We fabricated MoS2 transistor adopting electric double layer (EDL) as gate dielectric. So far, EDL has realized p-type conducting MoS2 in addition to well-known n-type conduction showing ambipolar operation. In our study, field-effect superconducting transition of MoS2 was realized with maximum T C around 10 K. This T C is the highest not only within MoS2 compounds but also among whole TMDs. The highest T C discovered in this study lies in the carrier density region much smaller than chemically investigated region. Such compounds with small doping level have never been successfully synthesized by chemical method. Furthermore, by combining HfO2 (typical high-k material for FETs) gating with EDL gating, continuous control of carrier density, and thus quantum phase, was demonstrated. As a result, we successfully obtained the phase diagram of MoS2. Interestingly, the T C exhibits strong carrier density dependence, showing dome-shaped superconducting phase. Superconducting dome in other materials than cuprates has been reported only a few times in doped 2D semiconductors. Since FET charge accumulation is basically two dimensional, our result implies the existence of common mechanism for superconducting dome in 2D band insulators.

In order to explore the feasibility for preparing defined crosslinked particulate structures, oligo(ε-caprolactone) [oCL] derived microparticles (MPs) were crosslinked in non-molten, non-dissolved, i.e. solid state in aqueous suspension by applying a controlled regime with well-defined polymer network precursors either with or without photoinitiator. The MPs (diameter ∼ 40 μm) were prepared by an oil-in-water emulsion process from linear 2oCL or 4-arm star-shaped 4oCL with methacrylate end groups. Crosslinking was initiated by UV-laser irradiation (308 nm) at room temperature. Conversion of methacrylate was monitored by ATR-FTIR spectroscopy and crosslinking was confirmed by a lack of MP dissolution in dichloromethane. In a quantitative evaluation of swelling by dynamic light scattering, higher swelling ratios were detected for particles synthesized with photoinitiator. Wrinkled particle surfaces and distorted particle shapes were observed by light microscopy in the solvent-swollen state and by scanning electron microscopy after deswelling. This work indicated some limitations due to internal inhomogeneity of the MP, but particle crosslinking in solid state was generally possible and may be further improved by higher chain mobility during crosslinking.

This investigation describes preliminary results of in-situ analysis of zinc deposition within an ionic liquid electrolyte utilizing electrochemical atomic force microscopy (EC AFM). From the AFM analysis, the morphology of the zinc deposition was analyzed by quantifying the surface roughness using height-height correlation functions. These results will be used to analyze the scattering data obtained from zinc deposition analysis utilizing an electrochemical ultra-small angle x-ray scattering (EC USAXS). The goal of this research is to link the early nucleation and growth behavior to the formation of detrimental morphologies.

Results of investigation of X-ray sensors on the basis of GaAs compensated with chromium (HR GaAs) are presented in this work. HR GaAs material is shown to have the following physical parameters: the resistivity about 1GOhm*cm, the nonequilibrium charge carrier lifetime – hundreds of nanoseconds. Prototypes of microstrip and array HR GaAs sensors have been manufactured and tested. It is demonstrated that the sensors provide spatial resolution according to the pixel pitch and allow obtaining high quality X-ray images.

Crystal structure change with an applied electric field was investigated by Raman spectroscopy and X-ray diffraction (XRD) for the 1 μm-thick (100)/(001) one-axis oriented tetragonal Pb(Zr0.3Ti0.7)O3 films prepared on Pt-covered (100) Si substrates by chemical solution deposition technique. As-deposited films were under the strained condition in good agreement with the estimation from the thermal strain applied under the cooling process after the deposition from the Curie temperature to the room temperature. This strain was ascertained to be relaxed by an applied electric field in accompanying with the dramatic increase of the volume fraction of (001) orientation. These results demonstrate the importance of the crystal structure measurement not only as-deposited films, but also after applied electric field, such as after poling.

Polymers possessing antimicrobial activity have been used for self sterilization surfaces as well as agents for treating contaminated water. Cationic polymers based on quaternary ammonium or guanidine groups have shown high inherent antimicrobial activity where the activity is related to the disruption of the microorganism cell wall. A range of antimicrobial nanoparticles possessing active quaternary ammonium groups with one of the alkyl is a an octyl chain have been synthesized. These nanoparticles were incorporated in dental restoration compositions to form self sterile composites. Quaternary ammonium polyethyleneimine nanoparticles with N-octyl dimethyl residues, demonstrated high antibacterial effect.

The interface between a matrix and its reinforcement is critical to the final composite properties. There are different ways to enhance bonding between the reinforcing fiber and the matrix, based mainly on surface plasma treatments which usually decrease the fiber tensile strength. In this research, atomic layer deposition (ALD) was tested as a possible way to enhance the chemical bonding between the fiber and matrix in the hope that it would not effect the fiber tensile strength. Microbond tests were carried out to measure the effect of an ALD aluminum oxide (Al2O3) coating on the fiber/matrix interfacial shear strength, and the fiber tensile strength was measured in order to assess whether this treatment harms the fiber strength. The ultrahigh molecular weight polyethylene (UHMWPE) fibers that were coated by ALD with aluminum oxide (Al2O3) showed a significant increase in the interfacial shear strength without reducing the fibers’ ultimate tensile strength.

