ZnO nanostructures have proven to be versatile functional materials with promising electronic, piezoelectric and optical properties. Here, we report on the application of (CdSe) ZnS Core Shell quantum dots decorated ZnO Nanowires (ZnONWs) and Nanobelts (NBs) in solar energy harvesting. Results indicate that both as grown and decorated ZnO Nanostructures are photoactive, have a fast response time and generate photocurrent under excitation in a photoelectrochemical cell setup. An order of magnitude enhancement in the photocurrent response of (CdSe) ZnS Core Shell quantum dots decorated ZnONBs is seen as compared to response from as grown ZnONBs. Generated photocurrent decreases with time but stabilizes at higher value for (CdSe) ZnS Core Shell quantum dots coated ZnONBs. Detailed performances of these devices are discussed.

Recent advances in fabricating controlled-morphology vertically aligned carbon nanotube (VA-CNTs) with ultrahigh volume fraction create unique opportunities for markedly improving the electromechanical performance of ionic polymer conductor network composite actuators (IPCNCs). Actuator experiments show that the continuous paths through inter-VA-CNT channels and low electrical conduction resistance due to the continuous CNTs in the composite electrodes of the IPCNC lead to fast ion transport and actuation speed (>10% strain/second). One critical issue in developing advanced actuator materials is how to suppress or eliminate unwanted strains generated under electric stimulation, which reduce the actuation efficiency and also the actuation strains. We observe that the VA-CNTs in the composite electrodes yields non-isotropic elastic modulus that suppresses the unwanted strain and markedly enhances the actuation strain (>8% strain under 4 volts). A transmission line model has been developed to understand the electrical properties of the actuator device.

Staggered bottom-gate hydrogenated nanocrystalline silicon (nc-Si:H) thin-film transistors (TFTs) were demonstrated on flexible colorless polyimide substrates. The dc and ac bias-stress stability of these TFTs were investigated with and without mechanical tensile stress applied in parallel to the current flow direction. The findings indicate that the threshold voltage shift caused by an ac gate-bias stress was smaller compared to that caused by a dc gate-bias stress. Frequency dependence of threshold voltage shift was pronounced in the negative gate-bias stress experiments. Compared to TFTs under pure electrical gate-bias stressing, the stability of the nc-Si:H TFTs degrades further when the mechanical tensile strain is applied together with an electrical gate-bias stress.

Double-shelled nanotubes composed of inner shell Pb(Zr0.52Ti0.48)O3 (PZT) and outer shell TiO2 are successfully fabricated by a spin coating of each sol-gel solution on porous anodic alumina template. Field emission transmission electron microscopy images show that they have a ~ 10 nm wall thickness. The selected area electron diffraction patterns show that they have two mixed crystalline phases of tetragonal PZT and anatase TiO2. The analyses of scanning transmission electron microscopy equipped with energy dispersive X-ray spectroscopy confirm their uniform distribution of each element.

We have demonstrated and studied polymeric solid-state dye lasers (SSDLs) fabricated by three-dimensional (3D) polystyrene colloidal crystals and tert-butyl roadamine B (t-Bu RhB) doped Poly (methyl methacrylate) (PMMA) films with different film thickness. The sandwich-typed resonator cavities with different active layer thickness display single-mode lasing oscillations in the reflection bandgap of the colloidal crystals. The lasing thresholds could be optimized by changing the thickness of t-Bu RhB doped PMMA films, which is as low as 7.43 W/cm2. Adjusting active layer thickness would provide an opportunity to accelerate the development of fabricating polymeric SSDLs with low threshold.

Electrochromics is a key “green” technology for massive energy savings in the built environment jointly with indoor comfort. This paper surveys basic electrochromic (EC) device designs, useful oxide materials and their nanostructures, and elements of a theoretical description of the EC phenomenon. It also outlines critical manufacturing technologies and their pros and cons. Focus is on EC foil technology, which is shown capable of mass fabrication via roll-to-roll web coating and continuous lamination.

