Synthesize and Characterization of Tin Oxide Nanowire Using Vapor-Liquid-Solid Technique

SnO2 nanowires have been successfully synthesized on silicon substrates using Vapor-Liquid-Solid (VLS) method. We employed SnO powder as the starting material (located in the hottest point of the furnace), and a thin layer of Au (with the thickness of 5 and 12nm) as the catalyst. The nanowire growth carried out in a horizontal tube furnace at the temperature of 900 C. The morphology and microstructure of nanowires are characterized by means of scanning electron microscopy (SEM) and X-ray diffraction pattern. The SEM images reveal that no nanowire was grown on the substrate without a gold catalyst, while SnO2 nanowires were grown on the substrates that were coated by Au. The diameter of nanowires that have catalyst with thickness of 5nm is about 50-100 nm while those that were grown on 12nm thick catalyst have a diameter between 80-300nm, indicating that the diameter of nanowires depends on the catalyst thickness. The effect of distance between substrate and powder source (SnO) in the furnace is also investigated and the result shows that the nanowires grown on the substrates close to the powder source are island shapes, while those grown on the substrates far from the SnO powder source are in the form of continuous thin film, resulting that the substrate temperature effects the nanowire structure. The X-ray diffraction patterns indicate that the structure of SnO2 nanowire is in the form of tetragonal with lattice constant of a=b=0.443nm and c=0.372nm.

کلیدواژه ها:

Nanowire ، SnO2 ، VLS