| Summary: | 碩士 === 國立中興大學 === 物理學系 === 93 === We treat closed-tipped multi-walled carbon nanotubes made from chemical vapor deposition with HNO3 solution and obtain open-tipped carbon nanotubes. Electrodes are made onto a single open-tipped carbon nanotube by optical lithography and E-beam lithography.
We put the device in a high vacuum system with a base pressure below 1×10-6 torr, apply high voltage, and measure the emission current by a multi-purpose source meter. We observe an emission current about 1μA between 120V-240V, then we analyze the emission mechanism by the Fowler-Nordheim model.
We discover the emission area of a single open-tipped carbon nanotube to be 10-21-10-23m2, much smaller than the theoretical value: 10-15m2. The tips of open-tipped multi-walled carbon nanotubes emit electrons easier and yield higher current than those from closed-tipped multi-walled carbon nanotubes.
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