Browsing by Author "Wang, W. P."

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Controlled density growth of carbon nanotubes and its improvement on field emission properties
(2004)
Juan, C. P.
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Tsai, C. C.
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Chen, K. J.
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Hong, W. K.
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Lin, K. C.
The density distribution of the CNTs is one of the crucial parameters for the field emission property of CNTs.We use an inactive thin film layer that was deposited on the catalyst to effectively control the density of the CNTs. The results showed the improved field emission property could be obtained with a thin SiO layer on the catalyst layer as the precursor. For the 3.5 nm Fe and 3.5 nm SiO on 3.5 nm Fe as the catalyst, the turn-on field can be reduced from 3.7 V/ mu m. to 2.2 V/ mu m and the field emission current density increased from 2.6x 10(-8) A/cm(2) to 2.4x 10(-4) A/cm(2) when the applied field was 4 V/mu m. The extremely low turn-on field of 1.3 V/ mu m was also discovered for the CNTs grown with the precursor contained 1.5 nm SiO on 1.5 nm Fe; the extremely high emission current density of 4x 10(-2) A/cm(2) was also achieved under the low electric field of 3.5 V/ mu m.
Optimal design of integrally gated CNT field-emission devices using a genetic algorithm
(2007-10-03)
Chen, P. Y.
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Chen, C. H.
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Wu, J. S.
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Wen, H. C.
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Wang, W. P.
A method to optimize the focusing quality of integrally gated CNT field- emission ( FE) devices by combining field- emission modeling and a computational intelligence technique, genetic algorithm ( GA), is proposed and demonstrated. In this work, the e- beam shape, as a characteristic parameter of electron- optical properties, is calculated by field- emission simulation modeling. Using a design tool that combines GA and physical modeling, a set of structural and electrical parameters for four FE device groups, including double- gate, triple- gate, quadruple- gate and quintuple- gate type, were optimized. The resultant FE devices exhibit satisfactory e- beam focusabilities and the extracted parameters with the best performance for each type of FE device were represented to be fabricated by a VLSI technique. The GA- based automatic design parameter extraction will significantly benefit the design of integrated electron- optical systems for versatile vacuum micro- and nano-electronic applications.