We have fabricated a hybrid nanodots floating gate (FG) in which Si quantum dots (QDs) and silicide nanodots (NDs) are stacked with a very thin SiO2 interlayer in order to satisfy both multiple valued capability and charge storage capacity for a sufficient memory window and to open up novel functionality for optoelectronic application. In electron charging and discharging characteristics measured with application of pulsed gate biases to MOS capacitors with a hybrid NDs FG, stepwise changes in the rates for electron injection and emission were revealed with increasing pulse width at room temperature. Also, nMOSFETs with a hybrid NDs FG show unique hysteresis with stepwise changes in the drain current - gate voltage characteristics. The observed characteristics can be interpreted in terms that the electron injection and storage into silicide-NDs proceed through the discrete charged states of Si-QDs. For MOS capacitors with a triple-stacked hybrid NDs FG fabricated by adding another Si-QDs, by subgap light irradiation from the back side of the Si substrate, a distinct infrared optical response in C-V characteristics was detected at room temperature. The result is attributable to the shift of charge centroid in the hybrid NDs FG as a result of transfer of photoexcited electrons from silicide NDs to Si-QDs.

A thermo-responsive hydrogel was prepared on the basis of terpyridine endfunctionalized polystyrene-block-poly(N-isopropylacrylamide) diblock copolymer. As a first level of assembly, the copolymer was dissolved in a selective solvent to yield micelles bearing terpyridine ligands at the extremity of the coronal chains. The second level of self-assembly was triggered upon addition of metal ions to the micellar solution. Mechanical properties of the accordingly obtained micellar gel were finally characterized by rotational rheometry, below and above the lower critical solution temperature.

Dye sensitized solar cells (DSSCs) are currently being explored as a cheaper alternative to the more common silicon (Si) solar cell technology with improved performance in low light conditions and less sensitivity to varying angles of incident light. One of the major challenges facing DSSCs is loss of the liquid electrolyte, through evaporation or leakage, which lowers stability and leads to increased degradation. To address this, batches of gel electrolyte cells are fabricated with 7 wt% nanoclay gel electrolyte and liquid electrolyte and were evaluated at standard test conditions over time. The gel cells achieved efficiencies as high as 9.18% compared to the 9.65% achieved by the liquid cells. Over a period of 10 days, the liquid cells degraded less than 20% of its maximum efficiency. By contrast, the gel cell's efficiency did not decrease to 20% of its maximum efficiency until 45 days. After several measurements, the liquid cells showed visible signs of leakage through the sealant, whereas the gel cells did not. This resistance to leakage likely contributed to the improved performance of the quasi-solid cells over liquid electrolyte DSSCs.

In this work, we report on local ferroelectric and piezoelectric properties of nanostructured polymer composites P(VDF-TrFE)+x(Ba,Pb)(Zr,Ti)O3 (x = 0 - 50 %). High-resolution imaging of ferroelectric domains, local polarization switching, and polarization relaxation dynamics were studied by piezoresponse force microscopy. In particular, we found that (Ba,Pb)(Zr,Ti)O3 inclusions usually show a strong unipolar piezoresponse signal, as compared to the polymer matrix. By scanning under high dc voltage the films can be polarized uniformly under both positive and negative electric fields. Stability of the polarized state is discussed.

In our work on laser scribing CdTe solar cells we have found what appears to be an unpublished laser material interaction that allows precise laser etching of SnO2 films to an arbitrary thickness with high uniformity. This precise and efficient laser etching mechanism allows arbitrary reduction of the film thickness in a controlled manner on the scale of tens of nm. In addition to the fine depth selection, we find that there develops a pulse duration dependent microstructure on the surface. This micro microstructure results in a strong diffraction effect in the visible portion of the spectrum. In this work we propose a physical mechanism behind this novel depth selective laser interaction as well as the resultant micro-structure. Finally we demonstrate and propose some possible applications for this process.

