will be shown that the stimulated emission cross section (σ = 1.8 × 10−16 cm2) is concentration independent which is quite different to a recently investigated small molecule based GHS. These effects will be discussed considering the rate and exciton diffusion constants.

Mesoporous silica materials have received much interest due to commercial applications in chemical separations and heterogeneous catalysis. Recent studies have reported via a sol-gel nanocasting technique, monolithic mesoporous silica with wormlike pore framework could be prepared by utilizing room-temperature ionic liquids (RTILs) as templates and solvents. Although previous reports have indicated that the wormlike pores would be formed in the silica, the detailed pore network structure still remained the crucial issues to be resolved. In the present study, we investigated the pore structure in the monolithic mesoporous silica, which was templated by RTIL (1-butyl-3-methyl-imidazolium-tetrafluoroborate). We revealed an open fractal pore network with a branched and self-similar appearance was formed by the aggregation of the individual spherical pores. Transmission electron microscopy micrographs displayed that the disordered wormlike pore framework was formed in the silica. Furthermore, the small angle X-ray scattering profile measured herein further exhibited three distinct regions of power-law scattering on the respective length scales. In the high-q region, the profile followed Power behavior and a power-law of -4 was observed for the surface fractal dimension of 2, manifesting the primary pore with a smooth surface and a spherical appearance. In the intermediate-q region, a power-law of -2.5 (mass fractal dimension of 2.5), indicating an open mass fractal network was formed by the aggregation of the individual primary pores. Moreover in the low-q region, the power-law of -4 was observed for mass-fractal agglomerates of aggregates. With the proceeding analysis of unified equation in terms of two structural levels, the radiuses of gyration of primary pore (Rg1)and its aggregates (Rg2) were fitted as ca. 0.9 nm and 5.5 nm, respectively. For a spherical-model pore, the radius of pore (R) was ca. 1.16 nm; thus, the averaged pore diameter (D) was 2.32 nm. The number of primary pores in a fractal aggregate (degree of aggregation, z) was calculated as ca. 67.

Single δ-layers of dispersed silver (Ag) nanoparticles are obtained by low-energy ion beam implantation in a silica thin film. TEM microscopy reveals that the obtained Ag particles are spherical, crystalline, and the particles layer is located at only few nanometers below the free silica surface. We use reflectivity measurements to probe the optical/plasmonic response of the fabricated structures and exploit plasmon resonance and optical interference effects in the silica film to record the Raman scattering by quadrupolar vibrations of the spherical particles.

We have been developing noble metal nanoparticles and nanocomposites for large scale application to glass surfaces. The novel functionality of the nanocomposites is attributed to the properties of both the metal nanoparticles and host matrix. Here a single-process route to nanocomposite thin films by spray deposition technique has been investigated. Preformed gold nanoparticles have been incorporated into several different transition metal oxides (TiO2, SnO2, ZnO). The nanocomposite films showed intense coloration due to the surface plasmon resonance effects of gold nanoparticles embedded in the host matrix. The gold nanoparticles were found well embedded into the host metal oxides homogeneously. This film deposition method can easily be scaled up and is compatible with current industrial on-line processes.

Carbon nanomaterials especially ultrananocrystalline diamond and nanocrystalline diamond films have attracted more and more interest due to their unique electrical, optical and mechanical properties, which make them widely used for different applications (e.g. MEMS devices, lateral field emission diodes, biosensors and thermoelectrics). Nanocrystalline diamond can also offer novel advantages for drug delivery development. Recent studies have begun to use nanocrystalline diamond for in-vivo molecular imaging and bio-labeling. To enable grafting of complex bio-molecules (e.g. DNA) the surface of ND requires specific fictionalization (e.g. H, OH, COOH & NH2). Due to the surface dipoles of functionalised nanodiamond band bending at the surface can be easily induced and from the measured band bending we can deduce the type of the fictionalization on the surface. The surface potential of H-terminated and OH terminated nanodiamond layers was investigated by Kelvin probe microscope. From the change of the surface potential value (as the departure of the material surface from the state of electrical neutrality is reflected in the energy band bending) the work function of the H-terminated nanodiamond layer was established to be lower than OH-terminated nanodiamond layer. The surface potential difference can be explained by the surface dipole induced by the electro-negativity difference between the termination atoms.

The effect of film thickness on the electrical resistivity of heavily-nitrogen-doped polycrystalline SiC (poly-SiC) thin films is investigated. The resistivity of poly-SiC thin films decreases by a factor of ˜7 for thickness increasing from 100 nm-thick to 1.78 μm-thick; the resistivity begins to stabilize as thickness approaches 1 μm. The increased resistivity for the thinner films is shown to be related to the grain boundary effect. Secondary ion mass spectrometry indicates a nitrogen concentration of 9×1020 atoms/cm3 in the films. However, Hall measurements reveal that only 45% of the dopants are electrically active in the 100 nm-thick film. The percentage of active dopants rises to 80% when film thickness increases to 680 nm. From the studies of surface roughness and microstructure, it is seen that small grains are formed at the initial stage of deposition, which then grow into larger columnar grains as film thickness increases. The presence of a large density of grain boundaries and limited grain growth for the very thin films contribute to increased electrical resistivity from increased trapped mobile carriers and reduced carrier mobility. The free carrier trapping phenomenon can further be observed in the temperature-dependence of resistance measurement.