Electrophoretic displays, the rewritable non-light-emitting display technology based on the movement of colored pigments inside a low dielectric liquid as a voltage is applied, have attracted a great deal of academic and commercial interests due to the combination of the advantages of both electronic displays and conventional paper, including paper-like high contrast appearance, ultra-low power consumption, thinness, flexibility etc. Fabrication of electrophoretic ink by microencapsulating the electrophoretic suspension into individual microcapsules is one way to realize such application. However, there are still some limitations for its commercial application, such as the dispersion and the electrophoretic mobility of charged particles due to the nano-particles aggregation, the barrier property and stability of microcapsule wall due to the suspension releasing, etc. In this presentation, systematic studies on the preparation of electrophoretic particles and microencapsulation by complex coacervation method were carried out to solve the mentioned problems. The obtained microcapsules can be quasi-monolayer coated on ITO/PET substrate and driven by static mode to obtain a matrix character display prototype.

Mineralized biological materials such as nacre and bone achieve remarkablecombinations of stiffness and toughness through staggered arrangements ofstiff components bonded by softer materials. These natural composites aretherefore substantial source of inspiration for emerging syntheticmaterials. In order to gain new insights into structureperformancerelationships of these staggered structures, nacres from four species werecompared in terms of fracture toughness and damage propagation pattern.Fracture tests revealed that all nacres display rising crack resistancecurves, but to different extents. Using in-situ optical and atomic forcemicroscopy, two distinct patterns of damage propagation were identified incolumnar and sheet nacre respectively. These two different patterns werefurther confirmed by means of large scale numerical models of staggeredstructures. Similar mechanisms possibly operate at the smallest scales ofthe microstructure of bone.

High-quality InGaN/GaN multiple quantum wells (MQWs) were fabricated on nano-scale epitaxial lateral overgrown (NELO) GaN layers which was prepared using nanometer-scale SiO2 islands, with an average diameter and interdistance of 300nm and 200nm respectively, as the growth mask. The active region of the device consists of five periods of GaN/InGaN MQWs were grown on top of the NELO layer using MOCVD technique. It is observed that some of the dislocations from the undoped GaN were blocked by the SiO2 growth mask and typical threading dislocation (TD) density found in the NELO samples is ~7.5×107cm-2. Significant improvement in the electroluminescence (EL) is observed which is believed to partly arise from the improvement in the internal quantum efficiency (ηi ). The experimental data on the temperature dependence of the photoluminescence (PL) were fitted to a proposed model using Levenberg-Marquardt approximation. Based on our analyses it is found that the relative improvement in ηi at 300K over a control device grown in the same growth condition but without the NELO layer to a NELO device is only 0.59. It is generally accepted that TD is the non-radiative recombination center which affects the IQE. Therefore, room-temperature IQE values also support that NELO device exhibits lower TD density.

Studies of the electronic transport properties of n-type doped hydrogenated amorphous/nanocrystalline silicon (a/nc-Si:H) films deposited in a dual-plasma co-deposition reactor are described. For these doped a/nc-Si:H, the conductivity increases monotonically for increasing crystal fractions up to 60% and displays marked deviations from a simple thermally activated temperature dependence. Analysis of the temperature dependence of the activation energy for these films finds that the dark conductivity is best described by a power-law temperature dependence, σ = σo (T/To)n where n = 1 – 4, suggesting multiphonon hopping as the main transport mechanism. These results suggest that electronic transport in mixed-phase films occurs through the a-Si:H matrix at lower nanocrystal concentrations and shifts to hopping conduction between clusters of nanocrystals at higher nanocrystal densities.

