parameters. Nevertheless, the preliminary findings here are expected to benefit the nanowire community in stimulating further investigation of these alternatives in nanowire growth, characterization, and application development. ExperimentalThe synthetic approach involves a carbothermal reduction process followed by catalyst-assisted heteroepitaxial growth using a previously reported reaction chamber setup [8]. Briefly, the source consisted of powder forms of stannous tin oxide (SnO, 99.999 % purity) and synthetic graphite (99.999 % purity) in a 1:1 weight ratio. The source was placed 2±3 cm upstream of the a-sapphire substrates inside a horizontal tubular reactor with an open egress. The substrate was coated with a 2 nm thin film of a catalyst material by ion-beam sputtering. Stannous tin oxide was the source material of choice here due to its relative thermal and chemical volatility compared with stannic tin oxide. The open-egress design creates a relatively more oxidative environment by back-diffusion of ambient oxygen and carbon dioxide. Crosscontamination was minimized by allowing only one catalyst species in the chamber per run and baking the chamber at 1000 C and 450 sccm argon for one hour between runs. Other process conditions were fixed at a constant argon carrier gas flow rate (Ar, 99.999 %, 450 sccm), 840±860 C temperature window, and a growth time of 60 min. Characterization was performed by scanning electron microscopy (SEM) using a field-emission Hitachi S4000 at 10 kV and 15 lA, without deposition of a gold coat on the samples. Embedded-capacitor technology is an important emerging technology that will enable significant improvement of the performance and functionality of future electronic devices.[1,2] Embedded capacitors are specially printed portions of printed-circuit-board (PCB) laminates which perform the charge-storing function but do not require space on the surface of the PCB. One major technical challenge for implementing this technology is the development of appropriate dielectric materials with good electrical and mechanical properties, because traditional ceramic dielectrics cannot be applied by current PCB manufacturing methodologies. [3,4] Particulate-filled (0±3 connectivity)polymer-based composites provide an ideal solution, possessing enhanced electrical properties and retaining the mechanical properties of the matrix. Much research work has been done on ceramic±polymer systems that adopt traditional ceramics as fillers, e.g., BaTiO 3 , [5] PZT, [6] and PMN-PT. [7,8] The advantages of these composites include predictable dielectric behavior, low dielectric loss, and easy fabrication. However, in most cases these composites have relatively low dielectric constants, e r , (usually < 100) even with high ceramic loadings (> 50 vol.-%). High ceramic loadings will deteriorate the mechanical qualities of the composites and the resulting PCBs. In developing the percolation theory of the conductor±insu-lator composites, [9] the observation of a dramatic increase of e r at the percola...

Dispersions of few-layer (1-3 layers), multi-layer (4-10 layers) and thick-layer (&gt;10 layers) graphene oxide (GO) were prepared by a modified Hummers method with different mass ratios of KMnO4 to graphite. Ultraviolet-visible (UV-vis) spectroscopic data show that few-layer GO dispersions can be distinguished from multi- and thick-layer dispersions by a more intense peak at 230 nm. Atomic force microscopy (AFM) images of few-layer GO contain a single peak, those of multi-layer GO exhibit a shoulder and those of thick-layer GO do not contain a peak or shoulder. These findings allow qualitative analysis of GO dispersions. X-ray photoelectron spectra (XPS) show that the change of UV-vis absorption intensity of GO is caused by a conjugative effect related to chromophore aggregation that influences the π-π* plasmon peak.

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