| Summary: | 碩士 === 國立交通大學 === 材料科學與工程系所 === 96 === In the study, multiwall carbon nanotubes (CNTs) were deposited on the Al substrate by electrophoretic deposition (EPD) as electron field emitters. In order to obtain stable and uniform CNT suspension for the EPD, we first optimized surface functionalization conditions to attach carboxyl group onto CNTs. According to Raman scattering spectroscopy and ultraviolet-visible (UV-Vis) absorption spectroscopy, stable CNT suspension could be prepared by immersing CNTs in the H2SO4/HNO3 aqueous solution for 24 hours. Electrophoretic deposition of CNTs on the Al substrate was carried out using various solvents: aqueous sodium dodecyl sulfate (SDS) solution, ethanol and dimethylformamide (DMF), followed by thermal anneal to remove solvents and improve adhesion between CNTs and the substrate. It was found that the surface morphology of the CNT films deposited in ethanol and DMF was independent on the anneal temperature. On the other hand, cracks developed over the CNT film deposited in aqueous SDS solution after high temperature anneal. The surface morphology of the EPD CNT films strongly affects electron field emission characteristics. The turn-on fields were determined to be 4.0 V/�慆, 3.7 V/�慆 and 3.7 V/�慆 for the CNT films prepared in DMF, ethanol and aqueous SDS, respectively.
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