Most of polishing conditions are not consistent during the polishing process such as pressure, velocity, temperature, pad surface asperity and slurry flow which determine the CMP performance. Traditionally, these parameters are detected by various monitoring methods on CMP polisher. This study introduces a new concept of intelligent pad system with multiple sensors and peripheral devices such as memory, CPU, battery, transmitter and so on. The main functions of the intelligent pad are sensing the change of major parameters and data processing in real-time during the polishing process. The developed intelligent pad has nine points of embedded pressure sensor and makes data processing, saving, and transmitting in real-time. Experimentally, the intelligent pad system was evaluated to understand carrier behavior and pressure distribution. Finally, the analysis of pressure distribution using the intelligent pad turned out a useful method to understand the polishing head behavior and the polishing profile.

We describe a mass transport TCAD simulation by using a Sentaurus S-Interconnect tool [1] that models reported electro-migration (EM) behaviors: EM induced resistance (R) change, line length (L) effect, and temperature (T) dependency on L and current density (j) products. We performed trend and sensitivity analyses for key physical EM model parameters: Cu-void formation, a sudden jump in line R associated with void growth, and Cu-vacancy (Cv) and void (Cvoid) profiles. In this manner, we develop a new methodology for accurately determining the EM lifetime by identifying an “EM-aware” region to define the L dependence of Cu-lines under high current stress. This includes electron flow dependency to explain line and via depletion effects for void formations under various stress conditions. We report a non-linearity in the L dependence on the jL product and a slight temperature dependence on the Blech Threshold (jL)c.

We present normal and inverted solution processed bi-layer solar cells using cationic cyanine dyes as the electron donor and a fullerene as the electron acceptor. The cells exhibit high open circuit voltages up to 1 volt showing the optimal alignment of donor and acceptor energy levels. We demonstrate the large effect that cyanine dye counter ions can have on the energetics of the solar cells and how the S-shaped current density vs. voltage (J-V) curves can be avoided.

Single phase erbium borides ErB2, ErB4, and ErB12 show Seebeck coefficients and power factors with absolute values that are significantly lower than those of a stable Er-B multi phase composite obtained through high temperature solid-solid reaction from the elements (molar ratio Er:B = 1:6). According to quantitative Rietveld analysis the composite consists of erbium diboride (1 %), tetraboride (83 %), and dodecaboride (16 %), and the measurement of the electrical conductivities, Seebeck coefficients, and thermal conductivities leads to ZT values as high as 0.53 at 830 K. Such refractory materials can be used for energy conversion in a range of high temperatures that are otherwise difficult to address.

This paper presents the study of the electrochemical deposition of Cu/Sn alloy nanoparticles on Boron Doped Diamond (BDD) films in order to improve their electrocatalytic activity and selectivity for application in nitrate electrochemical reduction. Cyclic voltammetry measurements evidenced the formation of Cu/Sn alloy electrodeposited on BDD electrode. The electrodeposited Cu/Sn can be better visualized by analyzing the dissolution process. By studying the dissolution peak separately, the dissolution peak of the Sn was obtained at a more positive potential, when compared with the dissolution peak of Cu. From the scanning electronic microscopy (SEM) analysis, the homogeneous distribution of the Cu/Sn alloys particles on BDD surface with grain size in nanometric scale was verified. From X-ray diffraction analysis, two Cu/Sn alloy phases (Cu41Sn11 and Cu10Sn3) were identified for the electrodeposits obtained at -0.5V and charge of 0.26 C. The electrocatalytic reduction of nitrate in 0.1 M Britton-Robinson (BR) buffer solution with pH 9 was analyzed. The BDD electrode modified with Cu/Sn alloy nanoparticles proved to potentiate the electrocatalytic reduction of nitrate.

We study ZnO-NiO mixed crystal thin film as a wide band p-type material for the hetero-junction with ZnO. As for the hetero-junction of the ZnO ( n-type ) and the NiO which have relatively stable p-type semiconductor characteristics, there are issues on the crystallographic mismatch and the band offset of the valence band as well as the conduction band . We made the ZnO-NiO mixed crystal thin film in all composition range with the substrate temperature of 250°C, using magnetron sputtering process and acquired the basic data for the change of electrical conductivity with conduction type. In addition, a high-quality thin film was made by using a Pulse Laser Deposition ( PLD ) , and the band diagram of the ZnO-NiO mixed crystal system was illustrated from the analyses of XPS, NEXAFS and optical absorption measurements. As a result, the offset of ZnO-NiO mixed crystal film is proportionally decreasing with increasing the content of ZnO in NiO film. And the characteristics of the diode with the hetero-junction of ZnNiO/ZnO were improved compared with that of NiO/ZnO. The reasons were discussed with the data of the band offset, the crystalline of the films and the interface properties with the NiO/ZnO and the ZnNiO/ZnO.

