One-dimensional Silicon Nanomaterials And Nickel-silicon Heterojunction Nanowires Preparation And Characterization

One dimension silicon nanomaterials are new kinds of optoelectronic materials. Since silicon nanomaterials are stabile with semiconductor property and compatible with modern silicon technology, they are promising in nanodevices. The synthesis, characterization and test of the one dimension silicon nanomaterials were studied in this paper.At first, The self-assembled silicon nanowires ( SiNWs) with small diameter were studied. The SiNWs were synthesized by decomposition of silicon monoxide under high pressure. Their diameters were no more than 10nm and the silicon cores were about 5nm. Influenced by the quantum effect, Raman spectrum of the SiNWs was found to be downshifted. The research of the small size SiNWs was valuable for nanodevices. The silicon nanoneedles (SiNNs) were firstly reported by us with the similar growth method. SiNNs were synthesized with a small quantity of deionized water as the reaction medium. During the nanoneedles growth, some protection gas was released.Secondly, synthesis of very long SiNWs was studied by thermal decomposition method. The SiNWs with the length more than 150μm were prepared in this work. They were promising for nanodevices, since the integrated level of device based on those nanowires would be effectively improved. The synthesis of half hollow silica nanomaterials and single crystal silicon nanotube (SiNTs) were also studied in this paper.The as-grown SiNWs were agglomerated with lots of nanoparticles. By using ultrasonic agitation, the agglomerated SiNWs were dispersed in traditional organic solvents incorporated with various surfactants or surfactantmixtures, such as sodium dodecyl sulfate, emulsifier-OP, N,N-dimethylformamide. The SiNWs with different length and nanoparticles were separated by centrifugal machine.In the end, the properties of nickel silicide heterostructure nanowires were studied. When the nickel implanted SiNWs were annealed at different temperature, Ni/Ni_xSi_y/Si core-shell heterostructure nanowires and NiSi₂ nanowires were formed. The formation and annealing behavior of the heterostructure nanowires were researched with the help of HRTEM images. Single heterostructure nanowire was manipulated in the FIB system and the I-V curve was tested in micro-current detection station. The research of the heterostructure nanowires was useful for the application of interconnection and nanodevices.