The roles of two model additives, bis(3-sulfopropyl) disulfide (SPS) and Janus Green B (JGB), in the deposition of copper from an acid-copper sulfate electrolyte containing polyethylene glycol (PEG) and Cl Ϫ were studied by deposition on microprofiled electrodes, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). It was found that leveling occurs only when all four additives are present, suggesting that additive-additive interactions are important to the leveling mechanism. Moreover, an optimal flux of the active leveling agent exists, an effect that may be explained by the classical diffusion-adsorption theory of leveling. SEM and TEM micrographs show that the additive SPS removes the columnar structure of the deposit and effects micron-sized, unoriented grains provided PEG and Cl Ϫ are present; the subsequent addition of JGB decreases the grain size of the film significantly.

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We have studied the optical properties of the ␦-doped ZnSe:Te system using photoluminescence ͑PL͒ and x-ray and Raman scattering. Two different types of sample were investigated, ͑1͒ with a single ␦ layer and ͑2͒ with three adjacent ␦ layers separated by undoped layers. All of these samples are of reasonable crystalline quality and have the symmetry of the host ZnSe lattice as determined by x-ray and Raman scattering. The PL from each sample is very similar to the PL from bulk Zn-Se-Te solutions at low Te concentrations. The PL from the single-␦-doped material shows emission relatively close to the band edge which we attribute partly to Te 2 clusters ͑nearest-neighbor pairs͒ and partly to non-nearest pairs. This PL changes with storage time, from which we conclude that the nearest-neighbor pairs are more stable than non-nearest-neighbor pairs. The triple-␦-doped material also shows a deeper PL feature, with a peak at about 2.48 eV, which we attribute to Te nу3 clusters as well as to corresponding non-nearest-neighbors pairs.

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Electrical properties of CeO2 thin films of different Y2O3 dopant concentration as prepared earlier were studied using impedance spectroscopy. The ionic conductivities of the films were found to be dominated by grain boundaries of high conductivity as compared with that of the bulk ceramic of the same dopant concentration sintered at 1500°C. The film grain‐boundary conductivities were investigated with regard to grain size, grain‐boundary impurity segregation, space charge at grain boundaries, and grain‐boundary microstructures. Because of the large grain boundary and surface area in thin films, the impurity concentration is insufficient to form a continuous highly resistive Si‐rich glassy phase at grain boundaries, such that the resistivity associated with space‐charge layers becomes important. The grain‐boundary resistance may originate from oxygen‐vacancy‐trapping near grain boundaries from space‐charge layers. High‐resolution transmission electron microscopy coupled with a trans‐boundary profile of electron energy loss spectroscopy gives strong credence to the space‐charged layers. Since the conductivities of the films were observed to be independent of crystallographic texture, the interface misorientation contribution to the grain‐boundary resistance is considered to be negligible with respect to those of the impurity layer and space‐charge layers.