聚甲基丙烯酸多缩乙二醇二酯－锂盐－溶剂三组份凝胶聚合物电解质的制备、导电性能和导电机理研究

由极性聚合物-碱金属盐构成的聚合物固体电解质（SPE）是一类很有前途的离子导电材料。但此类SPE，比通常非水介质电解质溶液约低3个数量级，故极需发展电导率更高的新型SPE材料。目前，由极性（或交联）聚合物、碱金属盐和高介电常数溶剂三组份构成的新一代SPE正在崛起，其室温电导率的达10~（－3）S·cm~(-1)。本工作以甲基丙烯酸多缩乙二醇二酯为大分子单体，研究了三组份凝胶电解质的制备、各组分的变化和温度等对膜强度和电导率的影响；并研究了该凝胶体系中离子传导机理。

PHOTOELECTROCHEMICAL BEHAVIOR OF THE GAAS/ALXGA1-XAS SUPERLATTICE ELECTRODE/ELECTROLYTE INTERFACE

Single and multiple quantum wells of lattice-matched superlattices material GaAs/AlxGa1-xAs have been studied as photoelectrodes in photoelectrochemical cells containing nonaqueous electrolyte. Structural photocurrent spectra in the potential range of -1.8 to 1.0 V (vs standard calomel electrode) were obtained. The quantum yields for both superlattice electrodes were estimated and compared.

CBE GROWTH OF GAAS/GAAS, GAAS/SI AND ALGAAS/GAAS USING TEG, ASH3 AND AMINE-ALANE PRECURSORS

The growth of high quality AlGaAs by CBE bas been limited by the high levels of carbon and oxygen contamination. The use of alane based precursors offers a significant reduction in such contamination. We report for the first time the CBE growth of AlxGa1-xAs from triethylgallium, dimethylethylamine-alane and arsine, and compare with. growth from triethylgallium, trimethylamine-alane and arsine. Some preliminary results of work on the CBE growth of GaAs on silicon will also be reported.

Interfacial behaviour of quantum well electrode/electrolyte: effect of redox species on EER spectra of a single quantum well GaAs vertical bar AlxGa1-xAs electrode

The EER spectra of a single quantum well GaAs\AlxGa1-xAs electrode were studied as a function of applied reverse bias in ferrocene, p-methyl nitrobenzene and hydroquinone+benzoquinone non-aqueous solutions. EER spectra were compared for different redox species and showed that a pronounced quantum-confined Stark effect and a Franz-Keldysh oscillation for a single quantum well electrode were obtained in the p-methyl-nitrobenzene- and hydroquinone+benzoquinone-containing solutions. A surface interaction of the single quantum well electrode with ferrocene led to fewer changes in the electric field of the space charge layer for reverse bias; this was suggested to explain the weak quantum-confined Stark effect and Franz-Keldysh oscillation effect observed for the single quantum well electrode in the ferrocene-containing solution. (C) 1997 Elsevier Science S.A.

Preparation and characterization of erbium doped sol-gel silica glasses

Erbium-doped silica glasses were made by sol-gel process. Intensive photoluminescence (PL) spectra from the Er-doped silica glasses at room temperature were measured. A broadband peak at 1535 ma, corresponding to the I-4(13/2)-I-4(15/2) transition, its full width at half-maximum (FWHM) of 10 nm, and a shoulder at 1546 nm in the PL spectra were observed. At lower temperatures, main line of 1535 nm and another line of 1552 Mn instead of 1546 nm appear. So two types of luminescence centers must exist in the samples at different temperature. The intensity of main line does not decrease obviously with increasing temperature. By varying the Er ion concentration in the range of 0.2 wt% - 5wt%, the highest photoluminescence intensity was obtained at 0.2wt% erbium doped concentration. Luminescence intensity decreases with increasing erbium concentration. Cooperative upconversion was used to explain the concentration quenching of luminescence from silica glass with high erbium concentration. Extended X-ray absorption fine structure measurements were carried out. It was found that the majority of the erbium impurities in the glasses have a local structure of eight first neighbor oxygen atoms at a mean distance of 0.255 nm, which is consistent with the typical coordination structure of rare earth ion.