Search

Hybrid inorganic-organic polymer electrolyte based on the monomer of organically modified polysiloxane was prepared by UV radiation curing in the presence of liquid electrolyte. The organically modified polysiloxane monomer with acrylate groups at the terminal position was synthesized by hydrolytic condensation of tetramethoxysilane (TMOS) and followed by demethanolation reaction using 2-hydroxyethyl acrylate (2-HEA). The rational formula of the monomer was SiO1.1436(OH)0.01606(OCH3)1.3394(OCH2CH2OCOCH= CH2)0.3574 which was determined by proton nuclear magnetic resonance (1H-NMR) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy and silica analysis. The monomer was polyfunctional with a number average molecular weight of 1185 and a weight average molecular weight of 2292 determined by GPC analysis. The electrochemical properties of the hybrid inorganic-organic polymer electrolyte were determined by ac impedance spectroscopy and cyclic voltammetry. Ionic conductivity was greatly enhanced with increasing amounts of liquid electrolyte. When the polymer electrolyte contained 80 wt% liquid electrolytes, the conductivities were around 3.3 × 10−3 S cm−1 at 21°C and 8.0 × 10−4 S cm−1 even at −23°C. Interface resistance increased initially and reached a steady value after 2 days. Oxidation stability was up to 5.0 V against the lithium reference electrode and electrochemical plating/stripping of lithium on the stainless steel electrode was reversible.

Gel nanocomposite polymer electrolyte (NCPE) was prepared by UV polymerization and thermal polymerization, respectively in the presence of liquid electrolyte with nanosize SiO 2 -contained poly(ethylene glycol) diacrylate (PEGDA) as the monomer. Nanosize SiO 2 -contained PEGDA was synthesized using aqueous colloidal silica as one of starting materials and its viscosity was very low. The partial silanol surface groups of SiO 2 were modified to acrylic group by employing of methacryloxypropyl-trimethoxysilane (MAPTMS), which made the dispersion of nanosize SiO 2 in PEGDA uniform and stable. Compared with the gel polymer electrolyte (GPE) based on PEGDA without nanosize SiO 2 , the ionic conductivity of the gel NCPE was higher and the electrochemical stability and interfacial stability were better, whether it was prepared by UV polymerization or thermal polymerization. It showed oxidation stability up to 5.0 V versus Li/Li + and lithium deposition/dissolution on the stainless steel electrode highly reversible. The applicability of the gel NCPE to lithium polymer batteries was demonstrated by graphite/SPE/LiCoO 2 cell, which was prepared by in situ thermal polymerization. It showed that the discharge capacity was stable with charge–discharge cycling.

Polymer gel electrolyte with addition of fumed silica was prepared by the UV polymerization of methyl methacrylate, oligomer of ethyl glycol dimethacrylate and liquid electrolyte. The effect of fumed silica on the interfacial stability of lithium electrode and polymer gel electrolyte membrane was studied by environmental scanning electron microscopy (ESEM), FTIR and electrochemical AC impedance. The addition of fumed silica has an effect on morphology of polymer gel electrolyte membrane. The silica is interactive with solvent and polymer matrix and it can trap impurities in the polymer gel electrolyte. All of them are beneficial to the interfacial stability, which is confirmed in the AC impedance spectrum.

In this paper, the morphology of chemically crosslinked polymer gel electrolyte (PGE) was investigated by environmental scanning electron microscopy. The crosslinking structure made the polymer matrix arrange tightly and blocked the ion transport, but it improved the mechanical properties and the capacity to hold the liquid electrolyte. With increasing liquid electrolyte in the PGE, it was shown that the polymer matrix became sparse and the cavities in the morphology became large. The addition of nanoparticle silica led to the formation of micropores, which was beneficial to improvement of the ionic conductivity.

Carbon nitride thin films with N‐concentration about 41% were synthesized by YAG pulsed laser ablation of graphite under a low-energy (

Boron-carbon-nitrogen thin films were deposited by laser ablation of boron carbide (B 4 C) under nitrogen ion beam bombardment. The as-deposited films were analyzed by X-ray photoelectron spectroscopy and Raman measurements. The results showed that carbon, nitrogen and boron species were chemically bonded to each other instead of simple mixtures. Detailed analyses showed that the ion beam bombardment had led to breaking of B-C bonds and formation of C-N and B-N bonds. An appropriate ion beam energy (probably less than 1 keV) was proposed for the purpose of the synthesis of high quality boron-carbon-nitrogen films.

