Study On Strcuture Control And Properties Of SiC-Based One Dimensional Nanostructures

With the development of the nano and semiconducting technology, it has been attracted more and more attentions for the reasearch and application of SiC one dimensional nanostructures (SiC-1DNs). SiC-1DNs have the combined advantages of both one demensional nanomaterials and SiC, which lead to their outstanding properties in the fields of electric, magnetic, optical, thermal and mechanical, and therefore, SiC-1DNs have been widely used in nanocomposite materials and electronic nanodevices. SiC nano heterojunction materials not only inherit the advantages of 1DNs, but also overcome their shortcomings. More importantly, they can greatly enhance their abilities and further broaden its application areas. So, it may be of a far-reaching significance for study on synthesis and properties of SiC-based heterojunctions.In this study, we focus the study of controlled growth of SiC nano-heterostructures, to develop novel heterostructures as the goal, by chemical vapor deposition (CVD) method for the preparation method and optimized the preparation parameters, achieve the large area, high-quality, controlled synthesis of SiC-SiO2 heterostructures, SiC-CNT/C heterojunction arrays and SiC/C nanocables, and finally realize the controlled structure-properties of SiC-based 1DNs. Based on systematic study of the XRD, SEM, TEM, XPS, Raman, and data, their structures, morphologies and composition were observed and analyzed and relevant growth mechanisms were also proposed. The relevant contents are as follows:(1) 3C-SiC nanowires tens of microns in lenght. The optimal prepared condition was obtained and their growth mechanisms were dominated by the VLS mechanism; (2) 3D SiC-SiO2heterojunction networks with excellent ability of UV light were synthesized, and their growth mechanisms were dominated by the VLS mechanism;(3) Aligned SiC-CNT/Cs heterojunction arrays were synthesized, the structures of which are of amorphous carbon layer deposited on the surface of multi-walled carbon nanotubes arrays, and SiC particles are grown on the tips of CNT/Cs. Their growth mechanisms were dominated by the combined action of tip growth mechanism and density limited mechanism.(4) A novel SiC/C-NCs were synthesized, the surface modification of C coating can not only enhance the electrical properties of SiC nanostructures, but also can modulate SiC surface property from hydrophilic to hydrophobic. Their growth mechanisms were dominated by a two-stepped SLS mechanism.