The thermal conductance of a gold/water interface has been found to change as a function of the surrounding’s adhesion energy. We measure the thermal conductance of a lithographically prepared gold nanowire with a thin film nanoscale thermal sensor composed of AlGaN:Er3+. The temperature of the nanowire is measured as a function of incident laser intensity. The slope of this plot is inversely proportional to the thermal conductance of the nanoparticle/surrounding’s interface. We show that the conductance of the nanoparticle/water interface increases with the molality of the solution. This was tested with multiple solutes including NaCl, and D-Glucose. The interfacial conductance of pure water is reported to be 44 MW/m2K and the conductance saturates to 100 MW/m2K at a molality of 0.21 m.

The birefringence of a cellulose triacetate (CTA) polymer film was evaluated based on density functional theory and molecular dynamics (MD) simulation. The polarizability of the monomer unit of CTA was initially calculated to determine the intrinsic properties of the birefringence of CTA. The most important conformational freedom of the CTA monomer unit is derived from the C-6 acetyl methyl groups. This exocyclic group is known to have three low energy conformers referred to as gg, gt, and tg according to the rotation of the different torsion angles. Because the polarizability can be viewed as dependent on the conformation of CTA, the polarizability of these three conformers was evaluated. The results demonstrated that negative intrinsic birefringence was associated with the CTA repeating units having gg or gt structures, whereas the monomer units with tg structures were characterized by positive intrinsic birefringence. A model of the polymer film was constructed based on MD simulation and the birefringence of the model was evaluated using the calculated monomer birefringence values. The birefringence of the CTA film was found to be negative because most of the CTA repeating units adopt the gg conformation in the film. The negative value of the simulated birefringence is in good agreement with the result obtained by the experiment.

A comparison of different Ni+Al reactive materials is conducted to elucidate the effects of microstructure morphology on performance. CTH, a multi-material Eulerian hydrocode, was utilized to study mesoscale deformation during simulated rod-on-anvil experiments. It is found that the cold sprayed Ni+Al, which has a more topologically connected nickel phase, is likely to be more reactive because of enhanced deformation in the Ni phase relative to explosively compacted Ni+Al, where the Ni phase undergoes less deformation. Rod-on-anvil impact tests verify that cold sprayed Ni+Al is indeed more reactive than explosively compacted Ni+Al when subject to impact.

We study the mutual effects of photoinduced processes (irradiation effects) and plasmonic emission enhancement in close-packed CdSe/ZnS colloidal quantum dots in the vicinity of gold metallic nanoparticles with two significantly different size distributions. For this we examine the impact of the heat generated by the metallic nanoparticles, the strength of plasmonic field enhancement, and the rate of energy transfer from the quantum dots to metallic nanoparticles in the presence of a laser field with low and moderate intensities. Our results show that the interplay between the photophysics of the quantum dots and their plasmonic emission enhancement is significantly pronounced when the metallic nanoparticles are large. In such a case we observed large suppression of photoinduced fluorescence enhancement (PFE). For smaller metallic nanoparticles the results suggest mostly an overall time-independent suppression of the quantum dots’ emission with no significant impact on PFE.

In this paper, we present ink-jet printing as an attractive alternative to lithography and etching methods for the development of multi-filamentary YBa2Cu3O7-δ coated conductors. Our research is mainly focused on the study of the influence of rheological parameters on the printability of water-based inks in order to produce superconducting patterns on SrTiO3 and CeO2-La2Zr2O7-Ni5at%W substrates. An aqueous YBCO precursor ink with a total metal ion concentration of 1.1 mol/L with a viscosity of 6.79 mPa s and a surface tension of 67.9 mN/m is developed. Its printing behavior using several ink-jet printing devices is verified using a camera with strobed illumination to quantify droplet velocity and volume. After optimization of the deposition parameters, YBCO tracks with different dimensions could be printed on both types of substrates. Their shape and dimensions were determined using optical microscopy and non-contact profilometry, showing 100-200 nm thick and 40-200 µm wide tracks. Finally, resistivity measurements were performed on the widest tracks on SrTiO3 showing a clear drop in the resistivity starting from 88.6 K with a ∆Tc of 1.4 K.