Novel field emission (FE) devices are introduced employing lateral architecture. Ultrathin multiwalled carbon nanotube (MWCNT) sheet were utilized to fabricate the emitter. Effects of basic configuration of sheets, including the orientation of CNTs and sheet thickness were examined. The novel device achieved the threshold field (the electric field at which current density reach 1 mA/cm2) of 0.67 V/µm and enhancement factor larger than 20,000.

III-V compounds such as InGaAs, InAs, InSb have great potential for future low power high speed devices (such as MOSFETs, QWFETs, TFETs and NWFETs) application due to their high carrier mobility and drift velocity. The development of good quality high k gate oxide as well as high k/III-V interfaces is prerequisite to realize high performance working devices. Besides, the downscaling of the gate oxide into sub-nanometer while maintaining appropriate low gate leakage current is also needed. The lack of high quality III-V native oxides has obstructed the development of implementing III-V based devices on Si template. In this presentation, we will discuss our efforts to improve high k/III-V interfaces as well as high k oxide quality by using chemical cleaning methods including chemical solutions, precursors and high temperature gas treatments. The electrical properties of high k/InSb, InGaAs, InSb structures and their dependence on the thermal processes are also discussed. Finally, we will present the downscaling of the gate oxide into sub-nanometer scale while maintaining low leakage current and a good high k/III-V interface quality.

In this work Carrageenan type κ was used as electrosteric stabilizer in order to prepare a biocompatible colloidal dispersion of novel metal nanoparticles. Gold and silver nanoparticles were synthesized by reducing the metal precursor using sodium borohydride in presence of Carrageenan type κ. The growth mechanism of metal nanoparticles and stabilization behavior by Carrageenan type κ was analyzed by UV-Vis spectroscopy and transmission electron microscopy. The morphology and particle size distribution were also studied as a function of reaction parameters and the particle size was dependent of the pH of the reaction media. The Ag nanoparticles with sphere-like morphology and average size of 10 nm were obtained. The morphology of Au nanoparticles was strongly affected by the pH value resulting in particles with snake-like morphology at alkaline conditions. The UV-Vis spectra showed that Ag nanoparticles were highly stable at alkaline conditions and for long period of time. Au nanoparticles dispersion showed a better stability for long period of time at acidic conditions. The nanoparticles dispersion electrosterically stabilized were used to prepare hydrogels by poured into a plastic mold and frozen with liquid nitrogen and then lyophilized. The morphology and thermal stability of resulting composites were analyzed by using scanning electronic microscopy and differential scanning calorimetry respectively. The degradation temperature of Carrageenan type κ was increased due to the presence of metal nanoparticles.

In this paper, a quantum-kinetic equivalent of Shockley-Read-Hall recombination is derived within the non-equilibrium Green's function formalism for a photovoltaic system with selectively contacted extended-state absorbers and a localized deep defect state in the energy gap. The novel approach is tested on a homogeneous bulk absorber and then applied to a thin film photo-diode with large built-in field in the defect-rich absorber region. While the quantum-kinetic treatment reproduces the semi-classical characteristics for a bulk absorber in quasi-equilibrium conditions, for which the latter picture is valid, it reveals in the thin film case non-classical characteristics of recombination enhanced by tunneling into field-induced sub-gap states.

The application of magnetography as a novel method to determine the state of charge (SoC) of commercial Li-ion Batteries is reported. The method is non-invasive and nondestructive and suitable to be applied during normal operation. It is based on spatially resolved measurement of the magnetic field B , induced by the changing current flow during cycling. A standardized measurement setup and procedure for conventional AMR-sensors has been developed, offering high reproducibility (∼0.1%) and the chance to characterize the different spatial components of the magnetic field (B x , B y , B z ). The percentage deviation of the B -distributions for different SoCs for a given current load reveals significant differences. A change of B of up to 20% between SoCs of 90% and 10% is found. The influence of current density at different SoC reveals a constant magnetic susceptibility χ at low SoC and a field dependent χ at high SoC. Both effects are attributed to the change of the magnetic properties upon varying the amount of intercalated lithium in the transition metal (LixNi1/3Co1/3Mn1/3O2) based intercalation cathode. The method can be used to provide an additional parameter for SoCestimation to battery management systems.

We present results of first-principles non-equilibrium Green’s function calculations for current-voltage (IV) characteristics of the electrode/HfO2/electrode model systems. In order to investigate the effect of the electrode materials on the IV characteristics, we considered two transition metals for electrode, Ta and W, which are both body-centered-cubic elemental metals but have different valence numbers. We simulated the ON state by placing oxygen vacancies in the HfO2 layer while the OFF state was modeled with HfO2 without oxygen vacancies. At the OFF state, no electric current flowed for -1 V up to +1 V, as expected. At the ON state, however, we found that the absolute current for the Ta electrode was twice as large as that for the W electrode. The analysis of the IV characteristics shows that the electronic coupling between Ta and HfO2 is substantially stronger than that between W and HfO2. Our study demonstrates the importance of the matching between electrode and insulator materials to achieve a high ON- to OFF-current ratio in ReRAMs at a low bias.