An exhaustive study of optical emission from a nitrogen arc produced by an arc-heated beam source is reported. Atomic nitrogen emission lines in the spectral region provide unequivocal evidence that the arc-heated beam source generates an appreciable flux of nitrogen atoms. Experimental results show that the ratio of [N] to increased as the arc pressure decreased. It is believed that this is because of the reduced probability of recombination of [N] atoms. Using this arc-heated beam source for pulsed laser deposition (PLD) film growth, we have synthesized carbon nitride and other nitride films with a high nitrogen content. AES and XPS results indicate that composition ratios ([N]/[C]) in the deposited films were between 0.2 and 0.6. It has been considered that [N] atoms, rather than molecules in the arc, are the most likely species responsible for the synthesis of nitride films.

or \(\)) nitrogen ion beam was used to bombard \(\) films to synthesize carbon nitride films. The bombarded films were examined by Raman and X-ray photoelectron spectroscopy (XPS) measurements. The experimental results showed that the destroyed carbon species chemically combined with nitrogen ions to form stable carbon nitride. An appropriate beam energy (possibly \(\)) was proposed in this method.

The synthesis of covalent carbon nitride films becomes an important subject in the materials research field. As a new synthetic method two low-energy (400 and 1000 eV) nitrogen ion beams are used to bombard on C60 thin films individually. The bombarded films are used for Raman and x-ray photoelectron spectroscopy (XPS) measurements. The results of the analyses show that under the bombardment of 400 eV nitrogen ion beam, the film still contains a large amount of undestructed C60 molecules. In the case of 1000 eV bombardment, only a little amount of C60 molecules is kept undestructed. The experimental results also show that the destructed carbon species will combine chemically with nitrogen ions to form stable covalent carbon nitride, confirmed by the Raman peaks of, e.g., 2240 cm-1. The XPS N1s and C1s lines also indicate the formation of covalent carbon nitride in the bombarded films.

We have studied the microstructure and photoluminescent properties of porous Si. High resolution observations revealed that the microstructure of porous Si consists with nano-crystallites Si embedded in the surrounding amorphous matrix. The structure of nano-crystallites of porous Si is not consistent with the usual diamond structure of bulk Si. The photoluminescence from porous Si is due to the quantum confinement of carriers in this structure.

The highly photo-sensitive characteristics of porous silicon (PS) were observed. The transient behaviors of photoconductivity in horizontal and perpendicular directions of PS surface were very different, through both of them include two decay components. The photoconduction spectra at room temperature and 14.5 K show that characteristics of PS are different from those of silicon substrate. The difference may be attributed to quantum confinement effect in nano-size microstructures of PS.

We have set up an experimental system consisting of an ion gun and a Rutherford backscattering spectrometry(RBS) analysis chamber. Using this system, in situ 2 MeV 4He+ RBS analysis of films is carried out by combination with sputter etching of low energy Ar+ ions. As an example of the sputtering/RBS method, the analysis of three samples, i.e., Si/(GexSi1-x/Si)/Si(100), WSix/SiO2/Si and CoSix/Si, is presented in this paper. After an appropriate fraction of the thick layer is removed by sputtering, the back edge of the Ge peak is separated from Si RBS spectrum on the interface and the O peak of the buried SiO2 layer can be identified. The change of the doped Ti and W concentrations related to Co on the top surface is observed. The advantages of this analytical method and its possible applications in film are discussed.

In this study, finite element modeling was used to evaluate the residual thermal stress in floating-gate tunneling oxide electrically erasable programmable read only memory (FLOTOX E2 PROMs) manufacturing process. Special attention is paid to the tunnel oxide region, in which high field electron injection is the basis to E2 PROMs operation. Calculated results show the presence of large stresses and stress gradients at the fringe. This may contribute to the invalidation of E2 PROMs. A possible failure mechanism of E2 PROM related to residual thermal stress-induced leakage is proposed.

In this study, non-equilibrium statistical physics is used to estimate the time-dependent fracture of inhomogeneous Si3N4 ceramic. The effects of structural inhomogeneity on mechanical properties of the Si3N4 ceramic are discussed. The numerical calculations show that the average lifetime will increase by means of introducing suitable inhomogeneity in materials, but it is not monotonous.

In order to obtain high quality carbon nitride films, x-ray photoelectron spectroscopy and Raman spectrum were used to analyze several kinds of film: (a) laser-ablated amorphous carbon (a-C) films, (b) a-C films after a 1 keV nitrogen ion beam bombardment. (c) carbon nitride (CNx) films synthesized by ablation assisted with ion beam bombardment, (d) CNx films after a 50 eV nitrogen ion beam bombardment, and (e) CNx films after 1 keV nitrogen ion beam bombardment. The comparison among these films showed that the concurrent deposition of CNx films by ablation and a nitrogen ion beam should be better than the post-treatment of a-C films by nitrogen ion beam bombardment. In the case of concurrent deposited CNx films, a post-treatment by a nitrogen ion beam bombardment with an appropriate energy (possibly less than 1 keV) was proposed to improve the ratio of C-N binding structures in the deposited films.

In the last decade, focused ion beam (FIB) technology has been attracting attention as a tool with submicron fabrication capabilities because of increasing circuit density and decreasing feature dimension in VLSI devices. This paper introduces basic FIB functions and a number of its technological applications in the field of microelectronics such as microscopic cross-sectioning, transmission electron microscopy (TEM) sample preparation, microcircuit repair and Al microstructure observation. Several examples are presented for these applications.