| Summary: | 碩士 === 國立中央大學 === 化學工程與材料工程學系 === 105 === One-dimensional (1D) silicon-based nanostructures have excellent properties due to their high aspect ratio. There are several synthetic techniques have been proposed. Recently, a low cost method, which is based on the polystyrene nanosphere lithography and metal-assisted catalytic etching process has attracted much attention. By using this technique, large area, well-ordered and vertically-aligned Si nanowires and Si nanorods can be readily produced on different types of Si wafers. However, compared with the fabrication processes of Si nanowires, the fabrication of Si nanotubes are relatively complex and difficult. Many recent studies have demonstrated that 1D nanostructures with hollow interiors have better properties than their solid counterparts. Therefore, in this study, we proposed a new and facile route for fabricating large area, well-order arrays of Si nanoholes and vertically-aligned single-crystalline silicon nanotubes on (001)Si substrates at room temperature by using the O2-plasma modified nanosphere lithography in conjunction with the Au-assisted chemical etching processes.
The experimental results reveal that all the produced Si nanotubes are single-crystalline and their axial orientation is the same as that of the (001)Si substrate. The sapcing and interior diameter of the Si nanotubes can be tuned by adjusting the diameter of nanospheres and the Au etching conditions. It is also found from SEM observations that the length of the Si nanotubes increase linearly with the Au-catalyzed etching time, indicating that the formation process is reaction controlled. The results of water contact angle and UV-vis spectroscopic measurements clearly show that, compared with Si nanowires, the produced Si nanotubes exhibit higher hydrophobicity and better antireflection properties. The obtained results present the exciting prospects that the new approach proposed here provides the capability to fabricate other Si-based nanotube arrays on various Si substrates.
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