| Summary: | 碩士 === 國立雲林科技大學 === 電子與資訊工程研究所 === 94 === In this dissertation, we present two effective methods to improve field emission property of triode emission device. One is to modify the structure of triode emission device for enhancing the field emission property, and the other is to modify the surface morphology of carbon nanotubes for increase the field emission site. According to our experiments that we got the result as below:
(1) The length of carbon nanotubes was decrease from 6.72μm to 4.1μm with an increase in size of gate hole from 10μm to 30μm. In our experiments, it was found that the characteristic of field emission was improved, decrease of turn on voltages and increase of current densities, when the different sizes of gate holes were applied suitable voltages. In other words, applying of higher gate voltages at a fixed source-drain bias, the current of field emission was increased.
(2) From Fowler-Nordheim diagram, the slope of F-N curve changed from abrupt to flat as the gate voltage was increased.
(3) The samples were treated with H2 plasma of MPCVD and PECVD. From the analysis of SEM and Roman, the surfaces of CNTs after treatment of MPCVD were different form the CNTs without MPCVD treatment. However, the results with and without PECVD H2 plasma treatment were hard to find out the differentiation. It also did not have obvious changes of turn-on voltages after treatment of H2 plasma of PECVD by using a ultrahigh vacuum measurement system. It meant that the turn-on voltages were not improved by the treatment of H2 plasma of PECVD.
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