Synthesis And Application Of High-purity Silicon Nanowires

The intention of this dissertation is to prepare orderly silicon nanowires with high purity. Accordingly, our efforts were focused on modifying these one-dimensional nanomaterials. The results show that the modified nanowires have promising applications in catalytic fields and may open up a whole new area for biosensor. The main results are summarized as follows:1 We report a new route to fabricate layer-deposited, low oxygen content and uniform silicon nanowires on a large scale, using hydrogen and quartz crystals as source materials in high-temperature furnace. Scanning electron microscopy images reveal that the morphology of the sample is wire shaped, with the average diameter of 65 nm. Energy dispersive X-ray spectra present the composition of the lowoxygen content products with the atom ratio of silicon to oxygen of 96.5:3.5.2 Agglomeration of nanoparticles during the preparation and utilization of nanocatalysts remains a problem. Here, we modified layer-deposited silicon nanowires with Pd nanoparticles on the surface. These Pd/Si catalysts were used in the reduction of methylene blue in the presence of sodium borohydride, which enhanced reaction rate by 30 times compared with unsupported Pd nanoparticles. They were also provided with more excellent stability than polymer-supported Pd. The catalytic rate of the catalysts only decreased by 20% when the cyclic time was up to 50.3 The unique properties of silicon nanowires have led researchers to investigate their use in composite materials for a variety of biosensor applications, which has been hindered by the poor solubility and processibility of silicon nanowires. This experiment aims at using of surfactants and wrapping with polymers to enable their solubilization for further processing.