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.

In this work, we investigate the effects of Sb, Bi, or Te interlayers at the Mo/Cu-In-Ga interface on the reaction to form Cu(In,Ga)(Se,S)2 in order to control void formation and improve adhesion. Interlayers with 10 nm thickness were evaporated onto the Mo back contact prior to sputtering the metal precursors. CIGSS absorber layers were formed by a three-step H2Se/Ar/H2S reaction and solar cells were fabricated. The influences of each interlayer were characterized in the precursor and reacted films in terms of the density of the void formation, film structure and morphology, adhesion, and device performance.

Structural and magnetic properties of Ni2-x Ptx MnGa alloys are investigated from first principles calculations with the help of the spin-polarized relativistic Korringa-Kohn-Rostoker and Plane-Wave Self-Consistent Field methods. The atomic chemical disorder at specific site has been implemented using coherent potential approximation. Calculated equilibrium lattice parameters are in a good agreement with experimental data and other theoretical calculations. The composition dependences of the magnetic exchange couplings and the Curie temperature for cubic phase are obtained. Our calculations have shown that an increase content of Pt results to decrease of magnetic interactions between Mn atoms and to change of interaction sign from ferromagnetic type to antiferromagnetic one for composition Ni1.0Pt1.0MnGa. Calculated Curie temperatures are in an agreement with experimental data.

A simple derivation of sub-bandgap exponential tails and fundamental absorption equations ruling the optical absorption of amorphous semiconductors are presented following the frozen phonon model. We use the Kubo-Greenwood formula to describe the average transition rate for the optical absorption process. Asymptotic analysis leads to the commonly observed exponential tail as well as the Tauc expression for the fundamental absorption. We test our theoretical results with experimental absorption coefficients of amorphous Si:H, SiC:H, AlN and SiN. The validity of the Urbach focus concept is evaluated.

Cellulose is one of the most abundant renewable resources and has high potential for the use as a future energy and materials for the chemical industries. We have investigated the crystal structure of cellulose IIII by using first principle density functional theory (DFT) calculation. The geometry optimization was performed with variable-cell relaxation with the Quantum ESPRESSO program package. We used Perdew-Burke-Ernzerhof (PBE) functional and compared the results with long-range van der Waals type correction term approach (PBE-D). The results are in good agreement with the experimentally obtained crystal structure of cellulose IIII when we used the PBE-D. Although the calculated cell parameters were slightly smaller than the experimental one, it can be well explained to include the thermal expansion effect in the experimental condition of ambient temperature. From the optimized crystal structure, the CH/O interactions included in the crystal structure were evaluated using NBO method. In this work, we showed that the density functional calculation is a powerful method to investigate the detail structure and the arrangement in the crystal and the nano-structured materials.

This article presents the use of flexible metal foam substrates for the growth of III-nitride nanowire light emitters to tackle the inherent limitations of thin-film light emitting diodes as well as fabrication and application issues of traditional substrates. A dense packing of gallium nitride nanowires were grown on a nickel foam substrate. The nanowires grew predominantly along the a-plane direction, normal to the local surface of the nickel foam. Strong luminescence was observed from undoped GaN and InGaN quantum well light emitting diode nanowires.

Six alloys based on Cr-10Ta-7Si (by at.%) with quaternary additions of 0.5Ag, 5Ti, 1Hf, 3Mo, 3Al, or 3Re (by at.%) substituted for Cr were produced by vacuum arc-melting. The microstructures of the alloys were found to predominantly consist of a eutectic mixture of an A2 Cr-based solid solution and a C14 Cr2Ta Laves phase along with proeutectic Cr2Ta dendrites. Microstructural macro- and micro-scale inhomogeneities were observed in all alloy ingots, which were attributed to the non-equilibrium arc-melting process. The measured lattice parameters of the constituent phases and the elemental partitioning behaviour between the phases have been correlated with the respective covalent atomic radii. The bulk hardnesses of the alloys, along with the hardness of individual phases, have also been reported.

This study reports a high-performance hybrid lithium-ion anode material using coaxially coated silicon shells on vertically aligned carbon nanofiber (VACNF) cores. The robust bush-like highly conductive VACNFs effectively connect high-capacity silicon shells for lithium-ion storage. Such architecture allows the Si shells to freely expand/contract in the radial direction during lithium-ion insertion/extraction. A high specific capacity of 3000-3650 mAh(gSi)-1 was obtained at C/1 rate, comparable to the maximum value of amorphous Si, and ∼89% of the capacity was retained after 100 charge-discharge cycles. The lithium-ion storage capacity remains nearly the same from C/10 to C/0.5 rates. The ability to obtain high capacity at significantly improved power rates while maintaining the extraordinary cycle stability demonstrates the utilization of the unique properties of such hybrid architecture for lithium-ion batteries.