We have investigated the effects of hydrogen plasma treatment on the hysteresis phenomenon and electrical properties of solid phase crystallized silicon thin film transistors (SPC-Si TFTs) employing alternating magnetic field crystallization (AMFC). We employed H2 plasma treatment on the SPC-Si active layer before SiO2 gate insulator deposition. By increasng the power and time duration of H2 plasma treatment, it was observed that hysteresis phenomenon of SPC-Si TFT was suppressed and electrical properties such as threshold voltage, field effect mobility was improved considerably. This is due to role of hydrogen atom by passivating the defects and grain boundary trap states in SPC-Si film. However, relatively high power and long hydrogen plasma treatment (100W, 5 minutes) could degrade the electrical characteristics of the device. SPC-Si TFT for 100W power of PECVD and 3 minutes with the H2 plasma treatment exhibit the significant improvement of electrical characterics (VTH = - 3.85V, μFE = 21.16cm2/Vs), and a smaller hysteresis phenomenon (∆VTH = -0.30V) which is suitable for high quality AMOLED Display.

Epitaxial Ge2Sb2Te5 has been successfully grown on GaSb(001) by molecular beam epitaxy. The films show a tendency for void formation and rough morphology, but at the same time a very strong epitaxial orientation, cubic structure and a sharp interface to the substrate. The layers can be reversibly switched between the crystalline and amorphous phases using short laser pulses.

This paper presents results for infrared transparent and conducting thin films based on In2O3. The films have been prepared by magnetrons sputtering equipment with different condition. Typical transmittance of 70%-80% with a film sheet resistance of 80-300Ω/□ in the 3.5-5.0μrn region has been achieved.

Optically transparent and electrically conductive semiconductor Oxide films have been extensively studied in recent years. Such films have been prepared by various methods. In general, these films have high visible transmittance, but are opaque in the IR wavelength range of 1-12μm IR transmission. The infrared transparent and electrically conductive thin films are useful in certain important applications. For example, these films can be use as antistatic coatings, and while permitting a reasonable transmission coefficient for IR. Another obvious application is to serve as the conducting electrode for various optical devices where good infrared transmission is important. So, it is important to research indium oxide base infrared (3-5 um) transparent conduction thin films.

It has been developed that preparation condition influence on properties of thin films. Such as the sputtering time, and pressure, and power, and the substrate temperature, had great influence on the crystal structure, optical and electrical properties of In2O3-based thin films.

The In2O3-based thin films obtained were characterized and analyzed by X-ray Diffractometer (XRD), Atomic Force Microscope (AFM), Vander Pauw Method and Fourier Transform Infrared Spectroscopy (FTIR).

Simple cycloalkylsilanetriols RSi(OH)3 [R =c- pentyl (1</b>) and c-hexenyl (2b</b>)] were synthesized as white powders in 70% and 90% isolated yields, respectively, from the hydrolysis of the corresponding trialkoxysilanes with mild acidic water. Silanetriols 1</b>,2</b> are soluble in water and polar organic solvents such as alcohol, acetone, THF, DMSO, and etc. They can be applied as surface modifiers for inorganic materials such as silica and titania through simple two step processes: 1) organosilanetriol interact with hydroxyl groups on inorganic materials through hydrogen bonding to make molecular layered thin coating on the inorganic surface, 2) then can undergo condensation by heating about 110 ℃ above to form M-O-Si covalent bond to give hydrophobic silica. With the treatment of ca. 50 nm spherical silica with 5 wt % alkylsilaneol 1, no precipitation of silica particles in water was observed, indicating good surface modifiers for silica particle. In this presentation we will discuss the application of silanetriols as surface modifier for inorganic materials such as silica and titania particles.

We report the first studies of electroabsorption in Cu(InGa)Se2 (CIGS) solar cell devices. We utilized a bifacial CIGS device with a Ga/(In+Ga) ratio of 0.8 (bandgap of 1.5 eV) deposited onto semi-transparent (40 nm thick) Mo coated glass as the back contact. By modulating the electric field using a small sinusoidal potential of amplitude δV across the CIGS layer, we were able to detect the modulation ΔT of the transmitted light. This was examined as a function of photon energy, DC bias, temperature, and modulation frequency (100 Hz to 10 kHz) and had a maximum amplitude of ΔT/T ≈ 10−5 for δV = 0.3 V. Very different characteristics were obtained for near bandgap light (1.3 eV) compared to photon energies considerable smaller (<0.95 eV). While the latter exhibited a strong temperature and frequency dependence, indicating an important role for deep defects in the effect, the former exhibited very little change with temperature or frequency, indicating the predominance of transitions involving bandtail states. Different metastable states of the CIGS layer produced by prolonged light soaking above the bandgap energy were also examined.