Preparation And Electrical Properties Of Metals (copper, Silver) / Silicon Nano-hole Pillar Array Composite System

With the development of nanoscience and nanotechnology, metal/silicon composite nanosystems have aroused much attention and might play key roles in fabricating silicon-based nanodevice in future. Researches have indicated that the process of the immersion plating of metals on PS highly depends upon the morphology and chemical status of PS surface, which implies that site-selective deposition of metals might be realized through surface treatment. This would be essential for the fabrication of metal/PS with periodically patterned surface structure. In this thesis, a new, nanostructured silicon template-Silicon Nanoporous Pillar Array (Si-NPA) is reported, and also Cu, Ag/Si-NPA composite nanosystems are prepared, and the calorifics and electricity properties of which are studied. Detailed contents in the thesis can be summarized as follows:1. Site-selective immersion plating of silver on Si-NPA which has different oxidation status on surface is observed. Different patterned morphologies of Ag/Si-NPA are obtained when silver is deposited on fresh, washed and aged Si-NPA by immersion plating, respectively. Owing to the existence of HF and the geometrical configuration of fresh Si-NPA, the morphology is characterized by dendritic silver which roots in the top of pillars. For the washed substrate, silver particles deposited on the top sites are small and dispersive, while accumulated particles with much bigger size are formed at the valley sites, which produce a hand-chain network spontaneously on the Si-NPA surface. The similar hand-chain structure is also formed on the aged substrate. For the increasing of oxidation status on the Si-NPA surface, there are few silver particles on the top sites of pillars. No silver particles deposits on the surface of the seriously oxidized Si-NPA, but after disposed with HF, it resumes the reducibility for silver ions.2. Coalescence and growth through boundary diffusion and Ostwald ripening happen during series annealing at high temperature of copper nanoparticles immersing plating on Si-NPA. The fresh Cu/Si-NPA is placed in horizontal tube furnace, the furnace is heated up to and kept for 2 hours at 400 °C, 600 °C, 800 °C under nitrogen respectively. By contrasting the morphologies before and after annealing, it is found that particles coalesce during annealing at different temperature. The average size of copper particles increases for the increasing of annealing temperature, and accumulated copper particles present as apherical. At the same time, the coarsening mechanisms of particles change with the increasing annealing temperature: the particles grow through boundary diffusion at low temperature and Ostwald...