In recent years, an increase in usage of methane gas in household and automobile industry has been observed. Detection of methane is always a great cause of concern for safety at home or automobile industries, productions in mines and chemical factories. This paper reports the response characteristics of rf-sputtered SnO2 thin films (90 nm thin) loaded with nanoscale catalytic clusters for detection of methane. Ultrathin (8 nm) metal and metal-oxide catalysts (Pt, Ag, Ni, Pd, Au, NiO, Au2O3) clusters are loaded over the surface SnO2 thin film. The SnO2-Pd cluster structure is found to exhibit an enhanced response (97.2%) for 200 ppm of methane at a relatively low operating temperature (220oC). The enhanced response is shown to be primarily due to the dominant roles played by both Fermi level energy control mechanism and spillover mechanism.

The relation between chemical potential and Seebeck coefficient was investigated by using high-resolution angle resolved photoemission spectroscopy. The temperature dependence of chemical potential was experimentally determined for the n-type TiS2 thermoelectric material and compared with the measured Seebeck coefficient. We found that the temperature dependence of chemical potential of TiS2 is significantly large, and its effect on Seebeck coefficient is not negligible. This fact strongly indicates that the temperature dependence of chemical potential has to be properly understood to construct the guiding principle for developing new, practical thermoelectric materials.

Lower absorption, lower refractive index and tunable resistance are three advantages of doped silicon oxide containing nanocrystalline silicon grains (nc-SiOx) compared to doped microcrystalline silicon, for the use as p- and n-type layers in thin-film silicon solar cells. In this study we show how optical, electrical and microstructural properties of nc-SiOx layers depend on precursor gas ratios and we propose a growth model to explain the phase separation in such films into Si-rich and O-rich regions as visualized by energy-filtered transmission electron microscopy.

In this work, NiSx was deposited on FTO by chemical bath and worked as the inner layer in order to enhance the photocurrent of CdS film. It is found the unannealed CdS/NiSx had a higher photocurrent than unannealed CdS, but after annealing, the photocurrent of CdS/NiSx showed dramatical decrease. The mechanism was discussed in detail by UPS and current-potential curves.

The heterogeneous integration of III-V semiconductors with the Si platform is expected to provide high performance CMOS logic for future technology nodes because of high electron mobility and low electron effective mass in III-V semiconductors. However, there are many technology issues to be addressed for integrating III-V MOSFETs on the Si platform as follow; high-quality MOS interface formation, low resistivity source/drain formation, and high-quality III-V film formation on Si substrates. In this paper, we present several possible solutions for the above critical issues of III-V MOSFETs on the Si platform. In addition, we present the III-V CMOS photonics platform on which III-V MOSFETs and III-V photonics can be monolithically integrated for ultra-large scale electric-optic integrated circuits.

In this work we demonstrate that the application of shear to a disordered lyoptropic liquid phase formed by a biological lipid, monoolein formed in water and butanediol results in the formation of an aligned lamellar phase. Furthermore we show that if shear is applied to this disordered phase in the presence of additional water, an highly oriented inverse bicontinous cubic phase is created. We suggest that these two phase may have applications as biological models, as templates for nanostructured materials and in improved protein crystallization techniques.

In this contribution, we present an effective strategy for assembling and integrating functional, in situ formed micro- and nanosized structures. Microfluidic platforms are employed to form anisotropic hybrid structures and coordination polymers at the interface of two precursor streams. Microstamps, embedded in the microfluidic device and actuated by pressure, provide a facile and reliable technology for structure trapping, localization and integration.

This paper reports on new experimental findings and conclusions regarding the pulsed-laser-induced melting-and-solidification behavior of PECVD a-Si films. The experimental findings reveal that, within the partial-melting regime, these a-Si films can melt and solidify in ways that are distinct from, and more complex than, those encountered in microcrystalline-cluster-rich LPCVD a-Si films. Specifically (1) spatially dispersed and temporally stochastic nucleation of crystalline solids occurring relatively effectively at the moving liquid-amorphous interface, (2) very defective crystal growth that leads to the formation of fine-grained Si proceeding, at least initially after the nucleation, at a sufficiently rapidly moving crystal solidification front, and (3) the propensity for local preferential remelting of the defective regions and grain boundaries (while the beam is still on) are identified as being some of the fundamental factors that can participate and affect how these PECVD films melt and solidify.