A value oriented conceptual model for innovation in local government

The political rhetoric that accompanied the introduction of eGovernment expected it to produce innovation in the way government agencies conducted themselves with citizen and business alike. It was assumed that innovation was both "good" and inevitable. This paper challenges these assumptions and presents a more realistic model of how innovation might occurs in UK local government. The model is supported by anecdotal evidence, literature and a recent study of eGoverment achievement in the UK - VIEGO. A key element in the model is the notion of innovation value

Passivation of Si nanocrystals in SiO[sub 2]: Atomic versus molecular hydrogen

Photoluminescence measurements were used to investigate the effect of atomic and molecular hydrogen on the passivation of Si nanocrystals in SiO₂. Significant increases in the luminescence intensity and lifetime were found in samples coated with a thin Al layer prior to a standard anneal in molecular hydrogen. This is shown to be consistent with enhanced passivation of the nanocrystals by atomic hydrogen.The authors acknowledge financial support from the Australian Research Council

Influence of As on the formation of mask-edge defects during stressed solid phase epitaxy in patterned Si wafers

The influence of As on the evolution of mask-edge defects during stressed solid phase epitaxy of two-dimensional Si⁺ pre-amorphized regions in patterned Si wafers was examined. Mask-edge defects∼60 nm deep formed at 525 °C for As⁺ implant energies of 7.5–50 keV with peak As concentration of ∼5.0×10²⁰ cm⁻³. Defect formation was attributed to an As-enhanced [110] regrowth rate relative to the [001] regrowth rate creating an amorphous/crystalline interface geometry favorable for defect formation. The similarity of mask-edge defect depths with As⁺ implant energy was attributed to surface retardation of [110] regrowth in shallow implants and enhanced [001] regrowth in deeper implants. Results indicate stress effects on regrowth rates are small compared to dopant effects

Active-oxidation of Si as the source of vapor-phase reactants in the growth of SiOₓ nanowires on Si

Gold-coated silicon wafers were annealed at temperatures in the range from 800–1100 °C in a N₂ ambient containing a low (3–10 ppm) residual O₂ concentration. A dense network of amorphous silicananowires was only observed on samples annealed at temperatures above 1000 °C and was correlated with the development of faceted etch-pits in the Si surface. Comparison with known thermodynamic data for the oxidation of Si and vapor-pressures of reactants shows that nanowire growth is mediated by a vapor-liquid-solid mechanism in which the dominant vapor-phase source of reactants is SiO produced by the active oxidation of Si

Pump-probe experiments at 1.54 μm on silicon-rich silicon oxide waveguides

Optical pump-probe measurements were performed on slab waveguides containing excess silicon in the form of nanoclusters or nanocrystals and erbium. The measurements were performed by prism coupling a 1.54μm probe beam into a waveguide formed by silicon-rich oxide and monitoring its intensity and temporal response as the waveguide was optically pumped from above with a chopped 477nm excitation source. Induced absorption (losses) of the 1.54μm probe beam in erbium-doped and undoped silicon-rich silicon oxide waveguides was observed in all cases. For the samples containing only well-defined nanocrystals, a fast (∼60μs) induced absorption component associated with free carriers within the siliconnanocrystals is reported, while for samples containing defective nanocrystals or nanoclusters, a much slower (>10min) component is observed. The free carrier absorption is shown to be reduced by delaying the probe beam relative to the pump beam in cases where it dominates

Secondary growth and photoluminescence from erbium implanted silica nanowires

Gold-catalyzed silicananowires were grown using vapor from the active oxidation of the silicon substrate and then implanted with erbium and annealed. During prolonged annealing at 1100 °C, where the concentration of vapor-phase reactants is sufficient to support nanowire growth, the erbium rich precipitates act as catalysts for the growth of a second generation of nanowires. These secondary nanowires increase in photoluminescence as they grow, suggesting that a fraction of the optically active erbium is incorporated into the growing wire. The resulting luminescent nanostructures have a very large surface-to-volume fraction and are well suited for optical-sensing applications.A.S. acknowledges funding from the Australian Research Council ARC

Regrowth-related defect formation and evolution in 1 MeV amorphized (001) Ge

Geimplanted with 1MeV Si⁺ at a dose of 1×10¹⁵cm⁻² creates a buried amorphous layer that, upon regrowth, exhibits several forms of defects–end-of-range (EOR), regrowth-related, and clamshell defects. Unlike Si, no planar {311} defects are observed. The minimal EOR defects are small dotlike defects and are very unstable, dissolving between 450 and 550°C. This is in contrast to Si, where the EOR defects are very stable. The amorphous layer results in both regrowth-related defects and clamshell defects, which were more stable than the EOR damage.This work is supported by Semiconductor Research Corporation Contract No. 00057787

Optical absorption measurements of silica containing Si nanocrystals produced by ion implantation and thermal annealing

Optical absorption spectra from silicon-implanted silica slides are shown to contain features due to optical interference. These features, which result from the modified refractive index profile produced by the implant, can readily lead to misinterpretation of absorption spectra. To demonstrate the importance of such effects, silica samples were implanted with 80, 400, and 600 keV Si ions to fluences in the range 0.6–3.0×10¹⁷ Si.cm⁻² and annealed at 1100 °C for 1 h to form Si nanocrystals. Optical absorption/transmittance spectra from these samples show considerable structure that is characteristic of the particular implant conditions. This structure is shown to correlate with the transmittance of the samples as calculated from the modified refractive index profile for each implant. The lack of such structure in absorption spectra measured by photodeflection spectrometry is used to confirm this interpretation

On optical activity of Er⁺³ ions in Si-rich SiO₂ waveguides

Photoluminescence spectroscopy was used to explore the optical activity of Er³⁺ ions in Si-rich SiO₂waveguides prepared by ion implantation. Measurements were performed for a series of materials characterized by different Si excess levels, Er concentrations, and annealing temperatures. The highest fraction of optically active Er³⁺ ions which can be efficiently activated by nonresonant pumping was found to be 2.6%. This was realized in a waveguide with an Er concentration of [Er]=10¹⁸cm⁻³ and Si excess of 20%, annealed at 900°C. This optical activity level is insufficient to realize optical gain. It is therefore clear that further material improvement is needed before optical amplification in SiO₂:Er matrices sensitized by Si nanocrystals/nanoclusters can be achieved

Luminescence from Si nanocrystals in silica deposited by helicon activated reactive evaporation

An alternative method is investigated for the preparation of Si-rich SiO₂films used for the fabrication of light-emitting Si nanocrystalstructures. The technique, helicon-activated reactive evaporation (HARE), combines e-beam evaporation of silicon with plasma activation of a reactive argon–oxygen atmosphere, and has the advantage of being able to produce thick, H-free films suitable for planar photonic device applications. The nanocrystal-rich films were formed by annealing as-deposited films at 1100 °C for 1 h. Room temperature photoluminescence was then measured and compared with that from ion-implanted samples annealed under similar conditions. The HARE-deposited films exhibited strong visible luminescence for a range of excess Si concentrations, demonstrating their potential for the manufacture of such materials. The films also exhibited a concentration dependence comparable to that of ion-implanted samples: the luminescence intensity initially increased with excess Si concentration up to a maximum before decreasing with increasing concentration thereafter. The cause of the decrease at higher concentrations is briefly discussed