Hydrothermal Preparation And Characterization Of One-dimensional Silicon-based Nanoscale Materials

One-dimensional silicon-based nanoscale materials have the potential to become the important basic material in silicon nanoscale devices owing to the excellent compatibility with the present silicon technology. Silicon nanotube (SiNT) is a kind of important silicon-based nanoscale materials and has attracted great interest. Solid silicon nanowires (SiNWs) can form easily due to sp3 hybridization in silicon. So SiNTs are difficult to synthesize in the experiments. Therefore, the research on SiNTs is still in primary stage in the world. In addition, one-dimensional silicon-based nanoscale materials such as SiNWs, silicon carbide nanotubes (SiCNTs) and nanorods (SiCNRs) are also the present research focuses because of their inimitable structures and outstanding properties. Silicon monoxide and silicon carbide are the basic silicon starting materials. The hydrothermal preparation and characterization, growth mechanism and photoluminescence (PL) properties of the self-assembled SiNTs, SiNWs, SiCNTs and SiCNRs have been studied in detail in the paper. The research is fundamental and pioneering, and is of great significance on theory and application potential.Self-assembled SiNTs have been prepared from silicon monoxide by the hydrothermal method with the temperature of 470℃, pressure of 6.8MPa without metallic-catalysts and templates. The research results demonstrate that the SiNTs have close caps at the tips. The structures of SiNTs are hollow inner pores with a size of several nanometers in the middle, crystalline silicon wall layers with the thickness of less than 5nm and amorphous silica outer layers with the thickness of less than 2nm. The research result on the stability of self-asembled SiNTs with 5wt% HF acid shows that silicon oxide outer layers can be removed and pure crystalline SiNTs survive after etching the SiNTs for enough time which implys that the self-assembled SiNTs are stable. Therefore, it's possible to research the application of self-assembled SiNTs. A hypothetical SiNT Si-H self-assembled growth model is proposed to explain the formation and growth process of the SiNTs and the stability of the SiNTs is closely relative to the growth process. The Raman and Infra-red (IR) spectra of the SiNT sample further show that the obtained nanotubes are a kind of crystalline SiNTs with silica outer layers. PL result of the SiNT sample demonstrates that PL peak center at 436nm is strong and asymmetrically broad. And the range of PL emission peak is...