Mg₂Ge/Si composite electrodes were prepared by a gas-deposition (GD) method and evaluated their electrochemical properties of anodes for Li rechargeable battery. The discharge capacity of the Mg₂Ge/Si composite electrodes increased in comparison with that of Mg₂Ge GD-film electrode. Among them, the Mg₂Ge/Si composite electrode with 30 wt% Si content exhibited good cycle stability, which is 603 mAh g⁻¹ after 200 cycles. At this composition of composite, each Si particle was surrounded with Mg₂Ge layer, and the Mg₂Ge layer appears to be easy to release the stress generated in the Si particle at Li insertion-extraction because Mg₂Ge is more ductile than Si. Thus, we succeeded to develop the electrode which can take advantage of both high capacity of Si and good cyclability of Mg₂Ge.

抄録全体を表示

The extra positive electrode of an EDLC where doesn’t face to a negative electrode was known as an easily corroded area. However, the mechanism was not clear. In this paper, in order to simulate an extra positive electrode, two sets of EDLC (Cell 1 and Cell 2) were arranged in a horizontal plane, and the positive electrode of Cell 1 (P1) and that of Cell 2 (P2) were connected or disconnected electrically. Four reference electrodes were embedded around Cell 1 and Cell 2 and electrical potential behavior in a horizontal plane of an EDLC twin cell was studied. With the extra positive electrode (P2), P2 potential shifted to high when charging and discharging the Cell 2, and electric current flow of several mA was observed between P1 and P2. By a simulation study of an electric equivalent circuit of an EDLC twin cell, an ionic movement resistance between P2 and the negative electrode of Cell 1 (N1) was estimated as several hundred ohm. The extra positive electrode (P2) was charged gradually and P2 potential also shifted to high as a result of the simulation study. Reliability of reference electrodes also was studied with the EDLC twin cell with four-reference electrodes.

抄録全体を表示

Planar optical waveguides (OWGs) formed by ion-exchange in glass are useful to fabricate optical sensors for biochemical and environmental use. Conventional OWGs need delicate equipment to adjust incident light position and angle. In order to overcome this difficulty, a fluorescent dye (Alq3) film was deposited onto an ion-exchanged waveguide layer and used as a broad-band light source. The properties of the OWG system were analyzed; e.g., the highest light transfer efficiency was obtained at the Alq3 film thickness close to the cutoff thickness of TE₀ mode.

抄録全体を表示

We have investigated the influence of Cu contamination induced failure (Cu/pit failure) on silicon semiconductor devices. In the evaluation by Cu decoration and SEM observation, pits of about 30 nm were observed at leak points of silicon oxide. Cu/pit failure introduced oxide breakdown. On the other hand, Cu/pit failure is improved by high temperature hydrogen anneal and epitaxial growth. These improvements are able to explain by migration and rearrangement of silicon atoms.

抄録全体を表示