Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/16959
標題: Dependence of field emission of individual carbon nanotubes on geometrical parameters of nanotubes
單根奈米碳管幾何參數對場發射特性研究
作者: Chen, Yu-Sheng
陳育生
關鍵字: 奈米碳管
carbon nanotube
場發射
場增強因子
field emission
field enhancement factor
出版社: 物理學系所
引用: 1.Iijima S. Nature 1991;354;56. 2.工業技術與資訊月刊第136期;page 2-5. 3.A G. Rinzler, J. H. Hafner, P. Nikolaev, L. Lou, S. G. Kim, D. Tomanok, P. Nordlander, D. T. Colbert and R. E. Smalley: Science 269 (1995) 1550 4.W. A. de Heer, W. S. Bacsa, A. Chatelain, T. Gerfin, R. Humphreybaker, L. Forro’ and D. Ugarte: Science 268 (1995) 845. 5.Jean-Marc Bonard, Kenneth A. Dean, Bernard F. Coll, and Christian Klinke, Phys. Rev. Lett. 89, 197602 (2002) 6.J. Y. Huang, K. Kempa, S. H. Jo, S. Chen, and Z. F. Ren, Appl. Phys. Lett. 87, 053110 (2005) 7.Zhi Xu, X. D. Bai, and E.G. Wang, Appl. Phys. Lett. 88, 133107 (2006) 8.奈米碳管,成會明編著,張勁燕校訂。 9.C. J. Edgcombe, and U. Valdre, Philos. Mag. B, 82, 9, 987-1007 (2002) 10.C. J. Edgcombe, and U. Valdre, J. Microsc. 203, 188 (2001) 11.王建翔, “單一GaN / GaP異質結構奈米線的電性傳輸研究,國立中興大學物理所”(2003). 12.G.Binning ,H.Rohrer, C.Gerber and E.Weibel, Phys .Rev. Lett, 49, 57 (1982) 13.Richard G. Forbes, J. Vac. Sci. Technol. B 17, 526-533 (1999) 14.Zhi Xu, X. D. Bai, and E.G. Wang, Appl. Phys. Lett. 87, 163106 (2005) 15.R. C. Smith, J. D. Forrest, and S. R. P. Silva J. Vac. Sci. Technol. B 23, 632 (2005) 16.R. C. Smith, D. C. Cox, and S. R. P. Silva Appl. Phys. Lett. 87, 103112 (2005) 17.電子工程專輯 “http://www.eettaiwan.com/ART_8800366227_480702_0c37e7f1.htm”
摘要: In the experiment ,the fabrication of single carbon nanotubes are made by using the method of electron-beam lithography. After completion, the single carbon nanotubes are measured and analyzed for the field emission characteristics. In the process of measurements, we put the samples in a high vacuum system with a base pressure of 10-7 torr. The galvanometer and the high voltage power supply are connected for data-taking. The tips of the smaples can be divided into three types: closed-tipped with rough end, open-tipped with rough end and open-tipped with flat end. We use the measured emission current-voltage relations to analyze field emission based on the theory by Fowler and Nordheim. Then we can obtain the field enhancement factor β and the emission area A. The enhancement factor β can be sorted into three ranges depending on the geometry of the CNT tip. The range of β for closed-tipped with rough end is 10~19;β for open-tipped with flat end is 60~105;β for open-tipped and with end is 210~340. The range of threshold voltage Vto are in the range 30~250 volts. We also find that the threshold voltage changes with β and the threshold voltage of smallβnanotubes is higher then the threshold voltage of large β. The enhancement factor β is a function of the distance from the carbon nanotube to the cathode d and the radius of tip. In experiment we find thatβincreases with increasing d and decreases with radius of the carbon nanotube. We find that β increases with d/r by obeying a good linear relationship, β=β0 , withβ0 and k depending on the geometry of the tip.
本論文內容裡樣品的製作上是利用SEM進行電子束微影術的方法來製作電極,接著把做好的單根奈米碳管樣品進行場發射量測並分析其特性。 量測過程中,我們將樣品放到10-7torr之高真空系統中,將電表和高電壓電源供應器接上,完成量測的系統。 在碳管的尖端特性方面,可分為三大類,分別為尖端封口型、尖端開口不規則型、尖端開口平整型。接著將量到的發射電流利用Fowler和Nordheim提出的理論去分析奈米碳管場發射的物理參數,可以得到場增強因子β和發射面積。 分析的β值又可以從尖端幾何分為三種分佈,尖端封口型的β值範圍在10-19,尖端平整型的β值範圍在60-105,尖端開口不規則型的β值範圍在210-340;而實驗中起始電壓Vto的範圍在30-250 volts之間,在實驗裡也發現起始電壓會隨著β有變化,β小的Vto會有比β大的Vto還大的趨勢。 而場增強因子β在理論的分析裡,是跟奈米碳管距離陰極的長度和尖端半徑有關係,但在本實驗裡我們也發現β會隨著奈米碳管尖端d變大而增加,對奈米碳管半徑r變大而減少的趨勢,而如果把d/r跟場增強因子β拿來比較的話,可以發現β也會隨d/r變大而增加,而且有很好的線性關係。
URI: http://hdl.handle.net/11455/16959
其他識別: U0005-2007200614152100
文章連結: http://www.airitilibrary.com/Publication/alDetailedMesh1?DocID=U0005-2007200614152100
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