Invstigation on Aliminum Template-directed Nanowires Fabrication

• Main Authors: CHIN-LUNG TSAI, 蔡金龍
• Other Authors: Hsi-Lien Hsiao
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/25388976553574885239

碩士 === 東海大學 === 物理學系 === 91 === Abstract Formation of ordered nanowires and nanotubes array with length up to 100μm and diameter down to nanometer have attracted many attentions for display, interconnect, optoelectronic, energy conversion and thermoelectric applications. Anodic alumina with its high aspect ratio nanopores is a potential template to direct the nanowires or nanotubes array formation. In this thesis, the preparation of alumina template with nanopores as small as possible was examined. The Au electroplating technique was developed either for metallic nanowires formation or as the catalysis for semiconductor nanowires and carbon nanotubes synthesis. Moreover, the silicon nanowires array catalyzed by gold nanowires was successfully obtained. A combined process of sulfuric acid anodic oxidation, phosphoric acid and chromium acid etching, and second anodic oxidation is used to fabricate ordered anodic alumina with pore length up to 100μm and diameter down to nanometer. Scanning electron microscope images (SEM)demonstrate that the fabricated alumina with ordered and straight nanopores and the diameter of these nanopores was estimated to be approximately 30nm. The measured length of these nanopores was about 100~110μm. The Fourier transformed images of surface topography by SEM exhibit excellent hexagonal close-packed feature. To electroplating the gold into the nanopores, the barrier layer at the back side of the alumina was removed by dipping into the 5% phosphoric acid. And then Ni was evaporated upon the back side of the alumina to be the back electrode for electroplating. The electroplating Au nanowires were characterized by using cross-sectional SEM, energy dispersive spectroscopy (EDS) and backscattering electron image (BEI). It is observed that the Au nanowires with length about 100 nm had been successfully fabricated within the nanopores. After 100nm Au nanowires formation, the samples were transferred into the low pressure chemical vapor deposition furnace. The silane gas mixed with argon and hydrogen gases were used to synthesize the silicon nanowires. It is noted that the synthesized silicon nanowires with much longer length was observed above the top surface of the alumina. A few nanowires break through the back Ni layer was also observed. It is indicated that the diameters of synthesized silicon nanowires were determined by the size of the nanopores.