The sand of glaciolacustrine origin is offered as a major component of the backfill in repositories for solid or solidified low and intermediate level waste (LILW). Clinoptilolite, hematite, and magnesium oxide are offered as additives for increasing of sorption. In this work was carried investigation of sorption properties of sand, clinoptilolite, hematite and magnesium oxide and mixtures of sand with these mineral additives.

Papers in the Appendix were published in electronic format as Volume 1534

High quality dilute nitride subcells for multijunction solar cells are achieved using GaInNAsSb. The effects on device performance of Sb composition, strain and purity of the GaInNAsSb material are discussed. New world records in efficiency have been set with lattice-matched InGaP/GaAs/GaInNAsSb triple junction solar cells and a roadmap to 50% efficiency with lattice-matched multijunction solar cells using GaInNAsSb is shown.

In this work, we study CdTe thin films used in CdTe/CdS solar cells with a substrate configuration, which allows for better control in forming the junction, and the possibility for using flexible non-transparent substrates. We studied the properties of CdTe films grown at 450° and 550°C, with and without a CuxTe layer, and before and after CdCl2 treatment. We analyzed the structural and electro-optical properties using electron backscatter diffraction (EBSD), cathodoluminescence (CL) and X-ray diffraction (XRD), and investigated how the film structure, stress, and defect structure changes with the different growth conditions.

Two growth techniques - antimony exposure and graded growth, were proposed to achieve the control over the morphology and optical properties of self-assembled InAsSb/InGaAs/InP nanostructures. By exposing the surface of InGaAs buffer layer to trimethylantimony precursor before the growth of InAsSb nanostructures, the surface/interface energy in the system is reduced, while the strain energy in the system is enhanced. This leads to a change of island shape from dot structure to wire structure. By using a higher initial mole fraction of trimethylantimony precursor during the graded growth of InAsSb, more Sb can be incorporated into the InAsSb islands despite the same Sb mole fraction averaged over the graded growth. This also results in a shape change from dot to wire structure. As a result of their shape change, photoluminescence from the InAsSb nanostructures shows different polarization characteristics.

Thin films of ZnO co-doped with lithium and phosphorus were deposited on sapphire substrates by RF magnetron sputtering. The films were sequentially deposited from ultra pure ZnO and Li3PO4 solid targets. Post deposition annealing was carried using a rapid thermal processor in O2 and N2 at temperatures ranging from 500 °C to 1000 °C for 3 min. Analyses performed using low temperature photoluminescence spectroscopy measurements reveal luminescence peaks at 3.359, 3.306, 3.245 eV for the co-doped samples. The x-ray diffraction 2θ-scans for all the films showed a single peak at about 34.4° with full width at half maximum of about 0.17°. Hall Effect measurements revealed conductivities that change from p-type to n-type over time.

In this study, Pd thin film is used as catalyst to grow epitaxial InAs nanowires on GaAs(111)B substrate in a metal-organic chemical vapor deposition reactor to explore the growth mechanism and the effects of non-gold catalysts in the growth of III-V epitaxial nanowires. Through detailed morphological, structural and chemical characterization using scanning and transmission electron microscopy, it is found that defect-free zinc-blende structured epitaxial InAs nanowires are grown along the <110> directions with four {111} sidewall facets forming a diamond shaped cross-section. Furthermore, the interface between the nanowire/catalyst is found to be the uncommon {113} planes. It is anticipated that these zinc-blende structured InAs nanowires are grown via the vapor-liquid-solid mechanism. The defect-free nature of these nanowires arises from the non-<111> growth direction and non-{111} nanowire/catalyst interface.